Technologies of Clean Drying - Study

Journal of Cleaner Production 320 (2021) 128706
Contents lists available at ScienceDirect
Journal of Cleaner Production

journal homepage: www.elsevier.com/locate/jclepro
Improvements in drying technologies - Efficient solutions for cleaner

production with higher energy efficiency and reduced emission
Katarzyna Chojnacka a, Katarzyna Mikula a, *, Grzegorz Izydorczyk a, Dawid Skrzypczak a,
Anna Witek-Krowiak a, Konstantinos Moustakas b, Wojciech Ludwig c, Marek Kułażyński a
a
Department of Advanced Material Technology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-372, ul. M. Smoluchowskiego 25,
Poland
b
School of Chemical Engineering, National Technical University of Athens, 9 IroonPolytechniou Str., Zographou Campus, GR-15780, Athens, Greece
c
Department of Process Engineering and Technology of Polymer and Carbon Materials, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw,
Poland
A R T I C L E I N F O A B S T R A C T
Handling editor. Cecilia Maria Villas Bôas de Drying is an integral part in the treatment of grains to maintain the freshness and good quality of agricultural
Almeida products, while protecting bioactive substances (vitamins, antioxidants). The processing allows long-term and
safe storage of products, but is one of the most energy-consuming steps in food production. Reducing drying costs
Keywords: by the proper energy management, including heat recovery and moisture removal from the drying air is the
Drying
current challenge. The purpose of this review was to present recent innovations in seed and grain drying systems
Hybrid technology
against the background of traditional techniques. The focus was on hybrid methods (microwave-assisted,
Enhanced systems
Renewable energy infrared-assisted and ultrasound-assisted methods), which according to data can reduce non-renewable energy
Energy recovery consumption by up to 80%. The implementation of innovations in drying is an important issue considering
consumer health and environmental protection. Techniques applied for the exhaust gas purification from ni
trogen oxides, sulphur oxides, carbon oxides, or volatile organic compounds by catalytic decomposition are also
described. It also points out the possibility of using energy from renewable sources (solar energy, geothermal
energy, energy from biomass combustion), minimizing the use of fossil fuels that have a negative impact on the
environment. Dissemination of knowledge in this area is necessary for the implementation of innovative solu
tions on a large scale, which will allow development towards cleaner production.
are emitted into the environment (Kumar and Kalita, 2017).

The moisture content of 18–25% in the harvested cereal grains can
1. Introduction
be reduced by drying (Table 1) (Kjær et al., 2018). Low moisture ensures
safe storage because it protects the grain from insects and prevents mold
Energy and food consumption is forecast to increase by even 40% by
growth. Drying maintains the high quality of the grain and extends its
2030 (Walsh et al., 2018). To efficiently cope with this challenge, it is
use by date (Mansor et al., 2011). In developing countries, most often
necessary to deal with food freshness prolongation and energy use
grains are dried in the sun, which is slow, weather dependent with some
optimization in drying. The food sector uses as much as up to 7% of the
of the grain being eaten by insects and birds or contaminated by dust and
total energy consumption in the EU (“JRC Publications Repository -
stone. On an industrial scale in developed countries, drying is mostly
Energy use in the EU food sector: State of play and opportunities for
done by conventional methods involving convection, induction and
improvement”). As reported by the Food and Agriculture Organization
energy field. These techniques use simple apparatus and are therefore
(FAO), the production of grains and oilseeds is steadily increasing
readily available but unfortunately very energy intensive (Barrozo et al.,
(Fig. 1) (FAOSTAT - Crops (data), 2021). Despite intensified agriculture,
2014). Mechanical drying controls the temperature of hot air. The
about a third of food production is post-harvest damage (1.3 billion
amount of energy required to eliminate water from grain by evaporation
tonnes per year). They include physical and quality losses that make
is greater than 4.5 MJ/kg, and 2.3 MJ/kg of energy is needed to evap
food non-suitable for consumption. The resources needed for their
orate water (Kjær et al., 2018).
production (water, land, energy) are also wasted, and greenhouse gases
* Corresponding author. Smoluchowskiego 25, 50-372, Wrocław, Poland.

E-mail address: katarzyna.mikula@pwr.edu.pl (K. Mikula).
https://doi.org/10.1016/j.jclepro.2021.128706
Received 31 January 2021; Received in revised form 9 August 2021; Accepted 17 August 2021
Available online 23 August 2021
0959-6526/© 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
K. Chojnacka et al. Journal of Cleaner Production 320 (2021) 128706
Table 1
Abbreviations list Moisture content of grains before and after drying.
Product Initial moisture Final moisture References
FAO Food and agriculture organization content (%) content (%)
IR Infrared radiation rice 21 10 Mehran et al. (2019)
IRC Hybrid dying with infrared radiation and convestion red lentil 16.5 10.5 Taheri et al. (2020)
MC Moisture content soybean 18 12 Zare and Ranjbaran
PID Proportional, Integral, Derivative (2012)
maize 31 14 Viegas et al. (2019)
SHS Superheated steam canola 18 8 Hemis et al. (2015)
VOC Volatile organic compounds seeds
rapeseeds 30 5 Łupińska et al.
(2009)
coffee bean 40 12 Orosco et al. (2018)
cocoa bean 40–50 6–8 Nascimento et al.,
In cereal cultivation, grain drying accounts for approx. 30% of direct
(2013)
energy input and 11% of total energy consumption (indirectly: fertil pea 28 5–9 Yang et al. (2018)
izers, agricultural machinery). Grain drying requires as much energy as
all other crop operations (Jokiniemi and Ahokas, 2014). Since energy
costs are constantly increasing, new methods are being sought to reduce
Table 2
them (Table 2) by introducing innovations in drying technology (Stru
Energy demand of different drying systems.
miłło et al., 2014). These activities are carried out through hybrid sys
Drying system Grain Energy References
tems and supported by infrared, microwave and ultrasound to decrease
type consumption
the cost of the process as well as the carbon footprint. Negative envi MJ/kg
ronmental effects can also be reduced by utilizing renewable energy
system with internal maize 4.46 (Wang et al., 2020)
sources - solar and geothermal energy (Mohapatra and Mahanta, 2012). circulation of the
Modern solutions also exploit the potential of biomass as an alternative drying medium
fuel for heat production with a zero carbon dioxide balance. Reducing three-stage convective wheat 3.50 (Kliuchnikov, 2019)
emissions of other GHGs is also a current global challenge, solved by the drying method
three-stage convective rice 3.43 (Kliuchnikov, 2019)
implementation of catalysts that primarily reduce NOx in waste gases to
drying method
molecular nitrogen N2 (Jabłońska and Palkovits, 2016a). Improvements laboratory-scale corn 21.1–56.1 (Abdoli et al., 2018a)
in drying should be based on efficient solutions that enable cleaner fluidized with high
production with reduced energy and pollution, which will benefit the power ultrasound
environment (Klemeš et al., 2010). ultrasound-assisted rice 5.44–24.8 (Jafari and Zare, 2017)
fluidized bed
A review by Llavata et al. (2020) reports that the use of pre-treatment
coaxial impinging rice 4.0 (Thuwapanichayanan
(soaking the material in ethanol, high pressure, ultrasound or pulsating stream drying system et al., 2020)
electric field) can improve food drying and at the same time reduce rotary dryer rice 10.5 (Gazor and Alizadeh,
energy consumption. Pre-treatment can significantly shorten the drying 2020)
conventional fixed bed rice 9.78 (Gazor and Alizadeh,
time, but cause a loss of quality of the processed food (e.g. inhibition of
dryer 2020)
enzymatic activity), so it must be properly applied. However,
pre-treatment may not be a sufficient innovation. Limited resources of
energy (crude oil, natural gas or fossil coal) encourage the search for drying efficiency of various plant materials (vegetables, fruits, cereals).
new, more efficient supplies of energy (Strumiłło et al., 2014). The The influence of process variables (IR power, exposure time, IR source
implementation of renewable energy sources is desirable for the sake of distance from the material surface) on drying time, the quality of the
sustainable development and the prevention of the production of pol dried material and energy consumption need to be considered in the
lutants released into the ecosystem (Panwar et al., 2011). design of advanced drying systems. Bashkir et al. (2020) presented an
Infrared (IR) radiation can be the source of energy in drying. Its ef innovative technology of hydrodynamic drying of food of plant origin.
ficiency can be increased through combining IR drying with micro The electric wind generated by the movement of the ions from the
waves, vacuum or hot air. Sakare et al. (2020) discusses the use of IR and electrode causes the air to flow. The process is non-thermal, which is
Fig. 1. Crop statistics of selected grains and oilseeds in 2000–2019 (FAO data).
2
advantageous for temperature-sensitive plant materials (due to the 2. Conventional drying systems
capillary-porous structure). Hydrodynamic drying is characterized by
the simplicity and quick control of airflow, and can reduce energy Many industries deal with different types of dried grains, so many
consumption (compared to traditional). The technology has not yet been design solutions of dryers have been developed (Barrozo et al., 2014).
commercialized due to lack of knowledge about electrode geometry and The basic condition for carrying out the drying process is the movement
experimental conditions. The innovation in solar powered drying was of energy consumed for the evaporation of moisture, which is why
also described by Kamfa et al. (2020). Agriculture, pharmaceutical in drying apparatuses are most often classified according to the method of
dustry, sewage treatment plants, mineral processing and polymer pro heat transfer to the dried material. There are convective dryers, contact
duction were indicated as potential industrial sectors which could use dryers and dryers using energy fields. Most of them may operate in both
this technology. Integrated solar energy systems can enable the shift continuous and batch mode (Fig. 3).
towards low-emission drying.
Earth does not make full use of solar energy: a third of that energy is 2.1. Convective dryers
reflected into space. Solar energy, which is regular in supply and has a
minimal impact on the environment, ought to be used more efficiently The largest group of devices used for grain drying are convective
by means of solar collectors. Sinhmar and Singh (2021) presented the dryers, in which the heat transfer from the drying gas to the dried ma
latest indirect (solar collectors) and direct (photovoltaic) methods of terial takes place by means of convection. Among these devices, there
capturing solar energy. They discuss types of solar dryers and the issues are the most classic solutions early introduced to the industry such as
of heat energy storage during food drying and present the parameters bin, cabinet and chamber dryers with natural and forced flow, as well as
required for food drying and characteristic factors related to the quality tunnel and belt dryers. In all these devices, the drying gas can move both
of the process (e.g. color, content of phenols and flavonoids). along and across the material to be dried. Convective dryers include
This review presents the latest innovations in seed and grain drying direct rotary drum dryers, which are one of the first designs of high-
on the background of conventional drying technology. As far as we capacity drying apparatus operating in the continuous mode (Wae-
know, no review has been published recently regarding the drying of hayee et al., 2020).
plant materials with renewable energy sources. Emphasis was placed on More modern machines are dryers in which grain is dried in the so-
drying seeds and grains, discuss in detail new solutions in drying tech called suspended state. In this case, a distinction can be made between
nology, with special attention being paid to solar energy or catalysts, devices operating with a highly concentrated bed and those operating
and present cleaner drying technologies. Reducing energy consumption with a more diluted bed. The first group primarily includes fluidized bed
and increasing the drying efficiency is the current challenge that must dryers. Their modification specially designed in the fifties for drying
ensure high-quality products, protect the environment and the health of cereals are spouted bed dryers (Mathur and Gishler, 1955). Pneumatic
consumers (Fig. 2). The solutions proposed in the paper will allow to dryers, on the other hand, operate in the dilute bed regime, where the
convince the dryer producers and their users to introduce beneficial grain is dried during pneumatic transport. The characteristics of
economic and ecological changes in the grain drying process. These different convective dryers are shown in Table 3.
changes can be made to existing or newly designed facilities. So far, the The most popular convective dryers (batch or continuous) use the
solutions described have not been implemented on an industrial scale, hot air or flue gases and they are energy-intensive devices (Yogen
which would allow development towards cleaner production. drasasidhar and Pydi Setty, 2018). When drying temperatures are close
to the gelatinization temperature of the starch, a change in the structure
Fig. 2. Innovations in seed and grain drying.
3
Fig. 3. Classification of the most popular grain dryers.
of the material may occur, resulting in changes in the properties of the operation) (Table 5).
final product (in the case of rice, for example, the quality of cooking or Each of the available drying technologies has strengths and weak
the degree of water absorption) (Truong et al., 2019). nesses. Choosing the optimal drying technique depends on the type of
Grains containing large levels of moisture must often be dried in a material and the desired results. Convection drying is an easy operation
multi-stage systems. In the first stages, intensive drying bringing their and provides long shelf life, but the drying time is long and crusts may
moisture down to 18–19% is applied, which is followed by a milder form on the product surface due to heat. Energy can be saved by inter
process that lowers the moisture to 14% (Jittanit et al., 2013). mittent drying, which reduces browning and extends shelf life while
In some convective dryers, superheated steam (SHS) is used as an protecting compounds with health-promoting properties (e.g., vitamins,
alternative to air drying. The use of SHS has a number of advantages flavonoids, carotenoids). Hybrid drying is promising because it can
such as increased efficiency, reduced fire risk, high heat transfer rate and provide high quality with possibly low energy consumption, which are
reduced odour emissions. SHS can be used to dry brewing grains after described in Chapter 3.
beer production in a rotary drum. Such grains can be used as animal
feed, but it is necessary to dry them first. The process has some disad 3. Methods that reduce energy consumption and improve the
vantages: much energy is required and grain tends to stick to the dryer efficiency of grain drying
surface (Stroem et al., 2009).
Studies have shown that the use of higher drying air temperatures
2.2. Contact dryers reduces energy consumption, but has an adverse effect on seeds
germination. Research is underway to develop methods that reduce
In contact dryers, most of the heat is transferred to the material by energy consumption by using higher temperatures and by controlling
conduction from the hot wall of the apparatus or belt, which is usually drying airflow. Energy saving was associated with higher air tempera
heated by steam or hot water, possibly electricity. Heated gases are ture and reduced flow as well as a higher humidity of exhaust air. There
rarely used as a heat source because the heat transfer coefficient from was a reduction in energy consumption by several percent and, unfor
the heating medium to the appliance wall should have a high value. tunately, a reduction in grain viability. In the future, it is necessary to
In this group of dryers, a distinction can be made primarily between define temperature limits for individual cereal species and to specify
contact drum and belt dryers, a description of which can be found in control ranges (Jokiniemi and Ahokas, 2014).
Table 4.
3.1. Hybrid methods
2.3. Dryers using energy fields
To shorten the drying time in conventional dryers and to reduce
Drying processes can be significantly intensified by applying energy energy consumption, hybrid methods are used as a combination with
fields (Pasichnyi et al., 2017). Radiant dryers use infrared or ultraviolet other techniques (Table 6).
radiation, dielectric dryers use high-frequency electric fields (radio and Microwave drying causes heat to be generated inside the grain and
microwave frequencies), and acoustic dryers use ultrasound. Among the the material heats up quickly, which can result in temperature hetero
dryers using energy fields, one can distinguish primarily between cabi geneity of the material (Wray and Ramaswamy, 2015). Microwave
net and chamber designs (batch operation) and belt designs (continuous drying requires good distribution of microwave energy in the grain,
4
Table 3
Characteristics of the most popular convective grain dryers.
Dryer Advantages Disadvantages References
Cabinet and • simplicity of construction • unevenness of the drying process in (Argo et al., 2018; Chilka and Ranade, 2019;
chamber dryers • good drying conditions for grains requiring long and not different parts of the dryer Jessica et al., 2019; Omofoyewa et al., 2017)
too intensive drying • significant heat loss during loading and
• low price unloading
• difficult process control
• significant air loss due to leakage
• long drying time
Bin dryers • simplicity of construction (a storage bin with a • low productivity (Vician et al., 2016)
perforated bottom and a blower to move air through the • long drying time
grain) • high pressure drop of the drying gas
• drying shall take place at the place of storage
Tunnel dryers • high efficiency of the installation with counter-current • high pressure drop of the drying gas (Cáceres-Huambo and Menegalli, 2009;
air flow Mançuhan, 2009; Precoppe et al., 2017)
• great scope for constructing multi-stage installations
• high performance
Belt convective • uniformity of drying for crossflow dryers • unevenness of drying in the dryers with (Alexi Holowaty et al., 2020; Böhner et al.,
dryers • no dust formation or material crumbling the gas flow along the bed 2013; Lutfy et al., 2015)
• easy adjustment of process conditions and plant • large air pressure drops in the dryers with
performance the gas flow through the bed
• high heat losses
Rotary drum • high capacity • only for grains requiring a short drying (Mikulionok, 2020; Wae-hayee et al., 2020)
convective • high versatility of applications time
dryers • high thermal efficiency • generation of large quantities of dust
Fluidized bed • the “fluidity” of the fluidized bed allows continuous, • inability to operate at higher gas flow (Borel et al., 2020; Mehran et al., 2019; Verma
dryers easy-to-handle operation of the equipment even on a rates and Paliwal, 2020)
large scale • difficulty in drying polydisperse grains,
• no moving parts • long drying time
• excellent heat and mass transfer conditions • high energy consumption associated with
• possibility of using additional heat sources, e.g. infra-red the need to fluidise the bed
heaters
• good mixing of the material in the bed, which allows
effective control of the process and the quality of the
final product
• possibility to work in a batch and continuous mode
Spouted bed dryers • uniformity of drying • limited bed height (for apparatuses (Esmailie et al., 2018; Go et al., 2007; Niksiar
• lower pressure drops than in fluidized beds without the draft tube) et al., 2013)
• possibility of drying grains with large diameters • due to intensive circulation possible
• facilitating drying of easily agglomerating grains damage to grains with low mechanical
• possibility to work in a batch and continuous modeno strength
moving parts
Pneumatic dryers • the possibility of drying materials not resistant to high • high operating costs (Bunyawanichakul et al., 2007; Satpati et al.,
temperature • high dust emissions 2020)
• possibility to dry and transport material at the same time • possibility to remove surface moisture
• small installation area only (very short process time)
• easy process control • use only for small diameter grains (up to a
• no moving parts maximum of 2 mm)
• low investment costs
which can be reached by drying in a fluidized bed with optimal micro was reduced by 30% when a microwave-assisted fluidized bed dryer in a
wave power, not too high in order not to lead to additional air tem power range of 300–400 W was used (Taheri et al., 2020).
perature rise (Taheri et al., 2020). Computer simulations enable an Hybrid drying with IR and convection (IRC) combines direct drying
optimization of drying parameters and prediction of temperature and and indirect heating. IR drying technology was developed 30 years ago,
humidity distribution inside the grain and drying air properties (Zare but has recently gained popularity due to energy efficiency and lower
and Ranjbaran, 2012). costs compared to vacuum or microwave drying, good quality of the
The comparison of convection drying with microwave-assisted dry dried product and reduction in drying time (Dai et al., 2017). IR drying is
ing of coffee beans indicated non-uniform temperatures of the grains considered to be environmentally friendly (Sakare et al., 2020). This
and more than twenty times higher Fick diffusion coefficients for mi method combined with hot air drying generates the lowest specific en
crowave drying. Microwave-assisted drying in the form of 5-s pulses was ergy consumption, especially for samples with high initial moisture
proposed in order to achieve uniform temperature distribution in coffee contents (Yilmaz and Tuncel, 2010). The use of this method can have a
grains (Muñoz-Neira et al., 2019). Microwave drying of grains that are beneficial effect on the extraction of bioactive components from grains.
animal feed materials can increase digestibility by modifying starch and A significantly increased total phenolic and flavonoid content was
protein complexes or facilitating mechanical processing of grains (Bro observed in pigmented rice grain extracts dried in a hybrid system with
die et al., 2019). Lowering the pressure with vacuum decreases the IR compared to hot air drying (Ratseewo et al., 2020). At high IR in
boiling point of water which raises the temperature inside the bean. The tensities, grain cracking due to high moisture gradient and kernel
antioxidant activity of coffee beans is found to be higher under vacuum stresses is possible (Nosrati et al., 2020).
microwave drying conditions and the total polyphenol content of the Alternatively, it is possible to use ultrasound, which as a non-thermal
extracts increases, which is important in maintaining the bioactivity of method can be applied for heat-sensitive grains (Abdoli et al., 2018).
coffee grains (Dong et al., 2018). The use of microwave radiation has the The ultrasound is passed through the material and causes a series of
additional advantage of a simultaneous disinfection, as shown by the compressions and relaxations, which acts as a sponge. The micro
example of red lentils. The percentage of seeds infected with grey mold channels created in the process remove water. Ultrasound generates
5
Table 4 Table 6
Characteristics of the most popular contact grain dryers. Hybrid methods of drying.
Dryer Advantages Disadvantages References Method type Characteristics
Rotary • high performance • greater complexity (Hanifarianty et al., Drying + microwaves + faster drying
drum • good drying of the apparatus 2018; Havlík et al., + method of grain disinfection
contact conditions for design than in the 2020; Wae-hayee + increases the availability of nutrients in grains
dryers grains requiring a case of convective et al., 2020) - non-uniform temperatures in the grain
long drying time dryers Drying + infrared radiation + faster drying
• uniform • difficulty in + good quality of product
temperature cleaning the heating + uniform drying
distribution inside tubes inside the - possible cracking at high IR intensities
the apparatus apparatus Drying + ultrasound +suitable for drying heat sensitive grains
• high accuracy of • lower productivity +reduced number of cracked grains
process control due to smaller size
• low dust compared to
emissions convective devices 3.2. Energy costs reduction
• possibility of safe
sterilisation of the
product during
Fossil fuels are the most commonly used sources of energy in grain
drying drying. Usually it is light oil, but it can be biofuels (e.g. wood chips). The
Belt • high efficiency • increased (Burmester et al., substitution of oil and gas with alternative energy sources, including the
contact • uniform complexity of the 2011; Janosik and use of nuclear power, can reduce energy costs (Strumiłło et al., 2014).
dryers temperature apparatus design Liedy, 1991; Nindo
An alternative to convective hot air drying can be waste heat recovery
distribution inside and Tang, 2007)
the apparatus from the combustion engine exhaust. Cogeneration is a process of
• low dust simultaneous production of heat and electricity from one fuel source,
emissions which can reduce the costs of the process. Reusing waste heat will in
• possibility of safe crease the effectiveness of the drying system and reduce the use of fossil
sterilisation of the
product during
fuels (compared to conventional systems) (Ononogbo, 2020). Samadi
drying et al. (2014) observed 11–12% increase in system efficiency when en
• flexibility of the ergy recovered from the combustion engine in the form of exhaust gases
installation (using combined heat and power) was used on drying banana slices. The
maximum efficiency and the lowest specific energy consumption were
recorded at 75% engine load.
Table 5 A potentially useful method can be heat recovery from exhaust air
Characteristics of the most popular grain dryers using energy fields. from the dryer. It might reduce energy consumption by 3–44%. It is
Dryer Advantages Disadvantages References possible to use a parallel plate heat exchanger to recover thermal energy
from the exhaust air from the recirculating batch grain dryer. An
Infrared • ease of use and • limited range of (Okeyo et al.,
dryers adaptability to application – 2017; Timm important factor in introducing new solutions is the assessment of heat
changing conditions basically for surface et al., 2020) transfer efficiency and functionality of dusting work (Jokiniemi et al.,
• less space occupied by drying 2016).
the dryer compared to • possibility of easy Considering heat recovery, an efficient solution is a heat pump that
other devices overheating and
• a significant damage to the grain
uses an evaporator, compressor and condenser to recover sensible and
reduction in surface latent air that is transferred to the supply air. The energy consumption in
operating time drying using hog pumps is 0.33 kWh/kg of evaporated water and for
compared with traditional convection systems it is 1–2 kWh/kg of water, which saves
convective drying
70–80% of energy (Jokiniemi et al., 2016). In the drying process, in
• the possibility of
drying only specific order to obtain a sufficiently high energy efficiency, it is necessary to
areas of the bed properly mix the air flow so that there are no gradients in the temper
Dielectric • heat transfer in the • high operating costs (Arballo et al., ature distribution in the grain drying chamber. Essential is the even
dryers whole volume of the associated with the 2018; Hemis temperature distribution to prevent overdrying of the grain close to the
material being dried use of electricity et al., 2019)
• short drying time • problems with
air channels. Drying by heating is more effective near the air channels in
• easy regulation and uniform the grain column (Kjær et al., 2018).
automation of the distribution of Drying one ton of grain consumes approx. 0.38–0.63 GJ of energy,
process radiation inside the depending on the type of dryer. Motevali et al. (2011) conducted a study
• possibility of apparatus
to evaluate the energy intensity of various methods of drying, including
complete drying of • uneven heating of
the grains the material microwave, vacuum, infrared, and hot air (as a control). The highest
• possibility of • rapid release of the energy consumption was recorded during vacuum drying (12.83 kW for
simultaneous vapor inside may 50 ◦ C). In the case of infrared drying, the highest energy consumption
sterilisation of the cause the grains to was recorded at 3.08 kWh (at 0.49 W/cm2 irradiance and 1 m/s air
material burst
intensity). The experiment showed that hot air convection with micro
wave pre-treatment significantly reduced the amount of energy used and
cavitation, which intensifies heat and mass transport (Yao, 2016). Rice shortened the drying time (by 1.16–3.41 and 1.15–1.93 times less en
drying under these conditions reduced the drying time by 23% ergy for 200 W and 100 W).
compared to classical fluidized bed drying. The grains were charac Improving the performance of drying processes can be realized in
terised by a lower percentage of cracking High-power ultrasound com three ways: optimizing the apparatus, heat recovery methods, and
bined with conventional drying significantly reduces by up to 25% optimizing the process control (Zohrabi et al., 2020b). Especially the
energy consumption for rice drying while reducing process time by strategy of energy recovery from such systems seems to be necessary.
26.5% (Dibagar and Amiri Chayjan, 2019). Advanced thermodynamic methods such as exergy analysis can help
6
increase the energy efficiency of the process from the point of view of save energy, air recirculation and a moving trays were used for faster
sustainability and environmental protection (Aghbashlo et al., 2013). and more uniform drying. The decrease in humidity from 70% to 10%
The management of exhaust air in terms of heat recovery is of great occurred within 4 h on a moving belt and 5 h on a fixed tray. The
importance. Attention has been drawn to the validity of drying air disadvantage of this solution was the loss of dried air whenever the
recirculation, which significantly improves the exergetic efficiency of valves were opened. A desiccant can be added to the seeds (oats, wheat,
drying (up to 200%) while increasing the drying time (Zohrabi et al., corn, soybeans), which increases the drying rate and improves the
2020b). Full recirculation of air may be associated with the necessity of quality of the seeds. Fluidized bed drying in the presence of silica gel
dehumidifying the exhaust air so it seems reasonable to return only a may be applied. Another solution is the use of forced drying with closed
part of the air for drying (Zohrabi et al., 2020a). Also, heat recovery air circulation (Gill et al., 2014).
from the air using a heat exchanger improves the exergetic efficiency of A variety of moisture absorbers should be used to maintain proper
drying (even 4 times) (Ghasemkhani et al., 2016). The technology of moisture content in stored cereals. Different materials are used for this
self-heat recovery has been applied to biomass drying processes, purpose, including silica gels, zeolites, and bentonite. Superabsorbent
achieving energy reductions of up to 25%. The countercurrent system polymers can be used as desiccants to dry grains and reduce aflatoxin
with a smaller minimum temperature difference proved to be the most contamination. Due to its reusability, the use of this desiccant is cost
energy-efficient (Liu et al., 2014). The heat self-recovery technology effective (Mbuge et al., 2016).
enables the recovery of latent heat and sensible heat, contributing to
significant energy savings (Fushimi et al., 2011). Large savings can also 4. The use of renewable energy sources in drying
be achieved by using solar energy to power the fans, heater and preheat
the air for drying corn kernels (Silva et al., 2021). A new trend is the search for renewable energy sources for drying
agricultural products. Solar, geothermal and biomass energy are among
3.3. Moisture removal from the drying air the proposed sources. Mostly, there are solutions based on hybrid in
stallations, where solar energy plays a key role, while geothermal and
The lower the moisture content and the higher the germination rate, biomass energy provide support (Table 7).
the higher the market price of seeds. The higher the temperature of the
air used for drying, the lower the germination capacity of the seeds. This 4.1. Solar energy
temperature should not exceed 40 ◦ C. As the temperature decreases, so
does drying performance. The use of techniques to remove moisture Renewable energy sources like solar can replace their non-renewable
from the drying air (desiccants) to increase drying efficiency is an op conventional counterparts to dry grains. A grain drying system which
tion. Various techniques can be used for this purpose: vapor compression included a fluidized bed dryer, which was supported by solar energy
dehumidifier or desiccant dehumidifier (Gill et al., 2014). obtained from the operation of photovoltaic panels, was used for rice
Grain drying based on a vapor compression dehumidifier in the form drying. The energy demand in such a system was almost four times lower
of a cabinet dryer is dedicated to low-temperature drying (25–45 ◦ C). To compared to the operation of a unit operated with natural gas (Mehran
Table 7
Selected studies on drying systems using renewable energy.
Dried Drying method Initial Final MR (final Drying air Drying Drying Specific energy References
product moisture moisture moisture temperature time (h) efficiency consumption
content of content of content to (◦ C) (%) (kWh/kg per kg of
product (%) product (%) initial moisture)
moisture
content)
Bitter gourd Greenhouse dryer with - - 0.640 45,0–55,0 13 – – Chauhan

flakes solar air heating et al. (2018)
collector
Red pepper Greenhouse dryer 87,7 <1.00 – 36.2–37.3 3–5.5 – 2.78–4.76 Azaizia
supported by solar et al. (2017)
collector
Black Convection solar dryer 73.4 8.50 0.116 46.5 18.5 12.0 5.21 Lingayat
turmeric with thermal energy et al. (2021)
(curcuma storage - paraffin wax
caesia)
Red chilli Convection solar dryer 72.3 7.60 0,105 40.4 24.5 18.8 3.34 Ndukwu
pepper with thermal energy et al. (2017)
storage - Na2SO4⋅ 10 H2O
and NaCl
Cocoa beans Solar dryer with thermal 53.4 3.60 0.0674 58.0–96.0 72 – – Fagunwa
energy storage - black et al. (2009)
gravel
Pea Solar-assisted spouted 2.50 0.10 0,0400 35,3–65,5 4 – – Sahin et al.
bed drier (2013)
Mint leaves A solar dryer with flat 82.8 9.10 0,110 40–45 24 28,2 – Jain and
plate absorber with Tewari
thermal storage natural (2015)
convection - phase
change material
Red chilli Solar assisted heat pump – – 0.200 53.0 24 33.2 2.21 Naemsai
pepper dryer with heat recovery et al. (2019)
Fresh Solar dryer 66,9 1,60 0,0239 – 120 15.0 – Jain and
pineapple Biomass-backup heaters 61,4 1,30 0,0212 72 11.0 Tewari
(Ananas Solar–biomass modes 66,9 1,10 0,0164 24 13.0 (2015)
comosus)
7
et al., 2019). Solar energy can be used for the work of systems with solar allows the dryer to operate regardless of atmospheric conditions. The
collectors, but they do not work on cloudy days (Yahya et al., 2017). system allows for storing energy on sunny days and using stored energy
In order to eliminate the inconvenience associated with discontin and heat from the ground all year round. The research proved that the
uous generation of solar energy, solar dryers store energy in the form of surface of the collectors, the volume of the tank, but the type of soil in
thermochemical energy, latent heat or sensible heat (ELkhadraoui et al., which it is placed have a significant impact on the efficiency of the
2015). One solution is to use the rock bed as a material for heat storage. drying process. A simulation showed that the system’s efficiency coef
The efficiency of such dryers depends primarily on the construction of ficient increases gradually until the fifth year of operation. The total
the apparatus and the parameters of the rock (size, thickness of the energy input to the drying system provided by solar energy is 77%, the
deposit, air flow rate) (Berinyuy et al., 2012). Cocoa beans drying made compressor operation is 22.7% and the fan power is below 1%. The
us of a sun dryer with forced convection. Black gravel stored heat. The authors pointed out that there is still a lack of optimization of this type of
drying mechanism was based on a combination of direct radiation and drying in order to obtain the appropriate size of the installation.
convection heating with airflow through the beans. The temperature in Photovoltaic installation with energy storage are used without the
the dryer ranged from 31 to 54 ◦ C. Dehydration of the grains was ach additional element – heat pump. The use of a combined system without
ieved from about 50% to 3.6% within 72 h. The quality of cocoa beans pump allows for shortening the drying time up to 50% and to obtain a
did not deteriorate (Fagunwa et al., 2009). El-Sebaii et al. (2007) tested temperature inside the dryer of about 65 ◦ C (Baniasadi et al., 2017).
the thermal parameters of a dryer powered with a two-flow solar air
heater with a bed of gravel and limestone. It was found that heat storage 4.3. Biomass energy
increases the thermal efficiency of the heater by about 27% in com
parison to an unfilled solar air heater. More than 30 of time reduction is A solution to the intermittency of solar-based solutions may be a
achieved by using sand after chemical treatment as a heat storage ma dryer based on natural convection supported by biomass heaters. The
terial. The substance is placed under the plate of the absorber (El-Sebaii main elements of the dryer were solar collectors, biomass burners and a
et al., 2002). The application of the solar-assisted spouted bed drier drying chamber. The dryer was tested in three modes of operation:
resulted in a 3.5 times faster drying compared to sun-drying, as collectors, biomass combustion, collectors – biomass combustion. The
demonstrated in the case of pea (Sahin et al., 2013). Phase change use of support in the form of biomass combustion allowed for the idea of
materials can be used to store latent heat energy. Technical paraffin running the process in adverse weather conditions (Madhlopa and
wax, characterized by chemical stability below 500 ◦ C and low price, is Ngwalo, 2007). Yahya et al. (2017) presented solution consisting of a
one of such materials (Paneliya et al., 2020). The influence of air tem fluidized bed, a biomass furnace and a solar collector. The installation
perature and air intake necessary to charge paraffin was investigated. was used to dry paddy rice. The average drying rate was 0.16 kg/s at
The research shows that the use of this type of installation allows for 61 ◦ C and 0.24 kg at 78 ◦ C. It was found that drying times were signif
energy savings of 40% (Devahastin and Pitaksuriyarat, 2006). A modern icantly shorter for drying in a hybrid system as compared to dryers using
drying room with thermal energy storage for drying herbs was devel only solar energy. This type of solution is satisfactory in terms of
oped. Under the chamber there is a system consisting of 48 cylindrical maintaining the continuity of drying, but it emits oxides during biomass
pipes filled with paraffin. This type of system kept the drying tempera combustion (Ozgen et al., 2021). The residual heat from combustion in
ture at the level of 40 ◦ C. The analysis shows that the return on in the diesel engine can be used for drying (Peter et al., 2018) while syn
vestment is 1.5 years (Jain and Tewari, 2015). Energy storage materials thesis gas from biomass gasification, e.g. energy from the gasification of
include materials with silica: paraffin/silica nanocomposite, expanded residues from coffee production can be used to dry coffee beans (Orosco
graphite paraffin/polypropylene (Luo et al., 2020) or salt-based phase et al., 2018).
change materials (Esakkimuthu et al., 2013).
Apart from solar collectors, greenhouse dryers provide a drying 5. Reduction of emissions from drying
system based on solar energy (Chauhan et al., 2018). Such dryers can be
used alone or in combination with solar collectors, which significantly Drying has a strong environmental impact due to the use of fossil
increases their efficiency (Azaizia et al., 2017). Smitabhindu et al. fuels that pollute the air and contribute to global warming (source of
(2008) developed a large-scale greenhouse dryer for drying fruit, veg NOx, CO, and CO2 gas emissions). Most systems use hot air that is heated
etables and coffee beans with a parabolic shape. The dryer was covered by burning fossil fuels (over 85% of industrial dryers) (Samadi et al.,
with polycarbonate sheets and the floor was black concrete. The dryer 2014). Low-quality fuel systems can be more polluting whereas other
was ventilated by 9 fans powered by three 50-W solar cells. It was found streams can produce dust and non-condensable vapours. Drying with
that the use of a glasshouse dryer shortened the drying time by two days, hot air may cause the absorption of odorous compounds or sulphur
as compared to natural drying in the sun. Tuncer et al. (2020) proved oxides contained in the exhaust gases into the grain. To prevent this,
that using an integrated system increases the temperature inside the electrostatic precipitators or catalytic drying can be used (Czajkowska,
greenhouse and shortens the drying time. In this case, a greenhouse 2018).
drying room with a four-pass solar collector was used to dry vegetables. More advanced tools such as LCA (Life Cycle Assessment) are also
The average efficiency was obtained within the range of 72–80%. used to analyze the environmental impact of drying. Typically, such an
analysis covers the entire life cycle of a product, from sowing to the final
4.2. Geothermal energy product. Due to this kind of analysis, it is possible to determine in detail
the influence of the whole production system on the environment, in
The high energy requirement for drying grain can be significantly particular the emission of greenhouse gases, other gases, pollution of
reduced in solar energy storage tanks combined with a heat pump. The surface water or soils (Abdul Rahman et al., 2019). It is possible to
use of a complex solar energy system and ground energy can signifi analyze the impact of individual stages and prepare a strategy to reduce
cantly increase the efficiency of drying systems (Wang et al., 2019). The the negative effects of the process on the environment. The drying stage
literature presents many publications comparing the innovative drying is an important element of the LCA model. Drying of grains can have a
method to traditional methods (e.g. hot air or vacuum drying), giving a significant impact on acidification or eutrophication of water bodies. It
major advantage for new techniques mainly in terms of increased effi has also been suggested that an important aspect of reducing negative
ciency and energy savings. Hasan Ismaeel and Yumrutaş (2020) pre environmental impacts is to reduce the consumption of fossil fuels in
sented the possibility of using an installation consisting of four main favor of using renewable energy (Nabavi-Pelesaraei et al., 2019). Un
elements: a dryer, an underground solar energy storage tank, solar col fortunately, there is a lack of literature reports on LCA analysis of grain
lectors and a heat pump, for drying wheat grains. The proposed solution drying which is a potential scientific gap and may be a challenging area
8
for further research. The first group are precious metals. The most popular, although
expensive catalyst is metallic platinum (Salehian and Shirneshan, 2020).
5.1. Particles removal Literature data often show examples that use the reduction properties of
palladium (Drault et al., 2018), rhodium (Jabłońska and Palkovits,
The exhaust gas produced by the drying systems must undergo me 2016b), nickel (Hu et al., 2020) and iridium (Song et al., 2020). The use
chanical cleaning to remove particulate matter. Special emphasis is put of precious metals as catalysts can lead to NOx conversion in a very wide
on the fractions most dangerous to human and animal health – PM10 and range, from 15 even to 100%. The least promising catalyst is Ru, which,
PM2.5 dust – which are carriers of heavy metals, allergens, polycyclic according to studies, minimizes NOx emissions by only about 15% (Song
aromatic hydrocarbons or dioxins (Styszko et al., 2017). et al., 2020). In contrast, Rh can lead to a 100% reduction of NOx
A wide market of dust collection equipment – dry and wet me emissions (Jabłońska and Palkovits, 2016). The application of such
chanical, electrostatic and filtration dust collectors – mostly use physical metals as catalysts is not accidental. They are transition elements that
phenomena like gravity, inertial collisions, centrifugal and electrostatic have an incomplete d-orbital and have low activation energies, variable
forces, coagulation or the sieve effect. To increase the reliability of the valence and easily form complexes. The metals are applied to different
equipment and reduce greenhouse gas emissions, chamber furnaces can types of carriers, which increases their mechanical strength and ability
be replaced with different types of cyclones (Naumkin et al., 2017) like to operate at high temperatures. The most common carriers are ceramics
shock-inertial dust collectors (Krawczyk et al., 2019), a settling chamber (Shen et al., 2016), perovskites (Zhou et al., 2016), zeolites (Ruggeri
(Liu et al., 2019), electrostatic precipitators (pipe and plate) (Viegas et al., 2018), non-metallic oxides (Song et al., 2020) or other metals
et al., 2019), and fiber, bag, and pocket filters (Ramachandran, 2019). (bimetallic catalysts) (Huang et al., 2016). The same type of media is
For the purpose of air protection and dust elimination from exhaust used by a group of catalysts – transition metal oxides. Application of
gases, wet dust collectors are used, where the separation is supported by transition metal oxides enables conversion of NOx on the level of
the forces of dust particle wetting by water introduced on the walls of 90–100%. The best catalysts are titanium oxides which enable 100%
the cyclone or sprayed inside the device. This technique has been reduction of oxides (Zhang et al., 2020). Most often the literature data
applied in various types of scrubbers: barbotage, unfilled, solid-filled, describe the industrial implementation of vanadium (Shen et al., 2016),
fluidized-filled and Venturi dust collectors (Chen et al., 2020). titanium (Zhang et al., 2020) and molybdenum oxides (Kwon et al.,
2019).
5.2. Catalytic processes The problem of nitrogen oxides emission is solved through their
catalytic decomposition that yields molecular oxygen and nitrogen. In
Natural gas, oil and waste biomass (raw or pelletized) is used more contrast to catalytic reduction, catalytic decomposition does not require
and more in energy production, which is energy recycling (Joselin other reagents like ammonia, methane, or carbon monoxide (Z. Liu
Herbert and Unni Krishnan, 2016). Obtaining heat from both fossil and et al., 2016). Likewise, the decomposition of nitrogen oxides uses
alternative fuels is connected with the production of significant amounts various catalysts – precious metals or transition metal oxides – deposited
of flue gases, which are carriers of gaseous pollutants – nitrogen oxides, on carriers.
sulphur oxides, and carbon oxides and volatile organic compounds Systems for catalytic exhaust gas treatment from nitrogen oxides
(VOC) – the abatement of which poses serious problems (J. Liu et al., often require flue gas return, which combusts nitrogen oxides,
2016). The adopted technical solutions in industrial dryers with a increasing process efficiency. The return of exhaust gases, which usually
multi-tonnage capacity and high energy and/or heat consumption are have a very high temperature, allows for the recovery of thermal energy,
based on the use of catalysts. Their aim is catalytic combustion of which improves the economy of the process and reduces fuel con
exhaust gases. In this way a pro-ecological effect of reducing the emis sumption (Gopan et al., 2020). The unit process, which is the exhaust gas
sion of greenhouse gases in the fumes is obtained, with simultaneous return, allows for directing the exhaust gas to subsequent stages, such as
energy recovery (Sinha Majumdar et al., 2017). desulphurization, removal of particulate matter or recovery of demin
The use of catalysts in energy production is primarily aimed at eralized water, which increases the ability of exhaust gas to absorb
reducing the emission of NOx as the most dangerous gaseous pollutants moisture in the return loop (Liu et al., 2018).
emitted during fuel combustion. The reduction in nitrogen oxides in the
exhaust gas occurs in the presence of ammonia, carbon monoxide, or 6. Reduction of seed biological contamination by drying
methane and catalytic activity of catalysts. The result is molecular ni
trogen, carbon dioxide, and water vapor. SCR – selective catalytic Proper drying of grain protects it from the development of grain pests
reduction – is the most common type of catalytic reduction (Jabłońska such as flour beetle (Triboliumconfusum), miller moth (Tenebrio molitor)
and Palkovits, 2016a). This solution is widely resorted to in industry and or grain beetle (Sitophilus granaries) (Stejskal et al., 2014). These insects
transport, where urea solution (use of ammonia too dangerous) and a cause acidification and mass loss, disqualifying the grain as sowing
wide range of catalysts are applied (Table 8). material. Phosphine or hydrogen cyanide are applied for quantitative
Table 8
Maximum NOx conversion using different catalyst.
No. Type of catalyst Active element/ Maximum NOx Fuel burnt Environmental impact Reference
compound conversion [%]
1 Precious metals Pt 55 20% ethanol, 50% -lower NOx emission Salehian and
biodiesel, 30% diesel -lower fuel usage Shirneshan (2020)
Pd 60 natural gas - reduction of NOx conversion temperature - Bozkurt and Apul
reduction of heat emission (2020)
Rh 50–100 diesel Jabłońska and
Palkovits, (2016b)
Ni 27.2 H2/O2 Hu et al. (2020)
Ir 34 NO/CO/O2 Song et al. (2020)
Ru 15
2 Transition metal V2O5 90 NO/NH3/O2/SO2/N2 Shen et al. (2016)
oxides TiOx 100 NO/NH3/O2 Zhang et al. (2020)
MoO3 90 NOx/O2/H2O Kwon et al. (2019)
9
control of pests and their eradication in small volumes (containers, solutions have not been implemented on an industrial scale.
bigbags) and large volumes (metal or concrete silos) (Carpaneto et al., Increasing drying performance by reducing energy consumption and
2016). More and more chemicals are banned from application because obtaining high quality agricultural products is the current challenge. It is
they change the properties of grain or cause risks to people, animals and in line with sustainable development, environmental protection, con
the environment. Despite their high effectiveness, methylbromide, sumer safety, and undeniably safeguards cleaner production. In most of
dichlorvos, drinking anticoagulant rodent baits have been withdrawn the presented examples of dryers based on renewable energy, solar
from use. There are no highly effective and simultaneously safe sub power plays a major role. A photovoltaic-driven ventilator completely
stitutes available (Stejskal et al., 2014). Storage tanks cleansed of reduces the dependence on fossil fuels/electricity. This type of solution
pest-infected grain are disinfected with organophosphorus compounds can be successfully supported by geothermal energy and energy from
or thermal disinfection. Both solutions – for grain and tank disinfection – biomass combustion. This significantly increases the prospects for
require additional energy or the use of chemicals (Opit et al., 2011). Low widespread use of hybrid systems.
humidity protects the grain from fungal diseases caused by Alternaria, The limitations in the research result, among other things, from the
Cladosporium, Aspergillus, Penicillium, Diplodia, Fusarium and Gibberella lack of the so-called good drying practices. On the other hand, it would
(Tittlemier et al., 2019). These fungi produce mycotoxins, dangerous for be a good idea to introduce emission standards for air leaving the grain
both humans and animals. Literature data show that the key parameters dryers. Drying products are marketed in foodstuffs and should be free of
influencing the growth of pathogenic fungi species are the igneous toxic compounds, such as hydrocarbons or sulphur compounds adsorbed
content, water activity and temperature. It is estimated that humidity on their surface. The cost of research could be reduced by the application
above 13.5% for cereal grains and 12.5% for soya is the limit above of modernization of ready-made solutions taken from other industries.
which fungal invasion begins. The induction factor is the storage tem The proposed new solutions can potentially be implemented to
perature of the grain, which, after exceeding 25 ◦ C, is responsible for operate at industrial scale. However, this approach needs to be simpli
intense fungal growth (Mannaa and Kim, 2017). Fungal growth, espe fied and improved. There are no ready-made solutions on the market, e.
cially of the Aspergillus genus in stored grain under conditions of g. for hybrid or renewable energy methods, and if they exist they are
excessive moisture, produces aflatoxin. These compounds demonstrate very costly. So far, rather modernization of current solutions has been
high toxicity, mutagenicity and teratogenicity and are lethal to small carried out, which was more cost-effective. Modern solutions, which are
animals. Drying is a preventive action against the decline in grain more efficient and environmentally neutral, should be more easily
quality associated with an increase in the content of anti-nutritional accessible, and thus find a wider group of users. Both old and new
substances (Bakhtavar and Afzal, 2020). technologies should be continuously improved to ensure sustainability
and cleaner production.
7. Conclusions and future directions
CRediT authorship contribution statement
Drying – a large-scale process of fundamental importance in agri
culture and agri-food processing – ensures good quality agricultural Katarzyna Chojnacka: Supervision, Conceptualization, Writing –
products and enables their long-term preservation. Drying is a protective original draft, Writing – review & editing. Katarzyna Mikula: Writing –
measure against the development of biological contaminants, such as original draft, Writing – review & editing. Grzegorz Izydorczyk:
insects and fungi. Maintaining low humidity leads to the inhibition of Writing – original draft, Writing – review & editing. Dawid Skrzypczak:
their life processes and blocks their development, which allows for the Writing – original draft, Writing – review & editing. Anna Witek-Kro
reduction in the use of pesticides and fungicides and ensures high wiak: Supervision, Conceptualization, Writing – original draft, Writing
quality of grain. – review & editing. Konstantinos Moustakas: Conceptualization,
The commonly used methodology of drying columns designing Writing – original draft. Wojciech Ludwig: Writing – review & editing.
consists in determining the parameters of the drying medium flow and Marek Kułażyński: Conceptualization, Writing – original draft, Writing
its ability to remove moisture from the grain. The drying control system – review & editing.
monitors the parameters of the drying agent and regulates the drying
efficiency depending on the parameters (mainly humidity) of the dried
grain. In the design of the dryer, the human factor and the cooperation of Declaration of competing interest
the drying process with the storage technology are also an important
parameter. The authors declare that they have no known competing financial
The application of the innovations in the drying process of cereals interests or personal relationships that could have appeared to influence
will allow to reduce the costs of drying and to obtain a positive envi the work reported in this paper.
ronmental effect in reducing the emission of toxic components in the
drying air. The innovative factors reducing the operating costs of the Acknowledgements
dryer include the use of heat exchange systems (exchangers) and the
change of the heating medium (e.g. gas to waste biomass). The use of This work was financed partly by statutory activity of Faculty of
combustion catalysts that clean the exhaust gases from gas burners or Chemistry of Wroclaw University of Science and Technology and by the
the exhaust gases from biomass-fired boilers will allow for ecological Polish National Centre for Research and Development (NCBiR) as a part
operation of the dryer. of the ECO-Dryer project (BIOSTRATEG3/344490/13/NCBR/2018).
Drying based on conventional and alternative fuels requires catalytic
flue gas cleaning methods. The market offers a wide range of catalysts
References
based on precious metals and metal oxides, which are responsible for the
catalytic reduction or decomposition reaction. The negative environ Abdoli, B., Zare, D., Jafari, A., Chen, G., 2018. Evaluation of the air-borne ultrasound on
mental impact of grain drying is reduced through flue gas dedusting and fluidized bed drying of shelled corn: effectiveness, grain quality, and energy
consumption. Dry. Technol. 36, 1749–1766. https://doi.org/10.1080/
conversion of greenhouse gases, especially NOx. Catalysts improve en
07373937.2018.1423568.
ergy efficiency of the process. Abdul Rahman, M.H., Chen, S.S., Abdul Razak, P.R., Abu Bakar, N.A., Shahrun, M.S., Zin
The solutions proposed in the paper will allow to convince the dryer Zawawi, N., Muhamad Mujab, A.A., Abdullah, F., Jumat, F., Kamaruzaman, R.,
producers and their users to introduce beneficial economic and Saidon, S.A., Abdul Talib, S.A., 2019. Life cycle assessment in conventional rice
farming system: estimation of greenhouse gas emissions using cradle-to-gate
ecological changes in the grain drying process. These changes can be approach. J. Clean. Prod. 212, 1526–1535. https://doi.org/10.1016/j.
made to existing or newly designed facilities. So far, the described jclepro.2018.12.062.
10
Aghbashlo, M., Mobli, H., Rafiee, S., Madadlou, A., 2013. A review on exergy analysis of El-Sebaii, A.A., Aboul-Enein, S., Ramadan, M.R.I., El-Gohary, H.G., 2002. Experimental
drying processes and systems. Renew. Sustain. Energy Rev. https://doi.org/ investigation of an indirect type natural convection solar dryer. Energy Convers.
10.1016/j.rser.2013.01.015. Manag. 43, 2251–2266. https://doi.org/10.1016/S0196-8904(01)00152-2.
Alexi Holowaty, S., Eduardo Schmalko, M., Enrique Schvezov, C., Enrique, C., 2020. ELkhadraoui, A., Kooli, S., Hamdi, I., Farhat, A., 2015. Experimental investigation and
Modeling of a double pass belt conveyer dryer of yerba mate. Dry. Technol. https:// economic evaluation of a new mixed-mode solar greenhouse dryer for drying of red
doi.org/10.1080/07373937.2020.1839488. pepper and grape. Renew. Energy 77, 1–8. https://doi.org/10.1016/j.
Arballo, J.R., Campañone, L.A., Mascheroni, R.H., 2018. Study of microwave drying of renene.2014.11.090.
vegetables by numerical modeling. Influence of dielectric properties and operating Esakkimuthu, S., Hassabou, A.H., Palaniappan, C., Spinnler, M., Blumenberg, J.,
conditions. Food Sci. Technol. Res. 24, 811–816. https://doi.org/10.3136/ Velraj, R., 2013. Experimental investigation on phase change material based thermal
fstr.24.811. storage system for solar air heating applications. Sol. Energy 88, 144–153. https://
Argo, B.D., Sandra, S., Ubaidillah, U., 2018. Mathematical modeling on the thin layer doi.org/10.1016/j.solener.2012.11.006.
drying kinetics of cassava chips in a multipurpose convective-type tray dryer heated Esmailie, F., Ghadamian, H., Aminy, M., 2018. Transport phenomena study in a solar
by a gas burner. J. Mech. Sci. Technol. 32, 3427–3435. https://doi.org/10.1007/ spouted bed dryer within a draft tube. Environ. Prog. Sustain. Energy 37, 488–497.
s12206-018-0646-2. https://doi.org/10.1002/ep.12670.
Azaizia, Z., Kooli, S., Elkhadraoui, A., Hamdi, I., Guizani, A.A., 2017. Investigation of a Fagunwa, A.O., Koya, O.A., Faborode, M.O., 2009. Development of an Intermittent Solar
new solar greenhouse drying system for peppers. Int. J. Hydrogen Energy 42, Dryer for Cocoa Beans.
8818–8826. https://doi.org/10.1016/j.ijhydene.2016.11.180. F, AOSTAT. Crops (data) [WWW Document], n.d. URL. http://www.fao.
Bakhtavar, M.A., Afzal, I., 2020. Preserving wheat grain quality and preventing aflatoxin org/faostat/en/#data/QC/. accessed 5.17.21.
accumulation during storage without pesticides using dry chain technology. Environ. Fushimi, C., Kansha, Y., Aziz, M., Mochidzuki, K., Kaneko, S., Tsutsumi, A.,
Sci. Pollut. Res. 27, 42064–42071. https://doi.org/10.1007/s11356-020-10212-5. Matsumoto, K., Yokohama, K., Kosaka, K., Kawamoto, N., Oura, K., Yamaguchi, Y.,
Baniasadi, E., Ranjbar, S., Boostanipour, O., 2017. Experimental investigation of the Kinoshita, M., 2011. Novel drying process based on self-heat recuperation
performance of a mixed-mode solar dryer with thermal energy storage. Renew. technology. Dry. Technol. 29, 105–110. https://doi.org/10.1080/
Energy 112, 143–150. https://doi.org/10.1016/j.renene.2017.05.043. 07373937.2010.482719.
Barrozo, M.A.S., Mujumdar, A., Freire, J.T., 2014. Air-drying of seeds: a review. Dry. Gazor, H.R., Alizadeh, M.R., 2020. Comparison of rotary dryer with conventional fixed
Technol. https://doi.org/10.1080/07373937.2014.915220. bed dryer for paddy drying, milling quality and energy consumption. Agric. Eng. Int.
Bashkir, I., Defraeye, T., Kudra, T., Martynenko, A., 2020. Electrohydrodynamic drying CIGR J. 22, 264–271.
of plant-based foods and food model systems. Food Eng. Rev. https://doi.org/ Ghasemkhani, H., Keyhani, A., Aghbashlo, M., Rafiee, S., Mujumdar, A.S., 2016.
10.1007/s12393-020-09229-w. Improving exergetic performance parameters of a rotating-tray air dryer via a simple
Berinyuy, J.E., Tangka, J.K., Fotso, G.M.W., 2012. Enhancing natural convection solar heat exchanger. Appl. Therm. Eng. 94, 13–23. https://doi.org/10.1016/j.
drying of high moisture vegetables with heat storage. Agric. Eng. Int. applthermaleng.2015.10.114.
Böhner, M., Barfuss, I., Heindl, A., Müller, J., 2013. Improving the airflow distribution in Gill, R.S., Singh, S., Singh, P.P., 2014. Design and development of desiccant seed dryer
a multi-belt conveyor dryer for spice plants by modifications based on computational with airflow inversion and recirculation. J. Food Sci. Technol. 51, 3418–3424.
fluid dynamics. Biosyst. Eng. 115, 339–345. https://doi.org/10.1016/j. https://doi.org/10.1007/s13197-012-0865-y.
biosystemseng.2013.03.012. Go, A., Das, S.K., Srzednicki, G., Driscoll, R.H., 2007. Modeling of moisture and
Borel, L.D.M.S., Marques, L.G., Prado, M.M., 2020. Performance evaluation of an infrared temperature changes of wheat during drying in a triangular rpouted bed dryer. Dry.
heating-assisted fluidized bed dryer for processing bee-pollen grains. Chem. Eng. Technol. 25, 575–580. https://doi.org/10.1080/07373930701227060.
Process - Process Intensification 155. https://doi.org/10.1016/j.cep.2020.108044. Gopan, A., Verma, P., Yang, Z., Axelbaum, R.L., 2020. Quantitative analysis of the impact
Bozkurt, Y., Apul, O., 2020. Critical review for microwave pretreatment of waste- of flue gas recirculation on the efficiency of oxy-coal power plants. Int. J. Greenh.
activated sludge prior to anaerobic digestion. Curr. Opin. Environ. Sci. Health. Gas Control 95, 102936. https://doi.org/10.1016/j.ijggc.2019.102936.
https://doi.org/10.1016/j.coesh.2019.10.003. Hanifarianty, S., Legwiriyakul, A., Alimalbari, A., Nuntadusit, C., Theppaya, T., Wae-
Brodie, G., Bootes, N., Dunshea, F., Leury, B., 2019. Microwave processing of animal Hayee, M., 2018. The development of rotary drum dryer for palm fruit sterilization.
feed: a brief review. Trans. ASABE (Am. Soc. Agric. Biol. Eng.) 62, 705–717. https:// IOP Conf. Ser. Mater. Sci. Eng. https://doi.org/10.1088/1757-899X/297/1/012031.
doi.org/10.13031/trans.13266. Hasan Ismaeel, H., Yumrutaş, R., 2020. Investigation of a solar assisted heat pump wheat
Bunyawanichakul, P., Walker, G.J., Sargison, J.E., Doe, P.E., 2007. Modelling and drying system with underground thermal energy storage tank. Sol. Energy 199,
simulation of paddy grain (rice) drying in a simple pneumatic dryer. Biosyst. Eng. 538–551. https://doi.org/10.1016/j.solener.2020.02.022.
96, 335–344. https://doi.org/10.1016/j.biosystemseng.2006.11.004. Havlík, J., Dlouhý, T., Sabatini, M., 2020. The effect of the filling ratio on the operating
Burmester, K., Fehr, H., Eggers, R., 2011. A comprehensive study on thermophysical characteristics of an indirect drum dryer. Acta Polytech. 60, 49–55. https://doi.org/
material properties for an innovative coffee drying process. Dry. Technol. 29, 10.14311/AP.2020.60.0049.
1562–1570. https://doi.org/10.1080/07373937.2011.582595. Hemis, M., Choudhary, R., Gariépy, Y., Raghavan, V., 2015. Experiments and modelling
Cáceres-Huambo, B.N., Menegalli, F.C., 2009. Simulation and optimization of of the microwave assisted convective drying of canola seeds. Biosyst. Eng. 139,
semicontinuous industrial tunnel dryers for fruits. Dry. Technol. 27, 428–436. 121–127. https://doi.org/10.1016/j.biosystemseng.2015.08.010.
https://doi.org/10.1080/07373930802683559. Hemis, M., Watson, D.G., Gariépy, Y., Lyew, D., Raghavan, V., 2019. Modelling study of
Carpaneto, B., Bartosik, R., Cardoso, L., Manetti, P., 2016. Pest control treatments with dielectric properties of seed to improve mathematical modelling for microwave-
phosphine and controlled atmospheres in silo bags with different airtightness assisted hot-air drying. J. Microw. Power Electromagn. Energy 53, 94–114. https://
conditions. J. Stored Prod. Res. 69, 143–151. https://doi.org/10.1016/j. doi.org/10.1080/08327823.2019.1607491.
jspr.2016.07.007. Hu, Z., Yong, X., Li, D., Yang, R.T., 2020. Synergism between palladium and nickel on
Chauhan, P.S., Kumar, A., Nuntadusit, C., Banout, J., 2018. Thermal modeling and Pd-Ni/TiO2 for H2-SCR: a transient DRIFTS study. J. Catal. 381, 204–214. https://
drying kinetics of bitter gourd flakes drying in modified greenhouse dryer. Renew. doi.org/10.1016/j.jcat.2019.11.006.
Energy 118, 799–813. https://doi.org/10.1016/j.renene.2017.11.069. Huang, L., Wang, Xiaomin, Yao, S., Jiang, B., Chen, X., Wang, Xin, 2016. Cu-Mn bimetal
Chen, Z., Zhao, S., Rao, Z., Zhang, R., 2020. Experimental study on low-resistance ion-exchanged SAPO-34 as an active SCR catalyst for removal of NOx from diesel
Venturi water film cyclone with vibrating string grid. Jordan J. Civil Eng. engine exhausts. Catal. Commun. 81, 54–57. https://doi.org/10.1016/j.
Chilka, A.G., Ranade, V.V., 2019. CFD modelling of almond drying in a tray dryer. Can. J. catcom.2016.03.010.
Chem. Eng. 97, 560–572. https://doi.org/10.1002/cjce.23357. Jabłońska, M., Palkovits, R., 2016a. It is no laughing matter: nitrous oxide formation in
Czajkowska, A., 2018. Installations for cleaning exhaust fumes from dust–gas pollutants. diesel engines and advances in its abatement over rhodium-based catalysts. Catal.
Environ. Prot. Nat. Resour. J. Inst. Environ. Prot. Res. Inst. 29, 26–32. https://doi. Sci. Technol. 6, 7671–7687. https://doi.org/10.1039/c6cy01126h.
org/10.2478/oszn-2018-0019. Jabłońska, M., Palkovits, R., 2016b. Nitrogen oxide removal over hydrotalcite-derived
Dai, A., Zhou, X., Liu, X., 2017. A GODFIP control algorithm for an IRC grain dryer. mixed metal oxides. Catal. Sci. Technol. https://doi.org/10.1039/c5cy00646e.
Math. Probl Eng. 2017 https://doi.org/10.1155/2017/1406292. Jafari, A., Zare, D., 2017. Ultrasound-assisted fluidized bed drying of paddy: energy
Devahastin, S., Pitaksuriyarat, S., 2006. Use of latent heat storage to conserve energy consumption and rice quality aspects. Dry. Technol. 35, 893–902. https://doi.org/
during drying and its effect on drying kinetics of a food product. Appl. Therm. Eng. 10.1080/07373937.2016.1230742.
26, 1705–1713. https://doi.org/10.1016/j.applthermaleng.2005.11.007. Jain, D., Tewari, P., 2015. Performance of indirect through pass natural convective solar
Dibagar, N., Amiri Chayjan, R., 2019. Rough rice convective drying enhancement by crop dryer with phase change thermal energy storage. Renew. Energy 80, 244–250.
intervention of airborne ultrasound – a response surface strategy for experimental https://doi.org/10.1016/j.renene.2015.02.012.
design and optimization. Dry. Technol. 37, 1097–1112. https://doi.org/10.1080/ Janosik, M., Liedy, W., 1991. Kontaktbandtrockner – Eine wirtschaftliche Lösung bei
07373937.2018.1485693. häufigem Produktwechsel. Chemie Ingenieur Technik 63, 1135–1137. https://doi.
Dong, W., Cheng, K., Hu, R., Chu, Z., Zhao, J., Long, Y., 2018. Effect of microwave org/10.1002/cite.330631120.
vacuum drying on the drying characteristics, color, microstructure, and antioxidant Jessica, E.E., Felipe, G.M.J., José, P.S.F., Eduardo, O.S.L., Fabián, L.G.H., 2019. Influence
activity of green coffee beans. Molecules 23, 1146. https://doi.org/10.3390/ of the thermal conductivity of air on the moisture homogeneity of a tray dryer. Int. J.
molecules23051146. Heat Technol. 37, 322–326. https://doi.org/10.18280/ijht.370138.
Drault, F., Comminges, C., Can, F., Pirault-Roy, L., Epron, F., Le Valant, A., 2018. Jittanit, W., Srzednicki, G., Driscoll, R.H., 2013. Comparison between fluidized bed and
Palladium, iridium, and rhodium supported catalysts: predictive H2 chemisorption spouted bed drying for seeds. Dry. Technol. 31, 52–56. https://doi.org/10.1080/
by statistical cuboctahedron clusters model. Materials 11, 819. https://doi.org/ 07373937.2012.714827.
10.3390/ma11050819. Jokiniemi, H.T., Ahokas, J.M., 2014a. Drying process optimisation in a mixed-flow batch
El-Sebaii, A.A., Aboul-Enein, S., Ramadan, M.R.I., El-Bialy, E., 2007. Year round grain dryer. Biosyst. Eng. 121, 209–220. https://doi.org/10.1016/j.
performance of double pass solar air heater with packed bed. Energy Convers. biosystemseng.2014.01.002.
Manag. 48, 990–1003. https://doi.org/10.1016/j.enconman.2006.08.010.
11
Jokiniemi, H.T., Ahokas, J.M., 2014b. Drying process optimisation in a mixed-flow batch solar water heater and solar-powered infrared lamp for paddy grains drying. Sol.
grain dryer. Biosyst. Eng. 121, 209–220. https://doi.org/10.1016/j. Energy 190, 167–184. https://doi.org/10.1016/j.solener.2019.08.002.
biosystemseng.2014.01.002. Mikulionok, I.O., 2020. Classification of convective drum dryers (survey of patents).
Jokiniemi, T., Hautala, M., Oksanen, T., Ahokas, J., 2016. Parallel plate heat exchanger Chem. Petrol. Eng. 56, 588–596. https://doi.org/10.1007/s10556-020-00814-8.
for heat energy recovery in a farm grain dryer. Dry. Technol. 34, 547–556. https:// Mohapatra, S.S., Mahanta, P., 2012. Performance evaluation of quality drying in a
doi.org/10.1080/07373937.2015.1061541. natural convection grain dryer. In: Applied Mechanics and Materials. Trans Tech
Joselin Herbert, G.M., Unni Krishnan, A., 2016. Quantifying environmental performance Publications Ltd, pp. 2094–2100. https://doi.org/10.4028/www.scientific.
of biomass energy. Renew. Sustain. Energy Rev. https://doi.org/10.1016/j. net/AMM.110-116.2094.
rser.2015.12.254. Motevali, A., Minaei, S., Khoshtagaza, M.H., 2011. Evaluation of energy consumption in
J, RC Publications Repository. Energy use in the EU food sector: State of play and different drying methods. Energy Convers. Manag. 52, 1192–1199. https://doi.org/
opportunities for improvement [WWW Document], n.d. URL. https://publications. 10.1016/j.enconman.2010.09.014.
jrc.ec.europa.eu/repository/handle/JRC96121. accessed 5.17.21. Muñoz-Neira, M.J., Roa-Ardila, M.F., Correa-Celi, C.R., 2019. Comparative analysis of
Kamfa, I., Fluch, J., Bartali, R., Baker, D., 2020. Solar-thermal driven drying technologies drying coffee beans using microwave and conventional oven. Rev. Fac. Ing. Univ.
for large-scale industrial applications: State of the art, gaps, and opportunities. Int. J. Antioquia 100–108. https://doi.org/10.17533/udea.redin.20191151.
Energy Res. https://doi.org/10.1002/er.5622. Nabavi-Pelesaraei, A., Rafiee, S., Mohtasebi, S.S., Hosseinzadeh-Bandbafha, H., Chau, K.
Kjær, L.S., Poulsen, M., Sørensen, K., Condra, T., 2018. Modelling of hot air chamber wing, 2019. Comprehensive model of energy, environmental impacts and economic
designs of a continuous flow grain dryer. Eng. Sci. Technol. Int. J. 21, 1047–1055. in rice milling factories by coupling adaptive neuro-fuzzy inference system and life
https://doi.org/10.1016/j.jestch.2018.02.002. cycle assessment. J. Clean. Prod. 217, 742–756. https://doi.org/10.1016/j.
Klemeš, J.J., Varbanov, P.S., Pierucci, S., Huisingh, D., 2010. Minimising emissions and jclepro.2019.01.228.
energy wastage by improved industrial processes and integration of renewable Naemsai, T., Jareanjit, J., Thongkaew, K., 2019. Experimental investigation of solar-
energy. J. Clean. Prod. 18, 843–847. https://doi.org/10.1016/j.jclepro.2010.02.028. assisted heat pump dryer with heat recovery for the drying of chili peppers. J. Food
Kliuchnikov, A., 2019. Development of new method of drying at energy-saving universal Process. Eng. 42 https://doi.org/10.1111/jfpe.13193.
dryer to improve quality of crops used in fodder production. Eng. Rural Dev. https:// Nascimento, M., Pena, P.O., Brum, D.M., Imazaki, F.T., Tucci, M.L.S.A., Efraim, P., 2013.
doi.org/10.22616/ERDEV2019.18.N125. Behavior of Salmonella during fermentation, drying and storage of cocoa beans. Int.
Krawczyk, J., Kocewiak, K., Talaga, J., Postnikova, I., 2019. Mechanisms of trapping fine J. Food Microbiol. 167, 363–368. https://doi.org/10.1016/j.
dust in wet dust collecting apparatus. ChemChemTech 62, 97–101. https://doi.org/ ijfoodmicro.2013.10.003.
10.6060/ivkkt.20196209.5926. Naumkin, A., Razva, A., Vasilevsky, M., Arkhipov, V., 2017. The characteristic and
Kumar, D., Kalita, P., 2017. Reducing postharvest losses during storage of grain crops to separation effects in a cylindrical cyclone dust collector. In: MATEC Web of
strengthen food security in developing countries. Foods 6, 1–22. https://doi.org/ Conferences. EDP Sciences, 01071. https://doi.org/10.1051/matecconf/
10.3390/foods6010008. 201711001071.
Kwon, D.W., Park, K.H., Ha, H.P., Hong, S.C., 2019. The role of molybdenum on the Ndukwu, M.C., Bennamoun, L., Abam, F.I., Eke, A.B., Ukoha, D., 2017. Energy and
enhanced performance and SO2 resistance of V/Mo-Ti catalysts for NH3-SCR. Appl. exergy analysis of a solar dryer integrated with sodium sulfate decahydrate and
Surf. Sci. 481, 1167–1177. https://doi.org/10.1016/j.apsusc.2019.03.118. sodium chloride as thermal storage medium. Renew. Energy 113, 1182–1192.
Lingayat, Balijepalli, R., Chandramohan, V.P., 2021. Applications of solar energy based https://doi.org/10.1016/j.renene.2017.06.097.
drying technologies in various industries – A review. Sol. Energy. https://doi.org/ Niksiar, A., Sohrabi, M., Rahimi, A., 2013. A model for the dynamics of spouted bed
10.1016/j.solener.2021.05.058. dryers. Dry. Technol. 31, 295–307. https://doi.org/10.1080/
Liu, J., Zhu, F., Ma, X., 2018. Industrial application of a deep purification technology for 07373937.2012.729768.
flue gas involving phase-transition agglomeration and dehumidification. Nindo, C.I., Tang, J., 2007. Refractance window dehydration technology: a novel contact
Engineering 4, 416–420. https://doi.org/10.1016/j.eng.2018.05.009. drying method. Dry. Technol. 25, 37–48. https://doi.org/10.1080/
Liu, J., Liu, Jian, Zhao, Z., Song, W., Wei, Y., Duan, A., Jiang, G., 2016. Synthesis of a 07373930601152673.
chabazite-supported copper catalyst with full mesopores for selective catalytic Nosrati, M., Zare, D., Singh, C.B., Stroshine, R.L., 2020. New approach in determination
reduction of nitrogen oxides at low temperature. Cuihua Xuebao/Chinese J. Catal. of moisture diffusivity for rough rice components in combined far-infrared drying by
37, 750–759. https://doi.org/10.1016/S1872-2067(15)61072-5. finite element method. Dry. Technol. 38, 1721–1732. https://doi.org/10.1080/
Liu, X., Zhang, Y., Wu, Q., Zhang, M., Liu, F., Guo, Y., 2019. Study on the key structure 07373937.2019.1658203.
parameters of a gravity settling chamber based on a flow field simulation. Eng. Appl. Okeyo, A.A., Olatunde, G., Atungulu, G.G., Sadaka, S., McKay, T., 2017. Infrared drying
Comput. Fluid Mech. 13, 377–395. https://doi.org/10.1080/ characteristics of long-grain hybrid, long-grain pureline, and medium-grain rice
19942060.2019.1595729. cultivars. Cereal Chem. 94, 251–261. https://doi.org/10.1094/CCHEM-07-16-0181-
Liu, Y., Aziz, M., Kansha, Y., Bhattacharya, S., Tsutsumi, A., 2014. Application of the self- R.
heat recuperation technology for energy saving in biomass drying system. Fuel Omofoyewa, M.G., Popoola, L.T., Giwa, A., 2017. Optimization of drying parameters of
Process. Technol. 117, 66–74. https://doi.org/10.1016/j.fuproc.2013.02.007. moringa seeds in a tray dryer using Box-behnken technique of RSM. Int. J. Eng. Res.
Liu, Z., He, F., Ma, L., Peng, S., 2016. Recent advances in catalytic decomposition of N2O Afr. 32, 86–99. https://doi.org/10.4028/www.scientific.net/jera.32.86.
on noble metal and metal oxide catalysts. Catal. Surv. Asia. https://doi.org/ Ononogbo, C., 2020. Equipment sizing and method for the application of exhaust gas
10.1007/s10563-016-9213-y. waste heat to food crops drying using a hot air tray dryer. Indian J. Sci. Technol. 13,
Llavata, B., García-Pérez, J.V., Simal, S., Cárcel, J.A., 2020. Innovative pre-treatments to 502–518. https://doi.org/10.17485/ijst/2020/v13i05/145593.
enhance food drying: a current review. Curr. Opin. Food Sci. https://doi.org/ Opit, G.P., Arthur, F.H., Bonjour, E.L., Jones, C.L., Phillips, T.W., 2011. Efficacy of heat
10.1016/j.cofs.2019.12.001. treatment for disinfestation of concrete grain silos. J. Econ. Entomol. 104,
Luo, D., Xiang, L., Sun, X., Xie, L., Zhou, D., Qin, S., 2020. Phase-change smart lines 1415–1422. https://doi.org/10.1603/EC11104.
based on paraffin-expanded graphite/polypropylene hollow fiber membrane Orosco, J., Patiño, F.J., Quintero, M.J., Rodríguez, L., 2018. Residual biomass
composite phase change materials for heat storage. Energy 197, 117252. https://doi. gasification on a small scale and its thermal utilization for coffee drying. Livest. Res.
org/10.1016/j.energy.2020.117252. Rural Dev. 30.
Łupińska, A., Kozioł, A., Araszkiewicz, M., Łupiński, M., 2009. The changes of quality in Ozgen, S., Cernuschi, S., Caserini, S., 2021. An overview of nitrogen oxides emissions
rapeseeds during microwave drying. Dry. Technol. 27, 857–862. https://doi.org/ from biomass combustion for domestic heat production. Renew. Sustain. Energy Rev.
10.1080/07373930903021717. 135, 110113. https://doi.org/10.1016/j.rser.2020.110113.
Lutfy, O.F., Selamat, H., Mohd Noor, S.B., 2015. Intelligent modeling and control of a Paneliya, S., Khanna, S., Utsav Singh, A.P., Patel, Y.K., Vanpariya, A., Makani, N.H.,
conveyor belt grain dryer using a simplified type 2 neuro-fuzzy controller. Dry. Banerjee, R., Mukhopadhyay, I., 2020. Core shell paraffin/silica nanocomposite: a
Technol. 33, 1210–1222. https://doi.org/10.1080/07373937.2015.1021007. promising phase change material for Thermal Energy Storage. Renew. Energy.
Madhlopa, A., Ngwalo, G., 2007. Solar dryer with thermal storage and biomass-backup https://doi.org/10.1016/j.renene.2020.11.118.
heater. Sol. Energy 81, 449–462. https://doi.org/10.1016/j.solener.2006.08.008. Panwar, N.L., Kaushik, S.C., Kothari, S., 2011. Role of renewable energy sources in
Mançuhan, E., 2009. Analysis and optimization of drying of green bricks in a tunnel environmental protection: a review. Renew. Sustain. Energy Rev. https://doi.org/
dryer. Dry. Technol. 27, 707–713. https://doi.org/10.1080/07373930902827692. 10.1016/j.rser.2010.11.037.
Mannaa, M., Kim, K.D., 2017. Influence of temperature and water activity on deleterious Pasichnyi, V., Ukrainets, A., Shvedyuk, D., Muhamed Al-Hashimi, H., Matsuk, Y., 2017.
fungi and mycotoxin production during grain storage. MYCOBIOLOGY. https://doi. Determination of the optimal sterilization regime of canned quail meat with
org/10.5941/MYCO.2017.45.4.240. hydrocoloids application. Eureka Life Sci 4, 21–25. https://doi.org/10.21303/2504-
Mansor, H., Mohd Noor, S.B., Raja Ahmad, R.K., Taip, F.S., 2011. Design procedure of 5695.2017.00379.
robust QFT-based controller for continuous-flow grain dryer plant. In: Advanced Peter, S., Daniel, P., Christian, W.W., 2018. The design of grain drying oven using
Materials Research. Trans Tech Publications Ltd, pp. 2318–2323. https://doi. residual exhaust gas from diesel engine with heat transfer analysis. In: E3S Web of
org/10.4028/www.scientific.net/AMR.328-330.2318. Conferences. EDP Sciences, 05028. https://doi.org/10.1051/e3sconf/20187305028.
Mathur, K.B., Gishler, P.E., 1955. A technique for contacting gases with coarse solid Precoppe, M., Chapuis, A., Müller, J., Abass, A., 2017. Tunnel dryer and pneumatic dryer
particles. AIChE J. 1, 157–164. https://doi.org/10.1002/aic.690010205. performance evaluation to improve small-scale cassava processing in Tanzania.
Mbuge, D.O., Negrini, R., Nyakundi, L.O., Kuate, S.P., Bandyopadhyay, R., Muiru, W.M., J. Food Process. Eng. 40 https://doi.org/10.1111/jfpe.12274.
Torto, B., Mezzenga, R., 2016. Application of superabsorbent polymers (SAP) as Ramachandran, G., 2019. Particulate controls: dry collectors. In: Air Pollution. CRC
desiccants to dry maize and reduce aflatoxin contamination. J. Food Sci. Technol. Press, pp. 113–129. https://doi.org/10.1201/9781315137056-16.
53, 3157–3165. https://doi.org/10.1007/s13197-016-2289-6. Ratseewo, J., Meeso, N., Siriamornpun, S., 2020. Changes in amino acids and bioactive
Mehran, S., Nikian, M., Ghazi, M., Zareiforoush, H., Bagheri, I., 2019. Experimental compounds of pigmented rice as affected by far-infrared radiation and hot air drying.
investigation and energy analysis of a solar-assisted fluidized-bed dryer including Food Chem. 306, 125644. https://doi.org/10.1016/j.foodchem.2019.125644.
12
Ruggeri, M.P., Nova, I., Tronconi, E., Schmeißer, V., Weibel, M., 2018. Modelling the harvest samples. Can. J. Plant Pathol. 41, 403–414. https://doi.org/10.1080/
hydrothermal ageing of a Fe-zeolite catalyst for automotive NH 3 -SCR applications. 07060661.2019.1592784.
Chemie Ing. Tech. 90, 803–815. https://doi.org/10.1002/cite.201700135. Truong, T., Truong, V., Fukai, S., Bhandari, B., 2019. Changes in physicochemical
Sahin, S., Sumnu, G., Tunaboyu, F., 2013. Usage of solar-assisted spouted bed drier in properties of rice in response to high-temperature fluidized bed drying and
drying of pea. Food Bioprod. Process. 91, 271–278. https://doi.org/10.1016/j. tempering. Dry. Technol. 37, 331–340. https://doi.org/10.1080/
fbp.2012.11.006. 07373937.2018.1452031.
Sakare, P., Prasad, N., Thombare, N., Singh, R., Sharma, S.C., 2020. Infrared drying of Tuncer, A.D., Sözen, A., Khanlari, A., Amini, A., Şirin, C., 2020. Thermal performance
food materials: recent advances. Food Eng. Rev. https://doi.org/10.1007/s12393- analysis of a quadruple-pass solar air collector assisted pilot-scale greenhouse dryer.
020-09237-w. Sol. Energy 203, 304–316. https://doi.org/10.1016/j.solener.2020.04.030.
Salehian, A., Shirneshan, A., 2020. The effect of cordierite-platinum SCR catalyst on the Verma, R., Paliwal, H.K., 2020. Analytical and numerical simulation of plug flow
NOx removal efficiency in an engine fueled with diesel-ethanol-biodiesel blends. fluidised bed dryers inside a paddy grain. Int. J. Ambient Energy. https://doi.org/
Catal. Lett. 150, 2236–2253. https://doi.org/10.1007/s10562-020-03138-7. 10.1080/01430750.2020.1785936.
Samadi, S.H., Ghobadian, B., Najafi, G., Motevali, A., 2014. Potential saving in energy Vician, P., Palacka, M., Holubčík, M., Jandačka, J., 2016. Effect of external temperature
using combined heat and power technology for drying agricultural products (banana on performance of bin dryer. AIP Conf. Proc. https://doi.org/10.1063/1.4953758.
slices). J. Saudi Soc. Agric. Sci. 13, 174–182. https://doi.org/10.1016/j. Viegas, C., Santos, P., Almeida, B., Monteiro, A., Carolino, E., Gomes, A.Q., Viegas, S.,
jssas.2013.09.001. 2019. Electrostatic dust collector: a passive screening method to assess occupational
Satpati, B., Koley, C., Datta, S., 2020. Nonlinear model of pneumatic conveying dryer for exposure to organic dust in primary health care centers. Air Qual. Atmos. Heal. 12,
economic process control. Dry. Technol. 38, 1516–1537. https://doi.org/10.1080/ 573–583. https://doi.org/10.1007/s11869-018-0650-9.
07373937.2019.1648286. Wae-hayee, M., Yeranee, K., Suksuwan, W., Alimalbari, A., Sae-ung, S., Nuntadusit, C.,
Shen, B., Wang, F., Zhao, B., Li, Y., Wang, Y., 2016. The behaviors of V2O5-WO3/TiO2 2020. Heat transfer enhancement in rotary drum dryer by incorporating jet
loaded on ceramic surfaces for NH3-SCR. J. Ind. Eng. Chem. 33, 262–269. https:// impingement to accelerate drying rate. Dry. Technol. https://doi.org/10.1080/
doi.org/10.1016/j.jiec.2015.10.004. 07373937.2020.1742150.
Silva, G.M. da, Ferreira, A.G., Coutinho, R.M., Maia, C.B., 2021. Energy and exergy Walsh, M.J., Gerber Van Doren, L., Shete, N., Prakash, A., Salim, U., 2018. Financial
analysis of the drying of corn grains. Renew. Energy 163, 1942–1950. https://doi. tradeoffs of energy and food uses of algal biomass under stochastic conditions. Appl.
org/10.1016/j.renene.2020.10.116. Energy 210, 591–603. https://doi.org/10.1016/j.apenergy.2017.08.060.
Sinha Majumdar, S., Celik, G., Alexander, A.M., Gawade, P., Ozkan, U.S., 2017. In-situ Wang, Y., Li, M., Qiu, Y., Yu, Q., Luo, X., Li, G., Ma, X., 2019. Performance analysis of a
incorporation of binder during sol-gel preparation of Pd-based sulfated zirconia for secondary heat recovery solar-assisted heat pump drying system for mango. Energy
reduction of nitrogen oxides under lean-burn conditions: effect on activity and wash- Explor. Exploit. 37, 1377–1387. https://doi.org/10.1177/0144598718823937.
coating characteristics. Appl. Catal. B Environ. 202, 134–146. https://doi.org/ Wang, G., Wu, W., Qiao, F., Fu, D., Liu, Z., Han, F., 2020. Research on an electric energy-
10.1016/j.apcatb.2016.08.062. saving grain drying system with internal circulation of the drying medium. J. Food
Sinhmar, N., Singh, P., 2021. Progress and latest developments in hybrid solar drying Process. Eng. 43 https://doi.org/10.1111/jfpe.13476.
with thermal energy storage system. In: Lecture Notes in Mechanical Engineering. Wray, D., Ramaswamy, H.S., 2015. Novel concepts in microwave drying of foods. Dry.
Springer Science and Business Media Deutschland GmbH, pp. 487–498. https://doi. Technol. https://doi.org/10.1080/07373937.2014.985793.
org/10.1007/978-981-15-5463-6_42. Yahya, M., Fudholi, A., Sopian, K., 2017. Energy and exergy analyses of solar-assisted
Smitabhindu, R., Janjai, S., Chankong, V., 2008. Optimization of a solar-assisted drying fluidized bed drying integrated with biomass furnace. Renew. Energy 105, 22–29.
system for drying bananas. Renew. Energy 33, 1523–1531. https://doi.org/ https://doi.org/10.1016/j.renene.2016.12.049.
10.1016/j.renene.2007.09.021. Yang, Z., Li, X., Tao, Z., Luo, N., Yu, F., 2018. Ultrasound-assisted heat pump drying of
Song, J.H., Park, D.C., You, Y.W., Chang, T.S., Heo, I., Kim, D.H., 2020. Lean NO: X pea seed. Dry. Technol. 36, 1958–1969. https://doi.org/10.1080/
reduction by CO at low temperature over bimetallic IrRu/Al2O3 catalysts with 07373937.2018.1430041.
different Ir:Ru ratios. Catal. Sci. Technol. 10, 2120–2136. https://doi.org/10.1039/ Yao, Y., 2016. Enhancement of mass transfer by ultrasound: application to adsorbent
c9cy02289a. regeneration and food drying/dehydration. Ultrason. Sonochem. https://doi.org/
Stejskal, V., Aulicky, R., Kucerova, Z., 2014. Pest control strategies and damage potential 10.1016/j.ultsonch.2016.01.039.
of seed-infesting pests in the Czech stores - a review. Plant Protect. Sci. 50, 165–173. Yilmaz, N., Tuncel, N.B., 2010. An alternative strategy for corn drying (Zea mays)
https://doi.org/10.17221/10/2014-pps. resulted in both energy savings and reduction of fumonisins B1 and B2
Stroem, L.K., Desai, D.K., Hoadley, A.F.A., 2009. Superheated steam drying of Brewer’s contamination. Int. J. Food Sci. Technol. 45, 621–628. https://doi.org/10.1111/
spent grain in a rotary drum. Adv. Powder Technol. 20, 240–244. https://doi.org/ j.1365-2621.2009.02175.x.
10.1016/j.apt.2009.03.009. Yogendrasasidhar, D., Pydi Setty, Y., 2018. Drying kinetics, exergy and energy analyses
Strumiłło, C., Jones, P., Żyła, R., 2014. Energy aspects in drying. In: Mujumdar, A. (Ed.), of Kodo millet grains and Fenugreek seeds using wall heated fluidized bed dryer.
Handbook of Industrial Drying, pp. 1075–1101. https://doi.org/10.1201/b17208- Energy 151, 799–811. https://doi.org/10.1016/j.energy.2018.03.089.
59. Zare, D., Ranjbaran, M., 2012. Simulation and validation of microwave-assisted fluidized
Styszko, K., Samek, L., Szramowiat, K., Korzeniewska, A., Kubisty, K., Rakoczy-Lelek, R., bed drying of soybeans. Dry. Technol. 30, 236–247. https://doi.org/10.1080/
Kistler, M., Giebl, A.K., 2017. Oxidative potential of PM10 and PM2.5 collected at 07373937.2011.630765.
high air pollution site related to chemical composition: krakow case study. Air Qual. Zhang, Z., Li, R., Wang, M., Li, Y., Tong, Y., Yan, P., Zhu, Y., 2020. Two steps synthesis of
Atmos. Heal. 10, 1123–1137. https://doi.org/10.1007/s11869-017-0499-3. CeTiOx oxides nanotube catalyst: enhanced activity, resistance of SO2 and H2O for
Taheri, S., Brodie, G., Gupta, D., 2020. Microwave fluidised bed drying of red lentil low temperature NH3-SCR of NOx. Appl. Catal. B Environ. 119542. https://doi.org/
seeds: drying kinetics and reduction of botrytis grey mold pathogen. Food Bioprod. 10.1016/j.apcatb.2020.119542.
Process. 119, 390–401. https://doi.org/10.1016/j.fbp.2019.11.001. Zhou, Z., Liu, X., Zhao, B., Shao, H., Xu, Y., Xu, M., 2016. Elemental mercury oxidation
Thuwapanichayanan, R., Kumklam, P., Soponronnarit, S., Prachayawarakorn, S., 2020. over manganese-based perovskite-type catalyst at low temperature. Chem. Eng. J.
Mathematical model and energy utilization evaluation of a coaxial impinging stream 288, 701–710. https://doi.org/10.1016/j.cej.2015.12.057.
drying system for parboiled paddy. Dry. Technol. https://doi.org/10.1080/ Zohrabi, S., Aghbashlo, M., Seiiedlou, S.S., Scaar, H., Mellmann, J., 2020a. Energy saving
07373937.2020.1775640. in a convective dryer by using novel real-time exergy-based control schemes
Timm, N., Lang, G.H., Ferreira, C.D., Pohndorf, R.S., de Oliveira, M., 2020. Infrared adjusting exhaust air recirculation. J. Clean. Prod. 257, 120394. https://doi.org/
radiation drying of parboiled rice: influence of temperature and grain bed depth in 10.1016/j.jclepro.2020.120394.
quality aspects. J. Food Process. Eng. 43 https://doi.org/10.1111/jfpe.13375. Zohrabi, S., Seiiedlou, S.S., Aghbashlo, M., Scaar, H., Mellmann, J., 2020b. Enhancing
Tittlemier, S.A., Blagden, R., Chan, J., Gaba, D., Mckendry, T., Pleskach, K., Roscoe, M., the exergetic performance of a pilot-scale convective dryer by exhaust air
2019. Fusarium and Alternaria mycotoxins present in Canadian wheat and durum recirculation. Dry. Technol. 38, 518–533. https://doi.org/10.1080/
07373937.2019.1587617.
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Journal of Cleaner Production 320 (2021) 128706

Contents lists available at ScienceDirect

Journal of Cleaner Production

Improvements in drying technologies - Efficient solutions for cleaner

are emitted into the environment (Kumar and Kalita, 2017).

* Corresponding author. Smoluchowskiego 25, 50-372, Wrocław, Poland.

Fig. 2. Innovations in seed and grain drying.

Fig. 3. Classification of the most popular grain dryers.

Bitter gourd Greenhouse dryer with - - 0.640 45,0–55,0 13 – – Chauhan

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