Distillation

Abstract The formation of methyl decanoate (MeDC) by esterification reaction of decanoic acid with methanol through batch/continuous reactive distillation columns is operationally challenging, energy intensive and thus cost intensive operation due to complex thermodynamic behaviour of the reaction scheme. Aiming to overcome the equilibrium restriction of the decanoic acid (DeC) esterification operation, to improve the process efficiency and to reduce the total annualised cost (TAC), the semi-batch distillation column (SBD) and the recently proposed integrated semi-batch distillation column configuration (i-SBD) are investigated here. The performances of each of these column operations are evaluated in terms of minimum TAC for a given separation task. In both column configurations, additional operating constraints are considered into the optimization problem to prevent flooding of still pot due to the continuous charging of methanol into it. This study shows the superiority of i-SBD mode of operation over SBD operation in terms of TAC. Also, the optimization results for a defined separation task indicate that the performance of multi-interval control policy is overwhelmingly superior to the single-interval control operation in terms of operating batch time, and overall annual cost in the i-SBD system providing about a time saving of 82.75%, and cost (TAC) saving of 36.61% for a DeC (product) concentration of 0.945 molefraction.

In this work, a new kind of autonomous solar still is proposed. This construction is used in the arid countries with intense solar irradiation and has shortage of potable water. The goal was to concept and to build a physical and mathematical model of solar sea water distiller. The model design and the comparative simulations with the measurement results are carried out offline at the CUTEC Institute GmbH with the arithmetical and technical equipment available there

Investigations on solar-driven membrane distillation (SDMD) were carried out for removal of arsenic from contaminated groundwater. Three different types of hydrophobic membranes made of polytetrafluoroethylene (PTFE) and polypropylene (PP) with surface area of 120×10−4m2 were used as flat sheet in a direct contact membrane distillation (DCMD) set up in a cross flow module. Effects of initial arsenic concentration in the feed, feed velocity, feed temperature and distillate inlet temperature on arsenic removal efficiency and flux were studied where temperatures of feed and distillate were found to have significant effect on the flux. Almost 100% arsenic separation was achieved without wetting membrane pore even after 120h of operation. The PTFE membrane with a flux of 49.80kg/m2h was found to the best one out of the tested membranes. The study shows that solar-driven DCMD can effectively separate arsenic from groundwater using a cross flow membrane module with PTFE hydrophobic membrane.

A 3-D two-fluid CFD model in the Eulerian-Eulerian framework was developed to predict the hydrodynamics and heat and mass transfer of sieve trays. Interaction between the two phases occurs via interphase momentum and heat and mass transfer. The tray geometries are ...

Dal tardo medioevo fino al Seicento, un "viaggio" piuttosto insolito alle origini della "grappa", la tipica acquavite di vinaccia prodotta in Friuli, distillato un tempo ben più noto in lingua friulana con l'accattivante e ormai desueto nome di "petes".

Things That Can Go Wrong in a Methanol Distillation Column

1 Contents 2
2 Introduction 4
2.1 Distillation Systems 5
2.1.1 Two Column System 5
2.1.2 Three Column Distillation System 5
3 Hardware Problems 7
3.1 Vapor Cross Flow Channelling 7
3.2 Low Tray Separation Efficiency 8
3.2.1 Tray weeping 8
3.2.2 Liquid Entrainment 9
3.2.3 Effect of Low of Efficiency 9
3.3 Removal of Topping Column Trays 9
3.4 PH Control 9
3.4.1 Corrosion 10
3.5 Damage to Tanks 11
3.5.1 Tank Bursting Due to Excessive Internal Pressure 11
3.5.2 Tank Collapsing Due to Insufficient Internal Pressure 11
3.5.3 Angle Rings 11
3.5.4 Rippling of the Floor 11
3.5.5 Edge Settlement 12
3.6 Plant Diagnostics 13
3.7 Leaks in Reboilers 14
3.7.1 Leaks in Steam Reboilers 14
4 Byproduct Problems 15
4.1 TMA Removal 15
4.2 MEK Removal 15
4.3 Fusel Oil Disposal 15
5 Other Issues 16
5.1 Permanganate Fading Time 16
5.2 Jet Flooding 16
5.2.1 Asia-Pacific Producer Experience 17
5.3 Weeping 17
5.4 Foaming 18
5.5 Downcomer Flooding 18
6 Troubleshooting 19
7 Conclusions 21

Currently  distillation  is  the  most  commonly  used separation  /  purification  technique  in  many  industrial applications.  Irrespective  of  its  higher  energy consumption  and  limited  separation  efficiency, distillation  remains  the  first  choice  of  process engineer.  Therefore  the  study  of  distillation  column has  unparalleled  importance  in  process  design.  This study  comprises  of  column  internals  like  trays  and packing’s.  The  paper  rigorously  reviewed  the literature published on  current  operational phenomena  and  economic  feasibilities  of  trays  in distillation  columns.  The  operational  features  of  the column  like  pressure  drop,  energy  consumption, liquid  holdup  etc  are  discussed  in  brief.  The assessment  of  column  based  on  the  challenges  in operation  like  weeping,  foaming,  entrainment  etc  is carried  out  individually.  Moreover  the  collective economical  footprint  of  these  problems  on  the operational  performance  of  whole  bioethanol  plant  is discussed  critically.  This  paper  summarizes  the operational  and  economic  analysis  of  state-of-the  art column  trays.  The  matrices  includes  sieve  tray,  valve tray  and  bubble  cap  tray.  In  most  of  the  cases industrial  results  are  unavailable.  Further,  the research  in  this  field  is  too  limited  to  be  of  value  for industrial application.

The basic properties of several palm oil biodiesel–diesel fuel blends were measured according to the corresponding ASTM standards. In order to predict these properties, mixing rules are evaluated as a function of the volume fraction of biodiesel in the blend. Kay’s mixing rule is used for predicting density, heating value, three different points of the distillation curve (T10, T50 and T90), cloud point and calculated cetane index, while an Arrhenius mixing rule is used for viscosity. The absolute average deviations (AAD) obtained were low, demonstrating the suitability of the used mixing rules. It was found that the calculated cetane index of palm oil biodiesel obtained using ASTM D4737 is in better agreement with the reported cetane number than the one corresponding to the ASTM D976. This result is most likely due to the fact that the former standard takes into account the particular characteristics of the distillation curve.

Bacterial populations inhabiting pharmaceutical grade water systems were investigated over a fifteen year period. The systems analyzed were mains water, purified and Water-for-Injection (WFI). Samples of water were tested by membrane filtration and the samples cultured using R2A agar. Culture based methods and phenotypic identification methods were used to characterize the isolates. The research was undertaken to produce an in-depth study of the microbiota of pharmaceutical grade water systems. The results presented act as a benchmark for industrial and pharmaceutical microbiologists to review comparable systems against, as well as to present a review of the typical culturable microorganisms recoverable from pharmaceutical water systems.

This paper presents the modeling and simulation of a distillation column using MATLAB. Simulation studies are often used to examine the operational behavior of distillation columns. A rigorous model for the simulation of the steady-state behavior of the distillation column has been developed. MESH equations, which actually represent the behavior of the distillation column have been solved through MATLAB, in order to study the effect of different parameters. In this paper, the effect of the feed condition and the feed composition on the steady state behavior of a methanol/MTBE/Iso-butylene column have been studied.

Distillation is separating and purifying two liquids that have been mixed together and identifying their respective boiling points by observing the point at which they condense. Simple distillation, used when two liquids have a large difference in boiling point, requires boiling a liquid in a flask and channeling the vapors through a cooling apparatus where the vapors will be converted back into a pure liquid that flows down a collection duct. Simple distillation experimental results indicate that acetone has a boiling point of 56.0°C when distilled comparative to book values of 56.5°C and experimental results indicate water has a boiling point of 98.2°C when distilled comparative to book values of 100.0°C. Fractional distillation is similar to simple distillation but differs in that a fractionating column is used to allow for successive condensations and distillations which produce a better separation between liquids that have a small difference in boiling point (Williamson, 1989). Fractional distillation experimental results indicate that acetone has a boiling point of 55.8°C when distilled comparative to book values of 56.5°C and experimental results indicate water has a boiling point of 98.2°C when distilled comparative to book values of 100.0°C Based on the data it can be inferred that boiling points may be identified using distillation techniques and the resulting products may be collected separately as separate pure substance of the original mixture.

Experimental data and simulations in Aspen Plus ® for the batch distillation process were obtained from an ethanol/water mixture. The simulation was carried out in order to verify the effectiveness of the calculations for the batch distillation process for recovering ethanol, using a plate column. The experimental data were taken from a packed batch distillation column. The separation of ethanol/water mixture was studied at different reflux ratios. The ethanol was quantified through a gas chromatography analyses. The simulation and the experimental data were performed considering the ethanol concentration in the wine that comes from the sugarcane fermentation. It was verified that the higher ethanol concentration was obtained in one hour of distillation and the accumulate ethanol concentration was above to 80% (mole) when operated at constant reflux. So, it is possible to obtain high yields and concentrations of ethanol in a short time.

Distillation Distillation is an important commercial process that is used in the purification of a large variety of materials. However, before we begin a discussion of distillation, it would probably be beneficial to define the terms that describe the process and related properties. Many of these are terms that you are familiar with but the exact definitions may not be known to you. Let us begin by describing the process by which a substance is transformed from the condensed phase to the gas phase. For a liquid, this process is called vaporization and for a solid it is called sublimation. Both processes require heat. This is why even on a hot day at the beach, if there is a strong breeze blowing, it may feel cool or cold after you come out of the water. The wind facilitates the evaporation process and you supply some of the heat that is required. All substances regardless of whether they are liquids or solids are characterized by a vapor pressure. The vapor pressure of a pure substance is the pressure exerted by the substance against the external pressure which is usually atmospheric pressure. Vapor pressure is a measure of the tendency of a condensed substance to escape the condensed phase. The larger the vapor pressure, the greater the tendency to escape. When the vapor pressure of a liquid substance reaches the external pressure, the substance is observed to boil. If the external pressure is atmospheric pressure, the temperature at which a pure substance boils is called the normal boiling point. Solid substances are not characterized by a similar phenomena as boiling. They simply vaporize directly into the atmosphere. Many of you may have noticed that even on a day in which the temperature stays below freezing, the volume of snow and ice will appear to decrease, particularly from dark pavements on the streets. This is a consequence of the process of sublimation. Both vaporization and sublimation are processes that can be used to purify compounds. In order to understand how to take advantage of these processes in purifying organic materials, we first need to learn how pure compounds behave when they are vaporized or sublimed. Let's begin by discussing the vapor pressure of a pure substance and how it varies with temperature. Vapor pressure is an equilibrium property. If we return to that hot windy day at the beach and consider the relative humidity in the air, the cooling effect of the wind would be most effective if the relative humidity was low. If the air contained a great deal of water vapor, its cooling effect would be greatly diminished and if the relative humidity was 100%, there would be no cooling effect. Everyone in St. Louis has experienced how long it takes to dry off on a hot humid day. At equilibrium, the process of vaporization is compensated by an equal amount of condensation. Incidentally, if vaporization is an endothermic process (i.e. heat is absorbed), condensation must be an exothermic process (i.e. heat is liberated). Now consider how vapor pressure varies with temperature. Figure 1 illustrates that vapor pressure is a very sensitive function of temperature. It does not increase linearly but in fact increases exponentially with temperature. A useful "rule of thumb" is that the vapor pressure of a substance roughly doubles for every increase in 10 °C. If we follow the temperature dependence of vapor pressure for a substance like water left