Chapter-1 1.1 Company Profile
Chapter-1 1.1 Company Profile
Chapter-1 1.1 Company Profile
INTRODUCTION
1.1 Company Profile
Wave Industries Pvt Ltd., one of the Major players of Sugar producing groups, has its
Sugar Complex at Dhanaura, UP (W) and expanded its footprint to the surrounding areas by
acquiring sugar plants at Amroha, Bijnor, Chandpur and Bulandshahar. Apart from meeting
the cane potential of the said areas of cane crop Growers, Wave is also producing the Green
Power and exporting it to Grid by evacuating the power at Amroha 132 KV s/s, through its
Cogeneration Power plant facility available at Dhanaura plant. The Power is produced by
burning the Sugarcane Solid Waste called Bagasse in a High Pressure Boiler of latest design
with high energy efficiency and the power is produced through its 30 MW Steam Turbo
Generator of latest technology, imported from Shin Nippon Machinery Company Ltd., Japan
1.2 SUGARCANE
Sugar Cane is a perennial grass in the family Poaceae. It is cultivated in tropical and
sub-tropical regions for the sucrose that is found in its stems. It requires a frost-free climate
with sufficient rainfall during the growing season to make full use of the plant's great growth
potential. The crop is harvested mechanically or by hand, chopped into lengths and conveyed
rapidly to the processing plant. Here it is either milled and the juice extracted with water or
the sugar is extracted by diffusion. The juice is then clarified with lime and heated to kill
enzymes. The resulting thin syrup is concentrated in a series of evaporators after which
further water is removed by evaporation in vacuum containers. The resulting supersaturated
solution is seeded with sugar crystals and the sugar crystallizes out, is separated from the
fluid and dried. Molasses a by-product of the process and the fiber from the stems, known as
bagasse, is burned to provide energy for the sugar extraction process. The crystals of raw
sugar have a sticky brown coating and can either be used as they are or can be bleached by
sulphur di-oxide or treated in a carbonization process to produce a whiter product.
CHAPTER-2
BOILER
A boiler is an enclosed vessel that provides a means for converting
water into steam. The steam under pressure is then used for transferring
the heat to a process. Water is a useful and cheap medium for transferring
heat to a process. When water is boiled its volume increases by about
1600 times, producing a force that is almost as explosive as gunpowder.
This causes the boiler to be extremely dangerous and must be treated
with a lot of care.
tubes to generate steam. Steam bubbles form in the tubes (risers) closest to the burner and
rises to the steam drum where they are separated from the water. The steam in the risers is
replaced by water in the downcomers to provide natural circulation in the water tubes. A
continuous supply of feed water is necessary to replace the steam leaving the boiler. In most
cases, the saturated steam leaving the steam drum is returned to the furnace for superheating.
A forced draft (FD) fan provides combustion air to the windbox from which it is
delivered to the burners. The induced draft (ID) fan draws the flue gases from the furnace and
drives them up the stack. Heat from the flue gas is used to preheat the combustion air to
improve efficiency.
The primary purpose of any boiler control system is to manipulate the firing rate so
that the supply of steam remains in balance with the demand for steam over the full load
range. In addition it is necessary to maintain an adequate supply of feed water and the correct
mixture of air and fuel for safe and economical combustion.
2.4 RANKINE CYCLE
The Rankine cycle is a model that is used to predict the performance
of steam engines. The Rankine cycle is an idealised thermodynamic cycle
of a heat engine that converts heat into mechanical work. The heat is
supplied externally to a closed loop, which usually uses water as the
working fluid. The Rankine cycle, in the form of steam engines, generates
about 90% of all electric power used throughout the world, including
virtually all biomass, coal, solar thermal and nuclear power plants. It is
named after William John Macquorn Rankine, a Scottish polymath and
Glasgow University professor.
2.6 UTILIZATION
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The boiler house or steam generation facility within any given plant is frequently
referred to as the heart. In the event this system shuts down for unexpected reasons or for
plant turnaround, most processes within the plant will not be operable. For this reason, very
conservative treatment measures are used in the boiler. Operating personnel can be reluctant
to change treatment programs if the one currently in use is deemed successful. On the other
hand, if a treatment program is linked to a boiler failure, change usually comes quickly.
dioxide are among the principal causes of corrosion in the boiler and pre-boiler systems. The
deposition of these metallic oxides in the boiler is frequently more troublesome than the
actual damage caused by the corrosion. Deposition is not only harmful in itself, but it offers
an opening for further corrosion mechanisms as well.
Contaminant products in the feed water cycle up and concentrate in the boiler. As a
result, deposition takes place on internal surfaces, particularly in high heat transfer areas,
where it can be least tolerated. Metallic deposits act as insulators, which can cause local
overheating and failure. Deposits can also restrict boiler water circulation. Reduced
circulation can contribute to overheating, film boiling and accelerated deposition.
The best way to start to control pre-boiler corrosion and ultimate deposition in the
boiler is to eliminate the contaminants from the feed water. Consequently, this section deals
principally with the removal of oxygen, the impact of trace amounts of contaminants
remaining in the feed water, and heat exchange impact. Deposition and boiler corrosion are
covered later in this chapter.
Feed water is defined as follows:
oxides (magnetite) are formed under reducing conditions that typically exist in an operating
boiler.
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Here, the down-comer is fitted on the bottom of the drum and riser is fitted on the top of the
drum via a horizontal tube as shown in the figure. 5o to 15 o inclined water tubes are
connected with down-comer and riser tubes in same manner of Babcock-Wilcox boiler.
Safety valve: It is used to relieve pressure and prevent possible explosion of a boiler.
Water level indicators: They show the operator the level of fluid in the boiler, also
known as a sight glass, water gaugeor water column is provided.
Bottom blowdown valves: They provide a means for removing solid particulates
that condense and lie on the bottom of a boiler. As the name implies, this valve is usually
located directly on the bottom of the boiler, and is occasionally opened to use the pressure
in the boiler to push these particulates out.
Flash Tank: High-pressure blowdown enters this vessel where the steam can 'flash'
safely and be used in a low-pressure system or be vented to atmosphere while the
ambient pressure blowdown flows to drain.
Hand holes: They are steel plates installed in openings in "header" to allow for
inspections & installation of tubes and inspection of internal surfaces.
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Steam drum internals, A series of screen, scrubber & cans (cyclone separators).
Low- water cutoff: It is a mechanical means (usually a float switch) that is used to
turn off the burner or shut off fuel to the boiler to prevent it from running once the water
goes below a certain point. If a boiler is "dry-fired" (burned without water in it) it can
cause rupture or catastrophic failure.
Surface blowdown line: It provides a means for removing foam or other lightweight
non-condensible substances that tend to float on top of the water inside the boiler.
Circulating pump: It is designed to circulate water back to the boiler after it has
expelled some of its heat.
Feedwater check valve or clack valve: A non-return stop valve in the feedwater line.
This may be fitted to the side of the boiler, just below the water level, or to the top of the
boiler.
Top feed: In this design for feedwater injection, the water is fed to the top of the
boiler. This can reduce boiler fatigue caused by thermal stress. By spraying the feedwater
over a series of trays the water is quickly heated and this can reduce limescale.
Chemical injection line: A connection to add chemicals for controlling feedwater pH.
Steam accessories
Combustion accessories
Soot blower
Pressure gauges:
Feed pumps:
Fusible plug:
Inspectors test pressure gauge attachment:
Name plate:
Registration plate:
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Zero Liquid Discharge plants, the reverse purpose applies; evaporation removes the desirable
drinking water from the undesired product, salt.
CHAPTER-3
STEAM TURBINE
A steam turbine is a device that extracts thermal energy from pressurized steam and
uses it to do mechanical work on a rotating output shaft. Its modern manifestation was
invented by Sir Charles Parsons in 1884.
3.1 TYPES
Steam turbines are made in a variety of sizes ranging from small <0.75 kW (<1 hp)
units (rare) used as mechanical drives for pumps, compressors and other shaft driven
equipment, to 1 500 000 kW (1.5 GW; 2 000 000 hp) turbines used to generate electricity.
There are several classifications for modern steam turbines.
3.2 BLADE AND STAGE DESIGN
Turbine blades are of two basic types, blades and nozzles. Blades move entirely due
to the impact of steam on them and their profiles do not converge. This results in a steam
velocity drop and essentially no pressure drop as steam moves through the blades. A turbine
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composed of blades alternating with fixed nozzles is called an impulse turbine, Curtis turbine,
Rateau turbine, or Brown-Curtis turbine. Nozzles appear similar to blades, but their profiles
converge near the exit. This results in a steam pressure drop and velocity increase as steam
moves through the nozzles. Nozzles move due to both the impact of steam on them and the
reaction due to the high-velocity steam at the exit. A turbine composed of moving nozzles
alternating with fixed nozzles is called a reaction turbine or Parsons turbine.
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Non-condensing or back pressure turbines are most widely used for process steam
applications. The exhaust pressure is controlled by a regulating valve to suit the needs of the
process steam pressure. These are commonly found at refineries, district heating units, pulp
and paper plants, and desalination facilities where large amounts of low pressure process
steam are needed.
3.4 CASING OR SHAFT ARRANGEMENTS
These arrangements include single casing, tandem compound and cross compound
turbines. Single casing units are the most basic style where a single casing and shaft are
coupled to a generator. Tandem compound are used where two or more casings are directly
coupled together to drive a single generator. A cross compound turbine arrangement features
two or more shafts not in line driving two or more generators that often operate at different
speeds. A cross compound turbine is typically used for many large applications.
3.5 TWO-FLOW ROTORS
The steam enters in the middle of the shaft, and exits at each end, balancing the axial
force.
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an agreement between the purchaser and the manufacturer, and has some significance to the
design of the turbine and associated systems. In the United States, ASME has produced
several performance test codes on steam turbines. These include ASME PTC 6-2004, Steam
Turbines, ASME PTC 6.2-2011, Steam Turbines in Combined Cycles, PTC 6S-1988,
Procedures for Routine Performance Test of Steam Turbines. These ASME performance test
codes have gained international recognition and acceptance for testing steam turbines. The
single most important and differentiating characteristic of ASME performance test codes,
including PTC 6, is that the test uncertainty of the measurement indicates the quality of the
test and is not to be used as a commercial tolerance.
3.12 ADVANTAGES OF STEAM TURBINE INCLUDE:
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CONCLUSION
Steam quality is a measurement of the amount of water entrained in the steam. It
depends not on the efficiency of the boiler but on the ability of the steam to separate from
boiling water, without carrying liquid water particles with it throughout the entire range of
boiler operations. Video camera studies of internal boiler operation indicate the following
operating recommendations for preventing poor quality steam:
Fuel availability affects the type of cogeneration system selected. The nature of the
industry choosing to cogenerate will often determine the fuel type, and thereby the
cogeneration system. Pollution concerns must be considered as well. States are beginning to
heavily regulate industrial emissions. Clean burning fuels, either natural gas or light grade
fuel oils, will often be required in these states. Cogeneration systems which most effectively
utilize these fuels will probably prove to be the most economically attractive.
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REFERENCES
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