The utility of steam is
multifold and can be put to use in a variety of industries for multiple
purposes. Steam is a secondary source of energy since it is produced from water
by combustion of any type of primary source of fuel in a boiler. Steam is produced
out of a single process of energy conversion; it is a cheap source of energy.
Following characteristics of
steam make it an ideal medium for heat
transfer applications:
Efficient and economical to generate
Uniform heating - easy to distribute
Easy to control
Easily transferred to the process by its own pressure
Steam plant easy to maintain
Heat transfer takes place at constant temperature
The applications for steam
are heating processes in plants and steam driven turbines in electric power
plants, used by the massive petrochemical complexes to the local microbrewery;
steam is an integral part of these processes.
Steam is one of the most
versatile utility in the industrial energy arena today. In addition to simple
heating applications, it can also be deployed in various industrial processes
like cleaning, sterilization, drying, concentration, separation and
evaporation.
In culinary applications, it
preserves flavours, textures, and retains nutrients. For processing of
vegetables and food, steam is used for sterilization and drying under vacuum.
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The use of steam in the
industry for the purpose of cleaning does not harm surfaces, motors, bearing
seals, sensors and machinery equipment. Hence the requirement of mask off or
cover equipment prior to cleaning is not there. There is very less chance of
any cross-contamination and thus it helps in faster clean up.
The freshwater, naturally
available from various sources, requires varying degrees of treatment before
being fed to the boiler. Treatment of boiler feed water prevents the formation
of scales and deposits, removes dissolved gases, protects against corrosion,
eliminates water & steam carry-over, optimizes boiler efficiency and
minimizes maintenance costs. Improper or nonexistent feed water treatment is the
major cause of boiler failure.
In biotechnology
applications, steam is produced in various grades of purity. Steam ranges in
purity from boiler grade for routine tasks, to culinary grade “Clean Steam” for
food and dairy, and goes up to super pure, pyrogen-free steam for
biopharmaceutical and intravenous use.
In case of “dry saturated
steam” there is a definite relationship between temperature and pressure of the
steam. This characteristic of steam helps in controlling the processes
precisely.
In the frigid oil & gas
fields, steam is used for heat tracing of tanks and pipelines to keep processes
moving.
Steam is a safe, flexible,
economical, aseptic, and environment-friendly. Steam can be generated through
combustion of fossil fuels, biomass or biogas. In the thermal power stations,
steam is required to be produced in huge quantity for generation of
electricity. The steam has to be produced at very high pressure (>150
kg/cm2) and high temperature (> 5400C), to produce steam in abundance, large
volumes of feed water are supplied to the boiler. Although feed water cycle of
a thermal power plant is a closed loop process, there is always some loss of
water while it moves through the closed cycle. This loss of water has to be
made up by addition of treated water into the feed water tank via de-aerator.
Feed water contains dissolved oxygen, which can cause corrosion in the boiler
tubes. Hence the dissolved oxygen must be removed from the feed water. This
process is carried out in the de-aerator with the help of steam. De-oxygenated
and heated feed water enters the boiler by means of feed water pump, where it
is further treated with chemicals.
Following processes are used
for the treatment of water
before it is fed into the boiler.
1) Clarification - Raw water with sediments may
require a settling tank. Flocculating agents like Alum have to be added to help
settling down of colloidal particles and the suspended matter. Clarified water
is then drawn off from an outlet near the surface.
2) Coarse and Fine Filtration - Suspended solid
impurities which have not settled down during clarification are reduced or
eliminated by passing make-up water through a filter. If the suspended solids
are very fine, a flocculation step may be required.
3) Water Softening - Scaling is formed in the boiler
tubes and steam related equipment because of minerals deposition which is
calcium and magnesium, resulting in costly repairs, increased energy
consumption, and plugged equipment. Softening occurs as minerals causing
hardness attach to the softening resin and “exchange” for sodium.
4) De-mineralization - De-mineralization is typically
an ion exchange process whereby minerals or mineral salts are removed from the
water. The process consists of Anion exchanger, Cation exchanger and mixed bed
units. The resin-beds in the exchanges have to be re-generated, periodically by
passing acid and alkali solutions through the resin-beds.
5) Storage Tank - The treated make-up water is kept
in the storage tank, from where it can be fed into the de-aerator and feed tank
as per requirement of the make-up water.
About Pune Techtrol
Pune Techtrol,a leader in designing and manufacturing the innovative
Process Automation, Level measurement and Control instruments for liquids and
solids. Used by many industries and professionals for more than three decades,
Pune Techtrols’ quality equipment is trusted around the globe.
Contact
Us
Pune Techtrol Pvt.Ltd
S-18, MIDC Bhosari,
Pune - 411026,India
Phone No- 020 66342900
Email Id- ho@punetechtrol.com
Website- http://www.punetechtrol.com
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