Thermal
group
of BHEL-Bhopal was formulated in year 1968 (Initial collaboration
with M/s AEI -U.K. took place in year 1970) and started its production
from year 1971 onwards. Subsequently, new collaboration
agreement with M/s BALCKE DURR- Germany for Moisture Separator Re-Heater
(MSR) took place in 1987. MSR to this new design were manufactured
and supplied for 236 MW RAPP 3, 4 & KAIGA 1, 2 and 500 MW TAPP 3&4
Nuclear plants.
BHEL-Bhopal
Thermal group products manufactured and supplied all over India to
different State Electricity Boards and exported to countries like LIBYA,
Malaysia, Azerbaizan, Bangladesh, OMAN etc. major customers of thermal
equipments are State Electricity Boards and NTPC. Similarly Industrial Heat
Exchangers have been supplied to IFFCO, FEDO, RELIANCE, GAIL, ONGC, IOCL,
etc. Production of some of the other products like Rubber Expansion Joints,
Flash Tanks, Miscellaneous storage tanks and Butterfly valves added in
subsequent years.
All
the Thermal products are tailor made and customer specific product. and Customer
requirements are continuously captured through pre-tender and post tender
discussions, contract review etc. Perception is collected through customer
surveys.
Thermal
group products are Technology intensive and therefore Technology
development is of strategic importance. Product technology is continuously
upgraded through in house development projects/ or Technical Collaboration.
Heat Exchanger
Auxiliary
Heat Exchangers
Different
types of auxiliary heat exchangers are being manufactured at BHEL.
Depending upon application these auxiliary Heat Exchangers are named as
. Air Coolers (CACW)
. Oil Coolers (Shell & tube type /
Frame and tube type (Single tube & Concentric double tube construction)
/ OFAF), Plug in type
. Water Water Cooler (Shell & Tube
type)
. Hydrogen Cooler etc. (Frame and tube
type).
. Air Cooler CACA ( Duct and tube type)
These
coolers are accessories to main equipment’s such as Generator, Turbine,
Transformer , Motors, etc. hence special attention is given to make these
coolers compact in design and for trouble free service.
To
ensure long life of these coolers materials for different components is
decided carefully considering its application and water chemistry.
Constructionally these coolers are very easy to maintain.
Technical Information/Application
Air
coolers, Oil coolers, Water-Water coolers and Hydrogen Coolers act as
accessories to Transformers, turbines, Motors and Generators, etc.
In
Generator, Air Coolers are used to cool the generator air which is a closed
circuit air of maintained humidity and which in turn cools winding of
stator. In turbine, oil coolers are used to cool bearing oil or the oil which
in turn cools the rotating parts. Similarly, Transformer Coolers are used
to cool transformer oil by air or water. These coolers play an important
role in smooth functioning of the main equipments. CACW type and CACA
type air coolers are also used for cooling air, which in turn cools motor
windings.
Industrial
Heat Exchangers
Industrial
Heat Exchangers, as the name implies are used in
industries dealing in various types
of chemicals. In general Heat Exchangers used are of shell and tube
type construction. Main components of shell and tube type heat
exchangers are tube nest assembly; shell assembly and types of enclosure
i.e. end closing.
BHEL is manufacturing different types of shell and tube type heat
exchangers for Industries like Refineries ,
Petrochemicals and Fertilizers, etc. Since different
type of chemicals is involved in Industrial
Heat Exchangers, material selection becomes an important criteria.
BHEL is capable of doing special types of mechanical design apart
from normal design of shell, tubes , dished
ends ,flat covers, backing ring and flanges etc.
Special type of mechanical design covers design of eccentric/concentric
types of shell i.e. kettle type construction , reverse flange type design,
fixed tube sheet with bellows, high pressure
enclosures , and double pipe type
heat exchangers.
BHEL is having a vast experience of
manufacturing and supply of Heat Exchangers with
Carbon steel , stainless steel, Alloy Steel and Non-ferrous tubes and shell
materials. In addition to the
type as mentioned earlier , Cladded Exchangers also have
been supplied by BHEL. Various types of constructional features as
described in TUBULAR EXCHANGER MANUFACTURER’S ASSOCIATED (TEMA) Standard can be offered by
BHEL.
Feed
Water Heaters
BHEL is
manufacturing feed water heaters for power stations of Unit Rating up-to
250 MW Thermal Power Project since more than last 25 years. Feed water
heaters (both High pressure and Low pressure) are used in feed heating
system of regeneration cycle by heating feed water by steam extracted from
suitable stages of turbine. Over the years design and technological
developments took place and at present feed heaters with stainless steel
tube materials are being used for longer life expectancy. Both Horizontal
and vertical type of heaters are manufactured with highest standard of
engineering to provide reliability in operation. Feed water heaters are
designed as per HEI standard and high pressure heaters comes under purview
of Indian Boiler Regulations. Hence these are designed and manufactured in
strict compliance to applicable code requirements.
Technical Information/Application
- The
high pressure & Low pressure feed water heaters are employed to
increase the overall efficiency of the regenerative cycle by heating the
feed water by the steam extracted from suitable stages of the turbine.
- The feed water passes through the 'U' tubes and the steam/drain
(condensed steam) passed over the tubes. These heaters are located in feed
water heating cycle and feed water going to boilers is heated with steam
extracted from different stages of turbine resulting in saving of energy
and increased efficiency. Feed heaters play a vital role in power plant.
The heaters are, therefore, subjected to very onerous duty and hence the
design and manufacture of both type of heaters, i.e. High Pressure heaters
and Low pressure feed water heaters complies with the highest standard of
engineering to provide adequate reliability in the operation of these heaters.
Both High pressure & Low pressure feed water heaters come under purview
of Indian Boiler Regulation hence compile with all code requirements.
Moisture Separator Re-heater
(MSR)
In Nuclear Turbines the Moisture separator
re-heater is
a thermo-hydraulic junction where two-phase (steam/ water) flows interact,
while separating the high energy phases and exchanging heat.
The superheated steam contributes a net
electric production gain and promotes extended turbine blade life.
Projectwise Details Of 236 Mw And 500 Mw
Moisture Separator And Re-Heaters Manufactured
And Supplied By Bhel Bhopal (22 No’s).
|
SL.NO. |
PROJECT |
No's |
YEAR OF SUPPLY |
|
1. |
KALPAKKAM-I
(MAPS)
|
02 |
1975 |
|
2. |
KALPAKKAM-II
(MAPS)
|
02 |
1976 |
|
3. |
NARORA
-
I
(NAPS)
|
02 |
1982 |
|
4. |
NARORA
-
II
(NAPS)
|
02 |
1983 |
|
5. |
KAKRAPARA
- I (KAPS)
|
02 |
1991 |
|
6. |
KAKRAPARA
- II (KAPS)
|
02 |
1991 |
|
7. |
RAPP
-
III
(RAPS)
|
01 |
1993 |
|
8. |
RAPP-
IV
(RAPS)
|
02 |
1994 |
|
9. |
KAIGA
-
I
(KGS)
|
02 |
1993 |
|
10. |
KAIGA
-
II
(KGS)
|
02 |
1994 |
|
11. |
TARAPUR-III
(TAPP)
|
01 |
2002 |
|
12 |
TARAPUR-IV
(TAPP)
|
02 |
2003 |
|
|
TOTAL
|
22 |
|
Note :
1. Above s.no 1 to 6 -
236 mw moisture separator and re-heaters were
manufactured and supplied as per the design from
then m/s GEC UK(presently M/S Alstom UK).
2. Above sno 7 to 12 - 236 mw and 500 mw moisture
separator and re-heaters were manufactured and
supplied as per the design of M/s BALCKE DURR Germany.
Moisture
Separator (MS)
The
quantity of water formed due to expansion of steam in the steam Turbine is
considerably high in Nuclear Power plant and particularly in lower rating
plants where steam entering H.P Turbine is of low pressure and temperature.
After
expansion in H.P Turbine steam becomes wet and water content is quite
high in the order of 15% to 20%. Removal of moisture becomes
essential in these Turbines before further processing to increase
efficiency and to avoid corrosion and erosion damages to turbine
components.
To
separate the moisture content of this wet steam ,Moisture separator is
employed. This separator works on the principal of Loss of Kinetic
energy and employs fine separators. Steam enters these carefully
arranged fine separators through coarse separator and dry steam is
separated through steam outlet at top, drain is collected through the
connection at the bottom. Devices such as vortex breaker, level controller
and water level gauges are suitably mounted for smooth operations and
monitoring.
Rubber
Expansion Joints
Rubber
Expansion Joints (REJ) consists of Bare Rubber Bellows and are
employed in cooling water pipe line of Condensers as well as pumps to
absorb differential thermal expansion/movements so that the equipments such
as Condenser , Turbines etc. are not affected by the thermal
expansion.
There
are two types of RE joints for Condenser CW pipe line
applications i.e. Pressure Balance type and Compensating type.
For
cooling water pump applications Ordinary type or Conventional type RE
joints are used.
Miscellaneous
Flash Tanks
Flash
tanks are cylindrical tanks having end enclosures as flat heads or dished
ends and are used in Feed heating cycle to allow drains of different
temperatures and Pressures to "Flash " and mix to form a common
stabilized drain and vent for feeding in Condenser. These individual
drains, if allowed to enter the condenser directly will cause flashing
inside Condenser leading to thermal imbalance which may cause damage to
tubes and their internals.
These
tanks have adequate thickness based on design conditions . The designing of
Flash tanks require utmost care that must be taken into account while
calculating geometry of the tanks and special type of nozzle connections.
These Tanks always remain under high vacuum condition during operation.
Miscellaneous
Storage Tanks
Misc.
Tanks are important part of a TG or Auxiliary plants and may include
different oil tanks such as Dirty oil tanks, Clean oil tank and Oil
unloading vessel, Equipment cooling water tank, DMCW tanks, Condensate
surge tank, Potable water tank, Service water tank etc.
These
tanks are used for storage of different fluids and thus are required in
specific capacity depending on volume of the fluid to be handled.
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