View
224
Download
2
Category
Preview:
Citation preview
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
1/52
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
2/52
INTRODUCTION OF NFL
National Fertilizer Limited was established in 23th August 1974, to set up
two fuel oil based plants at Bhatinda(Punjab) and Panipat (Haryana). Both of
them were commissioned in 1979. The Nangal fertilizer plant of fertilizer
corpoartion ofIndia (FCI) has been merged with NFL in 1978 on the
recoganition of FCI and NFL group of companies. Later NFL executed its gas
based plant at Vijaipur(MP) on HBJ gaspipe line.Vijaipur plant had gone in
commercial production in july,1988. NFL is now operating three fuel oil based
plants located at Panipat, Bhatinda, Nangal and gas based plant at
Vijaipur.
NFL prod uce s two popular brands of chemical fertilizer i.e. Kisan Khad (Calcium
A mmonium Nitrate-CAN) and Kisan Urea. Besides the fertilizers it manufacturesand mar ets the industrial products(Liquid Oxygen, Liquid Nitrogen, Nitric
Acid, Methanol, Argon) and byproducts (Sulphur). NFL had signed a mamorandum
of Understanding with the governmet of India in 1991 -92 all the years,
after signing the MOU , government has rated the performance of the
company as Excellent. Comapany has been performing at high level of capacity
utilization over the years.
FERTILIZER, INDUSTRIAL PRODUCTS AND SERVICES
Kisan Urea and Kisan Khad :- NFLs popular brands are sold over a large
marketing territory spanning the length and breadth of the company. The
company also manufactures and markets Biofertilizers and a wide range of
industrial products like Methanol, Nitric Acid, Sulphur, Liquid Oxygen etc.
Kisan
Urea
Kisan Urea is a highly concentrated solid nitrogenuous fertilizer, containing
46.0%. It is completely soluble in water hence nitrogen is easily available
to crops. It contains Nitrogen in amide form which changes to ammonical
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
3/52
forms and is retrieved by soil collides for longer duration. Urea is avilable
in Granular form and can be applied by drill and broadcasting. Kisan Urea is
ideally suited for all types of crops and for foliar spray, which instantly
removes nitrogen deficiency. Kisan Urea also has a strong and long lasting
effect on crop resulting in bumper crops.
NATIONAL FERTILIZER LIMITED
INTRODUCTION OF PANIPAT UNIT
The panipat unit if NFL is situated on National Highway no 1 and Delhi-
Amritsar railway trunroute. Panipat city is about 90 Km from Delhi and is
covered in National Capital Region. Panipat is a historical city , which was
the scene of historical battles.
Government of India passed a project on 10/2/1975 and contruction was
started fr om 30/4/75. The project was completed on 2/9/78 i.e in 40
months. TOYO Engineering Corporation, Japan and Engineers India Limited was
the main con tractors. Total expense on the project was of 221.33 crores of
which 56.45 crores was in t he form of forgien investment. Urea production
was started from 1/9/79. Till now NFL has produced 85 La h Metric Tons KisanUrea.
Performance of the unit in all the areas of its performance has also been
acknowledged. It has won number of awards and recoginition in the field of
production, safety, innovation, environment protection, s ill etc. The unit
is well known for its commitment towards environment protection and social
welfare in the region.
The brand name of Urea produced is KISAN UREA
Plant capacity of NFL Panipat is of 5,11,500 tons Kisan Urea (46.5% N) PA.
Capacity of Ammonia plant is 900 metric tons per day.
Capacity of Urea plant is 1650 metric tons per day.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
4/52
RAW MATERIAL REQUIRED
For the production of 900 Metrictons/day of Ammonia and 1650 Metrictons/day
of Urea following raw materials are required.
FUEL OIL : 910 metrictons/day
COAL : 1650 metrictons/day
WATER : 17 metrictons/day
ELECTRICITY : 26 MWH
Feed stock (Fuel oil ) is obtained from the refineries like IOCL Panipat and
IOC L Mathura
VARIOUS SECTIONS OF PANIPAT UNIT ARE
AMMONIA PLANT
UREA PLANTARGON RECOVERY PLANT
SULPHUR RECOVERY PLANT
DM PLANT
EFFULENT PURIFIER PLANT
CAPTIVE POWER PLANT
The plant is equipped with latest Mechanical and Electrical control system inwh ich microprocessors are used.
AMMONIA PLANT
The Amonia plant is based on fuel oil as feed stoc and is designed to
produce 900 MT/ DAY of ammonia. The Fuel Oil are low sulphur heavy sto e (LSHS)
is partially oxidized in the Gasification Reactors at 1350 0C by shell
gasification process. The raw gas produce in the reactors mainly consist of
H2, CO , CO2, and H2S. The heat generated in the process is recovered in the
waste heat boilers to produce high pressure steam at 100 Kg/Cm2. About 80 %
of the carbon produced in the Gasification Reactors is recycled along with
the feedstock.Hydrogen Sulphide (H2S) in the raw gas is removed by the
absorption in cold Methanol in Desulphurisation Section of Rectisol. The
Carbon Monooxide in the desulphurised gas is converted to carbon dioxide by
double stage CO - shift conversion. The CO2 is later removed from the
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
5/52
process gas in Decarbonation section of the rectisol. H2S and CO2 from the raw
gas are removed by low temp methanol in the rectisol and both gases are
recovered by the regeneration of methanol at low pressure. H2S in the form
of clause gas is sent to Sulphur Recovery plant for the recovery of sulphur.
The CO2 gas is sent to the Urea plant for synthesizing with ammonia to
manufacture Urea. An absorption refrigeration unit provides refrigera
tion in the rectisol section.
The process gas from the rectisol section is sent to the nitrogen wash
unit to
remove the traces of impurities by liquid nitrogen wash. Nitrogen is
further a
dded to the process gas to obtain a ratio of 3:1 of N2 and H2. This synthesis
ga
s mixture is compressed to 230 Kg/Cm2 pressure and synthesis of N2 and H2 is
car
ried out in the Haldor Topsoe Loop in a radial flow Ammonia Convertor and
Ammo
nia is produced. Oxygen requirement and Nitrogen requirement is met by an
air se
paration unit. In ASU the atmospheric air is compressed in HP and LP
distilation
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
6/52
columns at cryogenic
temperatures. SULPHUR RECOVERY PLANT
Sulphur is present in the fuel oil used as feedstoc for the manufactureof
ammo nia. Clause gas rich in hydrogen sulphide is obtained in the rectisol
section of the Ammonia plant. Clause gas is sent to sulphur recovery plant
and is burnt an
d partialy oxidised to SO2 in Acid Gas Heat Exchanger. It is followed by
reactio n between H2S and SO2 to form elemental sulphur. After separating
sulphur by con densing the residual H2S reacts with SO2 to form more sulphur
in two catalytic r eactors in series. The unconverted waste gas is burnt in
the incinerator and hea t is removed in heat recovery exchanger, where low
pressure steam is produced. T he sulphur recovery plant serves the double
purpose i.e. to recover costly sulph ur and to prevent pollution.
UREA PLANT
Urea plant is designed to produce 1650 TPD based Mitsui Toatsu Total Recycle C
Imp roved process. The Ammonia and Carbondioxide produced in Ammonia plant are
press urised to about 250 Kg/Cm2. Synthesis ta es place in the Urea reactor,
where Amm
onia and CO2 reacts at 250 Kg/Cm2 pressure and 200 0C temperature to
produce Ure a. The reactor outlet products are then decomposed . The urea
solution produced in this process is crystallised in vacumn crystallizer.
Crystal slurry is centri fugated to separate crystals, which are then dried
in the dryer and pneumaticall y conveyed to the top of Prilling Tower. Urea
crystals are melted in the Melter and the molten urea is sprayed through
Acoustic Granulators from 68 meter high p rilling tower.Urea in the form of
prills is collected at the bottom of the towe r on CFD bed, where it is
cooled by air. Product Urea is then sent to bagging pl ant and bagged in 50
Kg bags.
CAPTIVE POWER PLANT
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
7/52
Due to improper supply from northern grid the plant was facing the shortage
of e lectricity, resulting in the loss of production. To overcome this
problem a Capt ive Power plant was made.
The capacity of each boiler of power plant is 210 tons/hr. Each generator
has pr oduction capacity of 15 MWH. Stable electricity supply has resulted in
increased production. The plant is now self dependent in this field.
SALIENT FEATURES OF THE PLANT
ANNUAL CAPACITY
511500 MT IN TERMS OF UREA
235290MT IN TERMS OF AMMONIA
ANNUAL REQUIREMENT OF RAW MATERIAL FUEL
OIL/LSHS : 3,00,000 MT
COAL : 5,45,000 MT
POWER : 2,18,000 MWH
WATER : 5,630 MILLION GALLONS
ESTIMATED COST Rs 182.88 CRORES
FOREIGN EXCHANGE Rs 56.45 CRORES
LAND 442 ACRES-PLANT
131 ACRES - TOWNSHIP
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
8/52
PLANTS AND THEIR CAPACITIES
PLANT CAPACITY
AMMONIA PLANT 900 MT per day
UREA PLANT 1550 MT per day
SULPHUR RECOVERY PLANT 26.5 MT per day
STEAM GENERATION PLANT 3 x 150 MT per hour
CAPTIVE POWER PLANT 2 x 15 MWH
COAL HANDLING PLANT 150 & 250 MT per hour
BAGGING PLANT 4000 MT per hour
EFFLUENT TREATMENT PLANT 200 cubic meter per hour
RAW WATER PLANT 2400 cubic meter per hour
PLANT LAYOUT:-
AMMONIA PLANT
PROCESS DESCRIPTION: -
The plant has a production capacity of 900 metric Tons per stream day
of liquid ammonia by one train based on the SHELL Gasification Process for
gasific ation of heavy oil and carbon recovery, LURGI-Rectisol Process for
desulphurizat ion and carbon dioxide removal and Ammonia synthesis process
starting with heavy oil feedstoc and consists of the following section.
1. Air separation section
2. Shell gasification and carbon recovery section
3. Desulphurization section (Rectisol process)
4. Shift conversionsection
5. CO2 removal section (Rectisol process)
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
9/52
6. Nitrogen washing section
7. Ammonia synthesis section including refrigeration section
Air Separation Unit: -
There are theoretically three methods of obtaining oxygen
-Electrical : Water electrolysis
-Mechanical : Air centrifugation
-Chemical : Solubility in various liquids separation by passing through
p
orous
Materials.
But the only one which up to now is used on an industrial
scale i s the one consisting in extracting oxygen from air by low-pressure
distillation column.
This section explains the various parts of the plant, which
shall be described in the following section.
Air composition:-
Air is generally a mixture of 2 gases: Oxygen and Nitrogen in the
follo
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
10/52
wing proportions in the volume:
-1/5th Oxygen (O2), exactly 20.93%
-4/5th Nitrogen (N2), exactly 78.03%
It also comprises various other components which are present in
constant
proportions such as the 5 rare gases:
Argon (Ar) 0.93%
Neon Ne 1/60 000 0.0015%Helium (He) 1/200,000 about 0.0005%
Krypton (Kr) 1/1,000,000 about 0.0001%
Xenon (Xe) 1/11,000,000 about 0.000008%
And in variable quantities:
Water vapors (H2O)
Carbon dioxide (CO2: about 0.03%)
Hydrocarbons, acetylene (C2H2)
Ozone (O3).
Lastly traces of hydrogen and of oil if the air has been handled by lubricated
m
achines.
Air separation unit is provided for getting oxygen gas and nitrogen
gas from air. Produced oxygen gas is led to the reactors in SHELL Gasification
proc ess where it contributes to Partial oxidation of feed oil. On the other
hand nit rogen gas after being liquefied is mainly sent to Nitrogen Washing
Unit to purif y synthesis gas. Some of the nitrogen gas is also used as
utility, e.g. as compr essor sealing gas. Air chiller further cools the feed
air first cooled by precoo ler, which is an evaporator of refrigeration unit
in this Air Separation Unit. T hen the air passes throughair dryers filled
with molecular sieves and alumina g el for drying by adsorbent down to
extremely low dew point and also for complete
removal of CO2. The absorbersare alternately used two at a time with the
other going through a desorption process for regeneration by the dry waste
gas extract ed from the unit. After removal of water and CO2 by the
absorbers, the air is fe
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
11/52
d into cold box.
The cold air is liquefied in the liquefiers by heat exchange with
the
waste N2, O2 and pure N2 streams from the rectifying columns, and then is led
to
the lower rectifying column. The air for the expansion turbine is extracted
fro
m air heat exchanger and combined with cold air from lower rectifying column.
Before combined with the air from air heat exchanger the air from recti
fying column is warmed by heat exchanger with pure nitrogen gas from the N2
Wash
ing Unit. Because the turbine can be operated at rather higher temp. The
expansi
on turbines wor effectively and provide necessary refrigeration for the
unit.
The exhaust air from the expansion turbine is led to the middle part
of
upper rectifying column. The rectifying column comprises a lower column wor ing
at about 6 g/cm2G and upper column wor ing at about 0.8 g/cm2G and a main
cond
enser. Air from the air heat exchanger first enters the bottom of lower
rectifyi
ng column and reaches the main condenser after rising up through the lower
colum
n.
At the lower column, air is preliminarily separated to the N2 and O2
rich
liquid air. At the main condenser, N2 is liquefied by heat exchanger with theli
quid O2. As a result, liquid air of about 40% O2 purity is obtained at the top
a
nd middle of the lower column.
The liquefied air and N2, thus obtained by preliminary separation in the
lo
wer column, are sent respectively at the liquid state to the upper column.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
12/52
The liquefied air withdrawn from the bottom of lower column passes
through o
ne of the two alternately operating hydrocarbon absorber and liquid air
filters
to remove any possible contamination of hydrocarbon. It is then super cooled
aga
inst waist N2 from the upper column in the liquid air super cooler before
being
expanded top the pressure of the upper column through the expansion valve
which
automatically controls the liquid level at the bottom of lower column and fed
to
the upper column.
Liquid N2 withdrawn form the middle of the lower column is fed to the
upper
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
13/52
column through the expansion valve. Liquid N2 withdrawn from the top of
lower c olumn is super cooled in the N2 super cooler and fed to the upper
column through the expansion valve.
These liquid air and liquid N2 that are fed to the upper column are
rectifi ed further by repeated rectifying operation. Finally, liquefied O2 of
a specifie d purity us obtained in the main condenser.
A part of the liquid O2 continuously circulated by liquid O2 pump inorder to remove remaining hydrocarbons in circulating absorbers. The waste
N2 was is w ithdrawn from the middle part of upper column and warmed in the
liquid air super cooler and air heat exchanger then extracted from cold box.
SHELL GASIFICATION AND CARBON RECOVERY PROCESS: -
The raw synthesis gas is produced by gasification of the heavy oil with
O2 and steam in three parallel oil gasification reactors, using the shell
parti
al oxidation
process.
Desulfhurization
process:
This process is done to remove the sulphur compounds, as they are
har mful in next processes. Therefore we remove sulphur which is in the form
of H2S and COS from the raw gas which are purified by LURGI-RECTISOL physical
absorptio n process which is carried out at low temperature and high
pressure in the prese nce of an organic polar solvent, methanol. The raw gas
from the shell gasificati on process enters desulfurisation section of
Rectisol process at about 48 g/cm2
G and at
45C.
After cooling to about -22C in H2S absorber feed/effluent heat exchanger A-
EA201A
, B and H2S absorber feed NH3, chiller A-EA202 with cold gas and evaporating
NH3
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
14/52
, the gas charged to H2S absorber A-DA201 where H2Sand COS are reduced to 0.4
pp
m by being washed with methanol. The desulfurised gas after being heated in
H2S
absorber feed/effluent heat exchanger A-EA201A,B is sent to shift
conversion.
The lean methanol solvent for desulfurisation is ta en from the N2 stripping
fro
m CO2 regeneration A-
DA402.
From the bottom of the upper part of H2S absorber the fat methanol solvent
passe s to H2S flash column A-DA202 where it is flashed in two pressure
stages.
A split flow of regenerated methanol from the vacuum stage of CO2 regenerator
A- DA402 is charged to the top of H2S flash column by low-pressure methanol
pumps a nd to free the off gas to the incinerator at the sulfur recovery
unit up to 1000 ppm H2S, so that the methanol will be enriched with H2S.
Then the methanol solvent is supplied to H2S hot regenerator after being
warmed up in lean/semi lean methanol heat exchanger. After complete
regeneration the le an solvent is pumped through lean/semi lean methanolHeat exchanger, lean methanol NH3 chiller and lean methanol heat exchanger
where it is cooled down and is fed bac to the top of CO2 absorber A-DA401
for CO2 fi ne wash.
The flash gas of the first let down stage of H2S flash column and CO2
regenerato r are combined and recompressed by recycle gas compressor into
the raw gas. On t he other hand H2S rich gas is withdrawn from hot
regenerator reflux drum and sen t to the sulfur recovery plant to recoverthe sulfur as element.
CO-SHIFT CONVERSION PROCESS: -
In the shift conversion section, CO off desulfurisation process
ga s reacts with stem to produce H2 and CO2. the shift reaction ta es place
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
15/52
under t he proper tem. And pressure conditions in the presence of suitable
catalysts, ac cording to the following equation.
CO + H2O H2 +CO2
Excess stem is to be introduced to prevent the carbon formation and also
to a
chieve higher reaction efficiency to the right hand side of the above
equation b
ut there is a certain limit of
the
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
16/52
range in the quantity of the excess steam, as the time of contact between
gases and catalyst is reduced if too much excess steam exist.
This reaction is reversible. Equilibrium towards H2 production is favored by
lo w temperature, while reaction rate is favoredby high temperature. The
actual sh ift reaction ta es place at 350 to 500C in the presence of iron
chromium catalyst
.
In actual processing, the desulfurisation process gas from the
desulfurisatio
n section enters the Humidifier A-DA301, where it contacts hot water by counter
flow and is saturated with steam at 210C, the gas is heatedup by No.1 and No.
2
shift converter feed gas heaters A-EA301 and A-EA302A,B.
Then in order to achieve proper steam to dry gas ratio superheated steam
and
process condensate are injected into this gas before being introduced to the
shi
ft converter A-DC301.
The shift reaction proceeds in two stages of the shift converter at the
outle
t of the first stage CO content in the gas is reduced to 12 to 13%.
Hot gas from the outlet of the first stage is sent to No.2 shift
converter fe
ed gas heater to be cooled till 360C, which is suitable for second stage
reaction
.
The second stage inlet temperature is controlled by the heat exchanger
bypas s and/or process condensate quench.
In the second stage, the shift reaction is further promoted until the CO
cont ent in the gas is decreased up to3.5 volume%.
The outlet gas from the shift converter enters No.1 shift converter feed
gas heater whereit
heats up shift converter feed gas, and is fed to the
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
17/52
humidifier feed water heater A-EA303 and then to the dehumidifier A-DA302
where it is coole d down to about 186C after contact with water by counter
flow.
The outlet gas from the dehumidifier is sent to the absorption
refrigeration until to be utilized as a heating source of the NH3 desorber.
Further more, thi
s gas is used to generate the 3 g/cm2 G steam in the low-pressure boiler and
the n heat up boiler feed water in the shift converter effluent economizer
A-EA306 a nd finally is cooledby cooling water in the shift converter
effluent cooler. The converted gas, after being cooled to ambient
temperature is send to the Decarbonationprocess.
CO2 Removal Process: -
The CO2 of CO shift effluent gas is purified by LURGI-RECTISOL phy
sical absorption process, which is carried by the same methanol solution as
desu lfurisation process but at rather lower temperature. The gas from shift
conversi
on enters the CO2 removal section at about 45C. after cooling to app. -25C in
CO2 absorber feed ammonia chiller A-EA 402 with purified gas from N2 washing
unit, C
O2 gas and evaporating ammonia, the gas is charged to CO2 absorber where
CO2 is reduced to 10 ppm by absorption in the methanol at low temperature.
The lean methanol regenerated at H2S hot regenerator is fed to the top
of CO2 absorber for fine absorption at low temperature and the methanol
partly rege
nerated in the N2 stripping section of CO2 regenerator is charged to the
middle of CO2 absorber. In the lower part of CO2 absorber the heat of
absorption is ta en away in CO2 absorber circulation chiller.
The loaded methanol from the bottom of CO2 absorber is flashed in two
pressu re stages and finally stripped with pure N2 in CO2 regenerator.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
18/52
In the first bottom flashed stage of CO2 regenerator, the CO absorbed
noble hydrogen gas flashes and after washed by a small load of lean methanol
from N2 s tripping section to absorb the CO2 content of the expanded gas,
returns to the c rowd gas by recycle gas compressor together with the flash
gas from H2S flash co lumn.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
19/52
Approximate 25800 Nm3/hr of CO2 gas is sent to urea plant and the CO2 removal
se ction shall be capable of producing 10% additional CO2 over and above that
requi re for production of 1550 MT/ day urea. The quality of this additional
CO2 gas s hould be same as required for the production of Urea.
The low temperature in the Rectisol plant is maintained by the no. of
ammoni a chillers, the required ammonia absorption refrigeration unit is
operatedon th e waist heat of CO shifted gas.
To eliminate icing of the water vapor in the raw gas below 00Cat the
cooling down stage will the absorption temperature, a little methanol
injected into the respective gas streams. The
Nitrogen washing
unit
The CO contained about 5.2% in the CO2 absorption effluent raw gas,
is washed by liquid N2 at N2 washing unit. And also the N2 required for NH3
synthes is is mixed here.
The raw gas from the CO2 removal section first enters molecular sieves
adsorb er unit, where residual CO2, CH3OH are removed to prevent plugging in
the proces s.
Principle: -
Raw synthesis gas coming from Rectisol decarbonation section at 39.5
gs/cm2 and 55 C contains following impurities.
CO 5.21 vol.%
Ar 0.38 vol.%
CH4 0.50 vol.%
CO2 10 ppm
CH3OH 100 ppm
NOX 0.02 ppm
Purification of raw SYN gas is done in following steps: -
1. Purification by adsorption on molecular sieves- CO2, CH3OH and active
ca
rbon (NO, NO2).
2. Cooling down by countercurrent heat exchange with product gas coming
out
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
20/52
of N.W.U and there by condensing some of the impurities (CO, H2S and COS) at
1900C.
3. Purification by washing with liquid N2 in a distillation
column.
In the cold box the raw gas goes in first and second raw gas heat
exchanger
and made of aluminum plates. The raw gas has a temperature of about 190C at
the ou
tlet of the second raw gas heat exchanger and is fed to the N2 washing
column.
In the N2 washing column, impurities such as CO, Ar, CH4 are liquefied and
t
a en out as tail gas, since feed gas is washed by super cooled liquid N which
sp
ray from the top of column. The purified gas, which is mixture of H2 and N2,
can
be obtained from the top of the N2 washing column and gives it coldness to
the
raw gas and N2 gas while passing heat
exchanger.Before leaving the unit, purified gas is added to N2 to ma e the
proportion o
f H2 and N2 ratio 3:1 and fed to NH3 synthesis
section.
In this process, the purified gas is also used to compensate the frigory
of t
he Rectisol section. The residual condensate liquid in the N2 washing columnflo
ws into second and first tail gas heat exchanger and be sent out as tail
gas to
the steam super heater for fuel through HCN stripper. Waist gas blower and
waste
gasholder are provided in tan yard, for buffering.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
21/52
The liquid N2 which had been liquefied and super cooled during the heat
excha
nging in the first and second tail gas heat exchangers meet the liquid N2 for
co
ld compensation coming from the air separation unit and both are supplied,
as wa
shing liquid to the top of N2 washing column. The pressurized N2 gas by the
N2 c
ompressor is sent to the tail gas heat exchanger and also used for
adjusting the
mixing ratio. A part of N2 passing through the first tail gas heat
exchanger is
cooled to saturated gas temperature as low as app. 137C and sent to the air
separ
ation
unit.
The N2 gas is liquefied through N2 liquefier, the tubes mounted in the
main c
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
22/52
ondenser and N2 super cooler of the air separation unit and returns to N2
washin g unit as a state of super cooled liquid N2 with a temperature of -
190C.
To reactivate the molecular sieves in adsorber the N2 gas is introduced
from air separation unit. Reactivation heater heats up one part of
introduced N2. For adsorber regeneration and other part are cooled by
reactivation cooler for abso rber cooling.The N2 washing unit is based on the following design condition.
1). Raw gas: -
Quantity design
Normal pressure 40.5 +- 2.0 g/cm2 A
Temperature -55C
Composition
H2 93.62 vol.%
N2 0.29 vol.%
CO 5.21 vol.%
Ar 0.38 vol.%
CH4 0.50 vol.%
CO2 10 ppm
CH3OH 100 ppm
NOX 0.02 ppm
2). Product gas: -
Design Quantity
Normal pressure 99186 Nm3/hr
Temperature 33C
Composition
H2 75 vol.%
N2 25 vol.%Ar 50 m
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
23/52
O2 2 mCO 5 mCH4 1 ppm
Nitric oxide in the raw gas forms gums and deposits at feed gas side
of N2 washing column inlet heat exchanger. The accumulated gums cause heavy
explosi on at the following stage for plant shut down even under N2
atmosphere.
The NOX gum accumulation is limited up to 0.02 ppm of 1 year, and the process
sh all be subject to the acetone cleaning if the counted accumulation
exceeds this limit. The NOX content shall never exceed 0.2 ppm even on pea
and also not exce ed the 0.02-ppm over than total 1 month per year. If the
NOX content exceeded th e above value, the plant shall be shutdown.
Ammonia synthesis process: -
SYNTHESIS CATALYST OPERATION & ECONOMICS
1. Chemistry and Brief description of plant
Le ChateliersPrinciple - The principle states that if any of the RXN
parameter (T, P and Conc.) were changed in RXN equilibrium, then the RXN will
proceed in t hat direction, where the change in the parameter is
counteracted.
This principle can be used to discuss the Amm. Synth.RXN
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
24/52
N2 (g) + 3 H2 (g) = 2 NH3 (g) H =750 .Cal/ g.
This RXN is exothermic and moles of product are less than the sum of moles of
Re
actants. Then according to the above
principle: -
a) Increase of temp will shift the RXN in the reverse direction which isen dothermic i.e. heat is absorbed.
b) Decrease of temp. will shift the RXN in forward RXN and so that conc.
of ammonia will increase at the cost of decrease of conc. of N2 and H2.
c) Increase of Pr. will shift the RXN in the forward direction when the
No moles in product are less than that of Reactants. Hence this will
increase the conc. of Ammonia. And decrease the conc. of H2 & N2.
d) Increase of conc. of N2 and H2 will ma e the RXN to ta e place in the
fo rward direction where the added material is consumed.
e) Removal of ammonia formed after condensation with water cooler and
ammon ia chiller as early as possible increase the RXN. If products formed
are not re moved, then the RXN will not ta e place.
The syn gas from N2 washing unit is compressed from 37 g/cm2 G to 231
g/cm
2G in the centrifugal type synthesis gas compressor. Before compression the
ma e
up gas is mixed with flash gas from the product let down tan . After
compressio
n to 218 g/cm2 G , the total ma e up gas is mixed with the recirculation gas
th
e NH3 separator and the mixture is finally compressed to 231 g/cm2 in the
last
casing of synthesis gas compressor.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
25/52
The gas leaving synthesis gas compressor enters the synthesis hot
exchanger
A-EA602, where it is heated to the converter inlet temperature by heat
exchanger
with the hot effluent gas from the synthesis economizer A-EA601 A, B.
At the outlet of the ammonia converter A-DC601 the gas contains about 16% of
NH3
.
A considerable part of the heat content of the converter effluent gas is
util
ized in the synthesis economizer A-EA601A, B and then cooled down to about 71
oC
in the synthesis hot exchanger A-EA602.
The cooling of the gas continues first in the synthesis water cooler A-
EA603,
in which a substantial part of the ammonia is condensed. At the outlet of
the s
ynthesis water cooler the temperature is about 400C. The gas then passes
the syn
thesis cold exchanger A-EA604, in which it is cooled to about 330C by heat
excha
ngers with the recirculation gas coming from the ammonia separator. Finally,
the
gas is cooled to 100C in the Ammonia cooled condensorA-EB601. The mixture of
sy
nthesis gas and liquid ammonia is passedon to the ammonia seperatorA-FA601,
in
which the liquid ammonia is separated.The gas which separates the ammoniatill
4.92% is heated to about320C in the synthesis of cold exchanger, and enters
the
last casingof the synthesis gas compressor as recycle after mixed with ma e
up
synthesis gas. The liquid ammonia separated in the ammonia separator is
depress
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
26/52
urized to 45 g/cm2G and ta en to the product let down tan in which
considerabl
e part of the gases dissolved in the
Ammonia is released. This gas is recycled to the synthesis gas compressor
suctio n and reused in the synthesis loop.
The liquid ammonia from product let down tan delivered and led to the
urea pl ant under normal operation. The ammonia converter is the TOPSOE
radial flow type converter. It consists of a pressure shell and a bas et.
The bas et is divided into a lower heat exchanger and a catalyst section
consisting of two beds. A cen tral tube passes through the catalyst section.
The main stream of the synthesis gas is introduced into the converter
through two main inlets at the top and passes downwards through the annular
space betwe en the bas et and the pressure shell, eeping the later
cooled. At the bottom of converter, the gas enters into the shell side of
the lower exchanger, in which
it is heated to the reaction temp. By heat exchanger with gas leaving the
conver
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
27/52
ter. This reaction temp. can be adjusted by means of a cold bypass
introduced th rough the bottom nozzle of the converter.
The gas leaving the lower exchanger goes to the upper catalyst bed
through a transfer pipe placed inside the central tube in the lower bed.
The gas passes th e upper bed in radial direction and the reaction ta es
place. The distribution i s ensured by means of perforated plate placed in
the catalyst bed wall.The react gas in the upper bed enters the lower bed through the
outer a nnular space surrounding catalyst bed. The temp. Outlet of the upper
bed is abou t 5000C. This temp. is reduced to about 4050C before entering
into lower bed by addition of quench gas. The rxn. Gas passed the lower bed
in the radial directio n enters in to the lower exchanger through the
annular space between the inner b ed wall. The gas flow distribution on lower
bed is also ensured by the perforate d plate.
The outlet temp. of the gas from the lower bed is about5100C. The gas
passe d through the tube side of the lower exchanger and leaves the
converter through the bottom of the pressure shell. The refrigeration
system consist of the ammoni a cooled condenser and the ammonia
refrigerator which consist of the ammonia com pressor, the ammonia
condenser, the ammonia receiver.
The compressed ammonia vapor leaving the ammonia compressor is condensed
in t he ammonia condenser. The liquid ammonia is vaporized in the ammonia-
cooled cond enser at 3.9
g/cm2G, there by providing the cooling capacity necessary for cooling and
conde nsing the product ammonia.
The vaporized ammonia gas enters the suction of the ammonia compressor
for co mpression to about 16 g/cm2 G.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
28/52
GAS COMPOSITION
Particulars Inlet Converter Outlet converter
Feed gas 395515 NM3 340377 NM3
Temp. 1200C 3180C
Ammonia 3.12% 17.8%
H2 71.99% 60.05%
N2 24,0% 20.0%
Ar.+CH4+He 0.89 1.03%
CO+2xCO2+H2+2xO2 2ppm max.
CATALYST TEMP.
Particulars Max.design condition Prevailing
Ist bed-Inlet(Centre) 390oC 380 oC
In the bed 495 oC
O/L 522 oC 518 oCIId Bed Inlet 405 oC 390 oC
T.C in bed 450 oC
O/L center tube 505 oC 454 oC
1). H2/N2 ratio in the ma e up gas
H2 / N2 ratio 3:1 is maintained in loop. If H2/N2 ratio is below
2.
5:1 or higher than 3:1 reaction speed in the converter will decrease,
temp.will
tend to decrease and pressure of the loop increases. Some gas must be
purged th
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
29/52
rough loop vent to maintain ratio in the loop. Preferred ratio is
2.88.because
N2 is a limiting reactant in the reaction.
2). High inerts in the loop:-
Inerts in the loop > 1.26% increases the loop pressure but
the e
ffective pressure of H2 & N2 in the loop decreases and reaction velocitydecreas
es,. Hence inerts level shouldbe controlled to optimum.
3) Ammonia Conc. At Converter
inlet:-
Increase of Ammonia conc. In the converter inlet gas
reduce
d the reaction rate and decrease of Ammonia con. Inlet to converter
increases th
e reaction rate. GC-601 and EB 601 chiller operation should be adjusted to
main
tain Ammonia con. In the inlet to optimum level. GC-601suction pressure
should
be 3.8K
4). Circulatingrate:
Increase of circulating rate of gas reduces the pressure of
the lo
op. Though load on the circulating compressor and refrigeration compressor
incr
eases. However, the loop pressure decreases and consequently load on the
main c
ompressor reduces.
5). Pressure:
According to Le-Chattier principle, High pressure favors the
forwar
d reaction. But pressure increases in the loop due to following factors:
a) Increase of ma e up gas quantity
b) Decrease of circulating rate
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
30/52
c) Increase of inert level
d) Ammonia content increase in the converter inlet
e) H2/N2 ratio not proper
f) Reduction of catalyst activity due to poisoning or aging of catalyst.
Pressure rise due to point No.a) i.e increase of ma e up gas favors the
forward reaction but other factors b) to f) retard the reaction and steps
should be ta e n to control these parameters.
TYPE OF COMPRESSOR
PLANT COMPRESSOR:
1. OXYGEN COMPRESSOR 4. REFRIGERATION COMP.2. AIR COMPRESSOR 5. SYNTHESIS COMPRESSOR3. NITROGEN COMPRESSOR
Reciprocating compressors
Animation of reciprocating compressor
A motor-driven six-cylinder reciprocating compressor that can
oper
ate with two, four or six cylinders.
Main article: Reciprocating compressor
Reciprocating compressors use pistons driven by a cran shaft. They can be
either
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
31/52
stationary or portable, can be single or multi-staged, and can be driven by
ele
ctric motors or internal combustion engines.[1][4][5] Small reciprocating
compre
ssors from 5 to 30 horsepower (hp) are commonly seen in automotive
applications
and are typically for intermittent duty. Larger reciprocating compressors
well o
ver 1,000 hp (750 W) are still commonly found in large industrial and
petroleum
applications. Discharge pressures can range from low pressure to very
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
32/52
High pressure (>6000 psi or 41.4 MPa). In certain applications, such as air
comp ression, multi-stage double-acting compressors are said to be the most
efficient compressors available, and are typically larger, noisier, and more
costly than comparable rotary units.[6]
Rotary screw compressors
rew
compressor
Main article:
Diagram of a rotary sc
Rotary screw compressors use two meshed rotating positive-
disp
lacement helical screws to force the gas into a smaller space.[1][7][8] These
ar
e usually used for continuous operation in commercial and industrial
application
s and may be either stationary or portable. Their application can be from 3
hors
epower (2.2 W) to over 1,200 horsepower (890 W) and from low pressure to very
high pressure (>1200 psi or 8.3 MPa).
Rotary vane compressors
See also:
Rotary vane compressors consist of a rotor with a number of blades
inserted in radial slots in the rotor. The rotor is mounted offset in a
larger h
ousing which can be circular or a more complex shape. As the rotor turns,
blades
slide in and out of the slots eeping contact with the outer wall of the
housin
g.[1] Thus, a series of decreasing volumes is createdby the rotating blades.
Ro
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
33/52
tary Vane compressors are, with piston compressors one of the oldest of
compress
or technologies.
With suitable port connections, the devices may be either a compressor or avacu
um pump. They can be either stationary or portable, can be single or multi-
stage
d, and can be driven by electric motors or internal combustion engines. Dry
vane
machines are used at relatively low pressures (e.g., 2 bar) for bul
material movement whilst oil-injected machines have the necessary volumetric
efficiency to
achieve pressures up to about 13 bar
Scroll compressors
Main
article:
Mechanism of a scroll pump
A scroll compressor, also nown as scroll pump and scroll vac
uum pump, uses two interleaved spiral-li e vanes to pump or compress fluids
such
as liquids and gases. The vane geometry may be involutes, Archimedean
spiral, o
r hybrid curves.[9][10][11]They operate more smoothly, quietly, and reliably
th
an other types of compressors in the lower volume range
Often, one of the scrolls is fixed, while the other orbits eccentrically
without
rotating, thereby trapping and pumping or compressing poc ets of fluid or
gas b
etween the scrolls.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
34/52
(NITROGEN COMPRESSOR)
GENERAL DESCRIPITION
NITROGEN GAS COMPRESSOR IS OF TYPE driven by steam turbine, both of m/s mitsui s
hip building & engineering co. ltd. This compressor has he under mentioned
constr
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
35/52
uction features:
1. Casing can be horizontally split for easy maintenance. The lower half
is provided with the gas inlet and outlet connection.
2. it consists of two casing with different rotational speed (LPC&HPC)
and four stages .
3. Diaphragm coupling is used to minimize thrust force caused by thermalex pansion of the rotor.
4. Labyrinth type gas seal is used.
TECHNICAL DATA:
Specification of the compressor at normal condition (100% flow)
1. capacity ( g/hr)day 34,082
2. relative humidity(%) 0
3. molecular weight 28.01
4. cp/cv( 1) 1.4
5. compressibility 1.0
6. speed(rpm) 8000/11435(LPC/HPC)
7. Max. continuous r m 86508. t e of driver extraction steam9. DRIVE RATED (HP)
OXYGEN COMPRESSOR DESCRIPSTION
OF THE SYSTEM
THE oxygen compressor is suppliedby DEMG COMPRESSOR WEST GERMANY. It is
a two casting multistage turbo-compressor of single shaft construction. The
c ompressor is driven directly by a steam turbine supplied by compressor. A
reduct ion gear is provided b/w LP and HP compressor. Each casing has 6
impeller.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
36/52
The compressor is designed to supply 24970 NM3/hr of minimum 98%
oxygen gas at 63.03 g/cm2 G and final disch. Temperature of 450c to the
gasifiers.
The casing of the compressor is a pressure tight and dimensionally stable
horiz ontally split. The impellers are shrun on the shaft. These impellers
are so arr anged on the shaft that the longitudinal thrust is partially
cancelled out and i nternal lea age is minimized.
A dummy piston has provided to reduce the longitudinal thrust causing by
the impeller arrangement down to a value permissible for thrust
bearing.
Drain holes for lea age oil and condensate have been provided in the spares
betw een casing and bearing trestles to prevent liquid from entering the
machine.
A fire wallhas been provided around the oxygen compressor to confine the
danger to this area in case any explosion occurs in the oxygen compressor.
No operating personnel should be allowed to enter this area while the
compressor is running .s
Specification
COMPRESSOR DETAILS
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
37/52
1. type 10MH 6C 6MH 6C2. no. of impeller 6 63. no. ofprocess stage 1 1
Casing stage LPC HPC
4. Gas handled 98.00%o2. 0.70% 1.5% argon
5. s eed normal 9500 13598Maximum 19975 14278Tri 10973 157071st critical 3950 59002nd critical 14100 25300Prohibited range 3550 to 5140 (turbine
speed)
Description :-It is a centrifugal compressor having 3 casing driven by steam turbine with a
speed a 11100 rpm at 100% capable of compressing 99,960 NM3/ hr of systhesis ga
s and t builtup pressure from 37.5 g /cm2 to 221 g/cm2 G . in the ma e up s
tage and then finally upto 235ata in last stage which act as recirculator .
GAS FLOW:-
The purified gas available from nitrogen wash unit after removal of
carbonmonoxide and other impurities and after the addition of ma e up nitrogen ,
enter
the suction of first casing of sys . gas compressor at 37.5 ata pressure
. i
t is compressed to 81.6 ata in the first stage then passes to second stage
an
d is compressed to 148.5 ata pressure . the gas then enter the suction of the
r
ecycle stage casing and gets mixed with the recycle gas is compressed to 235 ata
pressure . it then goes to the synthesis section .
Inter cooler for cooling the gas to nearly 410c have been provided between the f
irst and second casing and second and third casing and after cooler has been p
rovided for cooling the ma e up gas 450c before it enter the suction of the re
cycle stage.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
38/52
The released separated from ammonia flash drum of systhesis section also
enter the suction of 5he compressor after the main isolation value for
utilization i n this section . there is a provision for controlling the
capacity of the recyc le stage by adjustable guide vanes provided on the
casing .
Nitrogen connections have been provided in the suction line after the main
iso lation valve for supply of nitrogen for purging the loope during shut
down.
Ammonia refrigeration compressor :-
Ammonia refrigeration compressor is a centrifugal machine catering to refrigera
tion requirement , of ammonia synthesis loop. Also this can handle the air sepa
ration units refrigeration load in case of emergencies . the compressor is
design
ed to compress 31.4Te/m of ammonia to 17.0 ata a from 4.7 ata . The compressor
is drivenby a steam turbine , the turbine is an extraction cumcondensing
type, t
he inlet pressure being 40ata and extraction pressure being 9ata .The unit is s
upplied by M/S BHEL HYDERABAD.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
39/52
AIR COMPREESOR
Axial compressors are rotating, aerofoil based compressors in which the wor
ing fluid principally flows parallel to the axis of rotation. This is in
contrast wi th other rotating compressors such as centrifugal, axe-
centrifugal and mixed-flo w where the air may enter axially but will have a
significant radial component o n exit. compressors
Axial flow compressors produce a continuous flow of compressed gas, and have
the benefits of high efficiencies and large mass flow capacity, particularly in
rel ation to their cross-section. They do, however, require several rows of
aerofoils to achieve large pressure rises ma ing them complex and expensive
relative to o ther designs (e.g. centrifugal compressor).
Axial compressors are widely used in gas turbines, such as jet engines, high
spe ed ship engines, and small scale power stations. They are also used in
industria l applications such as large volume air separation plants, blast
furnace air, fl uid catalytic crac ing air, and propane dehydrogenation.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
40/52
Axial compressors, now n as superchargers, have also been used to boost the
power of automotive recipro cating engines by compressing the inta e air,
though these are very rare. A good example of an axial supercharger is the
aftermar et Latham type built between 1955-65 which were used on hot rods
and ai r-cooled Vol swagens at that time, but these didn t catch on
Description
Axial compressors consist of rotating and stationary components. A shaft drives
a central drum, retained by bearings, which has a number of annular aerofoil row
s attached. These rotate between a similar number of stationary aerofoil rows
at
tached to a stationary tubular casing. The rows alternate between the rotating
a
erofoils (rotors) and stationaryaerofoils(stators), with the rotors
imparting en
ergy into the fluid, and the stators converting the increased rotational inetic
energy into static pressure through diffusion. A pair of rotating and
stationar
y aerofoilsis called a stage. The cross-sectional area between rotor drum and
ca
sing is reduced in the flow direction to maintain axial velocity as the fluid is
compressed.
Diagram of an axial flow compressor
Design
The increase in pressure produced by a single stage is limited by the relative v
elocity between the rotor and the fluid, and the turning and diffusion capabilit
ies of the aerofoil. A typical stage in a commercial compressor will produce a p
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
41/52
ressure increase of between 15% and 60% (pressure ratios of 1.15-1.6) at
design conditions with a polytrophic efficiency in the region of 90 -95%. To
achieve di fferent pressure ratios, axial compressors are designed with
different numbers o f stages and rotational speeds.
Higher stage pressure ratios are also possible if the relative velocity
between fluid and rotors is supersonic,however this is achieved at the
expense of effic iency and operability. Such compressors, with stage
pressure ratios of over 2, a re only used where minimizing the compressor
size, weight or complexity is criti cal, such as in militaryjets.
The aerofoil profiles are optimized and matched for specific velocities and
turn ing. Although compressors can be run at other conditions with different
flows, s peeds, or pressure ratios, this can result in an efficiency penalty
or even a pa rtial or complete brea down in flow ( nown as compressor stall
and pressure surg e respectively). Thus, a practical limit on the number of
stages, and the overal l pressure ratio, comes from the interaction of the
different stages when requir
ed to wor away from the design conditions. These off-design conditions can be
mit igated to a certain extent by providing some flexibility in the compressor.
This
is achieved normally through the use of adjustable stators or with valves
that can bleed fluid from the main flow between stages (inter-stage bleed).
Modernjet enginesuse a series of compressors, running at different
speeds; to supply air at around40:1 pressure ratio for combustion with
sufficient flexibil ity for all flight conditions.
Development
Early axial compressors offered poor efficiency, so poor that in the early 1920s
a number of papers claimed that a practical jet enginewould be impossible
to c
onstruct. Things changed dramatically after A. A. Griffith published a seminal p
aper in 1926, noting that the reason for the poor performance was that existing
compressors used flat bladesand were essentially "flying stalled". He showed th
at the use of airfoils instead of the flat blades would dramatically increase ef
ficiency, to the point where a practical jet enginewas a real possibility. He c
oncluded the paper with a basic diagram of such an engine, which included a seco
nd turbine that was used to power a propeller.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
42/52
Real wor on axial-flow engines started in the late 1930s, in several efforts th
at all started at about the same time. In England, Haine Constant reached an agr
eement with the steam turbine company Metropolitan Vic ers (Metrovic ) in 1937,
starting their turboprop effort based on the Griffith design in 1938. In 1940, a
fter the successful run of Whittle s centrifugal-flow design, their effort was r
e-designed as a pure jet, the Metrovic F.2. In Germany, von Ohain had produced
several wor ing centrifugal engines, some of which had flown including the world
s first jet aircraft (He 178), but development efforts had moved on to Jun
ers
(Jumo 004) and BMW (BMW 003), which used axial-flow designs in the world s first
jet fighter (Messerschmitt Me 262) and jet bomber (Arado Ar 234). In the
United
States, both Loc heed and General Electric were awarded contracts in 1941 to
de
velop axial-flow engines, the former a pure jet, the latter a turboprop.
Northro
p also started their own project to developa turboprop, which the US Navy event
ually contracted in 1943. Westinghouse also entered the race in 1942, their proj
ect proving to be the only successful one of the US efforts, later becoming the
J30.
By the 1950s every major engine development had moved on to the axial-flow type.
As Griffith had originally noted in 1929, the large frontal size of the
centrif
ugal compressor
caused it to have higher drag than the narrower axial-flow type.
Additionally th e axial-flow design could improve its compression ratio
simply by adding additio nal stages and ma ing the engine slightly longer. Inthe centrifugal-flow design the compressor itself had to be larger in
diameter, which was much more difficu lt to "fit" properly on the aircraft.
On the other hand, centrifugal-flow design s remained much less complex (the
major reason they "won" in the race to flying examples) and therefore have a
role in places where size and streamlining are no t so important.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
43/52
AIR COMPRESSOR
INTRODUCTION:-
The air compressor supplied by MITSUI SHIPBUILDING and ENGG.CO. Of Japan is of a
mult8i stage axial flow type consisting of low &high pressure casing with an
ex
ternal intercooler. The drive a steam turbine connected directly with a gear
cou
pling is MITSUI BROWN BOXER single cylinder impulse type condensing turbine.
Adjustable stator blades are
provided f
or all stage of both the LPC and HPC of comp. to control its capacity. This
comp
. has a pressure ratio control device which server to eep the proper
pressure r
atio of the LPC and HPC.
The design condition of feed air at the battery limit of ASU is:-
Quantity : 140000NM3/hr.
Pressure : 7.0 g/CM2
Temp. : 450c
Relative humidity : 100%
Composition
CO2 : 500PPM(MAX.)
C2H2 : 0.45 mg/M3
CmHn : 0.7 mg/NM3
NH3 : 10mg/NM3
No+NO2 : 1.27mg/NM2
Dust : 1mg/NM3
47
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
44/52
Spools
All compressors have a sweet spot relating rotational speed and pressure,
with h
igher compressions requiring higher speeds. Early engines were designed for
simp
licity, and used a single large compressor spinning at a single speed. Later
des
igns added a second turbine and divided the compressor into "low pressure"
and "
high pressure" sections, the latter spinning faster. This two-spool design
resul
ted in increased efficiency. Even more can be squeezed out by adding a third
spo
ol, but in practice this has proven to be too complex to ma e it generally
worth
while as there is a trade off between higher fuel efficiency and the higher
main
tenance involved pushing up total cost of ownership compared to a two spool
desi
gn. That said, there are several three-spool engines in use, perhaps the
most fa
mous being the Rolls-Royce RB.211, used on a wide variety of commercial
aircraft
.
Bleed air, variable stators
As an aircraft changes speed or altitude, the pressure of the air at the
inlet t
o the compressor will vary. In order to "tune" the compressor for these
changing
conditions, designs starting in the 1950s would "bleed" air out of the
middle o
f the compressor in order to avoid trying to compress too much air in the
final
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
45/52
stages. This was also used to help start the engine, allowing it to be spun
up w
ithout compressing much air by bleeding off as much as possible. Bleed
systems w
ere already commonly used anyway, to provide airflow into the turbine stage
wher
e it was used to cool the turbine blades, as well as provide pressurized air
for
the air conditioning systems inside the aircraft.
A more advanced design, the variable stator, used blades that can be
individuall
y rotated around their axis, as opposed to the power axis of the engine. For
sta
rtup they are rotated to "open", reducing compression, and then are rotated
bac
into the airflow as the external conditions require. The General Electric
J79 w
as the first major example of a variable stator design, and today it is a
common
feature of most military engines.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
46/52
Closing the variable stators progressively, as compressor speed falls,
reduces t he slope of the surge (or stall) line on the operating
characteristic (or map), improving the surge margin of the installed unit.
By incorporating variable stat ors in the first five stages, General Electric
Aircraft Engines has developed a ten-stage axial compressor capable of
operating at a 23:1 design pressure ratio. Bypass
For jet engine applications, the "whole idea" of the engine is to move air
to pr ovide thrust. In most cases, the engine produces more power to move
air than its mechanical design actually allows. Namely, the inlet into the
compressor is sim ply too small to move the amount of air that the engine
could, in theory, heat a nd use. A number of engine designs had experimented
with using some of the turbi ne power to drive a secondary "fan" for added
air flow, starting with the Mestro vic F.3, which placed a fan at the rear of
a late-model F.2 engine. A much more practical solution was created by Rolls-
Royce in their early 1950s Conway engine
, which enlarged the first compressor stage to be larger than the engine
itself. This allowed the compressor to blow cold air past the interior of
the engine, s omewhat similar to a propeller. This technique allows the
engine to be designed to produce the amount of energy needed, and any air
that cannotbe blown through the engine due to its size is simply blown
around it. Since that air is not com pressed to any large degree, it is
being moved without using up much energy from the turbine, allowing a
smaller core to provide the same mass flow, and thrust, as a much larger
"pure jet" engine. This engine is called a "turbofan."
This technique also has the added benefit of mixing the cold bypass air with
the hot engine exhaust, greatly lowering the exhaust temperature. Since the
sound o
f a jet engine is strongly related to the exhaust temperature, bypass also
drama tically reduces the sound of the engine. Early jetliners from the 1960s
were fam ous for their "screaming" sound, whereas modern engines of greatly
higher power generally give off a much less annoying "whoosh" or even
buzzing.
Mitigating this savings is the fact that drag increases exponentially at high
sp eeds, so while the engine is able to operate far more efficiently, this
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
47/52
typicall y translates into a smaller real-world effect. For instance, the
latest Boeing 7
37 s with high-bypass CFM56 engines operates at an overall efficiency about
30% better than the earlier models. Military turbofans, on the other hand,
especiall y those used on combat aircraft, tend to have so low a bypass-
ratio that they ar e sometimes referred to as "lea y turbojets."
Energy exchange between rotor and fluid
The relative motion of the blades relative to the fluid adds velocity or
pressur
e or both to the fluid as it passes through the rotor. The fluid velocity is
inc
reased through the rotor, and the stator converts inetic energy to pressure
ene
rgy. Some diffusion also occurs in the rotor in most practical designs.
The increase in velocity of the fluid is primarily in the tangential direction (
swirl) and the stator removes this angular momentum.
The pressure rise results in a stagnation temperature rise. For a given
geometry
the temperature rise depends on the square of the tangential Mach number
of the
rotor row. Current turbofan engines have fans that operate at Mach 1.7 or
more,
and require significant containment and noise suppression structures to
reduce
blade loss damage and noise.
Velocity diagrams
The blade rows are designed at the first level using velocity diagrams. A veloci
ty diagram shows the relative velocities of the blade rows and the fluid.The axial flow through the compressor is ept as close as possible to Mach 1 to
maximize the thrust for a given compressor size. The tangential Mach number
dete
rmines the attainable pressure rise.
The blade rows turn the flow through an angle ; larger turning allows a higher
te
mperature ratio, but requires higher solidity.
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
48/52
Modern blades rows have low aspect ratios and high solidity.
Compressor maps
A map shows the performanceof a compressor and allows determination of
optimal
operating conditions. It shows the mass flow along the horizontal axis,
typicall
y as a percentage of the design mass flow rate, or in actual units. The
pressure
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
49/52
rise is indicatedon the vertical axis as a ratio between inlet and exit
stagna tion pressures.
A surge or stall line identifies the boundary to the left of which the
compresso r performance rapidly degrades and identifies the maximum
pressure ratio that ca n be achieved for a given mass flow. Contours of
efficiency are drawn as well as performance lines for operation at
particular rotational speeds.
Compression
stability
Operating efficiency is highest close to the stall line. If the downstream
press
ure is increased beyond the maximum possible the compressor will stall and
becom
e
unstable.
Typically the instability will be at the Helmholtz frequency of the system,
ta i
ng the downstream plenum into
account.
Benefit
s
The benefits of this technology included reducing power cost, reducing power
sur
ges (from starting AC motors), and delivering a more constant pressure. The
down
side of this technology is the heavy expense associated with the drive, and
the
sensitivity of these drives - specifically to heat and moisture.
Compressed
air
Compressed air is air which is ept under a certain pressure, usually
greater th
an that of the atmosphere. In Europe 10 % of all electricity used by
industry is
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
50/52
used to produce compressed air. This amounts to 80 terawatt hours per
year.[1]
Dangers
A blast of air under 40 psi (pounds per square inch) from 4 inches away ca
rupt
ure an eardrum or cause brain damage.[citation
needed]
Directed at the mouth, compressed air can rupture the lungs.[citation
needed]
Uses:-
Compressed air can be used in or
for:
Pneumatics, the use of pressurized gases to do wor . See compressed a
energy s
torage
.
vehicular transportation using a compressed air
vehicle
Scubadiving, to inflate
buoyancy devices. Seealso: Breathing
gas
Cooling using a vortex
tube.
Gas dusters for cleaning electronic components that cannot be cleaned wi
water
. These are also called "canned air", however this is a misnomer because thepro
pellant is not air, but rather a hydro fluorocarbon which poses a health
ris if
inhaled.
air bra e (rail)
systems
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
51/52
air bra e (road vehicle)
systems
air bra e (air vehicle)
systems
compressed air breathers (such as Suisse Air)[citation
needed]
paintball ammunition
propulsion
airsoft ammunition
propulsion
ECONOMICS
1. High pressure favors the reaction but operation at less pressure for
the same production rate lowers load on the syn.gas compressor and thus
saving of s team, which cost at Rs. 600/Te.
2. Temp. Poisoning and permanent poisoning of the catalyst reduces the
life
of catalyst and catalyst fresh is forced to be changed earlier- Loosing Companys
money and production loss occurs.To avoid temp.poisoning - The ma e up gas should be pure, oxygen compound
such a
s CO, H2), CO2 in the gas should be limited. N2 purity should be
8/13/2019 (142276387) 102336953 Training Report at Nfl Panipat
52/52
und abnormal.
4. On changing of the bas et S-1to S-200, 5-6 Te./hr steam is saved which
in
turn reduces the energy consumption of 0.12 mmKcal/Te. of ammonia produced.
5. Optimum temp.operation in the catalyst increases the life
PRODUCTION PERFORMANCE
RECORDS : Pea s in Production Scale
Highest Production of
Ammonia on single Day : 1041 MT (on 02.01.1998)
(against 900 MT/Day rated Capacity)
Highest Production of
Urea on single day : 1918 MT (on 17.12.2000)
a ainst 1550 MT/Da rated Ca acit Hi hest Annual Productionof Ammonia : 316619 MT 97-98 a ainst 297000 MT rated Ca acit
Hi hest Annual roduction ofUrea : 562250 MT (97-98)
Recommended