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Process in brief……
AMMONIA
Ammonia, a chemical compound of nitrogen
and hydrogen is produced using naphtha, steam and air. Feedstock naphtha is the
source for hydrogen and atmospheric air for nitrogen.
Naphtha is desulphurised
in two stages and the hydrocarbon is reformed together with steam and air to
raw synthesis gas in the reforming section. The reforming section consists of
Pre-reformer, Primary Reformer and Secondary Reformer. Air is introduced in the
Secondary Reformer. Reformed gas containing H2, N2, CO and CO2 and minor amount
of unreformed methane (CH4) is sent to the CO conversion section where CO is
converted into CO2 in two steps in shift conversion units. CO2 is absorbed
using Methyl Di-ethanol Amine
(MDEA) in the CO2 Removal Section and sent
to Urea Plant as one of the raw materials for Urea production. The remaining CO
and CO2 from the process gas is converted to CH4 in
the Methanator. The processed synthesis gas is
compressed and sent to the catalytic converters (S 200 and S 50) where Ammonia
is produced by the catalytic action. Synthesized Ammonia is separated and sent
to Urea Plant as raw material and the remaining quantity is refrigerated and
sent to cylindrical storage tanks.
UREA
Urea is produced by reacting Ammonia with
carbon‑di‑oxide (obtained from Ammonia
Plant) in stainless steel lined reactors at 215-220 kg/cm2g pressure, using the
technology of UTI’s Total Heat Recycle Process. The
high efficiency Reactor has a conversion of CO2 to Urea of about 76% per pass. After
flashing and decomposition at medium pressure, an additional Carbon-di-oxide is injected into the Medium Pressure System
followed by flashing and decomposition at low pressure and then concentration
of urea solution at vacuum. Further concentration takes place at evaporators at
the top of
Here the hot Urea solution sprayed down in
a 210' cylindrical concrete
The entire off gas is absorbed in a bubble
cap tray absorber and then recycled to the reactors. The chloride-free effluent
is treated in a Hydrolyser Stripper and the contents are recycled fully. The
treated water is used for demister washing.
The product is sent through a system of
conveyors and elevators to bagging streams. There it is bagged and shipped as
Urea product.
NPK
There are 3 NPK trains that are identical
except that in one we use the 'TVA' Granulator while others have Blunger units in the fertilizer granulation section. The basic steps for NPK manufacture are:
* Reaction of liquid Ammonia
and Phosphoric Acid to form slurry of mono and di ammonium
phosphates in Pre-neutralizer in two trains (A & C Trains). In the other train
(B Train) reaction is carried out in pipe cross reactor installed inside the
granulator and dryer.
* Mixing of the slurry with
other feed materials: Liquid Ammonia, Urea, Muriate
of Potash, Filler and re cycled NPK granules. Solid raw materials are fed to
the system through the modern J&N Weigh Feeders (with Programmable Logic
Control device) which maintain accuracy according the set load. Mixing is done
in the `Granulator' or `Blunger’ units where the
fertilizer granules are formed.
* Drying of the granulated material in a
rotary dryer.
* Separation of granule
produced by screening followed by cooling, coating & polishing of the
granules and product bagging. MFL produces four grades of N P K fertilizers
viz. 17 17 17, 19-19-19, 20-20-0 and DAP 18
46 0.
B&S
One set three bagging streams for bagging
Urea and another set of four streams for bagging products from NPK A and B
Trains are provided in Bagging and Shipping Plant. A separate set of three
bagging streams are available for bagging the complex fertilizer from NPK C
Train.
The bagging streams are maintained in
humidity free atmosphere by Bry Air System since NPK
complex fertilizer is hygroscopic in nature.
The Bagging System consists of a high
precision machine (Jashubhai Richard Simon Ltd,
Mumbai) with an accuracy of + or – 10 gms from the
set 50 kg per bag of fertilizer and an auto-bagging mechanism.
The bagged product is moved in conveyors for loading trucks or wagons to transport to various warehouses / dealers.