In case of operation of any Oxygen Plant,
it is better not to disturb operation much. Normal operation of Plant is
best known by experience in individual Plants. However, the following are
guidelines:
Air Compressor Inlet stage separator drains and moisture separator drains
are to be opened and closed, 30 minutes, to let out condensed moisture. All
reading should be noted in a prescribed Log Sheet. A format of the same is
enclosed with the manual. Molecular Sieve Drier Heating and cooling cycles
are to be taken care (Refer M.S. Drier Chapter).
The rare gas vent valve R-22 should be kept slightly open to allow
non-condensed rare gases to escape from Lower Column. It is better to be
bubbled through water kept in a bottle or through a small rot miter.
After starting the Plant, the air pressure to be brought down slowly to
about 40 Kgs./cm2 , by further opening V3 or by bringing up the Inlet cam
position of Expansion Engine to 3 or 2, from 1. This will increase
production slightly. However, the upper column level L-2 and purities should
be maintained. The Plant can be maintained steadily if the Upper Column
liquid level, column pressure, air pressure are maintained properly. Every
half an hour products Oxygen Purity should be checked by drawing sample gas
from R-27 & R-28.
| S.NO |
NAME |
DESCRIPTION |
1
2
3
4
5
6
7
8
|
T1
T2
T3
T4
T5
T6
T7
T8
|
ENGINE INLET
ENGINE OUTLET
BEFORE V3
WN2 AFTER P.L SUB COOLER
L O BEFORE V8
WM2 AFTER LIQUID FAIR
N2 AFTER TOP COLUMN
R.L BEFORE V4 |
If any hydrocarbon (particularly Acetylene) is present, in the atmospheric
air, or is found due to excessive heating of the Air Compressor oil, the
Acetylene will settle as solid crystal, in the condenser liquid. Acetylene
crystals in liquid oxygen can explode spontaneously, casing serious
accidents. Therefore, once in 8 hours, Liquid Oxygen and liquid air should
be drained a little in order to avoid accumulation of Acetylene. Excess
presence of Acetylene in liquid oxygen can cause explosion. In 5 -liters of
liquid oxygen, presence of more the 5 milligrams of Acetylene (C2H2) or 200
mgs. Of other Hydrocarbons are hazardous. Analysis for presence of Acetylene
in explained separately, and analysis should be done in each shift.
If Acetylene is found to be present, the liquid is to be drained to reduce
contamination. If Acetylene still persists in the liquid oxygen, the plant
must be stopped immediately. All liquid should be drained and the Plant
should be defrosted.
The standard operating conditions are the following, but they differ from
Plant to Plant.
P-1
P-2
P-3
P-9
P-4
P-13
P-14
V3
V4
V5 |
40-45 KGS./ 5/6
KGS./ CM2
0.5/0.7 KGS./ CM2
75-165 KGS./ CM2
42-47 KGS./ CM2
1.5 KGS./ CM2
0.2 KGS./ CM2
VALVE
VALVE
VALVE |
T-1
T-2
T-3
T-10
T-7
T-8
-
4/17
1 + 10/17
10/17 |
100 Deg. C. TO - 115 Deg. C (Inlet to
Expansion Engine.)
-150/ -165 Deg. C. (Outlet to Expansion Engine)
-155/165 Deg. C. (Before V3)
+15 Deg. C. (Air Inlet)
-190 Deg. C. (Nitrogen from Top Column)
-170 (R1 before V4)
EXPANSION ENGINE INLET CAM - 1 TO 3 |
If the liquid levels drop and if the OXYGEN PLANT is getting warmed up,
throttle V3 valve and bring down Expansion Engine Cam position to increase
cold production. When the cam position is brought down from upper number to
lower number, the air inlet pressure will go up and outlet pressure will
come down. The air through Expansion Engine will go up. Similarly, if inlet
cam number is brought up to higher number, air inlet pressure will come down
and outlet pressure will go up. Air throughout will go up but temperature
drop across Expansion Engine will be less.
Cylinder filling should be checked. There should not be any gas leaks.
Avoid using only waste or oil in the filling procedure.
Water level should be maintained at half in evaporation cooler.
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