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.
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.
|40-45 KGS./ 5/6 |
0.5/0.7 KGS./ CM2
75-165 KGS./ CM2
42-47 KGS./ CM2
1.5 KGS./ CM2
0.2 KGS./ CM2
1 + 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