Gas processes

After passing through several stages of processing, gas pressure may need to be increased before it can be evacuated, used for gas lift or re-injected. Inter-stage pressure increases may also be required for further processing, particularly where wellhead pressure is low. Gas is compressed to increase its pressure. 

The catalytic vapor-phase oxidation of propylene is generally carried out in a fixed-bed multitube reactor at near atmospheric pressures and elevated temperatures (ca 350°C) molten salt is used for temperature control. Air is commonly used as the oxygen source and steam is added to suppress the formation of flammable gas mixtures. Operation can be single pass or a recycle stream may be employed. Recent interest has focused on improving process efficiency and minimizing process wastes by defining process improvements that use recycle of process gas streams and/or use of new reaction diluents (20-24). 

Properties. The properties of char products from two possible coal feeds, a low sulfur Western coal, and a high sulfur Midwestern coal, are shown in Table 11. The char derived from the low sulfur Western coal may be direcdy suitable as plant fuel, with only minor addition of clean process gas to stabilize its combustion. Elue gas desulfurization may not be required. Elue gas from the combustion of the char derived from the high sulfur Illinois coal, however, requires desulfurization before it may be discharged into the atmosphere. 

The iron carbide process is alow temperature, gas-based, fluidized-bed process. Sized iron oxide fines (0.1—1.0 mm) are preheated in cyclones or a rotary kiln to 500°C and reduced to iron carbide in a single-stage, fluidized-bed reactor system at about 590°C in a process gas consisting primarily of methane, hydrogen, and some carbon monoxide. Reduction time is up to 18 hours owing to the low reduction temperature and slow rate of carburization. The product has the consistency of sand, is very britde, and contains approximately 6% carbon, mostly in the form of Ee C. 

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