Compressor for

Axial Flow Compressors Axial flow compressors are used mainly as compressors for gas turbines. They are also used in the steel industiy as blast furnace blowers and in the chemical industry for large nitric acid plants. Thev are mainly used for apphcations where the head required is low and the flow large. 

Two characteristics of compressors for refrigeration are the most important refrigerating capacity and power. Typical characteristics are as presented in the Fig. 11-82. 

TABLE 29-6 Comparative Installation Costs of Integral-Engine Compressors for Pipeline Stations and Process Plants ... 

In 1985, the first active magnetic bearing in a pipeline compressor for continuous use was installed on the Alberta Gas Transmission System of NOVA Corporation. Tlie bearings have been running smoothly, with a noted improvement in compressor operation and efficiency. 

The expanders also remove energy from the gas, using that energy to drive a centrifugal compressor for pipeline recompression. As gas expands through the expander s inlet nozzle, pressure drops from 90 bar (1,300 psig) to 55 bar (800 psig). Temperature drops as well, below the dewpoint, and the liquids formed can be separated from the main gas stream. 

API Std 618, Reciprocating Compressors for Petroleum, Chemical, and Gas Industry Services, 4th Edition, June 1995... 

This standard could be adapted to the fuel compressor for the natural gas to be brought up to the injection pressure required for the gas turbine. Covers the minimum requirements for reciprocating compressors and their drivers used in petroleum, chemical, and gas industry services for handling process air or gas with either lubricated or nonlubricated cylinders. Compressors covered by this standard are of moderate-to-low speed and in critical services. The nonlubricated cylinder types of compressors are used for injecting fuel in gas turbines at the high pressure needed. Also covered are related lubricating systems, controls, instrumentation, intercoolers, after-coolers, pulsation suppression devices, and other auxiliary equipment. 

Coppage, J.E. et al., Study of Supersonic Radial Compressors for Refrigeration and Pressurization Systems, WADC Technical Report 55-257, Astia Document No. AD 110467, 1956. 

Woodhouse, H., Inlet Conditions of Centrifugal Compressors for Aircraft Engine Superchargers and Gas Turbines, J. Inst. Aeron, Sc., Vol. 15, 1948, pp. 403. 

API 617, Centrifugal Compressors for General Refinery Services, Washington, D.C., 1979. 

The total plant or train main process bottleneck will probably be identified by the licensor, such as the gasifier for a coal gasification train, the main exchanger for a mixed refrigerant LNG plant train, or the cracked gas compressors for an olefin plant. First and foremost, be sure that the licensor has not made the utility area a bottleneck. This can never be allowed since overloaded utilities could repeatedly shut the entire complex down on a crash basis, adversely impacting economics. 

After all the previous statements, it would seem very difficult to select a piston. speed. For someone without direct experience, the following guidelines can be used as a starting point. Actual gas compressing experience should be solicited when a new compressor for the same gas is being eonsidered. These values will apply to the industrial process type of compressor with a double-acting cylinder construction. For horizontal compressors with lubricated cylinders, use 700 feet per minute (fpm) and for nonlubricated cylinders use 600 fpin. For vertical compressors with lubricated cylinders, use 800 fpm and for nonlubricated cylinders use 700 fpm. 

Size an axial compressor for air service using the procedures outlined in the chapter. The following conditions are given ... 

The balance chamber leakoff line, while recommended to be held within the confines of the compressor casing may well turn out to require some user piping. There are some situations where the desire for keeping open space around the compressor for maintenance may require compromise on the part of the user. The balance of the connections on the axial are for lube oil and other auxiliary equipment not different from that found on other compressors. 

On those compressors where rotor dynamics can be a problem, which is on all but the standard units (even them sometimes) and reciprocaiiiit compressors, this is the point where the acceptance of the compressor for vibration and critical speed criteria should take place. Finding these in the field later is what the user and vendor want to avoid, and this is why ail the elaborate and careful work is done at the running test time,... 

API Standard 618, Reciprocating Compressors for General Rejinery Sc vices, Fourth Edition, Washington, D.C. American Petroleum Instituie. 

Enough data must be supplied to rate the compressor. For example, the mass flows, inlet and outlet pressure, inlet temperatures, type of gas or gas physical constants need to be itemized. The basic data must be very clearly stated and complete to the extent necessary to achieve a common understanding between the user and vendor. 

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