OVERVIEW OF CRACKED GAS COMPRESSOR FOULING: THEORIES AND PRACTICES

摘要

Most cracked gas compressors foul as they operate. The build up of polymer on the rotor and other internals results in increased frictional losses and altered flow patterns. These changes in turn cause losses in efficiency and head produced as well as the potential for unbalancing the rotor and damaging the seals. Increasing the compressor speed and steam turbine output can compensate for the losses in efficiency and head produced. However, once the capacity limit of the steam turbine has been reached or the compressor speed can no longer be increased, the throughput of the compressor will decline. In any event, the energy use per ton processed will increase with increasing fouling. The foulant is generally a polymeric material. The fouling mechanism is not completely understood, but it appears to be a strong function of both compressor temperature and foulant precursor and promoter concentrations. The foulant precursors include styrene, indene, butadiene, and cyclopentadiene. Compounds containing oxygen promote the polymerization reaction. The fouling reaction is thought to occur on the compressor surfaces resulting in the deposition of a layer of polymer. Several methods are employed alone and in combination to control fouling: 1. Wash Oil Addition 2. Water Injection 3. Inhibitor Injection 4. Coating of the Compressor Internals This paper will provide an overview of the problem and solution methods.