Beware of gas compressor designs with sub-atmospheric suction pressures

Electrification of the chemical industry has become a popular topic in recent years with green electricity from wind and solar sources claimed to become more abundant. An important component of this technology is the use of vapor recompression in process units to substitute electricity, driving compressors, for larger amounts of thermal energy. Vapor recompression in distillation columns has become more widely studied. Gas compressor design principles recommend avoiding low suction pressures because of the strong effect of suction pressure on compressor capital cost. This paper presents a recently published example of when this wisdom is not applied, resulting in a design with unrealistic compressor capital costs.