Using a centrifugal compressor to separate mixed gases – hoping to get everyone’s help
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Dear experts, I have a question and am hoping to get your help. At present, our company has a mixture of gases that needs to be compressed. The components of this mixture are hydrogen chloride, sulfur dioxide, and chloromethane, in a weight ratio of 30:55:15. The vapor pressure of sulfur dioxide at 20 degrees Celsius is approximately 0.4 MPa, that of chloromethane is about 0.5 MPa, and that of hydrogen chloride is around 4 MPa. All of these gases are dry and do not cause corrosion to carbon steel. We now need to initially separate the above mixture of gases. The proposed process is as follows: the mixed gas passes through a centrifugal compressor, after which the pressure at the outlet of the compressor is maintained at around 0.7 MPa, thereby causing sulfur dioxide and chloromethane to be largely liquefied. Hydrogen chloride, on the other hand, remains in gaseous form and is absorbed through falling film absorption to form hydrochloric acid solution. Or hydrogen chloride is also compressed to become liquid hydrogen chloride. Can such a process route be implemented using your company’s centrifugal compressors?
Due to the high-speed rotation of the impeller, a large amount of heat is generated inside the centrifuge. Therefore, an internal cooler is required between the equipment-level impeller and the stage impellers. But this internal cooler is very difficult to clean. Condensation will also be generated here. The inlet guide vanes are also places where condensate often appears. Condensate reacting with hydrogen chloride and sulfur dioxide will certainly cause corrosion to the equipment.
Reply to 2# Lotus Lake: For process compressors, as long as the operating procedures are followed – by carrying out proper cleaning and drying before startup, as well as proper gas replacement during normal operation – and provided that the process gas supplied by the manufacturer is of good quality, no condensation water will form in the inlet filter and intermediate cooler. Regarding the processing method desired by the poster, I believe: Key point 1: Use a suitable process compressor to compress the medium to 0.7 MPa (it is necessary to control the intermediate pressure and temperature to prevent condensation). Key point 2: Cool the medium at 0.7 MPa (the temperature must be carefully controlled), carry out gas-liquid separation, and pay attention to the efficiency of this separation as well as the choice of container material. Key point 3: How can the hydrogen chloride gas after gas-liquid separation be further purified?