Abstract: This paper mainly focused on the study of the application of oil-free screw compressor in the recovery of low-pressure exhaust containing DMC from coal-to-ethylene glycol plant. It proposed and solved the key technical problems such as the process flow of compressor, selection of compressor type and spray medium, and the relationship between circulating spray volume, methanol replenishment volume, waste liquid discharge volume, and shaft power with the exhaust temperature. The optimal outlet operating temperature (78 ℃) under the design condition (inlet state of 0.002 mpaG /45 ℃ and discharge pressure of 0.25 MPaG) was obtained by the simulation software ASPEN, and the reliability of the study was verified by the data comparison of the actual operating device. The research results can be used to guide the application of screw compressors in the recovery of low pressure exhaust containing DMC from coal-to-ethylene glycol plant.

Key words: oil-free screw compressor, coal-to-ethylene glycol, low pressure exhaust, exhaust temperature