The vacuum system adopts a fully mechanical vacuum pump set, which is composed of a pre-condenser + a first-stage roots pump + a second-stage roots pump + a liquid ring pump, and a first-stage roots pump is set between the first-stage roots pump and the second-stage roots pump. Condenser, a two-stage condenser is arranged between the two-stage Roots pump and the liquid ring pump.
The top gas of the decompression tower enters the pre-condenser for heat exchange, and the condensed liquid is discharged from the atmospheric leg into the liquid sealing tank; the temperature of the uncondensed process gas is reduced after heat exchange, and enters the first-stage Roots vacuum pump. The first-stage Roots vacuum pump is compressed and pressurized and discharged into the first-stage Roots post-condenser. The condensed liquid is collected and discharged into the liquid sealing tank by the atmospheric leg; the uncondensed process gas is collected and enters the second-stage Roots vacuum pump , After being compressed and pressurized by the second-stage Roots vacuum pump, it is discharged and collected to the exhaust manifold, and then enters the second-stage Roots post-condenser. The condensed liquid is collected and discharged from the atmospheric leg into the liquid sealing tank, and the uncondensed process gas enters The liquid ring pump unit realizes a new type of vacuuming process.