Absorption of impurities from hydrogencarbon monoxide synthesis gas

Claim 1

PROCESS FOR REMOVING GASEOUS IMPURITY SELECTED FROM THE GROUP CONSISTING OF METHANE, ETHANE AND NITROGEN, FROM THE EFFLUENT GAS STREAM DISCHARGED FROM THE SYNTHESIS AUTOCLAVE OF THE SYNTHESIS LOOP IN THE CATALYTIC PRODUCTION OF SYNTHETIC METHANOL AT A PRESSURE ABOVE 50 ATMOSPHERES, SAID AFFLUENT GAS STREAM PRINCIPALLY CONTAINING HYDROGEN AND CARBON MONOXIDE, WHICH COMPRISES COOLING SAID AUTOCLAVE EFFLUENT GAS STREAM BY A FIRST INDIRECT HEAT EXCHANGE WITH IMPURITY-LADEN LIQUID METHANOL, FURTHER COOLING SAID EFFLUENT GAS STREAM TO CONDENSE AND REMOVE PRODUCT CRUDE SYNTHETIC METHANOL, FURTHER COOLING THE RESIDUAL SYNTHESIS GAS STREAM CONTAINING GASEOUS IMPURITY TO A FINAL TEMPERATURE BELOW 20* C. BY A SECOND INDIRECT HEAT EXCHANGE WITH COLD PURIFIED SYNTHESIS GAS STREAM, SCRUBBING THE IMPURITY-CONTAINING SYNTHESIS GAS STREAM WITH LIQUID METHANOL, AND THEREBY ABSORBING SAID IMPURITY INTO SAID LIQUID METHANOL, SEPARATING THE RESULTING METHANOL STREAM CONTAINING DISSOLVED IMPURITY FROM THE PURIFIED SYNTHESIS GAS STREAM, HEATING SAID PURIFIED SYNTHESIS GAS STREAM BY SAID SECOND HEAT EXCHANGE, COMBINING THE PURIFIED SYNTHESIS GAS STREAM WITH FRESH FEED GAS TO FORM A COMBINED GAS STREAM, PASSING THE COMBINED GAS STREAM TO METHANOL SYNTHESIS IN THE SYNTHESIS AUTOCLAVE OF THE SYNTHESIS LOOP, HEATING SAID LIQUID METHANOL STREAM CONTAINING DISSOLVED IMPURITY BY A THIRD INDIRECT HEAT EXCHANGE WITH REGENERATED LIQUID METHANOL, FURTHER HEATING AND STRIPPING THE METHANOL STREAM OF DISSOLVED IMPURITY IN A DISTILLATION ZONE BY SAID FIRST INDIRECT HEAT EXCHANGE, SEPARATING STRIPPED GASEOUS IMPURITY FROM THE LIQUID METHANOL STREAM AS A DISTILLATE OVERHEAD GAS, COOLING THE REGENERATED LIQUID METHANOL BY SAID THIRD HEAT EXCHANGE, AND FURTHER COOLING AND RECYCLING THE REGENERATED LIQUID METHANOL TO SAID SCRUBBING STEP.