MY124143A - Preparation of fuel grade dimethyl ether - Google Patents

Abstract

A PROCESS FOR THE PREPARATION OF FUEL GRADE DIMETHYL ETHER FROM A HYDROGEN AND CARBON OXIDES CONTAINING SYNTHESIS GAS, WHEREIN THE SYNTHESIS GAS IS CONVERTED TO A MIXED PROCESS GAS OF DIMETHYL ETHER, METHANOL AND WATER IN ONE OR MORE CATALYTIC REACTORS IN THE PRESENCE OF A CATALYST HAVING ACTIVITY BOTH IN SYNTHESIS OF METHANOL AND METHANOL DEHYDRATION;THE MIXED PROCESS GAS IS COOLED TO OBTAIN A LIQUID PROCESS PHASE CONTAINING THE PRODUCED METHANOL, DIMETHYL ETHER AND WATER AND A GASEOUS PROCESS PHASE CONTAINING UNCONVERTED SYNTHESIS GAS AND A PART OF PRODUCED DIMETHYL ETHER, WHICH PROCESS COMPRISES FURTHER STEPS OF SEPARATING THE GASEOUS PHASE AND LIQUID PHASE; PASSING THE LIQUID PHASE TO A FIRST DISTILLATION UNIT AND DISTILLING OFF A TOP PRODUCT STREAM CONTAINING DIMETHYL ETHER AND METHANOL AND WITHDRAWING A BOTTOM STREAM CONTAINING METHANOL AND WATER; PASSING THE BOTTOM SRTEAM TO A SECOND DISTILLATION UNIT AND DISTILLING OFF A METHANOL CONTAINING STREAM, INTRODUCING THE METHANOL INTO A PURGE WASHING UNIT; WASHING THE GASEOUS PROCESS PHASE WITH THE METHANOL IN A PURGE WASHING UNIT AND WITHDRAWING FROM THE UNIT A WASHING STREAM OF DIMETHYL ETHER AND METHANOL; CONVERTING A PART OF THE METHANOL IN THE WASHING STREAM TO DIMETHYL ETHER AND WATER IN A CATALYTIC DEHYDRATION REACTOR BY CONTACT WITH A DEHYDRATION CATALYST; WITHDRAWING FROM THE DEHYDRATION REACTOR A PRODUCT STREAM OF DIMETHYL ETHER, WATER AND UNCONVERTED METHANOL; AND COMBINING THE TOP PRODUCT STREAM FROM THE FIRST DISTILLATION UNIT WITH THE PRODUCT STREAM FROM THE DEHYDRATION REACTOR TO OBTAIN A COMBINED PRODUCT STREAM OF FUEL GRADE DIMETHYL ETHER.(FIG. 1)