ROUTING EXCESS VAPOR FROM HIGH PRESSURE FLASH DRUM TO GREY WATER STRIPPER REBOILER
Publication Date: 2014-Aug-27
The IP.com Prior Art Database
HP flash drum in the gasification island generate amounts of vapor during flashing stage. Part of this vapor can be routed for direct injection in condensate ammonia stripper in shift section. The remaining excess vapor can be routed to grey water stripper reboiler shell side (replacing low pressure steam) to recover the heat and utilize it as an indirect heat input for the grey water ammonia stripper.
The Grey Water Pre-treatment (GWPT) unit utilizes a stripper to remove excess ammonia and other trace components from the pretreated grey water. The grey water stream from the grey water stripper feed tank is first cross-heated with the stripper bottoms stream in the grey water stripper feed bottoms heat exchanger for improved heat integration. The heated feed stream enters the top section of grey water ammonia stripper and flows down to the reboiler section. Stripped grey water is circulated through the grey water stripper reboiler where low pressure (LP) steam is used for stripping steam generation. Stripping steam formed in the reboiler section flows up counter-current to the grey water and is used for stripping ammonia from the grey water. In this process enhancement, the low pressure steam will be replaced by excess high pressure flash vapor generated in high pressure flash drum in gasification section. The condensate from the grey water stripper reboiler will be routed to the daeartors in the gasification island.
This process enhancement resolves the following concerns: enhanced heat recovery of the high pressure flash vapor reduce or essentially eliminate heat loss to cooling water save cooling water reduce overall low pressure steam consumption increase overall plant efficiency.
The various advantages of the process enhancement may be: efficient heat recovery...