A NEW APPROACH INTEGRATING CO{sub}2 CAPTURE INTO A COAL-BASED POLYGENERATION SYSTEM OF POWER AND LIQUID FUEL

摘要

Reducing the energy penalty for CO{sub}2 Capture and Storage (CCS) is a challenge. Most of previous studies for CCS have been focused on power generation system. When CCS is included in the polygeneration system, a new methodology that jointly considering CCS and liquid fuel production should be introduced. In this paper, we proposed a new approach integrating CCS into a coal-based polygeneration system for power generation and methanol production: the syngas produced from the coal gasifier, without adjusting the composition (CO/H{sub}2 ratio) by shift reaction, is used to synthesis methanol directly. Moreover, the partial-recycle scheme, in which a part of unreacted gas is recycled back to the synthesis reactor, is adopted in the synthesis unit. Another part of unreacted gas is treated to remove CO{sub}2, and then is used as clean fuel for the power generation subsystem. Compared to the conventional CCS approaches adopted by the power generation systems, the new approach is mainly characterized by two features: firstly, the combination of the removal of the composition adjustment process and a partial-recycle scheme can not only reduces the energy consumption for methanol production, but also obtains a high concentration of COX (CO and CO{sub}2) in the unreacted gas; secondly, the CO{sub}2 is captured from the unreacted gas, instead of from syngas generated by the gasifier.