Constructability study on a German reference IGCC power plant with and without CO_2-capture for hard coal and lignite

摘要

This paper describes several cases of technical design, performance and an economic evaluation for IGCC-power plant concepts with and without CO_2 capture and storage (CCS) operated on world market hard coal and German lignite. Evaluations include IGCC concepts based on commercially available and competitive state-of-the-art technologies. In concept pre-assessment pressure concepts for heat recovery steam generation, configuration of air separation unit, gas conditioning alternatives and synthesis gas cooling in comparison to full water quench options for gas cooling were investigated. The economically most beneficial and efficient cases were evaluated identifying target values for carbon capture rate and plant efficiency. These requirements lead to the application of a HP/IP heat recovery system in gasification, a HP/IP/LP system in combined cycle, 70% air integration, sour CO shift conversion for hard coal and lignite cases with CCS and a full water quench in case for hard coal with CCS. The comparison between capture and non-capture cases shows a potential CO_2-avoidance of 89% in case of hard coal and 74% in case of lignite, respectively. The additional auxiliary consumption due to CCS leads to a decreasing net efficiencies based on LHV basis from 45.9% to 34.9% (hard coal) and from 51.5% to 41.3% (lignite). In case of hard coal the cost of electricity increases by 13.4% with the addition of carbon capture and in case of lignite by 11.8%, respectively. A sensitivity analysis for different factors affecting relative cost of electricity was carried out as well.