In foregoing discussion, results of NETL's comprehensive study comparing the performance and cost of various fossil fuel-based power generation technologies with and without carbon dioxide (CO2) capture were reviewed. Of particular interest in that study was the companion set of integrated gasification combined cycle (IGCC) designs, using GE's gasification technology, which can be used to illustrate the design changes needed for CO2 capture.
Current Technology - IGCC Plant Design
Figure 1 shows a simplified block flow diagram (BFD) of a market-ready IGCC design without CO2 capture. As shown, the IGCC plant consists of the following processing islands, of which a more detailed description of each can be found in the cited NETL referenced report: 1
IGCC Design Change to Enable CO2 Capture
Figure 2 shows a companion simplified block flow diagram (BFD) of a market-ready IGCC design with CO2capture. The design is for 90% CO2 capture from the IGCC plant. As shown, in comparison with the no-capture design, there are two key process plant modifications needed:
Figure 3 shows a simplified BFD for a selective Selexol design for both H2S (acid gas to the Claus plant) and CO2 removal.2
An additional processing step of CO2 dehydration and compression (shown in Figure 2 as CO2 Compression) is added to bring the produced CO2 to pipeline transport pressure and purity specifications.
|1.||Cost and Performance Baseline for Fossil Energy Power Plants study, Volume 1: Bituminous Coal and Natural Gas to Electricity (Nov 2010).|
|2.||Recent Selexol Operating Experience with Gasification Including CO2 Capture, Curtis R. Sharp, 20th Annual Pittsburgh Coal Conference, Pittsburgh, PA, September 15-19, 2003.|