463172 Techno-Economic Analysis of Indirect, Direct, and Hybrid Coal-Biomass to Liquids (CBTL) Plants with CO2 Capture and Storage (CCS)
In the indirect CBTL plant, coal and biomass are first gasified to syngas. Then the syngas is converted to syncrude via Fischer-Tropsch (FT) synthesis. CO2 is captured from both raw syngas and FT vapor product. In the direct CBTL plant, coal and biomass are directly converted into syncrude in the catalytic two-stage liquefaction (CTSL) unit by adding hydrogen produced from gasification of coal/biomass/liquefaction residue or reforming of shale gas. Significant amount of CO2 that is generated in the hydrogen production unit(s) is captured to satisfy the target extent of CO2 capture. In the hybrid CBTL plant, pre-processed coal and biomass are sent to either syngas production unit or the CTSL unit. Produced syngas is sent either to FT unit or hydrogen production unit. Naphtha and diesel products from the FT unit and the CTSL unit are blended to reduce the syncrude upgrading penalty. Different CCS technologies are considered and optimized for the indirect, direct and hybrid CBTL plant depending on the sources of CO2 containing stream and corresponding CO2 partial pressure.
The focus of this presentation will be on optimal synthesis of the hybrid plant. In particular, following aspects will be presented: (1) development of plant-wide process model and rigorous economic model in Aspen Plus®, Aspen Exchanger Design and Rating®, Excel, and APEA®, (2) sensitivity studies to analyze the impact of key design parameters (i.e. biomass/coal ratio, extent of CCS, CCS technologies, blending ratio of indirect and direct syncrude in the hybrid route) and investment parameters (i.e. price of coal and biomass, project life, plant contingency and plant capacity) on key economic measures, such as net present value (NPV), internal rate of return (IRR) and break-even oil price (BEOP), (3) analysis of the potential environmental credits due to use of biomass and CCS for all liquefaction approaches, (4) comparisons and analysis of trade-offs of indirect, direct, and hybrid CBTL plants.