Demonstration of a Piston Plug Feed System for Feedingt Coal/Biomass Mixtures Across a Pressure Gradient for Application to a Commercial CBTL System. Final Scientific/Technical Report for October 1, 2008 to June 30, 2011.

摘要

Producing liquid transportation fuels and power via coal and biomass to liquids (CBTL) and integrated gasification combined cycle (IGCC) processes can significantly improve the nation's energy security. The Energy Independence and Security Act of 2007 mandates increasing renewable fuels nearly 10-fold to >2.3 million barrels per day by 2022. Coal is abundantly available and coal to liquids (CTL) plants can be deployed today, but they will not become sustainable without large scale CO(sub 2) capture and storage. Co-processing of coal and biomass in CBTL processes in a 60 to 40 ratio is an attractive option that has the potential to produce 4 million barrels of transportation fuels per day by 2020 at the same level of CO(sub 2) emission as petroleum. In this work, Southern Research Institute (Southern) has made an attempt to address one of the major barriers to the development of large scale CBTL processes - cost effective/reliable dry-feeding of coal-biomass mixtures into a high pressure vessel representative of commercial entrained-flow gasifiers. Present method for dry coal feeding involves the use of pressurized lock-hopper arrangements that are not only very expensive with large space requirements but also have not been proven for reliably feeding coal-biomass mixtures without the potential problems of segregation and bridging. The project involved the development of a pilot-scale 250 lb/h high pressure dry coal-biomass mixture feeder provided by TKEnergi and proven for feeding biomass at a scale up to 6 ton/day. The aim of this project is to demonstrate cost effective feeding of coal-biomass mixtures (50:50 to 70:30) made from a variety of coals (bituminous, lignite) and biomass (wood, corn stover, switch grass).