Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup, and Oxygen Separation Equipment. Task 2: Gas Cleanup Design and Cost Estimates Wood Feedstock

摘要

As part of Task 2, Gas Cleanup and Cost Estimates, the team investigated the appropriate process scheme for treatment of wood derived syngas for use in the synthesis of liquid fuels. Two different 2,000 metric tonne per day gasification schemes, a low-pressure, indirect system using the BCL gasifier, and a high-pressure, direct system using GTI gasification technology, were evaluated. Initial syngas conditions from each of the gasifiers were provided to the team by NREL. Nexant was the prime contractor and principal investigator during this task; technical assistance was provided by both GTI and Emery Energy. The first task explored the different process options available for the removal of the main process impurities, including particulates, sulfur, carbon dioxide, tar, ammonia, and metals. From this list, selection of commercial technologies appropriate for syngas clean-up was made based on the criteria of cost and the ability to meet the final specifications. Preliminary flow schemes were established and presented to NREL; after discussion and modification, final designs, including unit sizes, energy use, capital and operating costs, and labor requirements, were developed. Finally, Nexant performed an analysis to determine how changes in syngas flowrates and compositions would impact the designs, for future reference as the plant size changes.