Hybrid Membrane-PSA System for Efficient Oxygen Generation for Transportable, Modular Gasification Systems

For the foreseeable future, the energy needed to sustain economic growth will continue to come largely from hydrocarbon fuels. Advanced Fossil Energy technologies must allow the Nation to use its secure indigenous fossil energy resources more wisely, cleanly, and efficiently. The development of innovative, cost‐effective technologies for improving the efficiency and environmental performance of advanced industrial and utility fossil energy power generation and natural gas recovery systems is imperative to accomplish this goal. The Gasification Systems Program, conducted under the U.S. Department of Energy’s Office of Fossil Energy FE) is developing innovative, flexible and small‐scale, modular gasification systems. Gasification is the partial oxidation of combustible materials and operates in an oxygen‐lean environment and oxygen can be provided by either air or high‐purity oxygen produced by an oxygen separation unit from air OSU). The focus is in the development of an OSU that can show significant capital cost reduction compared with a cryogenic distillation‐based oxygen separation from air, in application of smaller, modular systems, of which size is in the range of 1–5 MW of total power capacity. Mainstream will experimentally demonstrate efficient concentrating of O2 from air using mixed matrix membranes MMMs), which feeds a process‐integrated pressure swing adsorption PSA) system to generate high‐purity O2 for small, modular gasification systems. Pre‐concentrating the O2 using special membranes allows the integrated PSA system to generate high‐purity O2 with smaller cycle times and reduced power requirements. Mainstream proposes to integrate the PSA system with a waste heat recuperator to rapidly regenerate the adsorbent bed using heat recovered from the modular gasifier. Several membranes will be synthesized to characterize the O2 separation capacity and efficiency from air. Based on the experimental membrane results, a pilot‐scale PSA system will be demonstrated at the Energy and Environmental Research Center EERC) to monitor power and energy, cycle time, and effluent O2 concentration in Phase I. Ultimately, Mainstream will model the hybrid membrane‐PSA system using experimental results to generate a representative performance model and conduct a technoeconomic analysis for comparison to commercial‐scale PSA and cryogenic oxygen separation units OSUs). The U.S. can increase energy independence and security in the U.S. by utilizing existing fossil fuels, including those in specific regions, through modular gasifier plants. Small, modular gasifier plants for power and energy generation, H2 production, high‐value chemicals, and liquid fuels would offer reduced capital and operating costs while simultaneously increasing operational flexibility in meeting location‐specific demands. High‐quality syngas can be generated using O2‐blown gasifiers, which requires a dedicated OSU. At the 1–5 MW scale, cryogenic distillation‐ based separation is restricted by significant capital costs. Demonstrating the feasibility of a hybrid membrane‐PSA by experimentally validating subsystems would provide a clear pathway to reducing costs associated with point‐ source O2 production. The Phase I will address feasibility through lab‐ and pilot‐scale testing of membrane‐based separation for improving the operability of a process intensified PSA system. Phase II would develop an integrated pilot‐scale membrane‐PSA system to address technical hurdles associated with scale‐up and modularization.