Walter and Lalita Janke Innovations in Sustainability Science Research Fund

Single-Stage Biogas Upgrading to Biomethane: A Collaborative Project with Palm Beach County

• PI: Masoud Jahandar Lashaki, Ph.D.
• Co-PI: Daniel Meeroff, Ph.D.
• Department: Civil, Environmental and Geomatics Engineering
• Award: $50,000 

Project Summary: Biogas is a carbon-neutral source of renewable energy that may be produced by anaerobic digestion of agricultural waste or collected in landfills. In addition to methane, biogas contains carbon dioxide and other ubiquitous impurities such as water vapor and hydrogen sulfide. Hence, biogas purification, to produce biomethane, is required prior to using it as transportation fuel or injecting it into natural gas grid. Whereas current biogas upgrading processes require multiple upstream units for desulfurization, drying, and biogas compression or cooling before carbon dioxide removal, we hypothesize that FAU’s amine-modified silica adsorbents can concurrently separate all impurities. Thus, the objective of this research is to purify biogas in one single step using FAU’s made-to-order adsorbent materials. This research is of strategic importance to the U.S. energy security and well-being and prosperity of our small/rural communities and is in line with Environmental Protection Agency’s (EPA) commitment to curb our emissions, to protect the environment, and to support environmentally sustainable technologies. Our proposed process drastically simplifies biogas upgrading using adsorbent materials engineered specifically to produce grid-quality biomethane. This innovative technology is comprised of concurrent removal of carbon dioxide, hydrogen sulfide and water vapor from the feed gas, followed by adsorbent regeneration and cooling in air before starting the subsequent cycle. Since the end users are the disadvantaged rural/small communities across the U.S. and landfill facilities, which are operating through taxpayers’ money, cost efficiency is critical to ensure the viability of the technology. To address this critical piece, cost considerations have been factored in throughout the experimental design by choosing inexpensive silica as support, utilizing hot air as the cheapest purge gas available, and maximizing adsorbent lifetime through material design. While the proposed technology holds significant merit, there are scientific challenges to tackle, namely developing adsorbent materials capable of (i) simultaneous removal of all impurities from synthetic biogas, (ii) withstanding air oxidation at high temperature, (iii) achieving minimal pressure drop in the adsorption bed, (iv) stable long-term performance, and (v) successful field testing with actual biogas. Materials development lends itself to industrial engagement – after all, application should be the goal. In the last phase of the research, a large batch of the best-performing material will be tested for upgrading actual biogas generated by landfill facilities in Palm Beach County, FL. The Solid Waste Authority of Palm Beach County has pledged their support of our research efforts in this regard. Once developed and implemented, the process will replace current technologies, eliminating the need for (i) air injection in digester to prevent hydrogen sulfide formation, (ii) separate desulfurization unit, (iii) drying step, and (iv) biogas compression/cooling. Therefore, this integrated process will have a much smaller environmental footprint, with lower capital and operating costs compared to competing technologies. The research results will also contribute to lowering the emissions of air pollutants and odor-generating compounds, enhancing air quality and human health. In brief, the project outcomes will positively impact our socio-economic and environmental well-being, directly contributing to all sustainability pillars, namely economic, environmental and social.