JOINT MAE-CER SEMINAR
Utilization of Lignocellulosic Biomass for Power and Fuels
The energetic conversion of biomass is of interest to California in order to meet its Renewable Portfolio Standard (RPS) goals. With favorable climate and soil, a wide array of agricultural products are available, many of which create byproducts such as shells, trimmings, orchard removal, sawmill residue, and forest thinnings. Removing materials from forests is also beneficial for fire prevention, amplified by current conditions of drought and bark-beetle infestations. Biomass can be converted thermochemically by gasification to a producer gas (H2, CO, CO2, and hydrocarbons), and this gas can be further converted to electricity and fuels. There are many gasification technologies depending of the type of biomass, scale of the installation, and desired end product. Each of the technologies needs to be well adapted to these parameters to be profitable. In Europe, several FICFB gasifiers (Fast Internally Circulating Fluidized Bed) are operating in the mid-sized range of power (2-32 MWfuel). These gasifiers need no oxygen plant because air is injected into the combustor side of the dual-fluidized bed only, and therefore, the output gas from the gasifier is nearly nitrogen-free. This allows the gas to be used not just for electricity generation, but also synthesis to other fuels and chemicals. UCSD is conducting research together with West Biofuels on a 5-ton/day FICFB gasifier in Woodland, CA. The operating conditions and gas compositions are recorded with various instruments, such as micro-GC and FTIR. Besides the desired gases, the raw output from the gasifier contains unwanted compounds such as particulates, tars, and inorganics. Sulfur is a poison for many catalysts, such as used for Fischer-Tropsch synthesis or methanation. A GC-SCD is used to measure sulfur compounds in the gas. Besides H2S and COS, other organic sulfur compounds are present, such as organic sulfides, mercaptans, and thiophenes. For commercial methanation, all sulfur compounds need to be reduced down to the parts-per-billion range. A clean producer gas can then be converted to renewable natural gas. A fluidized-bed methanation has been designed on the laboratory scale to test nickel-based catalysts on a cleaned producer gas. Because of particle circulation in the fluidized-bed, various reactions are occurring in different zones, and coke formation/regeneration reaches a balance. The fluidized beds are modeled using Barracuda software to simulate the circulation, heat management, and bubble formation.
Dr. Reinhard Seiser received his PHD in Chemical Engineering from the Technical University Graz, Austria, in 2000. After his graduation, he joined UCSD as a Postgraduate Researcher and as Assistant Project Scientist, where he worked on various combustion problems including liquid and gaseous fuels, and solid and gaseous extinguishing agents. He designed several experimental setups for measuring ignition, extinction, and pollutant species in laminar flames. In 2005, Dr. Seiser joined ORYXE Energy, Inc. as a Principal Research Scientist to work on fuel additives for the diesel fuel and residual fuel market. In this role he supervised emissions measurements on a diesel engine as well as scientific projects with universities. Since 2008, Dr. Seiser is conducting research for UCSD at the Woodland Biomass Research Center, where supervises the measurements on a dual-fluidized-bed gasifier. He conducts gas, tar, and sulfur measurements on the producer gas and emission measurements on the combustor section and SI engine. Other experiments include tar reforming and conversion of producer gas to fuels, such as renewable natural gas and mixed alcohols.