Advanced biofuel production via gasification – lessons learned from 200 man‐years of research activity with Chalmers’ research gasifier and the GoBiGas demonstration plant

Abstract

According to the Intergovernmental Panel on Climate Change (IPCC), scenarios that have a good chance of restricting global warming to less than 2°C involve substantial cuts in anthropogenic greenhouse gas (GHG) emissions, implemented through large-scale changes in energy systems. The use of renewable energy sources and fossil fuels, in combination with carbon capture and storage (CCS), could help to reduce GHG emissions in the AbstractThis paper presents the main experiences gained and conclusions drawn from the demonstration of a first-of-its-kind wood-based biomethane production plant (20-MW capacity, 150 dry tonnes of biomass/day) and 10 years of operation of the 2-4-MW (10-20 dry tonnes of biomass/day) research gasifier at Chalmers University of Technology in Sweden. Based on the experience gained, an elaborated outline for commercialization of the technology for a wide spectrum of applications and end products is defined. The main findings are related to the use of biomass ash constituents as a catalyst for the process and the application of coated heat exchangers, such that regular fluidized bed boilers can be retrofitted to become biomass gasifiers. Among the recirculation of the ash streams within the process, presence of the alkali salt in the system is identified as highly important for control of the tar species. Combined with new insights on fuel feeding and reactor design, these two major findings form the basis for a comprehensive process layout that can support a gradual transformation of existing boilers in district heating networks and in pulp, paper and saw mills, and it facilitates the exploitation of existing oil refineries and petrochemical plants for large-scale production of renewable fuels, chemicals, and materials from biomass and wastes. The potential for electrification of those process layouts are also discussed. The commercialization route represents an example of how biomass conversion develops and integrates with existing industrial and energy infrastructures to form highly effective systems that deliver a wide range of end products. Illustrating the potential, the existing fluidized bed boilers in Sweden alone represent a jet fuel production capacity that corresponds to 10% of current global consumption. 7

Economic assessment of advanced biofuel production via gasification using cost data from the GoBiGas plant

“…The waste products from the plant include waste water, fly ash, and bottom ash. As described previously, the costs for consumables can be significantly reduced through:…”

“…The methanation technology, which has been used in commercial plants that are based on fossil fuels, had to be scaled down significantly to match the DFB gasifier. An analysis of the performance of the process concluded that it is technically feasible to reach a biomass‐to‐biomethane efficiency of up to 70% based on the lower heating value (LHV) and dry ash‐free (DAF) fuel …”

“…As described in the technical review of the GoBiGas project, one of the main lessons that has been learned is that the equipment can be assembled using mainly commercially available components that have already reached a level of maturity corresponding to the n‐th numbered installation. In the GoBiGas project, the major technical component that had not yet reached a mature commercial state was the gasifier.…”

“…This means that the technology used for constructing the gasification section of the plant can be assumed to have a level of maturity similar to that of commercial CHP plants based on the fluidized bed technology, and that significant cost reductions due to learning cannot be expected. However, as GoBiGas is a first‐of‐its‐kind plant, these types of gasification and methanation technologies have been combined, and there is still potential to reduce the production cost by learning how better to combine and operate the different process sections …”

“…To achieve this, investment and operational costs were estimated based on data accrued from the GoBiGas demonstration plant. Aggregated reference data and SFs for a commercial APB plant have been established based on a detailed study of the investment costs of the GoBiGas plant, in combination with the previously published technical review of the process …”