Shaping Future Opportunities for Biomass Gasification - The Role of Integration

Abstract: A considerable number of studies indicate that biofuels produced from lignocellulosic biomass will most probably play a significant role in achieving the climate goals stated in the Paris agreement. Several candidate technologies could be implemented to produce these fuels, and one of the most promising is thermal gasification. Gasification is a robust technology that has been demonstrated successfully at industrial scale and shown to be able to achieve high conversion efficiencies and relatively low production costs. However, there are currently no large-scale plants in operation or under construction, since such plants are unable to compete with their fossil counterparts under current conditions. This thesis explores how different forms and levels of integration could facilitate deployment of large-scale biomass gasification for future production of biofuels. Three levels of integration are considered, a technological level, a process level and a value-chain level. Different integration concepts are then assessed with respect to these levels. From a technology perspective, the implications of switching feedstock are studied. At the process level, heat integration with existing sawmill plants as well as integration of an electrolyser unit with a gasification plant are investigated. From a value chain perspective, integration with the value chain for producing fuels for use the Swedish iron and steel industry is considered, as well as integration with the electricity system. The results presented in this thesis indicate that the different integration options investigated can contribute to making biofuel production through biomass gasification more cost-efficient. Switching gasifier feedstock can lower biofuel production costs by up to 42%. Efficient heat integration with sawmills is the most attractive option to decrease production costs from a plant-owner perspective. Integration of a flexible gasification unit equipped with CO2 capture capacity for either long-term storage or re-use as feedstock for biomethane production through the Sabatier reaction with hydrogen produced through electrolysis increases the economic competitiveness of the gasification unit, while stimulating increased construction of renewable electricity generation capacity. The thesis thus demonstrates that well-planned integration of biomass gasification plants can contribute significantly to making the technology more competitive

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