Co-production of Pyrolysis Oil in District Heating Plants: Systems Analysis of Dual Fluidized-Bed Pyrolysis with Sequential Vapor Condensation

摘要

Flash pyrolysis of biomass yields a liquid applicable as a fuel oil substitute and as a basis for production of chemicals and fuels. Biomass, being a renewable resource, is foreseen to be in increasing demand. An increased usage may lead to scarcity of biomass and emphasizes the need for high-efficiency conversion processes. In this study, the efficiency and capacity aspects of an integration of pyrolysis oil production with a district heating plant by means of dual fluidized-bed technology has been modeled. Further, fractional condensation of the pyrolysis vapors has been applied, enabling part of the condensation energy to be recovered. The concept shows potential for significant pyrolysis oil production while keeping the delivered power and heat constant The use of excess heat from the pyrolysis production in the district heating net results in a 10% higher overall efficiency than production without heat supply to the district heating net.