Economic and Technical Perspectives of Chlorine and Sulphur Removal from Product Gas (Non-confidential version)

This project has the objective to investigate the economic and technical perspectives for the replacement of woody biomass with non-woody biomass in a biomass gasification process. Non-woody biomass fuels like straw, manure and sludge are cheap fuels with an increased chlorine, sulphur and ash content. A representative biomass composition for non-woody biomass is 13 wt% ash, 0.3 wt% chlorine and 0.6 wt% of sulphur. The replacement of expensive woody biomass fuels with non-woody biomass has a high economic potential, due to the low price of non-woody biomass. However, in a biomass gasifier the chlorine and sulphur is partly released as gas phase compounds or bounded in the ash. In order to fulfil the emission limits the chlorine and sulphur compounds should be partly removed. Consequently additional gas cleaning equipment is necessary for the removal of the chlorine and sulphur containing compounds. These additional measures in the gas cleaning increase the operational and investment costs of the gas cleaning. In this report the economic and technical perspectives for the use of non-woody biomass in a biomass gasification process for the production of electricity and/or heat with a boiler, gas engine and fuel cell were discussed. The project focussed on the additional measures needed in the gas cleaning for the removal of chlorine and sulphur containing compounds. The economic perspectives are positive for the use of non-woody biomass in a gasifier for the application of the product gas in a boiler, gas engine or fuel cell. The total additional gas cleaning costs for the removal of chlorine and sulphur compounds are approximately 26 euro/tonne biomass for the boiler application, 23 euro/tonne biomass for the gas engine application and 19 euro/tonne biomass for the fuel cell application. Therefore with a woody biomass price of 50 euro/tonne biomass the application of non-woody biomass in a gasifier becomes attractive when the price of the non-woody biomass becomes below 15 to 20 euro/tonne on the condition that the ash disposal costs are lower than 60 euro/tonne biomass.