Advanced two-stage biomass gasification process

The visible final exploitation of fossil energy sources and the greenhouse discussion have initiated the search for a more efficient use of available energy sources and raw materials. Further more, research activities have started to develop utilisation systems for renewable sources. Here, the energetic and non energetic use of biomass and bio-waste is supposed to play an important role. Gasification technologies are said to have a greater potential than incineration technologies. Gas produced with gasification technologies can be used for various processes as synthesis or fuel gas. The formation of tars still represents the main problem during the conversion of biomass using pyrolysis or gasification. With entrained flow reactors, which were developed for the gasification of coal, a tar-free synthesis gas can be produced. An economic use of this technology requires large plants. Due to lower energy density in comparison with coal biomass should be converted in decentralized, small plants. The implementation of technologies which only need simple equipment and therefore better suited for smaller, decentralized plants, fails because of formation of tars and expensive gas and waste water cleaning units, which are necessary for their removal. The implementation of one-stage technologies which are originally developed for the gasification of coal like atmospheric fluidised bed reactors, pressurized fluidised bed reactors, circulating fluidised bed reactors, co-current or counter-current fix bed gasifiers do not produce a gas which meets the requests of the following applications until today. To reduce tars and other impurities inside the process, various multi-stage technologies are developed and tested partly in technical scale. The advantage of these multi-stage technologies is the separation of particular process steps. This renders possibilities to control the reaction conditions of every single step and to choose various and adjusted parameters. Such multi-stage technologies are discussed below. The Integrated Pyrolysis and Combustion is a new two-stage gasification process for fuels with a high amount of volatile matter of organic material as for example different biomasses, bio-waste or municipal waste with the goal to produce a hydrogen-rich gas without nitrogen is discussed in detail, too.