The objective of this project is to enhance the technical and economical viability of small up to medium sized (1.0 to 2.5 MW power output) decentralised biomass CHP units basing on the combination of gasification technology and gas engines which are designed for rural areas in Europe and developing countries. The project is designed for a clear assessment of two different gasification technologies (pressurised air blown and pressurised advanced steam blown fluidized bed gasification) against a wide spectrum of operating conditions which means a temperature range of 700 to 925 C and a pressure range of 0.5 to 1.0 MPa. Three different kinds of biomass will be considered as there are birch, salix and crushed pelletised straw. Main goal of the project is to minimise the impurities (condensable tar and dust) of the gas up to 50 mg/Nm3 in order to receive a suitable gas for a gas engine. Furthermore, a robust gas engine will be designed and adapted for direct utilisation of the biomass fuel gas generated without extensive gas cleaning between the gasifier and the engine in order to simplify the overall system. However, the acceptable amount of tar for utilisation of the biogas in a gas engine depends on the optimal gas inlet temperature which has to be defined.
Experiments on air and steam blown gasification will be carried out using three types of biomass. For comparison of both gasification modes the same pressurised fluidized bed gasifier will be used in order to receive comparable results. For minimisation of the tar content also tar cracking processes by the bed material of the reactor will be taken into account. If necessary in addition further tar cracking can be achieved by injection of oxygen or air in the biogas. Regarding the robust gas engine a fast hydraulical valve actuating system will be developed which withstands the stress at gas inlet temperatures up to 1 60 C and which is able to charge the cyclinder of the engine sufficiently. This includes pre-tests and a new design of the inlet valves of the engine. The experience gained from the test runs will be used for engineering of a well tuned highly integrated overall system consisting of an allothermal steam blown pressurised fluidized bed gasifier (2.5 MW,h) and a lean engine at an economical size in the range of 1.0 to 1.5 MW power output.
Expected Achievements and Exploitation
- Experiences on biomass gasification concerning efficiency, conversion rate, gas composition in particular with respect to tar content minimisation. - Design of a robust lean engine for biomass gas utilisation. - Engineering of an overall system for decentralised biomass utilisation at a commercial size. Implying the availability of economical biomass conversion systems, in particular decentralised applications in the range of l to 10 MWel) this market could be developed.
The dissemination strategy of the partners is to continue in the development, to publish results of their investigations in order to indicate the prospects of the biomass technology and to offer this technology on the market. The expected aim of this project is to improve European companies' market position in the field of engine manufacturing. The marketing of the robust lean engine for biomass gas utilisation to be developed in this project will be forced and assured by the industrial partners involved.
Funding SchemeCSC - Cost-sharing contracts
100 44 Stockholm