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CHP gas turbine fuelled directly by a biomass gasifier

Exploitable results

This project focused on the development of technically and commercially viable small (5 to 250 kWe) combined heat and power (CHP) plants involving a gas turbine fired directly by a pressurised biomass-fuelled gasifier followed by a cyclone combustor. Direct-fired systems avoid the complexity and cost of sophisticated heat exchangers and offer a strong opportunity for commercial exploitation. The project took state-of-the-art gasifier and combustor technology and advanced it with the aid of computational fluid dynamics (CFD) modelling. The experimental facility with a pressurised gasifier and cyclone combustor firing a gas turbine powered generator of about 40 kWe was designed, the gas turbine unit was built and ready for installation; the pressurised gasifier and the cyclone combustor were constructed and the low pressure commissioning had started. The facility was constructed to research and establish the deposition, erosion, corrosion and performance parameters for a number of biomass fuels; to define allowable operating temperatures (and hence efficiencies) and establish (through modelling and experimental measurement) control and protection arrangements for a pre-production prototype unit utilising a robust low cost gas turbine generator. Preliminary dynamic modelling of most of the system was then completed. Modelling of the combustor and turbine gas and particle flows was also an integral part of the project with a reacting flow model being utilised to assist in combustor design; the development of validated models was intended to assist in the interpretation of the experimental results and in the design of the pre-production prototype. Four wood fuels, with their relatively low ash and alkali contents were identified and, depending on the success of the results with these fuels, experimental work with less benign fuels could have been included.