Biomass CHP optimisation

Abstract

Ever increasing competition in the energy market place is driving companies to revaluate their current operation and develop means o f delivering their product in a more cost effective manner. Electricity generation is a prime mover in the Irish market and with the open market there is a drive for fuel efficiency where companies are looking to indigenous fuel sources, such as biomass. In biomass power plant the use of dry fuel provides significant benefits over wet biomass fuels. Utilisation of dry biomass fuel can increase system efficiency, lower air emissions, and deliver improved operation. The provision of installing heat recovery systems to reuse rejected heat in order to dry biomass fuel can reduce the moisture of the fuel, which can have a significantly positive affect on the operation of the system. The results of this study clearly indicate for the case of Grainger’s Sawmill and IBS that the recovery of heat from the condensers to be used for the purpose of drying the biomass fuel will results in a optimizing the system. However, further study is required to fully ascertain the exact affect of operating the plant with a consistent fuel size and moisture content of 50%. The two areas of heat recovery which were inspected for their viability are the condensers and flue stack. The latter was an unviable option due to the low amount of thermal energy that can be recovered safely. Where as there is ample capacity in recovering heat from the condensers to meet the fuel moisture reduction requirements of the system. As part of the study, in-depth analysis of the fuel streams were analysed against European standards and best practice, mainly focusing on IE A Bioenergy Task 32 studies. Results yielded that a reduction in the fuel moisture content from the 2009 average of 60.43% per kg of biomass fuel to the lowest acceptable plant limit of 50% per kg would equate to a reduction in fuel requirements of 20% per year.