Large Scale Biomass Gasification Plant Integrated to a PC boiler

摘要

Gasification allows biomass to be co-fired at higher percentages than in traditional biomass cofiringmethods for a PC boiler, and makes it possible to use a variety of fuels that are cheaperthan high quality pellets. This provides an economical alternative for power producers looking toincrease their share of renewable energy generation and meet renewable portfolio standards(RPS). With the increase of coal boilers being decommissioned in North America, gasification isa method to retrofit existing coal boilers to biomass, partially or in full. This provides a means ofutilizing an already existing infrastructure to increase electricity production from renewablesources, leading to savings in capital costs. Utilizing gasified solid fuels in a large scale, highefficiencypower boiler enables better power production efficiency compared to utilizing thefuels in a small biomass boiler. Substituting biomass for fossil fuels has a positive effect ongreenhouse gas emissions and on the local economy. Metso’s gasification solutions are based on circulating fluidized bed (CFB) gasifiers. Metsocurrently offers two different gasification solutions, each able to cover a wide range of fuels. Thefirst solution is suitable for clean biomass. The second solution is more sophisticated and able tohandle high alkali fuels such as waste and agro fuels. Metso supplied the first solution toVaskiluodon Voima in Vaasa, Finland. At 140 MWth fuel input it is the largest biomass CFBgasifier in the world. The second solution was supplied to Lahti Energy, also in Finland. Itconsists of two (2) 80 MWth fuel input gasifiers, making it the largest waste CFB gasifier in theworld. This paper gives a brief overview of gasification, and then focuses on using thetechnology in a co-firing application.