Abstract:
Biomass is an energy source that receives attention, since it is abundant and low cost. When used for generating electricity, biomass fuels are combined with coal for combustion and transformation water into steam, which is then used to drive turbines and generators for producing electricity. This paper aims on developing a model simulation for a cogeneration system which composes of two Circulating Fluidized Bed boilers (CFB), a steam header, two turbines, and two generators. The data and related information were provided by Siam Kraft Co., LTD. The sensitivity analysis was also investigated the impact of uncertainly information on the steam production and load allocation for the boilers and turbines. The result shows that, the decisions on types of fuels are dependent on price and heating value of fuels. The study simulated the combustion of mixed fuels with three and four types of fuels. For the mixtures of three types of fuels, the minimum cost of steam production is 379,452 Baht/day or 71.87 Baht/ton of steam. The fraction of the mixture composition is 50.0% lignite (lanna), 12.1% sludge, and 37.9% pith. For the mixtures of four types of fuels, the minimum cost of steam production is 378,470 Baht/day or 71.68 Baht/ton of steam. The fraction of the mixture composition is 50% lignite (lanna), 12.2% sludge, 18.6% bark, and 19.2% pith. The more efficient boiler, the more load is allocated. Turbine producing less electricity, is less load allocation. While the same amount of electricity is produced, the thermal output becomes less