| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 103 === An arrangement of heat exchanger is a key point in the design of fluidized boiler. This arrangement is depend on the amount of heat released in each section of the combustor, including bubbling zone and freeboard zones. In addition, heat release rate is defined as the amount of heat released in each section of the combustor. Heat release rate can be calculated from the oxygen consumption of each section per total oxygen consumption. The purpose of this study is to investigate the relationship between in-bed heat release rate and fuel properties, such as particle size, volatile/fixed carbon ratio. The effects of in-bed stoichiometric oxygen ratio on in-bed heat release rate are also investigated.
Combustor can be divided into two regions from bottom to top, namely, bed zone and freeboard zone. The two types of fuels, coal and thorny bamboo are used as feeding material. The particle size of the coal ranges from 854 to 3644 μm. The operated in-bed stoichiometric oxygen ratios are between 80% and 100%. Total primary air is 3 Nm3/min and the secondary air is 2 Nm3/min. The excess oxygen ratio was kept at 40%. The silica sand is used as the bed material.
The experimental result shows that the in-bed heat release rate is increased with the decreasing volatile/fixed carbon ratio in all fuels. As the mean particle size is increased, the in-bed heat release rate is also increased. Here we regress the data to build the empirical equation, . It can be summarized that the effect of fuel properties on the in-bed heat release rate is insignificant.
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