The Study of Nitric Oxide and Nitrous Oxide in a Vortexing Fluidized Bed Combustor

• Main Authors: Sheng-Hung Yang, 楊勝鴻
• Other Authors: Chien-Song Chyang
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/92808565907086814362

碩士 === 中原大學 === 化學工程學系 === 87 === All experiments are carried out in a 0.45 m I.D. pilot scale vortexing fluidized bed combustor. In this work, rice husk, soybean, and high sulfur subbituminous coal are used as feeds and silica sand is employed as the bed material. The effects of various operating conditions, such as bed temperature, excess air ratio, and method of bed temperature control on NO and N2O emissions have been investigated. The experimental results reveal that the NO emission increases with excess air ratio and is almost independent of the temperatures of bed and outlet of combustor. In addition, It''s been concluded that the amount of NO and N2O formed while water injection is be employed is more than that formed while heat transfer tube in combustor chamber. Above the bed surface, the high-volatile fuel appears to yield significant NO and N2O initially and NO emission increases with volatile content. In respect of the distribution of NO concentration in freeboard, it decreases with the distance from the axis of freeboard by the vortex effect. Bed temperature makes a greater influence on the trade-off between NO and N2O than primary air. In general, NO forms on the bed surface initially; achieves a maximum value before the inlet of secondary air and reduces considerably during freeboard eventually. N2O wouldn’t be generated in combustion of biomass.