Dissertation > Excellent graduate degree dissertation topics show

The Cold and Hot Experimental Research on Biomass Fluidized Combustion

Author: LiShuangJiang
Tutor: YuChunJiang；FangMengXiang
School: Zhejiang University
Course: Thermal Power Engineering
Keywords: Biomass Fluidization characteristics Mixing characteristics Particle concentration Temperature distribution Burning share
CLC: TK6
Type: Master's thesis
Year: 2008
Downloads: 177
Quote: 1
Read: Download Dissertation

Abstract

Energy is the basis of development of human society, a major change in the energy structure has led to the tremendous progress of human society, the growth of the gross national product is always simultaneous increase in energy consumption. Oil will be depleted in the 21st century, a new energy structure will be formed in the new century, a variety of energy coexist energy system will become the characteristics of the new century's energy structure, biomass energy will become an important energy source for the 21st century. Biomass direct combustion power generation technology, as a biomass energy use step of the process, and highlight the economic benefits, is an effective way of utilization of biomass energy in China. Circulating fluidized bed combustion with fuel adaptability, low combustion temperature, combustion efficiency, and load regulation performance and other unique advantages, suitable for burning biomass fuels, especially high alkali straw biomass fuels. Because of the particularity of biomass shape and physical properties, and compared to conventional fossil fuels, biomass specificity of the flow in a circulating fluidized bed, can significantly affect the combustion within the furnace, circulating fluidized bed by cold experiments endogenous substances fluidization characteristics of the bed material, mixed separation characteristics and the characteristics of in-depth study of the distribution of particle concentration will guide the engineering practice a lot of sense. In the FURNACE research based on the thermal experiments can learn more about biomass combustion characteristics in the furnace, in order to optimize the circulating fluidized bed combustion of biomass fuels combustion organizations to improve combustion efficiency. To the fluidization characteristics of the biomass in the fluidized bed, mixing separation characteristics and particle concentration distribution characteristics of understanding, to build their own cold circulating fluidized bed test rig, the influence of different factors on the bed fluidization characteristics effects, including: biomass particles with the ratio of the bed material, raw material particles of the bed material particle size and shape as well as the process time from the fluidizing impact. Found through experimental studies, in the same conditions, when the bubbles within the bed, the biomass particles from the upward movement of the trend, except rice husk, the upward movement of the bubbles can change the biomass mass share of the distribution within the bed. The experiments showed that when raw material particles and the size of the bed material particles vary greatly when two particles quality than fluidized bed critical characteristics significantly when two particles of similar size, less affected. Particles of different shapes and river sand mixed with river sand grain structure of rice husk can accommodate a greater impact on the critical fluidization characteristics of the bed. From the particle distribution, biomass and river sand mixture showing a significant stratification in the bubbling state, the uneven distribution of biomass in the furnace height, almost all concentrated in the upper part. Circulating fluidized bed state, the biomass particles in the furnace height is relatively evenly distributed, but the particle concentration of the mixture as a whole or the direction of the bed height decreases, the concentration of biomass particles in the bed with a high rise shown a gradual decreasing trend. The two biomass straw and straw test bench in the small hot burning biomass circulating fluidized bed combustion test, the temperature distribution along the furnace height analysis, binding Cold experimental results Explore the circulating fluidized hot conditions bed furnace combustion share distribution. On the basis of the partition heat transfer balance Thought of the introduction of the concept of effective area than the endothermic share distribution the thermal test station along the height direction of the furnace combustion modeling and quantitative Solving distribution along the direction of the furnace combustion share. The study found that biomass circulating fluidized bed combustion furnace temperature distribution is inhomogeneous process, the high temperature zone in the upper part of the furnace, and the dense phase zone temperature about 50 ° C lower than the high temperature zone. Combustion furnace dense region share is small, burning mostly in the dilute phase, the dilute phase zone temperature rises. The paper also run the circulating fluidized bed boiler fuel raw material for practical engineering data acquisition and analysis, the effects of different load furnace temperature distribution. The study found that the temperature in the chamber after the dense region exports with height increased gradually increased, the maximum temperature at the furnace exit position. Used in the thermal test Thought biomass combustion furnace under different loads share distribution, found in the practical industrial-scale furnace combustion share distribution is similar to the thermal test, combustion occurs most in the dilute phase zone , and in the less dense region and furnace exit. The use of the combustion build share model predictive furnace temperature distribution of the obtained results with the actual measurement result is in good agreement.

Related Dissertations

CLC: > Industrial Technology > Energy and Power Engineering > Bio-energy and its utilization
© 2012 www.DissertationTopic.Net Mobile