Equipment And Technology Research On Waste Heat Utilization For Coal Water Mixture Boiler With Upward-spray Water Washing Method

The energy problem has become one of main restricting factors gradually, which restricts our country's economy and society's development. In order to improve energy's utilization efficiency, one of the most feasible methods is energy conservation. Coal accounts for 70 percent of Chinese energy consumption, and coal boilers account for 80 percent of all boilers, so it is very important to develop efficient industrial coal boilers. Because the CMW's (Coal Water Mixture) character is energy-saving and beneficial to environment, Waste heat of Coal Water Mixture boilers'flue gas is the research subject of this paper.According to heat quantity equilibrium method, the value of fuel gas's heat recovery from CMW boilers exceeds that from oil boilers. Comparing with the value of fuel gas heat reclaimed from other fuel such as coal, oil and natural gas, CMW (65%) was taken for example, while the fuel gas temperature drops from 195℃to 55℃, the heat given off contributes to boilers'thermal efficiency by 17.4%.This paper analyses the reasons to industrial boilers'high releasing gas's temperature, and points out that it is feasible to low releasing gas's temperature at present. Based on the conclusion above, a kind of new wet method and a set of new equipment to use fuel gas's heat from CMW boilers were brought forward. The principle is to heat up boiler feed-water with obvious heat and latent heat got from fuel gas by the wet method using a secondary heat-exchanger.Aim at 6t/h CWM boiler, the paper designs equipment to get energy from CWM fuel gas. The paper pays attention to up-big-hole-spray-break- up system(UBHSBUS), optimizes the four factors-the water outlet diameter, the boult type, the distance between the boult and the water outlet and the angle between the boult plane and level. Furthermore the paper gets the water droplet distribution formula in the conditions of the four factors. Meanwhile gas-guide boards were design with the help of CFD software FLUENT.The primary research results show that based on the new technology of spin-flow-fluidization on heat-transfer surface it is feasible to use waste heat energy from flue gas of CWM Boilers at the aspects of technology and economy.