Applicability Research Of Spray Tower For Recovery Of Waste Heat From Natural Gas Flue Gas

With the rapid development of China's economy,the pressure of energy and environment is increasing day by day.Natural gas,as a clean energy,is environmentally friendly and produces little soot or sulfur dioxide.In recent years,it has rapidly increased its market share.As a primary energy source,the use of natural gas is restricted by the total amount of resources and supply capacity.Therefore,the efficient utilization of natural gas is of great practical significance.Deep recovery technology of the flue gas waste heat is an important way to improve the utilization efficiency of natural gas.In this paper,entranspy dissipation of the heat transfer process in which the flue gas and the water are in direct contact in the waste heat recovery spray tower was analyzed,and the method of segmenting spray was proposed to reduce the irreversible loss in the heat transfer process.The entranspy dissipation of sensible heat transfer and latent heat transfer in one-stage and two-stage spray towers was compared.The effect of subsection spraying of gas-fired thermal power plant and gas-fired boiler at different exhaust temperature is analyzed.The theoretical model of the flue gas waste heat recovery spray tower was established,based on which the influence of different factors such as water-gas ratio,heat exchange height,droplet size,spray temperature and section height on the heat exchange effect of spray tower was analyzed.The experimental platform of the segmented flue gas waste heat recovery spray tower was set up,and the accuracy of the theoretical model was verified through the experiment,the effects of water-air ratio,spraying height,spraying water temperature and subsection ratio on heat transfer efficiency of spraying tower were studied by changing experimental conditions.Based on the mathematical model analysis and experimental study of the spray tower,the structural and operational parameters of the spray tower are optimized under the given conditions of practical engineering.Waste heat recovery is carried out in one-stage spray tower and two-stage spray tower with optimized parameters,by analyzing the annual cost of waste heat recovery per unit of the two schemes,the suitable application conditions are determined.The ground concentration of NOx in flue gas was calculated by AERSCREEN model,and the influence of deep recovery of waste heat of flue gas on the diffusion of pollutants in flue gas was analyzed from the aspects of smoke exhaust temperature,smoke exhaust velocity and environmental temperature.