An Application Analysis Of Solution Circulation Heat Recovery System In Natural Gas Fired Boiler

Natural gas gets more extensive application in various fields all over the country as a clean energy. The main component of natural gas is methane and a large amount of water vapor generates after combustion. How to recover the latent heat of water vapor in the flue gas is crucial to improve the efficiency of natural gas fired boiler.This paper introduces a kind of application of liquid desiccant technology with lithium chloride solution to absorb the water vapor in natural gas boiler flue gas to recycle its latent heat circulation system. The design analysis of solution circulation heat recovery system has been made, and the heating and mass exchange process has been study with the method of numerical simulation in a packed tower under different working conditions. The main contents of this paper are as follows:1 、 This paper introduces the research background and current situation of the development of liquid desiccant technology, and makes a feasibility analysis of solution circulation heat recovery system.2、According to the characteristics of the natural gas boiler, solution circulation heat recovery system can be divided into three subsystems which benefit for the analysis of the principle. Based on the choice of solution cyclic working substance and the screening of packing layer, a physical and mathematical model which is counter flow and heat insulation was established.3、The different parameters of heat and mass transfer coefficient, effective infiltration area, solution surface vapor pressure were analyzed, and the preliminary approximation in different stages was be set up. By using matlab software,the heat and mass transfer process simulation has been made with the different parameters of the inlet condition. The results show that in the counter-flow packing tower, the gas liquid ratio and packing layer height are the main influence parameters and the flue gas temperature at the inlet of a small scale changes is the secondary impact parameters in heat and mass transfer process.4、According to the analysis of combustion characteristics of Shaanxi natural gas,the sensible heat and latent heat value have been calculated in the case of constant flow when the excess air coefficient was at 1.1. The thermal efficiency of gas boiler was estimated by the analysis of the absorption efficiency of flue gas and the gas boiler energy conservation. And the economic and environmental benefits are briefly analyzed.