Method to determine dew point temperature of natural gas combustion products

Currently, there are various methods to determine the dew point temperature of humid air and combustion products of distinct types of fuels. It is especially important when designing deep flue gas cooling systems in boiler plants that do not consider the composition of a particular type of fuel. In this regard, the urgent issue is the development of a simple method to calculate this value when using natural gas as fuel. The authors have used the methods of thermodynamic analysis of processes in humid air and fuel combustion products, and the results of thermal calculations of fuel combustion processes. The authors have conducted the analysis of existing methods to determine the dew point temperature for natural gas combustion products, since it is necessary to prevent condensation of water vapor in chimneys and chimney flue to ensure their operation conditions, especially during deep cooling. A simple method to calculate this value is proposed, and an example of its use is presented. The authors have analyzed the influence of such factors as the moisture content of air and natural gas, the absolute pressure of combustion products and the air flow coefficient per the dew point temperature. It is shown that the final refinement of the given value can be quite significant, and therefore the use of the method that allows considering these patterns is advisable when designing deep flue gas cooling systems. It is established that the proposed method is quite universal and can be used during combustion of natural gas of various compositions and various values of factors characterizing fuel combustion.