Modeling of fuel combustion processes in a steam boiler when replacing standard burners

To date, most of Ukraine's thermal power equipment has exhausted its factory resource and is physically and morally obsolete. One of the ways to solve this problem is to modernize it with the introduction of modern fuel-using equipment. The decisive direction in this situation is the focus on domestic technologies, which differ from imported counterparts due to better adaptability to domestic equipment, as well as a more favorable price policy for domestic manufacturers. The presented work was carried out in order to check the feasibility of replacing standard burners with burners built on the basis of jet-niche technology in power boilers, for example, such as the GМ-50 (Е-50-3,9-440GМ) steam boiler. For this, a computer model of a steam boiler and regular burners was developed. The research was carried out using the ANSYS Student software package. The application of the numerical modeling method using the ANSYS Student software complex made it possible to perform a detailed analysis of the fuel combustion process in a steam boiler, evaluate its efficiency and study the impact on environmental indicators. The object of the research was the processes that take place during the combustion of gaseous fuel and their influence on the performance indicators of the GМ-50 power boiler. The subject of the study was a CFD fuel model of the GМ-50 boiler, whose regular burners are capable of working on both liquid and gaseous fuel. Methane was used as fuel. Both regular axial burners and burners built on the basis of jet-niche technology, which are more environmentally friendly, were used as burners. Verification of the CFD model, which took place using a known analytical technique, shows that the discrepancy between the values of analytical calculations and model calculations does not exceed 6.7 %. The average temperature of flue gases in the festoon window was selected as a comparison parameter. The temperature value of 1117 С was obtained analytically. Calculation using the CFD model developed in the ANSYS-CFX environment shows that the temperature value should be 1042 С. It was determined that regular burners are less environmentally friendly than, for example, modern jet-niche ones. So, for the coefficient of excess air  = 1.2, the average value of nitrogen oxides at the fuel outlet is 187 ppm. It makes sense to replace standard burners, for example, with jet-niche ones, which are most suitable for replacing standard ones.