Nitrogen oxides generated from combustion are mainly the combination of NO and NO2 (both are generally referred to as NOx), in which NO is the major component. As the industrial heating grows, the rapid rise of NOx emission has deteriorates air pollution in China, caused a series of environmental problems in some regions and constructed a big threat against human health and living environment. Therefore, how to reduce NOx emission has become a key issue all over the world.The flat flame combustion technique has been popularly applied to various industrials furnaces due to its advantages such as good flame stability, even flame temperature distribution. There are two flat flame combustion techniques: the premixed combustion and the partially premixed combustion. The former is adopted by a majority of burners in our country. In the premixed combustion, fuel and air are premixed and the flame temperature is higher. Hence, the high temperature of flame is bound to lower the durability of burners and raise the generation of NOx exhaust, which are the limitations of the premixed combustion. In comparison, the partially combustion can slow down the mixing time of fuel and oxidant and reduce the burner's local temperature, which helps to reduce the concentration of NOx exhaust.It is introduced in detail the structure of the flat flame combustion test bed and the selection of test equipments and the design of test parameters. Subsequently, the combustion experiments were conducted to investigate temperature distribution characteristics in the top part of the furnace and NOx emission behaviors. In addition, the effects of the excess air ration on the furnace heating and the NOx emission were analyzed as well. The study can be concluded as follows:1) It is established a flat flame combustion hot test bed, and do four different groups of the excess air ration of flat flame combustion test on hot test bed. In experiment, the temperatures of furnace top and bottom plate and inside the flue are measured by thermocouple; the flue gas emission concentration is measured by Gas analyzer.2) In the initial combustion period, the combustion rate is low and the flame area is relative large. As the furnace temperature increases, the fuel combustion rate increases and the flame area decreases. 3) While the excess air ration rises from 0.92 to 1.09, the furnace temperate and the emission concentration of NOx go up accordingly. However, its continuous rise results in the decrease of the furnace temperature and the emission concentration of NOx.All in all, the study offers technical supports on further optimizing the flat flame combustion process and controlling the NOx exhaust emission. |