Simulation Study On The Influence Of Secondary Air Regulation Strategy On Combustion Of Pulverized Coal Furnace

Since the founding of our country,various industries have experienced from the start to the vigorous development.The second industry is the core of the economic development of our country at present,and the production and manufacturing industry can not do without electricity,the so-called industry can not move without electric power.At present,China's electric power consists of traditional thermal power,nuclear power and emerging wind power,hydropower,solar power,biomass power generation,etc.However,thermal power will still occupy a dominant position in the future for a long time.Thermal power accounts for 71.6%of the electricity generated until the end of2016.This means that coal-fired and gas-fired power plants are essential energy plants in China,which provide a source of power for the development of various industries.Most of the thermal power generation is coal-fired power generation,and this paper mainly focuses on coal fired power plant pulverized coal furnace.In the operation of pulverized coal furnace,the primary air carries pulverized coal into the furnace,and the primary air is mainly used to carry fuel,of course it also plays the role of combustion support.The secondary air flows into the furnace from other vents,and the secondary air mainly contributes to combustion,so the reasonable degree of the secondary air distribution has a direct impact on the combustion in the furnace.There are often two kinds of unreasonable conditions in secondary air distribution:too much air distribution,too much air distribution will affect combustion temperature and combustion stability in furnace;and too little air distribution will cause insufficient combustion of pulverized coal in furnace and causes chemical incomplete combustion heat loss to increase.So we focus on these questions,take the supercritical pulverized coal furnace in a power plant as the model,uses the commercial software CATIA to model the three dimensional model,and then carries on the mesh division,finally carries on the numerical calculation.In the course of calculation,the air flow rate of each secondary air nozzle is adjusted,and the air flow parameters are obtained from the cold model test bench of our group.By observing the combustion temperature in the furnace and the content curve of each combustion product,such as NO_X?SO_X?CO?O₂,the combustion effect in the furnace with different air distribution can be obtained,and the optimum air distribution ratio can be found,which plays a guiding role in practical production.In the numerical simulation,each boundary condition is set to be the same as the actual parameter,which can make the data more convincing,and the 3D modeling is also carried out according to the actual size of the unit.The adjustment of secondary air distribution is also carried out according to the operation rules of the power plant,so the work in this paper is in line with the actual situation,and the obtained data are also more persuasive.There are two conclusions we got according to the research.First,by summarizing the variation of temperature and velocity in combustion area and after-combustion area before and after reducing the secondary air,we can analyze the effect of reducing the secondary air on combustion stability and circular firing generating.Second,according to the analysis of variation of CO and CO₂ content,we can estimate it that if the combustion is sufficient.The research results will be applied on the secondary air regulation plans.The optimized plans will improve the operation efficiency of boiler significantly and reduce the cost of production.