The Application Study Of Spiral Coil High Efficiency And Low NO_x Pulverized Coal Burner

Pulverized coal clean combustion technology is a relative reasonable way to satisfy the energy structure of China,and to alleviate the emissions.Research team and cooperative enterprise develop a high efficiency and low NOX liquid slag pulverized coal burner with years,and match with a ma organic heat carrier chain furnace.The environment in combustion chamber is terrific as burner runs in a slag manner,and the lining will be easily eroded for long.Considering production demand,enterprise uses jacket water-cooled furnace lining to get “slag removal ”.The burner has been operated for many years with good performance in this cooling way.The operation and test results show that: when the burner works,the emission index of boiler below the national standard limiting value,and thermal efficiency above 90 %.This technology has reached the conditions of market promotion.Cooling water absorbs the heat in lining and produce a lot of hot water in the process of burner cooling.This water can be consumed for steam and hot water boiler.Organic heat transfer material heater uses heat transfer oil as heat carrier,the system has no water demand.If production in company without hot water consumption,this cooling way will cause great waste of energy.To enlarge the application of pulverized coal burner,this paper bases on the research of the project team,and intends to use heat-transfer oil cooling the burner.The main contents include the research of heat transfer oil coil structure development,burner water-cooling experiment,numerical analysis of lining structure and the feasibility verification of oil cooling scheme.First of all,the cooling structure of spiral coil pulverized coal burner is designed and manufactured in this paper,then carried on the furnace successfully.The determination of tube parameters is critical,from the aspects of heat transfer oil flow rate,anti load fluctuation capability and coil processing difficulty,the pipe diameter is ?108×6.Determine the burner structure parameters in giving sturcture,and arrange the pin with numerical analysis conclusion.The burner meets the design requirements after manufacturing process and post-processing process.The installation size of new burner surpass that of furnace,and uninstalled directly on the furnace.By arranging the four tubes of furnace,the burner and furnace dock well.Secondly,considering the security,this paper researches the experiment of the cooling water flow in spiral coil burner,analyzes the factors on slag covering process and heat transfering,and then tests the emissions and thermal rate of boiler.The results show that: slag on furnace lining surface are stable in water cooling way,and easily affected by coal quality.The calorie of coal suits the ash melting point,ash content moderates and the viscosity-temperature curve flats is required in coal selection.Reasonable water flow and ash content contributes to slag covering process.Heat transfer of lining increases with the augment of flow and combustion load.Influence of excess air on heat transmission stems from the comprehensive effect of combustion temperature and flame dynamic.When burner operates well,the thermal loss of incomplete combustion in boiler is better than the common coal-fired boiler,without denitration equipment,the NOx emission less than 150 mg / m3.Thirdly,establish the model of lining structure with the finite element method,and analyzes the effect of pin,convection heat transfer coefficient and slag layer condition on lining.The results show that the temperature of pin and the solid-liquid interface decreases with pin number increase,wall temperature almost unchange.With the ratio of pin arrangement increases,the pin temperature tends to be uniform,the change of tube wall temperature unchange.The solid slag layer thickness mainly protect the lining,the length of pin has great influence on the thickness of the solid layer.When the heat transfer coefficient is low,the lining temperature distribution can be controlled by adjusting the flow.The flow rate should not be too high if cooling capacity demand is enough.With the increase of liquid slag coefficient,the temperature of each monitoring point increases obviously.Slag is solid when boiler starts,the temperature of each point exceeds the allowable temperature.However,the operating conditions turn the solid layer into liquid quickly,the lining structure keep stable,heat transfer oil safety.Finally,judge from the cooling degree,pin temperature and pipe wall temperature,using heat transfer oil can meet the cooling requirements.The flow of heat transfer oil meets the cooling flow demand of boiler heating surface and spirial coil burner with single pump.The tube wall temperature distribution of burner is uneven.In order to reduce the capacity of heat transmission,weaken heat concentration,and improve the load adaptability of the Spiral Coil burner,it is recommended to optimize on the filler in pipe gap,nail parameters and multiple tube side structure.