Study On Structure And Thermal Parameters Of Dual-pressure Boiler In Vertical Tank For Recovering Sinter Waste Heat

Waste heat boiler is the energy conversion equipment in vertical tank for sinter waste heat recovery system, connecting the waste heat recovery tank and turbines and playing an essential role in the system, whose parameters affects the performance level of the whole system. Based on the vertical tank for sinter waste heat recovery system, waste heat boiler’s heat medium is hot air, whose temperature can reach520-580℃, beyond the temperature of heat medium which is known as350-400℃for sinter ring cooling waste heat recovery. At present, the literature of sintering waste heat boiler can be drawn lessons is less, and the heat medium temperature520-580℃in waste heat boiler research is rarely reported. Based on this, the paper carried out related research which based on the sinter tank for waste heat recovery of waste heat boiler, provide a good theoretical basis for subsequent waste heat boiler technology research.First of all, according to the thermal level and the flow rate of hot air in boiler import, the characteristics of the general structure of the boiler was determined; Secondly, according to maximum exergy value corresponding hot air parameters carried by hot air in the waste heat recovery tank’s export, determine design parameters for the boiler thermodynamic calculation, and then, figure out the structural parameters by boiler thermodynamic calculation; Finally, through the energy analysis to study the relations of3class variables in waste heat boiler, through the analysis of the operation of the boiler thermal medium parameters and structure parameters and import influence on subsequent generation and boiler efficiency, appropriate boiler imported thermal medium parameters is obtained and the operation of the boiler and the structure parameter, for subsequent pointed out the direction of the parameter optimization of waste heat boiler.The main results are as follows,(1) The vertical dual-pressure with no reheat forced circulation boiler is chosen in this system, fixing up high-pressure superheater, high-pressure evapvrator, low-pressure superhrater, high-pressure economizer, low-pressure evapvrator, low-pressure economizer; (2) Within the adjusting range of possible production in the future, the higher the high pressure steam’s temperature and pressure, the lower the high pressure pinch point temperature difference and approach temperature point, the lower the low pressure steam’s temperature, the higher the low pressure steam’s pressure, the higher the low pressure pinch point temperature difference and low pressure approach temperature point, the higher the power generation; On the contrary, the power generation would be lower; the high pressure steam’s temperature, low pressure steam’s pressure, low pressure pinch point temperature difference and low pressure approach temperature point are the main factors on power generation;(3) Increasing the high pressure steam’s temperature, the low pressure steam’s temperature and pressure, the low pressure pinch point temperature difference and low pressure approach temperature point, reducing the high steam’s pressure, the high pressure pinch point temperature difference and approach temperature point, leading to the dropping of waste heat boiler efficiency; On the contrary, the parameter would be higher;the high pressure steam’s temperature, low pressure steam’s pressure, low pressure pinch point temperature difference and low pressure approach temperature point are the main factors on boiler efficiency;(4) With the change of the air parameters at the import of waste heat boiler, waste heat power generation power would change, as for a360m2sintering system, the system got the highest power, which is29.17MW, when the hot air temperature is576℃, the flow rate of573300m3/h. The power was higher than traditional ring waste heat recovery system by61%.