Study Of A Waste Heat Recovery System In A Steel Plant

There is a very large of energy consumption in iron and steel metallurgy industry,and the steel waste heat resource distributed in each link of the steel production process.The condenser circulating cooling water of the steel plant power station belongs to low grade heat source,in practical application process,usually they are vented to atmosphere through the cooling tower,which wastes a large amount of waste heat resource,and cause thermal pollution to the environment.If we can recycle this part of waste heat,not only can produce a good economic benefit for the steel enterprises,at the same time conforms to the requirements of the national policy of energy conservation and emissions reduction.In recent years,with the mature of the absorption heat pump technology constantly,many domestic thermal power plant began using absorption heat pump to recycle the condenser cooling water waste heat.However,conventional thermal power plant of waste heat recovery system is through extract a part of steam from the steam turbine as the driving heat source of the heat pump,this way will not only affect the normal operation of the steam turbine,but also can reduce power generation efficiency.Based on the above two points,The main research contents are as follows:(1)Have a brief comparison and analysis of the combined heat and power direct extract steam heating scheme,compression heat pump heating scheme,the traditional absorption heat pump heating scheme,and combined with the specific waste heat resources in steel plant,put forward an improved absorption heat pump heating scheme,that is using evaporative cooling steam heating furnace as the driving heat source of the heat pump,thus for the condenser cooling water waste heat recovery,used for the heating of the steel plant in winter,this kind of waste heat recovery plan can not have an adverse effects for the normal operation of the steam turbine than directly extract steam from the steam turbine.(2)Design an absorption heat pump system apply to recycle the heat of the condenser circulating cooling water of the steel plant power station,and have a detailed analysis of the basic principles of system operation,design the process of the system for a steel plant in Hebei,and have a thermodynamic calculation and Heat transfer calculation for the new system,in the end have a model selection for the main equipment.(3)Analysis the influence of the driving heat source temperature,heat supply network backwater temperature,circulating cooling water inlet temperature and heat supply network water supply temperature for the performance of heat pump heating coefficient.(4)In allusion to the insufficient of the system,put forward an optimized retrofit scheme,and have a design and calculate for the optimized retrofit scheme,comparison and analysis with the original waste heat recovery system,verify the feasibility and economic benefits of the optimized retrofit scheme.(5)Have an economic and environmental protection analysis for the waste heat recovery system.The results show that,the payback period is 2.9 years,a heating season can save 747356 tons of standard coal,to reduce emissions of Carbon dioxide 1958072 tons,sulfur dioxide 6352 tons,nitrogen oxides 5530 tons,ash 194312 tons,soot 11210 tons,so this waste heat recovery system have a good economic and environmental benefits.