Application Analysis Of Pinch Point Technology In Heat Exchanger Network Of Ammonia Synthesis System

Energy is an important material base for the development of the world economy.Although China's energy resources are rich,but the efficiency is low and irrational use compared with the countries with developed energy utilization in the world.The shortage of energy is becoming more and more serious with the continuous growth of the world population and the continuous development of industry.These factors have seriously restricted the development of national economy.And The shortage of energy become one of the bottlenecks of economic growth.Energy conservation has become a growing concern of the whole society.Heat exchanger network is an important subsystem of energy recovery.There are more than ten kinds of heat exchanger network optimization methods at present,pinch technology is still the most simple and frequently-used method.The heat exchanger network is analyzd effectively which is based on the technology of the pinch network on the status of the energy utilization of the ammonia production system in Henan Xinlianxin Fertilizer Limited Company,and a scheme for improving the energy efficiency of the system is provided.The heat exchanger network is analyzd effectively which is based on the technology of the pinch network.The heat exchanger network of the shift conversion,synthesis,water vapor device and gasification device in our company were analyzed by using the data simulation and energy balance analysis methods,respectively.The analysis results show that the the gasification part of the system has small energy consumption,low waste heat temperature and small heat load.The optimization of the heat exchanger network is not considered in the optimization of the heat exchanger network,rather the optimization of the conversion,synthesis and water vapor part is considered.The optimization method is as follows: recycling the outlet heat of the desalted water exchanger(E1834A).The cold water inlet of the heat exchanger(E1832)is preheated by using the recycled heat of the the circulating water cooler(E1834A),and the capacity of the 2.5 MPa steam can be increased while the load of the heat exchanger is reduce.The steam turbine condensate is mixed with the desalted water tank to cool the synthesis and transformation part,and the outlet cold material is heated to supply the boiler water supply.After optimization,the integration between the three sets of devices can save 0.5 MPa steam 10.32 t/h,produce 2.5MPa steam 9.78t/h,and save 924 t/h of circulating water.Nine schemes of heat exchanger network for ammonia production system are proposed based on the analysis of pinch point of heat exchanger network system,and a suitable scheme is made according to the Data comparison of heat exchanger data and energy saving potential of each retrofit scheme.The suitable scheme is as follows: Transform part of desalted water outlet of the heat exchanger heat logistics by EN1 and demineralized water tank water heat,heated to 53 ? after mixing with steam condensate to the synthesis and transformation workshop;recycled synthetic soft water heater outlet syngas heat through the EN2 preheating gas mixture to 85 ? and then sent to the circulating water cooler,adding EN3 with the E1832 heat exchanger in parallel,increase of exit temperature can also increase the yield of high pressure steam boiler,constant water preheater.Finally,the energy consumption of the ammonia production system before and after the transformation was compared.After transformation,the comprehensive byproduct of the transformation system was 2.5 MPa,the steam volume increased by 2 t/h,the ammonia synthesis by-product 2.5 MPa steam increased by 5 t/h,and the comprehensive converted byproduct 2.5 MPa steam increased by 96 kg/t NH3.The steam consumption of synthetic ammonia was 102.52 t/h before modification,and the steam consumption was 72.24 t/h after retrofit.Compared with before and after the retrofit,the steam consumption decreased by 30.28 t/h,which indicated that the energy consumption of ammonia production system was greatly reduced and the energy utilization was more fully.