Design And Operation Optimization Of A Central Heating Pipe Network In Changchun

With the continuous advancement of China’s urbanization process,building energy consumption is increasing year by year,and central heating is the most energy-saving potential part of building energy consumption at present.Usually,in the design process of district heating pipe network,only experiential design will increase the preliminary investment of the pipe network,which will lead to the problem of hydraulic imbalance in the operation stage,and it is difficult to meet the safety and economic requirements of the pipe network.In addition,the mismatch between heat supply and heat load in the process of operation regulation makes the energy consumption of the pump too high and the energy waste is serious..Pipeline design optimization of the central heating pipe network can minimize construction and operating costs.The operation adjustment and optimization of the pipe network can improve the safety and reliability,enhance the quality of heating and reduce the cost of heating.Therefore,the optimization of the design,and operation adjustment of central heating pipe network is of great significance to meet the requirements of energy conservation and emission reduction in China.In this paper,the design and operation optimization of a central heating pipe network in Changchun No.3 Thermal Power Plant are studied.Firstly,the engineering information of the pipeline network is summarized and analyzed,and the topology model of the pipeline network is established by using EPANET software to verify the pipeline design of the existing pipeline network.Taking the annual cost of pipe network as the objective function,the optimization model of pipe network design was established by using genetic algorithm to optimize the pipe network design.Contrastive analysis is made on the influence of different mutation probability,crossover probability,electricity price and load rate on pipe diameter optimization and the influence on the solution results of the whole optimization mathematical model.The comparison results show that when the mutation probability is 0.1 and the crossover probability is 0.4,the minimum annual conversion cost of the pipeline network investment is 9,011,500 yuan,and the problematic pipe sections in the pipeline are optimized.Through the analysis of the influence of the change of power price and the change of pipe network load rate on the optimization of pipe diameter,it is verified that the optimization scheme of pipe network design is universal.Secondly,based on network graph theory and loop matrix calculation model,established the mathematical model of the hydraulic condition by the method of MKP,loop matrix is solved,and use the Hac Net software to check the accuracy of the algorithm,thus for the hydraulic imbalance and the reasons are analyzed in detail,and puts forward corresponding measures to improve the stability of the hydraulic.In this paper,Python programming language is used to write the simulation and analysis software of hydraulic initial regulation,which can realize the intelligent optimization of hydraulic balance,and apply the software to analyze and optimize the initial regulation of pipe network.Before the initial hydraulic regulation,as many as 20 of the 35 heat exchange stations in the heating pipe network have hydraulic imbalance.After the on-site hydraulic regulation,all users have reached hydraulic balance.Thirdly,based on the network operating mode of the heating period of 2019-2020 statistical analysis,the comprehensive efficiency according to the operation of parallel pumps and variable load pump energy saving operation strategy,adopts qualitative regulation of pipe networks,the adjust and two stages and three stages of the variable mass flow is analyzed,mapped the pipeline flow,for the return water temperature and temperature changing curve.Taking the minimum power consumption of circulating pump as the goal,the optimal regulation mode of pipeline network under four different operation regulation modes is optimized.The results show that the energy consumption of the three-stage variable flow quality regulation is the lowest,and the power consumption can be reduced by 46.9%compared with the quality regulation.Finally,in the process of pipe network operation and regulation,the efficiency,power and energy consumption of the pump are different when the pump adopts different frequency conversion operation and regulation modes.Combined with the test system,this paper analyzes the water pump under different frequency conversion modes and different load rate of pipe network,with the change of frequency,the change of power and efficiency of the water pump device,and concludes that the synchronous frequency conversion operation mode is better than the combination mode of asynchronous frequency conversion and fixed variable.