Study On The Insulation Thickness And The Setting Of Booster Pump Station In Long-Distance Heating Pipe Network

With the development of the economics and the improvement of people's living standards, the requirements for environmental comfort increase as well. Due to the superiority of the city central heating system in primary energy source conservation, environment improvement and comfort enhancement, it has been developed rapidly.As the size of the heating network is getting larger, and with the requirement of the city environmental protection, many cities are not allowed to build city central heating source in the city. Heating source is built in far away from the urban area leading to the increase of heating radius. Due to the increase of the size of the heating as well as the heating radius, the long distance heating arises. The city central heating system has a big demand for large diameter pipeline insulation, and laying scheme of the pipelines is mainly a combination of direct buried and overhead, of which determination of the thickness has great significance on initial and operating cost of the district heating system. For the large-scale and long-distance heating pipe network, the layout of booster pump station is able to solve the problems of high pressure in the heating network and the large energy consumption of the main circulating pumps.In this paper two parts of research work have been done. The first part mainly deals with the optimization of insulation thickness of a heating network, which has both direct buried and overhead layout. Combing practical engineering example, thermal calculations of the direct buried and overhead pipelines are done, the minimum annual average total cost of the network insulation, including the initial and operating cost are calculated. Economical factors which affect the economical insulation thickness and the affecting reasons are analyzed. According to the standards of direct buried pipeline insulation design, a comprehensive method for determination of the pipeline insulation thickness is proposed, which contains constraints of the external surface temperature and optimum calculation. And the relative factors of the calculated thickness are analyzed with the method of restricting the exterior surface temperature.The second part discusses problems on the layout of booster pump station. Pressure diagrams of a practical example are drawn by means of hydraulic calculations. And a proper design is obtained, which both satisfies hydraulic constraints and load requirements. The number of pump station is discussed, and the advantages of booster pump stations in long-distance distribution network are proved.The conclusions of this thesis can provide technical support for the design of long-distance heating pipe network.