Pressure Setting Pattern And Application Research On The By-pass Pipe

With the rapid development of the central heating and the expanding of the heating scale, many kinds of heating systems have been emerging in the urban central heating gradually, and there are often high-level users and low-level users co-exist in a community. The network with multi-heat sources has been the direction of the development of central heating system for the purpose of more effective use of energy, the protection of environment and the reduction of running costs. But there are many problems in the Heat & Power plant and coal-burning boiler joint operation for the immature technology. This paper proposes a new program of the Heat & Power plant and coal-burning boiler joint operation by studying the constant pressure with the by-pass pipeThe by-pass pipe of the constant pressure can maintain constant hydrostatic pressure line while adjusting the dynamic pressure line. This program is flexible for adjustment and design, and it has a great significance for the single-heat source and multi-heat sources joint operation, especially when there exists a great terrain elevation.In order to apply this program, this paper details the design method of the by-pass pipe of the constant pressure, analyse the advantages and disadvantages of the two kinds of bypass connections, discusses the affection of circulating pump and pipe network operating point generated by the bypass, study the principles of the determination of the upper and lower limits of the dynamic pressure, elaborates the methods of the valves selection and gets some important conclusions through the comparative analysis of the changes in the pressure points during the adjustment of the valves using the pipeflow simulation and the theoretical calculation.This paper analyse the application of the by-pass pipe of the constant pressure in the single-heating source system through a practical project example, determines the bypass valve opening and the limits of the dynamic pressure at all stages, introduces how to adjust the dynamic pressure by adjusting the opening of the bypass valves.This paper verifies the principle of unique constant pressure point in the multi-heating sources joint operation by the pipeflow simulation, analyse the law of the variation of pressure during the adjustment of the bypass vavles, discusses the control plan of the main heating source and the minor heating source, study the application of the pressure pump in the multi-heat sources joint operation. This paper takes the joint operation of the Taiyuan NO.1 Heat & Power plant and Chengnan coal-burning boiler as an example, establishes the control plan of the bypass valves during all the stages of joint operation in the heating period. This paper establish a practical, flexible and reliable calculation software for the by-pass pipe of the constant pressure using the VB tools, which is valuable for the design, operation and management of the by-pass pipe of the constant pressure...