Circulating cooling water system is a system that uses circulating water as cooling medium. The circulating water in the condenser condenses the exhaust gas of the steam turbine, taking away the latent heat of steam evaporation and forming a high vacuum in the condenser, thus reducing the exhaust pressure of the steam turbine and increasing its ideal enthalpy and capacity.
In the process of power production, a lot of water resources are consumed, and China is a country with serious shortage of water resources, so it is very necessary to choose circulating water cooling system according to local conditions. On this premise, this paper designs the pipeline of circulating water cooling system of 600MW unit in thermal power plant. The system is a closed circulating water cooling system with two pumps and two passes, and three main problems are involved in the design: the design of main pipeline diameter; Diameter design of condenser cooling pipe and power selection of circulating water pump.
A lot of water resources need to be consumed in the process of power generation; Considering that China is a country with serious shortage of water resources, it is necessary to adopt circulating cooling water system according to local conditions. Therefore, this paper designs the pipeline of the circulating cooling water system of a 600MW unit. This design is a double-pump and double-pass closed circulating water cooling system, which involves three major issues: the design of main pipeline diameter, the design of condenser cooling pipe diameter and the selection of circulating water pump power capacity.
The first is the pipe diameter design of the main pipeline of the system. First, assume a pipe diameter, and find a corresponding pipe diameter that can control the flow loss within the design range by calculating the flow loss in the main pipeline. Secondly, the design and calculation of the diameter of the cooling pipe in the condenser, according to the Guide to Material Selection of Condenser Tubes in Thermal Power Plants, select reasonable cooling water flow and cooling pipe materials, assume the pipe diameter and wall thickness, calculate the size of the condenser cooling pipe, calculate the water side loss by using the calculation method of the water resistance HEI of the condenser, and find out the corresponding pipe diameter with the loss within the design range. Finally, choose the power of the circulating water pump.
Firstly, assume a designed pipe diameter of the main pipeline, and determine a corresponding pipe diameter that can control the flow loss within the design range by calculating the flow loss inside the main pipeline. Secondly, the design of radiator diameter in condenser is calculated. The flow rate of cooling water and the selection of cooling pipe materials should meet the requirements of "Guide for Selection of Condenser Tubes in Thermal Power Plants". The size of the condenser cooling pipe is calculated by assuming the pipe diameter and thickness, and the water-side loss is calculated by applying the HEI condenser water resistance calculation method, so as to determine the pipe diameter corresponding to the loss within the design range. Finally, select the power capacity of the circulating water pump.
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