The cooler is the most commonly used heat exchange equipment in the heating system.


Release time:

2018/10/29

The cooler is the most commonly used heat exchange equipment in the heating system, and its operation directly affects the quality of external heating. The analysis of the causes of the problems in the operation of the cooler is of great significance to the safe operation, energy saving and consumption reduction of the heat exchange station. A problem encountered in the operation of the system throughout the heating season, the main problem is the lack of heat transfer peak heater. The cooler is installed on the bypass of circulating water supply and adopts double-grain tube cooler. Its design parameters are: flow rate G = 1500 t/h, heat exchange area F = 170 m2, design steam inlet parameter t = 180 ℃,P = 0.2MPa, and circulating water inlet and outlet

The cooler is the most commonly used heat exchange equipment in the heating system, and its operation directly affects the quality of external heating. The analysis of the causes of the problems in the operation of the cooler is of great significance to the safe operation, energy saving and consumption reduction of the heat exchange station.

A problem encountered in the operation of the system throughout the heating season, the main problem is the lack of heat transfer peak heater. The cooler is installed on the bypass of circulating water supply and adopts a double-textured tube cooler. Its design parameters are: flow rate G = 1500 t/h, heat exchange area F = 170 m2, design steam inlet parameter t = 180 ℃,P = 0.2MPa, and design temperature difference △t = 15 ℃ between inlet and outlet of circulating water. During the operation of the cooler, the inlet and outlet water temperature difference △t is only about 5 ℃, although adjusted, the effect is not big, its role can not be fully played.

(II) the air in the cooler is not discharged, the cooler body is not designed with tube side and shell side high point release valves, which will affect the heat exchange effect to a certain extent. In order to reduce the impact, we in the entire heating system, the highest point of the water supply and return pipeline is equipped with an air release valve, in the early operation of the system filled with water and the operation of irregular steam release, as far as possible to reduce the impact of air in the system heat exchange effect.

(III) the phenomenon of fouling in the cooler, the fouling of the cooler will have a great impact on the heat exchange effect of the cooler, resulting in a lower heat transfer coefficient, a greatly reduced heat exchange efficiency, and a low outlet water temperature. In order to avoid the fouling of the cooler, the double-grain tube cooler is selected. The special structure of the heat exchange tube of the cooler makes the water flow in the tube in a turbulent state, the flow rate is high, and it is not easy to scale. When the system is shut down, we will check the heater to see that there is basically no scaling inside.

(IV) steam quantity is insufficient In this system, the steam metering device adopts vortex flowmeter. Due to the limitation of installation conditions, the installation requirements of steam metering device cannot be met, and accurate data cannot be obtained for the steam quantity entering the cooler.

The blockage of the (V) water path will reduce the amount of circulating water flowing through the cooler, resulting in large temperature difference between the outlet and inlet water of the cooler water path, large pressure difference and high drain temperature. However, in actual operation, the pressure difference between the inlet and outlet of the cooler is about △P = 0.02MPa, and the pipe resistance provided by the manufacturer is △P = 0.04Mpa. From the analysis of operation conditions, the possibility of waterway blockage is unlikely. During the disassembly inspection of the heater, the pipes were inspected and no blockage was found.

Poor (VI) drainage The system has the phenomenon of poor condensate drainage during operation. The water level in the cooler often reaches the high limit, and a bypass must be opened for drainage. Otherwise, the water level in the cooler will rise and the steam pressure on the steam side will rise, causing the steam side safety valve of the heater to jump. The existence of this situation, so that the operator can only reduce the amount of steam, and long-term bypass operation, which greatly reduces the heat exchange efficiency of the cooler. Initially suspected that the trap is blocked, but after the disintegration of the trap inspection did not find abnormal, which requires the drainage capacity of the trap to check the calculation.

The solution to the problem of insufficient heat exchange of the cooler is as follows:

1. Re-select the trap and install a drain regulating valve in the drain pipeline. The trap is controlled by DDZ-Ⅱ electronic regulating system according to the water level change of the heater. The water level signal of the heater is controlled by the differential pressure transmitter, the proportional integral unit, the operating unit, and finally the electric actuator to control the regulating valve, and the size of the water delivery volume is controlled by adjusting the valve opening. In this way, the drain in the cooler can be discharged in time to ensure the heat exchange effect.

2, daily attention to control the circulating water quality, strengthen water quality supervision, minimize the occurrence of cooler scaling phenomenon;

3. For the steam metering device of the system, find a way to solve it as soon as possible;

4. Disassembly inspection or backwashing of the heater shall be carried out regularly to remove sundries in the heater and improve the efficiency of the heater; In addition, when the system is filled with water at the initial stage of equipment operation, the air in the heater shall be drained to avoid affecting the heat exchange quality.