【Daily Question】In-depth Processing 20160916 Short Answer Question: What are the steps for starting up and shutting down a heat exchanger?

Commissioning steps: (1) Pre-commissioning inspection: Check to ensure that all condensate water in the heat exchanger has been drained； Check and confirm that the inlet and outlet blind flanges have been removed ； Check and confirm that all drain valves are closed ； Confirm that the pressure gauge, thermometer, and thermocouple are in use ； Check to ensure that the heat exchanger is properly grounded and that the anchor bolts are not loose ； Check to ensure that the nuts matching the flange and cylinder bolts are all installed, the bolts are fully tightened, and the connections are secure. (2) First, introduce the cold medium: Open the outlet vent valve first, then slowly open the cold medium inlet valve until it is fully open. Once an oil and gas odor is detected from the vent valve, reduce its opening degree; close it completely once oil is visible in the vent stream. After the heat exchanger is filled with the medium, open the outlet valve fully and close the bypass valve. (3) Introducing the heat medium later: Open the exhaust valve at the inlet side first, then slowly open the outlet valve for the heat medium until it is fully open. Once an oil and gas odor is detected from the exhaust valve, reduce its opening degree; close it completely once oil is visible in the exhaust stream. After the heat exchanger is filled with the medium, open the inlet valve fully and close the bypass valve. (4) Inspection after commissioning: Check whether the temperature and pressure are ； Check for leaks at the static seal points ； Check whether the traffic is normal. 2. Shutdown procedure for the heat exchanger: (1) First, stop the heat medium: fully open the bypass valve first, then close the inlet and outlet valves for the heat medium. (2) Cooling medium shutdown: First, fully open the bypass valve, then close the inlet and outlet valves for the cooling medium. Precautions: (1) Drain the oil in a timely manner after removal to prevent damage to the equipment inside the heat exchanger due to negative pressure. (2) When releasing the medium through the vent valve, if it is a hot medium, the valve should be opened slowly to prevent the hot medium from spraying out and causing injury. (3) When introducing the medium into the heat exchanger, the valves should be opened slowly to prevent excessive flow rates of the medium, which could generate static electricity and lead to a flash explosion.

Commissioning steps: (1) Pre-commissioning inspection: Check to ensure that all condensate water in the heat exchanger has been drained； Check and confirm that the inlet and outlet blind flanges have been removed ； Check and confirm that all drain valves are closed ； Confirm that the pressure gauge, thermometer, and thermocouple are in use ； Check to ensure that the heat exchanger is properly grounded and that the anchor bolts are not loose ； Check to ensure that the nuts matching the flange and cylinder bolts are all installed, the bolts are fully tightened, and the connections are secure. (2) First, introduce the cold medium: Open the outlet vent valve first, then slowly open the cold medium inlet valve until it is fully open. Once an oil and gas odor is detected from the vent valve, reduce its opening degree; close it completely once oil is visible in the vent stream. After the heat exchanger is filled with the medium, open the outlet valve fully and close the bypass valve. (3) Introducing the heat medium later: Open the exhaust valve at the inlet side first, then slowly open the outlet valve for the heat medium until it is fully open. Once an oil and gas odor is detected from the exhaust valve, reduce its opening degree; close it completely once oil is visible in the exhaust stream. After the heat exchanger is filled with the medium, open the inlet valve fully and close the bypass valve. (4) Inspection after commissioning: Check whether the temperature and pressure are ； Check for leaks at the static seal points ； Check whether the traffic is normal. 2. Shutdown of the heat exchanger: Shutdown steps: (1) First, stop the heat medium: fully open the bypass valve first, then close the inlet and outlet valves for the heat medium. (2) Cooling medium shutdown: First, fully open the bypass valve, then close the inlet and outlet valves for the cooling medium.

Commissioning of the heat exchanger: (1) Inspection before commissioning; (2) Introduce the cold medium first; (3) Then introduce the hot medium; (4) Inspection after commissioning. Shutdown procedure for the heat exchanger: (1) Stop the hot medium first; (2) Then stop the cold medium

Enabled: First inject the cold medium, then the hot medium； Open the outlet first, then the inlet ； Shutdown: Stop the hot medium first, then the cold medium ； Close the inlet first, then the outlet.

At startup: turn on the cold flow first, then the hot flow. When shutting down: turn off the hot flow first, then the cold flow.

(1) When in use, first activate the cold circuit and then the hot circuit; open the outlet first and gradually introduce the heat flow. At the same time, open the vent valve to release the gas inside the device and then close it. (2) When shutting down, turn off the hot circuit first, then the cold circuit, while simultaneously performing line flushing, evacuation, and oil drainage. Its purpose is to gradually increase (or decrease) the temperature of the heat exchanger, thereby avoiding excessive temperature changes that could lead to thermal expansion and contraction, resulting in oil leakage or damage. (3) When performing line cleaning, first drain all the cooling water. Open the vent valve; regardless of which section is being cleaned, do not close the inlet and outlet valves on the other side to prevent pressure buildup. (4) When starting up or shutting down, operate the valves slowly. (5) If one of the stages is operated via the bypass line, first open the bypass line valve, then close the inlet valve; the outlet valve remains open.

1. Activation steps: (1) Pre-activation check: Verify that all condensate water within the heat exchanger has been drained； Check and confirm that the inlet and outlet blind flanges have been removed ； Check and confirm that all drain valves are closed ； Confirm that the pressure gauge, thermometer, and thermocouple are in use ； Check to ensure that the heat exchanger is properly grounded and that the anchor bolts are not loose ； Check to ensure that the nuts matching the flange and cylinder bolts are all installed, the bolts are fully tightened, and the connections are secure. (2) First, introduce the cold medium: Open the outlet vent valve first, then slowly open the cold medium inlet valve until it is fully open. Once an oil and gas odor is detected from the vent valve, reduce its opening degree; close it completely once oil is visible in the vent stream. After the heat exchanger is filled with the medium, open the outlet valve fully and close the bypass valve. (3) Introducing the heat medium later: Open the exhaust valve at the inlet side first, then slowly open the outlet valve for the heat medium until it is fully open. Once an oil and gas odor is detected from the exhaust valve, reduce its opening degree; close it completely once oil is visible in the exhaust stream. After the heat exchanger is filled with the medium, open the inlet valve fully and close the bypass valve. (4) Inspection after activation: Check whether the temperature and pressure are ； Check for leaks at the static seal points ； Check whether the traffic is normal. 2. Shutdown procedures for the heat exchanger: (1) First, stop the flow of the heat medium: open the bypass valve fully first, then close the inlet and outlet valves for the heat medium. (2) Cooling medium shutdown: First, fully open the bypass valve, then close the inlet and outlet valves for the cooling medium.

Enable cold first then hot, disable hot first then cold

Enabled: Cool first, then heat. Disabled: Heat first, then cool