[Q&A Question 040] 2017.02.09
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This post was last edited by 955559 on 2017-7-21 21:52. [Q&A Question No. 040] February 9, 2017: How to put a heat exchanger into use? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) ① Following the principle of introducing the cold flow first and then the hot flow, first open the cold flow outlet valve, and then open the cold flow inlet valve. ②Open the heat exchanger circuit, open the outlet valve on the hot flow side, and then open the inlet valve on the hot flow side. ③After the heat exchanger is put into operation, its flanges as well as those of the associated pipelines should be inspected for any signs of leakage; if any abnormalities are detected, immediate action should be taken to address them. ④For heat exchangers with higher temperatures, thermal tightening should be contacted when the temperature exceeds 250°C. Petrochemical Area – “Creative Ideas for Energy Saving” event: http://bbs.hcbbs.com/thread-1666758-1-1.html The New Normal Cup – Voting for the top 10 members of HaiChuan in 2016 is now underway; vote for the member you care most about (please cast your valuable vote for those in the Petrochemical Area). http://bbs.hcbbs.com/thread-1667649-1-1.html Summary post of Q&A questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657793-1-1.html Summary post of daily questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657794-1-1.html Summary post of Q&A questions from 2016 (all updates completed). http://bbs.hcbbs.com/thread-1597792-1-1.html Third round of selection for outstanding management members of HaiChuan. http://bbs.hcbbs.com/thread-1655902-1-1.html Petrochemical Area – “Creative Ideas for Energy Saving” event: http://bbs.hcbbs.com/thread-1666758-1-1.html Xiaomi phones are up for grabs. Summary post collecting chemical industry technical materials from the “Petrochemical Section”. http://bbs.hcbbs.com/thread-1654603-1-1.html Many prizes are waiting for you (Source: HaiChuan Chemical Forum)
1. First inject the cold fluid, then the hot fluid.
Open the drain valves on the tube and shell sides of the heat exchanger, drain all the liquid remaining, and then close them. Open the outlet valve for the cold medium. Open the inlet valve for the cold medium, and close the branch line valve at the same time. Once the cold medium is operating properly, slightly open the inlet valve for the hot medium to carry out preheating.
1. Open the drain valves on the tube side and shell side of the heat exchanger, drain all the liquid stored there, and then close the valves; 2. Open the outlet valve for the cold medium; 3. Open the inlet valve for the cold medium, while closing the bypass valve; 4. Once the cold medium is functioning properly, slightly open the inlet valve for the hot medium to carry out preheating.
Check, shut off the vent drain; first turn on the cold medium, then the hot medium
1. In accordance with the principle of feeding the cold stream first and then the hot stream, first open the cold stream outlet valve, and then open the cold stream inlet valve. 2. Open the heat exchanger circuit, open the outlet valve on the hot flow side, and then open the inlet valve on the hot flow side. 3. After the heat exchanger is put into operation, its flanges as well as those of the associated pipelines should be inspected for any signs of leakage; if any abnormalities are detected, immediate action should be taken to address them. 4. For heat exchangers operating at high temperatures, thermal tightening should be carried out when the temperature exceeds 250°C.
1. Install the properly prepared hanging plates and test tubes; 2. Open the inlet and outlet valves of the hanging plate holder and the heat exchanger; 3. Open the steam inlet and outlet valves; 4. Adjust the valves of the hanging plate holder and the heat exchanger’s inlet and outlet to control the flow rate； 5 Adjust the steam valve to control the temperature difference between the inlet and outlet of the circulating water.
First, check to confirm it is in good condition; then connect the cold circuit, followed by the hot circuit. After that, check for any leaks
1. Check whether all drain and vent valves are operating smoothly and in proper position, and ensure that all pressure gauges and thermometers are installed. 2 Check whether the foundation supports are secure, and ensure that all bolts are properly tightened. When putting it into operation, the cold flow should be introduced first followed by the hot flow; this is because introducing the hot flow first causes the various components to expand due to heat, while introducing the cold flow afterward causes them to contract sharply. Such a temperature difference will immediately lead to leaks at the static sealing points. Conversely, when shutting down the heat exchanger, the hot flow should be stopped first, followed by the cold flow. 4 When introducing a cold medium or a hot medium, it is first necessary to ensure that the bypass line is unobstructed. After slowly opening the outlet valve and confirming there are no issues, the inlet valve should also be opened slowly to prevent pressure buildup. During this process, it is important to monitor any changes in the equipment. 5 After the heat exchanger is put into use, leaks may occur due to changes in temperature and pressure, so it should be inspected promptly.
When starting up, cold flow is introduced first followed by hot flow; when shutting down, hot flow is stopped first and then cold flow. Only one stream is operated at a time, with the other stream being vented
1. After the heat exchanger passes the pressure test, it can be put into use; before that, the water remaining inside the heat exchanger must be drained. 2. Check whether all drain and vent valves are flexible and functional, as well as their operating positions; ensure that all pressure gauges and thermometers are properly installed. 3. Check whether the foundation supports are secure and whether all bolts have been fully tightened. 4. When putting it into use, the cold flow should be introduced first followed by the hot flow; this is because introducing the hot flow first causes the various components to expand due to heat, while introducing the cold flow afterward causes them to contract sharply. Such a temperature difference will immediately lead to leaks at the static sealing points. Conversely, when shutting down the heat exchanger, the hot flow should be stopped first, followed by the cold flow. 5. When introducing a cold medium or a hot medium, it is first necessary to ensure that the bypass line is unobstructed. After slowly opening the outlet valve and confirming there are no issues, the inlet valve should also be opened slowly to prevent pressure buildup. During this process, it is important to monitor any changes in the equipment. 6. After the heat exchanger is put into operation, leaks may occur due to changes in temperature and pressure, so it should be inspected promptly.