【Q&A Question 206】2017.07.25
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【Q&A Question 206】July 25, 2017: How to properly shut down a cooler? 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 Contact the relevant department. ②Close the hot fluid inlet valve. ③Close the hot fluid outlet valve. ④Close the cooling water inlet valve. ⑤If the cooler is to be serviced, all connection valves of the cooler are closed. ⑥Drain the pipe and the liquid remaining in the shell side. ⑦If no maintenance is carried out, the cooler water outlet valve should be closed. Scoring criteria: 2 Wealth points for incorrect attempts; 3–8 points for *incomplete* answers. 10 Wealth points for correct answers, provided with detailed explanations; 15–20 Wealth points for correct answers with additional *insufficient* details. Please score according to these criteria. Note: If there are editing records after answering, only those who participated will be given points. For continuous malicious spamming, 2 points will be deducted each time, with no upper limit. Pure numbers, pure emojis, or random letters unrelated to the answer are all considered malicious spamming; points will start to be deducted after three warnings. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Petrochemical Sector – “Creative Ideas for Energy Saving” Campaign (Second phase is in full swing) http://bbs.hcbbs.com/thread-1666758-1-1.html 2017 Coal Chemicals – “My Technical Upgrades” http://bbs.hcbbs.com/thread-1786290-1-1.html
1) Pre-commissioning inspection: Check to ensure 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 to 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 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 operation: 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.
Stop the hot medium first, then the cold medium
①Contact the relevant position. ②Close the hot fluid inlet valve. ③Close the hot fluid outlet valve. ④Close the cooling water inlet valve. ⑤If the cooler is to be serviced, all connection valves of the cooler are closed. ⑥Drain the pipe and the liquid remaining in the shell side. ⑦If no maintenance is carried out, the cooler water outlet valve should be closed.
Turn off the heat source first, then the cold source, to prevent pressure buildup in the heat exchanger
1) First, close the return water valve, then close the supply water valve. 2) Open the drain valve before the return valve to drain all the water in the tube side. 3) During winter shutdown of the cooler, the valves connecting the water supply and drainage lines should be opened to prevent the pipes from freezing.
1. First, close the return valve, then close the supply valve. 2. Open the drain valve before the return valve to drain all the water from the tube side. 3. When the cooler is shut down in winter, the valves connecting the water supply and drainage lines should be opened to prevent the pipes from freezing.
Stop the hot medium first, then the cold medium
(1) Open the heat transfer medium bypass valve. (2) Close the heat transfer medium inlet valve. (3) Close the heat transfer medium outlet valve. (4) Close the circulating water inlet valve. (5) Close the circulating water outlet valve