【Q&A Question 038】2018.02.07
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【Q&A Question 038】February 7, 2018: What issues should be considered when preheating a pump using a preheating line? It is important to ensure that the preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from rotating in reverse. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating. The cooling water for the bearing housings, pump bases, and end-face seals must all be turned on to protect the bearings and shaft seals. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Due to the limits on the number of posts in the “One Question per Day” section, “One Image per Day” has been moved to the registered devices section; you can access it through the directory I posted. For management purposes, if you need to access content from a few days ago, please go to the summary post below to enter the “My Registration Season” event – (Note: This event is currently underway in the Chemical Engineering section) https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=18978. Summary post of daily questions for the 2018 Chemical Engineering Technology Training section: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888971. Summary post of daily images for the 2018 Registered Equipment section: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888970. Summary post of Q&A questions for the 2018 Hydrogen Production and Hydrogenation Technology section: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888968. Summary post of daily questions for the 2018 LNG Technology Discussion section: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888973. Summary post of Q&A questions for 2017 (updates have started): https://bbs.hcbbs.com/thread-1657793-1-1.html. Summary post of daily questions for 2017 (updates have started): https://bbs.hcbbs.com/thread-1657794-1-1.html. Summary post of daily images for 2017: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1875160. List of daily questions for the 2017 LNG section: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1804162. Summary post of Q&A questions for 2016 (updates completed): https://bbs.hcbbs.com/thread-1597792-1-1.html
The preheating valve should not be opened too wide to prevent the pump from reversing. The preheating rate of the pump body generally should not be too fast; it should be less than 50°C/h. In special cases, the preheating speed can be increased by methods such as introducing steam or hot water into the pump body. During preheating, the pump shaft should be rotated 180 degrees every 30 to 40 minutes to prevent warping due to uneven heating on the upper and lower parts of the shaft. The cooling water systems for the bearing housings and pump bases must be turned on to protect the bearings and shaft seals
Answer: It should be noted that the preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating.
The preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating.
The preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating.
The preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating.
The preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating.
①The preheating process is correct. Generally, the pump outlet pipeline preheats the pump inlet through a preheating bypass valve that spans the inlet and outlet. Do not open the preheating valve too much to prevent the pump from reversing. ②Preheating is carried out at a rate of 50°C/h; in emergency situations, the preheating speed can be increased by taking appropriate measures (such as using steam to blow on the pump body to assist with preheating). If you go too fast, the pump body will heat up rapidly, leading to leaks at the various joints and bending or jamming of the rotor. ③The shaft should be rotated during preheating, usually once every 30 to 45 minutes, to prevent bending of the main shaft and to help remove gases from within the pump. ④The cooling water for the bearing housings, pump bases, and end face seals must all be turned on to protect the shafts and bearings.
It should be noted that the preheating sequence is correct: pump outlet pipeline → preheating valve → pump body → pump inlet valve. Do not open the preheating valve too wide to prevent the pump from reversing. The preheating rate should not exceed 50°C/h, and the rotor should be rotated during preheating.
The preheating valve should not be opened too wide to prevent the pump from reversing. The preheating rate of the pump body generally should not be too fast, and it should be less than 50°C/h. In special cases, the preheating speed can be increased by methods such as introducing steam or hot water into the pump body. During preheating, the pump shaft should be rotated 180° every 30–40 minutes to prevent bending due to uneven heating on the upper and lower parts of the shaft. The cooling water systems for the bearing housings and pump bases must be activated to protect the bearings and shaft seals.
The preheating valve should not be opened too wide to prevent the pump from reversing. The preheating rate of the pump body generally should not be too fast; it should be less than 50°C/h. In special cases, the preheating speed can be increased by methods such as introducing steam or hot water into the pump body. During preheating, the pump shaft should be rotated 180 degrees every 30 to 40 minutes to prevent warping due to uneven heating on the upper and lower parts of the shaft. The cooling water systems for the bearing housings and pump bases must be turned on to protect the bearings and shaft seals.