Equipment (heat exchanger) – where to go? (8)
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This post was last edited by “High-end, classy, and stylish” on July 15, 2014, at 09:05. “The closer it gets to the weekend, the more I miss my loved ones.” The nearer it is to the weekend, the more I want to stay at home. However, spring is inherently a restless season; with warm weather and blooming flowers, my heart is filled with joy, and I feel like going out to relax. Ah~~~ It’s quite a dilemma! “Some people leave in a hurry; some experience sweet love. But who cares about the heartbreak that comes from passing each other by...” I’m in a good mood now. Back to the main topic: today, we’ll discuss the layout of heat exchangers. Issue 8: Layout of Heat Exchangers. Heat exchangers come in many different forms; here I will first discuss the general principles of layout, and then focus on the layout of floating-head heat exchangers, as the core removal and piping arrangement in these types of heat exchangers are quite representative. Regarding the principles for arranging heat exchangers, please refer to the general provisions in 20546. What I will discuss here are the aspects that are not covered in the standards, as well as the important data and points that are subject to debate within those standards. All distances mentioned below refer to the effective distance starting from the insulation enclosure. 1. For the layout of each heat exchanger, priority must be given to considering the space required for lifting and core removal, as well as the corresponding equipment such as cranes, hoists, and slings. Additionally, passageways for pedestrians are necessary, with a minimum width of 1 meter for vertical heat exchangers and 0.8 meters for horizontal ones. 2. Heat exchangers can be arranged in an overlapping manner as needed, with generally no more than 3 units overlapping each other. Heat exchangers with a shell diameter of ≥1.6 m should not be arranged overlappingly. When heat exchangers handling different media are placed overlappingly, care must be taken to ensure that the installation height meets the piping requirements. 3. The distance between heat exchangers or between them and other equipment shall be no less than 0.8 m. 4. Heat exchangers that facilitate heat exchange between one material and several different materials should be arranged in groups; for heat exchangers where two materials exchange heat, they should be placed as close as possible to the inlet and outlet pipes of those two materials. 5. The heat exchangers installed on the frame should be aligned along the center line of the support foundation at one end ； The heat exchangers arranged on the ground can also have their tube side inlet and outlet centerlines aligned. 6. Above and below heat exchangers whose operating temperature is equal to or higher than the auto-ignition temperature of the material or exceeds 250°C, no other equipment containing flammable media shall be installed if there is no partition made of non-combustible material to provide separation and protection. 7. The installation of the heat exchanger shall ensure that the clearance between the pipes and the ground or platform surface is not less than 150 mm, and the clearance at the end of the drain valve is not less than 100 mm. If the installation height is too low, it becomes very inconvenient in actual use; for example, it’s not possible to reach in to get a pipe or some other item. Additionally, when there is some pressure while draining liquid, opening it slightly more can cause the liquid to splash all over the operator, which is extremely dangerous. After discussing it, we decided that a distance of 100 to 150 units is the most reasonable choice – it’s both cost-effective and practical. Therefore, if you observe carefully, the base of a regular heat exchanger is about 500 units in height; in fact, after adding the short pipes at both ends and a drain valve, there is still roughly 100 units left. In addition, the installation height of the heat exchanger must also meet the requirement of the pump’s NPSHr plus 0.5 m. 8. When pumping liquid from the bottom of the tower or container through a heat exchanger, the heat exchanger should be located close to and below the tower or container. If the heat exchanger is equipped with an exhaust valve, it must be within easy reach; if not, a straight ladder or temporary ladder should be used. The requirements for floating-head heat exchangers on the ground and on frames are slightly different. On the ground: There is a clearance of over 0.8m on both sides of the floating head and the tube box, with a clearance of more than 1.5m in front of the floating head end. On the frame: there is a clearance of over 0.8m on both sides of the floating head and the tube box, with a clearance of more than 1.0m in front of the floating head end. Here, there is again a difference from the specifications; the specifications specify 0.6 and 1.2. But in reality, when you go to carry out maintenance and remove bolts, it’s impossible to squat at a distance of 0.6 meters – one can only stand there with bent back, which makes it impossible to use proper strength, so it’s quite useless. So I suggest that we spare no effort to save space; we can afford to ignore those 200 units of distance, just to avoid getting scolded. Well, that’s all I have to say about the layout of the heat exchanger. Everyone is welcome to share their opinions and upload photos generously. Finally, I’ll show you the layout of a grouped heat exchanger. You can take a look at the examples available on 20546; I won’t take screenshots. See you next time. ---------------------------------------I am a divider line------------------------------------- Where to go with the device? (1) http://bbs.hcbbs.com/thread-1286874-1-1.html Where are the devices going? (2) http://bbs.hcbbs.com/thread-1287989-1-1.html Where are the devices going? (3) http://bbs.hcbbs.com/thread-1288786-1-1.html Where are the devices going? (4) http://bbs.hcbbs.com/thread-1290002-1-1.html Where are the devices going? (5) http://bbs.hcbbs.com/thread-1291005-1-1.html Where to go with the equipment? (6) http://bbs.hcbbs.com/thread-1292114-1-1.html Where are the devices going? (7) http://bbs.hcbbs.com/thread-1293086-1-1.html For more interesting content, please visit my space{:1_90:}{:1_90:}{:1_90:} http://bbs.hcbbs.com/home.php?mod=space&uid=891276 I will share each update with my audience; feel free to communicate, ask questions, and provide feedback.
Sofa? :) Hehehe, I have a question: how should the inlet pipe of the pump be set to be level at the top and at the bottom?
This time, take a spot in the front row; P
For the medium inside the vessel, if it is in the gas phase, the bottom is level; if it is in the liquid phase, the top is level. That’s how I remember it: in the reducer of the pump inlet pipe, there is normally a liquid phase. However, after passing through the reducer, some of the liquid forms vortices in the uneven areas, which results in the formation of a gas phase. At this point, the bubbles have to rise upward; if the surface above is uneven, the bubbles will keep rotating and colliding, leading to localized cavitation. If the top surface is flat, the bubbles will move along the pipe into the pump and then be discharged through the pipe again. But in reality, it’s not that exaggerated; it’s all at a very minimal level.
The home page should work; register first and then learn*
It seems that experience is more reliable than standards, hehe……
It is essential to take the operational conditions on site into consideration during design; otherwise, even if something meets the specifications, it will still be criticized if it does not meet the workers’ requirements. What impressed me the most about Teacher Jia’s posts was the understanding of the work site and the consideration for the workers’ operations that showed up in a subtle way; it’s clear that he can become a good designer. Like it!
This post was last edited by Annie’s Baby on 2014-4-25 at 09:17. It’s difficult to find images online; the ones we commonly see are shell-and-tube heat exchangers, as well as large heat exchangers with frames that are installed vertically. Plate and frame heat exchanger, radiator
This post was last edited by manman2000 on 2014-4-25 09:21. I read in the documentation that, to prevent cavitation, it is essential to avoid any \"V-shaped air pockets\" in the suction pipe. Installation direction of the eccentric reducer at the inlet: it should be horizontal, or when suction is taken from below, the inclined side of the reducer should be on the lower side (with the top flat). When the pump draws in fluid from below and the suction pipe is vertical, the inclined side of the reducer should face upward (with the bottom flat). On a related note, why is the reduced diameter of control valves always designed with the bottom flat?