Which is more effective for a reaction kettle: a jacket or semi-tubes?
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Our company has 50-cubic-meter hydrolysis reactors, with a heating medium of 0.9 Mpa steam; the temperature ranges from 80 to 150°C. Which provides better heat exchange efficiency, an external jacket or semi-tubes? P: The reaction releases a large amount of heat; stirring is used, and it is a batch reaction. Previously, 25-cubic-meter hydrolysis reactors were manufactured using jackets. Now the company plans to expand its equipment, and it would like to know which option is more suitable overall in terms of heat exchange, manufacturing, safety, etc I hope everyone will share their opinions more often. Thank you. This post was last edited by danfeng on 2009-3-22 11:07.]
:) Semi-tube. The reason is as follows: the heat exchange efficiency depends on flow velocity, temperature difference, and heat exchange area. Under the same conditions of heat exchange area and temperature difference, it is the flow velocity of the fluid that determines the efficiency of heat exchange. Compared to jackets, semi-tubes have a much smaller cross-sectional area, resulting in a significantly higher flow velocity. Therefore, I believe that semi-tubes offer better heat exchange performance, but they are much more difficult to manufacture.
50m3, with a jacket; half-pipe is too difficult to work with, and the steam path is also way too long – it turns into water long before reaching its destination.
Jackets are generally used; although the heat transfer efficiency is not very good, the heat exchange area is large after all
Based on the information provided by the original poster, I think this question is difficult to answer. Regarding the question of which heating method is more effective for a 50-cubic-meter reactor heated by steam – either using semi-tube heat exchangers or jackets – I can provide two opposite answers: 1. Jackets offer a better heating effect, provided that the semi-tube heat exchanger has steam entering on one side and condensed water exiting on the other; in this case, the jacket has a larger heat exchange area, lower resistance, and a higher heat transfer coefficient K, hence it provides better heating performance. 2. The semi-tube type is advantageous provided that it has three or more inlet ports for steam and outlet ports for condensate; in this case, its resistance is actually lower than that of a jacket, and its heat transfer coefficient K is higher than that of a jacket. As a result, the factor of the larger heat exchange area associated with jackets can be ignored, making the heat exchange efficiency better than that of jackets. Of course, this question only compares the heat exchange efficiency, determining which is better – a half-pipe or a jacket – based on the assumptions put forward by the original poster. In fact, it’s quite interesting to compare this issue on a broader scale. For example, considerations include the medium used (steam or water), its application, the difficulty of processing, whether it is possible to take advantage of loopholes in pressure vessel regulations, and the possibility of maintenance, among others.
It is recommended to use half-tubes, and to do so in multiple sections. It improves heat exchange efficiency while avoiding the problem of overly long pipeline routes. Although the cost is a bit higher, for equipment like reactors that require precise temperature control, the advantages outweigh the disadvantages.
I think we should first determine how large the heat release from this hydrolysis reaction is, and we also need to consider whether the reaction is batch or continuous, as well as whether the equipment is equipped with a stirrer or not. The information provided by the original poster is too limited, making it difficult to proceed~
A reactor with a capacity of 50M3 would require a diameter of around 4M; manufacturing it with a jacket is difficult and costly. From a cost perspective alone, choose a jacket. When it comes to heat energy utilization, the two are pretty much the same. The jacket has a large heat exchange area and low resistance, as well as a high heat transfer coefficient K, thus achieving excellent heat exchange performance. The half-pipe has a high steam flow rate, a large heat transfer coefficient K, and thus good heat exchange performance. In terms of maintenance, most semi-tubes are made of carbon steel, while most reaction vessels are made of stainless steel. When these two materials are welded together, the difference in their expansion coefficients upon heating can cause the welds to crack, which is not conducive to stable production. For intermittent operation, a structure with internal coil heating can be considered; the downside is that internal leaks are not easy to detect. However, since it is intermittent operation, regular inspections over time can help avoid such issues.
It’s better to use a semi-tube jacket, and this approach seems to be quite popular these days. Processing a semi-tube jacket is a bit difficult, but the results are better than those achieved with a full jacket
If only steam is used and no cooling water, semi-tubes are recommended due to the large size of the reactor. If cooling water also needs to flow in addition to steam, a jacket is still the better choice.
Half-pipe tubes require simple processing for the equipment, but their heat exchange area is smaller than that of jackets, and there are considerations regarding poor drainage of condensate. The jacket places high demands on equipment manufacturing. If water flow is still required, then it’s definitely half done; the jacket for allowing water flow to pass through is even more difficult to construct. This post was last edited by comm_zhang on 2009-3-20 11:13]