Intermediate reboiler in the desorption tower
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In a desorption tower, the feed is usually divided into cold and hot streams. What would be the effect of using the oil from the stabilizer bottom to exchange heat with the reboiler located in the middle of the desorption tower? This could help reduce the heat source needed at the bottom of the desorption tower, thus saving energy. Do any of you have experience with such a setup? Please share any relevant insights
The desorption tower I have installed is equipped with an intermediate reboiler; from a design perspective, this helps to reduce the load on the reboiler at the bottom of the tower, allowing for a more even distribution of the vapor-liquid load within the tower. Since the feed at the top of the tower is cold, this also helps to reduce the load on the absorption tower. Since the facility has not yet started operating, it is hard to say whether the results will meet expectations.
Our catalytic unit stabilization system’s desorption tower is equipped with an intermediate reboiler, which uses stabilized gasoline as the heat source. This can improve the desorption efficiency, while reducing the thermal load on the reboiler at the bottom of the desorption tower, thereby facilitating further utilization of the heat source. For example, by using fractional distillation as a heat source, the amount of heat lost can be reduced, thereby increasing the temperature of the hot water system.
Intermediate reboiler in the desorption tower? Our device doesn’t have this setting. Only the reboiler at the bottom is needed.
The desorption tower was modified with an intermediate reboiler; compared to the cold feed method, this approach reduces the thermal load on the reboiler at the bottom of the desorption tower, allows for the recovery of heat at low temperatures from the stable gasoline, results in a low content of C3 components in the desorbed gas, and thus does not increase the load on the absorption system. It combines the advantages of both cold feeding and hot feeding in a fairly effective manner. Industrial applications show that it requires low investment and yields significant economic benefits, making it an energy-saving technology worth adopting.
- Hehe, the intermediate reboiler – our design for Phase 2 also features one like this, but it hasn’t been put into use yet; theoretically, it seems to be quite good
Here, the intermediate reboiler of the distillation column exchanges heat with stable gasoline. The heat demand of the analysis tower is not very high either, and it generally meets the requirements.
I’ve seen that there seem to be two types of designs for desorption towers. 1) All are top cold feed with a reboiler in between ； 2) There is a cold feed and a hot feed, with no reboiler in between. These two seem similar; the heat source for the intermediate reboiler and the heat source for the hot feed are both stable gasoline, and the temperature of the intermediate reboiler as well as that of the hot feed is around 100–105 degrees.
Our desorption tower is equipped with an intermediate reboiler, which uses stabilized gasoline as the heat source, and the results are quite good
Regarding the issue of hot and cold feed in the desorption tower, if there is sufficient heat source at the bottom of the tower, it is possible to eliminate hot feed and use only cold feed, which will result in a better desorption effect. Some studies indicate that increasing the temperature of the hot feed can alleviate the problem of insufficient heat at the bottom of the desorption tower, but it has a negative effect on the desorption efficiency of the tower. The intermediate reboiler in the desorption tower is an excellent energy-saving measure; on one hand, it helps to address the issue of insufficient heat supply in the desorption tower, and on the other hand, from the perspective of energy utilization, thermal energy is utilized in a hierarchical manner. The intermediate reboiler makes use of the heat from stabilized gasoline; its temperature is much lower than that of the oil in the middle stage. The high-temperature heat source replaced can, through adjustments made in the main distillation tower, allow more heat to be extracted from the oil slurry, thereby generating more steam. It not only achieves energy-saving goals but also brings certain economic benefits. I once saw an absorption stabilization system equipped with an intermediate reboiler; it operated very stably, which was great, and it’s worth recommending. Hehe