Help with adjusting the operation of the debutanizer tower!
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Since the processing method of our cracking unit was changed from full cycle to one-time pass, the conversion rate increased and the product became lighter, which resulted in the lighter nature of the feed to the debutanizer, which had a great impact on the operation. The specific manifestations are: below C4, the liquefied gas components cannot be removed cleanly, resulting in an increase in non-condensable gas in the fractionation tower, an increase in tower pressure, and even the pressure control cannot be controlled at full pressure. personal analysis: As the feed becomes lighter, the stripping effect is reduced, so the light components cannot be removed completely. It is necessary to reduce the reflux ratio and the feed temperature, but I don’t know how to adjust the pressure and bottom temperature? Is it to lower blood pressure and increase body temperature? Let's see, in this case, how to adjust the tower top pressure, temperature or feed temperature, tower bottom temperature, reflux ratio and other parameters? To clarify, our tower has only one feed port.
Your problem is not complicated. The main reason is that after the conversion rate increases, the light components increase, that is, the gas phase load increases, and the tower opening ratio can no longer meet the production requirements, causing the liquefied gas to not be discharged smoothly from the top of the tower. You can send us your data and we will calculate it for you. Data required: Composition of materials entering the tower, quality, tower diameter, type of tray, opening ratio, ctstzqy@163.com , open
Feed quantity kg/h 111000 Feed temperature ℃ 186 Feed pressure MPa 1.95 Tower top temperature ℃ 77.6 Tower top pressure MPa 1.65 Top reflux flow kg/h 22000 Tower top sulfur-containing gas Nm3/h 3600 Tower bottom temperature ℃ 256 Tower bottom reboiler furnace return temperature ℃ 269 Tower bottom extraction volume kg/h 105000 Project feed material density d420 kg/m3 755.6 Distillation range: Initial boiling point ℃ 33 10% ℃ 77 50% ℃ 160 Distillation volume at 350℃ ml 87 Open hole ratio: It seems to be 4.95% or 8.1%. I can’t remember clearly. I’m sorry I’m not in the workshop now and can’t find the information. There are 48 layers of float valve tower, 20 layers of feed, and the tower diameter is: 48 layers 21911-41833mm Φ1800 7911mm-21911mm Φ2800 0-7911mm Φ3200
If the load increases, it is recommended to try increasing the operating pressure plan.
Judging from the operating data provided by the poster, the feed volume is 111t/h and the reflux volume is 22t/h. According to the normal stabilization tower operation, the liquefied gas production volume is about 11t/h. If the feed volume is 111t/h correct, it means that there is a serious problem in the absorption tower and the absorption effect is not good. The supplementary absorption dose can only be increased. In the end, the liquid phase of the absorption, desorption and stabilization towers will be overloaded and the tray efficiency will be reduced. It is recommended to conduct a detailed accounting of the absorption stabilization system, determine the current hydraulic conditions of each tower, and finally decide which tower to carry out technical transformation. The required data has been sent to your message folder.
According to what you mean, because the feed to the distillation tower becomes clear, under normal operating conditions, the bottom product will contain light components, causing the bottom product to be unqualified. When the bottom of the tower contains light components, the temperature at the bottom of the tower will also decrease under the condition of gas-liquid equilibrium. At this time, if we want to extract the light components at the bottom of the tower, we can increase the heating amount at the bottom of the tower (the amount of steam in the reboiler) to increase the temperature at the bottom of the tower and make the product at the bottom of the tower qualified. The increase in light component content will inevitably increase the tower pressure. At this time, in order to prevent the tower from overpressure operation, pressure relief can only be used to reduce the tower top pressure. At the same time, the extraction volume at the top of the tower should also be increased. Of course, if the raw materials change too much, the distillation tower may not be able to meet product quality requirements. This post was last edited by whq520 on 2008-1-28 13:29 ]
Classmate on the 5th floor, ours is a debutanizer tower, not an absorption stabilization tower, but I still want to thank you for your enthusiastic help!
If it is the debutanizer tower of the hydrogenation unit, the upper section is 1800 and the lower section is 2800. There is definitely no problem with the tower diameter. If the void rate of the upper section is 8.1% and the void rate of the lower section is 4.95%, there will be no problem with the tray opening rate. It is necessary to calculate the downcomer area and bottom gap. For 600,000 tons of hydrogenation, we design the tower diameter to be 1800, and the operating flexibility is 60 to 120%.
Host, it should be that the current gas phase load has increased, and the increase in the temperature of the tower reactor will increase the gas phase volume. There may be problems with the opening ratio of the original trays, but it does not mean that the tower diameter is not enough. Replacing it with large-flux and high-efficiency trays should solve the problem. We have many achievements in this area.
I don’t understand a lot and need to learn* , I want to know how to build a debutanizer model so that the simulation results are the same as the field results.
Personally, I think that the feed composition becomes lighter, which is quite different from the composition of the feed plate (the heavy components in the feed plate composition are higher than the feed composition, and the light components are lower than the feed composition). Compared with the separation of the feed plate to an upper tray, the feed position should be moved upward to a suitable position to make it close to the feed plate composition, and the number of trays in the distillation section should be increased. If it cannot be increased, the tower height should be increased at the same time, or trays and internals with higher separation efficiency should be used. :handshake