Explanation for fluctuations in stabilizer pressure and top temperature
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Recently, with my catalytic unit handling reformed overhead oil (light-component vapor), the temperature at the top of the stabilizer has been rising rapidly from 60 degrees to over 80 degrees. At the same time, the pressure decreases, and this drop in pressure occurs very quickly when the temperature reaches 80 degrees. The adjustment of the reflux pressure to control the temperature works normally, without any irregular fluctuations; the pressure is kept at around 1 MP, with the lowest value dropping to a little over 0.8 MP. It’s definitely the oil from the reformation process that enters V201 causing the stabilizer to operate under overload. However, I can’t figure out the reason for these fluctuations – I’d appreciate everyone’s advice
A simple estimate is that the bottom temperature of the tower is too high or the feed composition has changed; a high bottom temperature causes the heavier components to rise, increasing the gas phase temperature and reducing the pressure. As the feed composition becomes heavier, the gas phase temperature rises naturally; however, the tower pressure generally does not change significantly as a result of adjustments. At least an increase in your vapor phase temperature definitely means an increase in the heavy components.
If it were that simple, oh yeah, anyone could think of it! The key is that both the rate of increase in top temperature and the rate of decrease in pressure are very fast! !
1. Has a similar phenomenon occurred before adding drawing oil? 2. It is recommended to sample and analyze the components of liquefied gas before and during fluctuations, respectively. 3. Based on our previous experience in handling degumming oils here, the main issue lies in the C5 content of the liquid hydrocarbons, which results in a relatively high top pressure. 4. Are there operational fluctuations caused by significant changes in the components of the feed?
1. Everything was normal before processing the oil from the distillation column top. 2. It’s possible; the oil coming from the reforming unit contains both the vapor from the top and the liquid from the bottom of the column. 3. But no matter how the composition changes, how can we explain the increase in top temperature and the decrease in pressure?
This post was last edited by liaifeng on 2009-9-20 07:34. If understood in the opposite way, it might explain some of it. A drop in pressure causes the temperature to rise, and the rising material then restores the pressure? Now the question arises again: what causes the pressure to drop?
When the top temperature rises to 80 degrees, do the feed temperature and the bottom temperature of the tower also increase? Has it been observed that it is a decrease in pressure that causes the top temperature to rise, or do both changes occur simultaneously?
Changes in the composition cause pressure changes, which in turn lead to temperature changes. The rapid drop in pressure is due to some of the lighter components liquefying at a certain pressure level, resulting in a swift decrease in pressure.
If the temperature at the furnace outlet and at the top of the tower are so unstable, it is mainly due to changes in the composition of the feed material – an excess of light components leads to an increase in temperature and a decrease in pressure. By increasing the reflux at the top of the tower, the temperature drops, but then the pressure rises again. I suggest adjusting the temperature at the furnace outlet as well as the gas injection at the bottom of the tower, in combination with adjustments to the reflux at the top of the tower.