The hydrorefining feed oil contains water
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Yesterday, the master organized a study session*. During that time, a situation was mentioned in which the feed oil for hydrorefining contained water. It’s not a large amount of water, but rather a small amount. So the changes in parameters are not very noticeable. Later, on the low-pressure interface the pressure was extremely high; even with the control valve bypass fully open, the flow couldn’t be increased enough. I won’t go into details about the handling of the accident; the technician mentioned a phenomenon in which the hydrogen consumption dropped by over a thousand units at that time. Is this phenomenon caused by the increase in system pressure resulting from water vaporization, which prevents hydrogen from entering the system? Or other reasons?
I’ve never done hydrogenation. I’m wondering if, since there’s a lot of water, it might be possible to reduce the amount of water used!
Does the vaporization of water increase system pressure, preventing hydrogen from entering the system? It can be said that the impact is minimal. Possible reasons: 1. The water contained in the raw material may enter the catalyst and be absorbed by its pores, thereby occupying the active sites and preventing the hydrogenation of the crude oil ； 2. It is possible that water reacts directly with some components in the raw material (olefins), thereby reducing H2 consumption. Generally, the reduction in hydrogen consumption is caused by changes in the feed oil; you can check the historical records to see if there were any significant changes in the feed oil at that time.
I agree with the opinion above; if the raw material contains water, it is generally removed through high-voltage treatment. To determine if the raw material contains water, factors such as the reaction temperature, system pressure, hydrogen consumption, and changes in the valve position of the high-pressure cut-off valve come into play.
A very small amount of water wouldn’t be enough to cause the regulator valve’s bypass to open fully, right?
I mean, can such a small amount of water cause that much drainage? It’s doubtful; shouldn’t there be high scores before the low ones? Is it a matter of inflating scores? Changes in the density of the crude oil affect the high-density interface; has water moved from the lower density region?
I think the situation you’re describing can only occur if your rank isn’t updated in a timely manner; the hydrogen consumption has nothing to do with the amount of water present. If water enters the reaction system, the reactor should show obvious reactions, and the temperature will continue to drop – at that point it would be a serious accident.
It could be a problem with the high-pressure hydraulic control, or it might be caused by a high content of resins and asphaltenes in the crude oil
It is also possible that the high-pressure separator, due to the large volume of material to be processed, does not perform its separation function properly, thereby carrying water into the low-pressure separator! You can keep the high-level liquid level higher to extend the residence time of the oil at that level!
Water in the crude oil should be able to be removed at high fractions; excessive water at low fractions is likely due to high water addition rates. However, it should be noted that water is strictly prohibited in the crude oil, as otherwise it will cause the catalyst to break down.
Water and olefins need to be at 300 degrees and under 70 kilograms of pressure in the presence of an acid catalyst; it shouldn’t be a reaction between water and olefins. First analyze the situation, then identify the cause, and finally determine a solution. Water has a higher latent heat of vaporization than oil; it expands upon vaporization. Therefore, when the feedstock contains water, the temperature generally decreases while the pressure increases. Some studies suggest that water can undergo a water-gas reaction with the carbon deposits on the catalyst, producing carbon monoxide and carbon dioxide; these substances then undergo methanation, leading to a significant rise in reactor temperature. However, in actual production, we have encountered situations with water present without any significant increase in temperature, so it seems to be merely a theoretical possibility. The instantaneous decrease in the circulating hydrogen flow rate is due to reasons such as problems with the flow meter, issues with the compressor, or problems within the system. First, rule out the flow meter and check whether the pressure lead pipe is filled with fluid or not. Factors such as changes in the compressor speed can also affect the reading of the flow meter, and the hydrogen composition has an impact as well. If the traffic only decreases temporarily before returning to normal, it might be due to the reason your mentor mentioned – the pressure holding things in place. If it’s to the point where a bypass line has to be installed just to carry water to the boundary, it’s probably already ruined. If the previous part is valid, check whether there is an issue with the high-score threshold, which may be causing the score to be lowered. Water needs to be injected before cooling the high-pressure fraction in hydrogenation; I’m not sure whether you use cold high-pressure fractions or hot low-pressure fractions. When encountering a problem, first analyze what could cause it, and then rule those out.