Harm of water content in the feed oil of hydrogenation units
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Water content in crude oil has various hazards. First, it causes fluctuations in the operation of the heating furnace, resulting in unstable temperature at the furnace outlet; as a consequence, the reaction temperature also fluctuates, and fuel consumption increases. Second, the large amount of water vaporizing in the raw materials causes the system pressure to rise. Thirdly, it is harmful to the catalyst. Under high-temperature operating conditions, if the catalyst is exposed to moisture for an extended period, it can easily lead to aging and agglomeration of the active metal components on its surface. This results in a decrease in both activity and strength; moreover, the catalyst particles may become pulverized, thereby clogging the reactor. This post was last edited by Zhenzhenyouci on April 18, 2009, at 08:16.]
One more thing: it can easily cause pipeline vibration. It needs to be reinforced. This post was last edited by Zhenzhen Youci on 2009-4-18 08:16.]
Could it prevent the reaction temperature from rising?
Two more points: First, it can easily lead to a low cold liquid level, which in turn causes water to be present in the oil sent for distillation, making distillation control difficult! Secondly, a high hot low-level liquid level may cause the circulating hydrogen to contain liquid, leading to excessive vibration in the circulating hydrogen compressor and affecting its normal operation.
An incident we experienced involving water in the hydrogenation feed: As for the amount of water present, after the final reaction feed pump stopped operating and the raw material buffer tank was dehydrated, 70% of the liquid level had to be reduced to 10% before oil could be detected. High scores and low scores are both meaningless. It can be seen that the feed at that time was basically all water. The handling was fairly correct later on. Hydrogen is circulated at a constant temperature for a day before feeding begins, in order to completely vaporize the moisture inside the catalyst. The pressure drop and activity of the catalyst bed were essentially unaffected.
Another hazard of water in the feed oil is that the water in the feed oil reacts with the carbon deposits on the catalyst surface to produce CO and CO2, resulting in an increase in the levels of CO and CO2 within the reaction system.
The main harm is that it damages the strength of the catalyst, causing it to turn into ash; this is detrimental to the catalyst, and it can also cause fluctuations in the reaction temperature. Additionally, high-pressure feed pumps are prone to experiencing vacuum conditions! ! !
During that incident when the feed contained such high levels of water, on the DCS operation screen, which parameters changed the most? Please give your advice
The reasons were all explained upstairs; there’s not much left to say downstairs.