The temperature difference between the two feed streams to the diesel hydrogenation feed heater is nearly 100 degrees
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In the diesel hydrogenation feed heater, about one hour after the occurrence of feed fluctuations, a difference in temperature between the two feed streams begins to appear; one stream operates normally while the temperature of the other stream keeps dropping. It is known that the properties of the crude oil remain almost unchanged, but the amount of hydrogen mixed with the feed varies significantly, with a noticeable decrease in this amount when there are feed fluctuations. Neither of the two feed streams is controlled by regulating valves, and there is no flow measurement available. The pressure difference between the two streams increases. Have any of you encountered this situation before? What could be the cause, and how should it be addressed?
Has there been any change in gas consumption? There is a high possibility of deviation in flow; have there been instances where the temperature was much higher?
It can happen; I’ve encountered it before. Since there’s no control valve, one could consider using a manual valve to regulate the flow, but this carries risks. In essence, what’s happening here is a deviation in the flow direction, and once such a flow pattern is established, it becomes difficult to address the issue. Additionally, if hydrogen is mixed before entering the furnace, adjustments can be made; it’s important to increase the amount of circulating hydrogen and ensure its even distribution. As for the issue of gas flow deviation mentioned earlier, I don’t think it’s a problem – you just need to check the furnace temperature to see if there’s any deviation.
What was said upstairs is correct; it was caused by an overly low hydrogen mixing ratio, and the issue has been resolved. Thank you. . .
No thanks, no need. Let’s learn from each other and help one another
The original question can actually be phrased differently: What is the flow state of hydrogenated oil after being mixed with hydrogen? If you figure this problem out, you’ll know how to solve your issue! In my personal opinion, different levels of hydrogen mixing result in varying mixing effects and flow patterns; even in the case of heavy oil hydrogenation with a high degree of hydrogen mixing, it is not possible to achieve a completely homogeneous state – the flow is generally laminar (with lighter materials at the top and heavier ones at the bottom). As the ratio of hydrogen mixing changes, so too does the flow pattern. When encountering this problem, the person in charge only needs to adjust the hydrogen mixing ratio to see improvement; in essence, this involves adjusting the flow state so as to achieve mass balance between the two pipelines. Under normal circumstances, uneven burning issues improve on their own without any adjustments, but in your case the problem is getting worse and worse; therefore, it’s time to consider cleaning the furnace tubes during the next maintenance session! Personal opinions are not necessarily correct; they are for reference only
The device mentioned by the poster is the same as ours; in this case, it’s possible that both furnace tubes are suffering from coking issues, though to varying degrees. It’s impossible to completely resolve this problem – one can only maintain production. Measures include increasing the hydrogen-to-oil ratio, raising the temperature at the furnace inlet, and increasing the system pressure.