The pressure drop across the entire system of the diesel hydrogenation unit suddenly increased
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The pressure drop in the reaction system has risen to 16 kilograms, which is 3 kilograms higher than normal. The pressure drops in the furnace and reactor are within acceptable ranges; however, an increase in high-pressure drops occurs. Increasing the water injection into the system has not yielded any significant results. Experts, please analyze the reasons for this
Is there a relation between high temperature and high pressure air cooling, and the heater?
It should be caused by blockage due to ammonium salt crystals
Can the water injection be redirected near the reactor outlet? If possible, please make a correction! That’s one point; the second is to check whether there is a high-pressure heat exchanger in the fractionation feed section – if so, consider the possibility of internal leakage, which can be determined by checking the pressure in the fractionation section as well as the opening degree of the pressure control valve. Severe internal leakage can have catastrophic consequences. Thirdly, check whether it’s an issue with the instruments
Until just before the high-temperature exchange, the temperature of the water used for injection was 230 degrees; crystallization should not occur at this temperature. There are two instances of low-grade oil undergoing high-temperature exchange, and the distillation process is proceeding normally
There should be a water injection point at the high-pressure switch; by redirecting the water injection there and increasing the amount of water injected, it will be possible to clear the blockage
How many sets of heat exchangers are there between high temperature and high pressure? Between which groups is the water injection point? Check the heat exchange temperature of the reaction products before the water injection point; if this temperature is low, increasing the amount of water injected will be ineffective. It is necessary to ensure that the temperature before the water injection point is higher than the crystallization temperature
It’s either ammonium salt crystals or fouling in the reactor, requiring shutdown for cleaning
If the raw material contains too high a level of SN, it leads to the formation of ammonium salts, causing the water injection point to shift forward; this should yield better results
Could it be severe scaling on the air cooler, or is it the result of continuously adding water before the heat exchange, which causes uneven distribution of that water and leads to severe salt buildup?
The question mentions a sudden increase – does this sudden increase refer to a few days or a few hours? If it’s only a few hours, then it’s definitely not a problem with the bed layer; perhaps salts have fallen off and blocked the air cooler.