What is the impact of water injection in the high-pressure air cooling system of hydrocracking on the cracking reactor?

Short-term interruptions are fine as long as the system voltage drop allows it, the temperature after air cooling remains low, and there are no issues.

The main purpose of injecting water is to prevent the crystallization of ammonium salts. Generally, the interval between water injections should not exceed four hours; if the pressure drop in the reaction system increases, it will affect the operation of the reaction system as well as various operating parameters of the compressor

Is it the reactor you mentioned, or is it the catalyst inside that has an impact? It is possible to reduce the processing volume for a short period of time; depending on the impurity content in the raw materials, the pressure difference in the reaction system can be used to determine whether there is blockage in the pipelines or equipment. An increase in pressure difference in the reactor related to the catalyst can lead to the catalyst being crushed, or even damage to the internal components of the reactor!

Pre-cooling water injection is generally maintained as a continuous flow, whereas water injection into the heat exchanger at the high-pressure outlet is done intermittently.

The water injection before air cooling is primarily intended to prevent the crystallization of ammonium hydrosulfide. Once ammonium hydrosulfide crystallizes, it causes under-scale corrosion and increases the system pressure drop. If the interruption is short-lived, pay attention to the temperature after cooling; generally, there is no major issue.

Will the interruption of water injection lead to an increase in ammonia content in the circulating hydrogen? If the ammonia concentration increases, will it cause ammonia poisoning of the catalyst in the cracking reactor?

The ammonia nitrogen content in circulating hydrogen is very low, generally below 100PPM, and it will not have an adverse effect on the catalyst in the short term.

It won’t have a significant impact in the short term; closely monitor the purity of the recycled hydrogen. If its purity drops, discharge waste gas to maintain a high level of purity for the recycled hydrogen； Either reduce the temperature and flow rate, and pay attention to the system pressure difference, that is, the pressure difference between the inlet and outlet of the circulation pump; stopping the water supply for a short period of time will not result in shutdown, so there’s no need to worry

The organic nitrogen compounds in the feedstock are converted into ammonia through a reaction. Since ammonia is basic, it competes with the reactants for the acidic active sites of the catalyst, thereby suppressing the catalyst’s activity. However, by injecting flushing water into the reaction product, most of the ammonia in the reaction loop can be removed, thereby avoiding a significant impact on catalyst activity. If water injection is stopped for a period of time, a large amount of ammonia will accumulate in the circulating hydrogen, which will cause a sudden and sharp decline in catalyst activity upon entry into the reactor; once water injection is resumed, the catalyst activity will return to normal. If the reaction temperature is increased to compensate for the reduced activity of the catalyst when water injection is interrupted, the reaction temperature should be lowered before resuming water injection to prevent excessive cracking of the reaction products. A prolonged interruption in water injection will force the device to shut down. Ammonia will no longer be removed from the reaction effluent and will begin to clog the recycle hydrogen pipeline. As the ammonia concentration increases, the catalyst activity also decreases, and the conversion rate drops rapidly. Furthermore, when water injection stops, the ammonium salts in the air cooling will no longer be washed away. Salt buildup will occur very quickly.