Hydrocracking side column
Thread Content
Our hydrocracking fractionation tower has side streams, and the products are heavy fuel oil and jet fuel. The extraction temperature as well as the dry point of jet fuel increase as the amount of jet fuel extracted increases. Why does the extraction temperature of heavy fuel oil decrease as the amount of heavy fuel oil extracted increases, while its dry point increases at the same time?
The main factors affecting the side draw temperature of the fractionation tower are the draw rate, tower inlet temperature, top temperature of the tower, and outlet temperature of the reboiler at the bottom of the tower. If only one factor is considered, the extraction temperature is directly proportional to the amount of extraction. When considering multiple factors, the relationship between extraction temperature and extraction volume needs to take into account both the bottom temperature and the top temperature of the tower.
After extracting for a long time from the heavy stones, if there is less pumice, the reason for the lower extraction temperature is the presence of pumice during the extraction process.
But if there is pumice, the dry weight of the heavy stones should decrease relatively, right?
This can’t be right; have you checked if it’s a problem with the gauge thermocouple? It should get worse the more you draw. The heavier it is, the higher the temperature.
The temperature at which the heavy stones are removed – do you mean the temperature at the top of the distillation tower? Normally, the higher the temperature at the top of the tower, the greater the amount of product produced. If the situation you described occurs, it might be due to changes in the raw materials or in the conversion rate