As it was mentioned earlier, the choice of catalyst and operating param­eters affect the reactions that take place within the hydroprocessing reac­tor. The key operating parameters of hydroprocessing include the reactor temperature, hydrogen partial pressure, liquid hourly space velocity and hydrogen feed-rate.

2.2.3.1 TEMPERATURE

Most catalytic hydrotreating and hydrocracking reactors operate between 290-450°C. The temperature range is selected according the type of cata­lyst and feedstock type to be processed. In the first stages of the catalyst life (after its loading in the reactor) the temperature is normally kept low as the catalyst activity is already very high. However as time progresses and the catalyst deactivates and cokes, the temperature is gradually in­creased to overcome the loss of catalyst activity and to maintain the de­sired product yield and quality.