Regarding the issue of increasing the hydrogen-to-oil ratio?
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Theoretically, increasing the hydrogen-to-oil ratio raises the hydrogen partial pressure and thus increases the reaction depth. However, when the hydrogen-to-oil ratio is increased, the circulation volume also increases, which leads to more reaction heat being carried away and consequently reduces the reaction depth. Doesn’t that create a contradiction?
What is taken away is the excess reaction heat, resulting in an increased reaction depth.
In practice, the reaction temperature is kept constant.
So what counts as excess reaction heat? How can we be sure that what is taken away is indeed the excess reaction heat and not a decrease in the reaction temperature?
Yes, in practice I know that generally it’s fine to increase or decrease the circulation rate as long as it remains within the designed range. But how can we determine what the most appropriate value for this circulation rate, or hydrogen-to-oil ratio, is?
Our feed temperature is heated using the reaction heat from the output, which saves on fuel costs
A decrease in the heat of an exothermic reaction is beneficial for the reaction to proceed in the forward direction; it increases the reaction rate without reducing the degree of reaction. The reaction temperature is based on the temperature at the reactor inlet; it remains a constant value under the influence of heaters, heat exchangers, etc., and does not decrease or increase as a result of more reaction heat being carried away
The reaction temperature generally refers to the temperature at the inlet of the reaction zone; it is influenced by the operation of the heating furnace and heat exchangers. Increasing the amount of circulating hydrogen is certainly beneficial for the reaction, although it leads to an increase in the energy consumption of the plant as well as a higher load on the heating furnace