Hydrogen upgrading refineries

This source of hydrogen is being effectively utilized with the aid of the cryogenic hydrogen upgrader to recover and purify hydrogen for return to such refinery applications as residuum hydrocracking and hydrodesulfurization. 

The hydrogen upgrading in refineries is traditionally carried out by means of PSA and cryogenic separation processes. However, the application of membrane systems for this type of separation is rapidly growing toward the commercial level, owing to the advantages related to the low capital costs, low energy requirements, and modularity. 

In many refineries hydrogen upgrading processes, the impurities to be rejected include hydrocarbons that have value significantly above fuel value. This is particularly true for olefin-containing streams. The relative amounts of high-value hydrocarbons and the incremental cost of further separation determine whether by-product recovery is an important parameter to be considered. 

On the fuel side, the issues are even more complex. Hydrogen, although currently it is made in relatively large amounts inside oil refineries for upgrading petroleum products and for making many bulk chemicals (e.g., ammonia), it is not currently distributed like conventional fuels. 

Nevertheless, it became evident that reforming processes instituted in many refineries were providing substantial quantities of by-product hydrogen, enough to tip the economic balance in favor of hydrodesulfurization processes. In fact, the need for such commercial operations has become more acute because of a shift in supply trends that has increased the amount of high-sulfur crude oils employed as refinery feedstocks. Because of this, many topping refineries have shut down due to their inability to process these heavier crude oils. In comparison, the total capacity of those processes that are intended for upgrading the heavier distillates of crude oils have increased (Rhodes, 1991). 

As a source of hydrogen that can be separated from the gas stream and used as a fuel or as a feedstock for refineries (which use the hydrogen to upgrade petroleum products). 

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