Hydrogen supply for hydrogen production plant
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For natural gas-based hydrogen production facilities, how is the amount of hydrogen allocated and controlled? In our facility, the feed materials are natural gas and PSA off-gases from hydrocracking. Analytical tests show that 50% of these hydrocracking off-gases consist of hydrogen; however, the volume of these off-gases varies. The pressure in the hydrogen pipeline is regulated based on the amount of natural gas available, with no additional hydrogen being supplied. Under such circumstances, how should the amount of hydrogen to be supplied be calculated? It seems that the required hydrogen-to-oil ratio of 80 to 100 by volume cannot be achieved? I hope everyone can offer some advice
In the hydrogen-to-oil ratio, hydrogen refers to the amount of recycled hydrogen, not the amount of hydrogen added.
Are you referring to hydrogen production? ? ? ? ?
If the feedstocks are merely natural gas and PSA off-gases from hydrocracking, without any other refinery gases containing sulfur or olefins, then there is no major problem; the organic sulfur content in natural gas is extremely low, and even after passing through the hydrogenation reactor, the amount of hydrogen consumed is very small.
The hydrogen preparation prior to hydrogen production mainly involves the hydrogen consumption in the raw material purification system; analyzing the hydrogen content at the outlet of the hydrogenation reactor shows that a volume ratio of over 20% is sufficient.
Could you explain how those 20% were determined?
Well, the sulfur content here is very low. But what if it is naphtha or liquefied gas? How should the hydrogen addition amount be controlled in that case? In other words, what do we use to control this hydrogen addition amount?
It is mainly controlled based on the content of organic sulfur and unsaturated hydrocarbons in the feedstock. Theoretically, 1 mol of olefin requires 1 mol of hydrogen for hydrogenation, but it is necessary to take into account the complete hydrogenation of organic sulfur in the feedstock as well as reducing the content of light hydrocarbons
It seems to have been mentioned in the book on hydrogen production operators; I haven’t read it in a long time. Based on 10 years of production experience, there’s no problem