Calculation of hydrogen production raw material volume in refineries
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I am currently in charge of hydrogen production at the factory, and there are a few things I don’t understand, so I would like to ask everyone here for their help. Our plant has hydrogen production methods including naphtha-based hydrogen production (reformation hydrogen production), dry gas-based hydrogen production, natural gas-based hydrogen production, and hydrogen production using fertilizer DOA. I’m facing a tricky problem right now: in order to conduct cost calculations and forecasts, what is the amount of raw materials required per ton of hydrogen produced? It makes it impossible for me to proceed; for example, the raw materials used for hydrogen production such as naphtha, dry gas, natural gas, and the fertilizer DOA are all mixtures, and it’s simply impossible to predict the amounts of these raw materials based on the reaction mechanism equations ； According to usual operational experience, there are fluctuations again. Dear experts, could you please guide me on how to calculate the raw material quantities for hydrogen production via naphtha (reformation), dry gas, natural gas, and fertilizer DOA? Thank you.
I think these hydrogen production units are all used for purifying hydrogen, rather than producing it through chemical reactions. It’s possible to calculate things such as the yield and purity of hydrogen; additionally, the hydrogen flow rate can be read from the flow meters in the DCS system. This is just my personal opinion – I’m not sure if it’s correct – but it’s offered for reference.
What I mentioned is not hydrogen production from brain oil (reformation), dry gas, natural gas, or fertilizer DOA – these are chemical reactions. It’s not the PSA and membrane separation methods used in refineries for hydrogen purification; the amount of hydrogen produced through purification can be calculated based on the recovery rate. Therefore, it is more complicated to calculate the raw material consumption for chemical hydrogen production.
Dear poster: The hydrogen production rates vary among different devices. You can collect the raw materials and the hydrogen produced by your hydrogen-generation devices to determine the yield; once you have that, the calculation formula will be available, making it easier to conduct cost calculations and predictions. Sir, move around a bit; you’ll have a good harvest.
Central Plains person: Hello. Since the raw materials used in different devices vary, the content of key components in each type of material also differs. What we do is to carry out cost predictions prior to production; it would be ideal to predict the amount of raw material required per ton of hydrogen produced, based on the key components in the raw materials (such as the C3, C4, and C5 components of naphtha). What we do is pre-production statistics, not post-production statistics (post-production statistics are quite simple), hehe; I’m open to hearing good advice.
I have made this prediction by primarily using chemical equations based on the composition of the raw materials. First, the amount of hydrogen produced in the conversion reaction is calculated based on the hydrogen yield and efficiency, and then the amount of raw material required is determined by reversing the equations to make a prediction. The portion that is used as fuel and has not reacted completely also needs to be taken into account.
Bro Sizx123, you’ve put it very well. But I’m rather slow to understand; could you explain it in more detail?
Actually, I’d like to know too about the calculations related to this aspect; we need to carry out such calculations before production
The hydrogen production rate of the feedstock is related not only to the type of feedstock but also to the operating conditions of the plant, such as the water-to-carbon ratio, the temperature at the outlet of the converter, and the type of shift process used. It is best to conduct process simulation calculations based on the composition of the raw materials and the operating conditions, determine the amount of raw materials required, and then the hydrogen production rate can be obtained. This is just my personal opinion for reference.
Calculate the carbon content, determine the virtual molecular formula of the mixture of raw materials based on their composition, and then calculate the hydrogen production amount using the carbon content. For more detailed information, you can refer to the book on hydrogen production from hydrocarbons, which contains examples of such calculations
There are also many types of dry gas; methods for drying it vary, as do the processes involved in producing hydrogen