Question
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In our Hydrogen unit feed Natural gas having around 5-8% Nitrogen. We are maintaining steam to carbon ratio on weight% of steam to feed. At present we are maintaining 2.85 steam to carbon ratio by weight %. What if we calculate steam to carbon ratio on mole%. Will it help in optimize the steam to reformer. Will it reduce energy consumption of the unit?
Feb-2022
Answers
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Marcelo Tagliabue, Air Liquide, marcelo.tagliabue@airliquide.com
In the calculation I agree with the previous answer. Now for the safety of the correct operation, to eliminate any possibility of carbon formation in the tubes and shift the reaction equilibrium to the right, I suggest operating between 2.8 to 3 mol/mol. Regarding the issue of N2 I do not see any problem. There are academic works that show that the addition of certain inerts such as He, Ar, N2, among others, favours the conversion of CH4.
Mar-2022
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Adrie Visser, Natref, adrie.visser@natref.com
2.85 kg Steam / kg Carbon = (2.85/18) kmol Steam / (1/12) kmol Carbon = 1.9 kmol Steam / kmol Carbon.
The equilibrium shift reaction requires 2 kmol water per kmol carbon. So your S:C ratio is too low. It Should be around 2.3 to 2.5. on a molar basis.
Feb-2022
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