Carbon neutral hydrogen production

A system comprising:

• a hydrocarbon stream comprising at least one hydrocarbon and having a molar flow rate of carbon (C) and a molar flow rate of hydrogen (H);
• an oxidizing stream comprising oxygen gas and having a molar flow rate of oxygen gas (O2) in a range of from 10% to 70% of C+H/4;
• a combustion reactor configured to receive the hydrocarbon stream and the oxidizing stream, the combustion reactor configured to combust the hydrocarbon stream to produce soot and syngas, wherein sub-stoichiometric combustion of the hydrocarbon stream within the combustion reactor converts at least 10% of the carbon in the hydrocarbon stream into soot;
• a mechanical separator configured to separate the soot from the syngas to produce a syngas stream comprising carbon dioxide, carbon monoxide, and hydrogen;
• a shift reactor configured to receive the syngas stream and steam, the shift reactor comprising a water-gas shift catalyst, the water-gas shift catalyst configured to convert at least a portion of the carbon monoxide of the syngas stream and steam to carbon dioxide and hydrogen to produce a shifted gas stream;
• a quench tower configured to receive the shifted gas stream and separate water from the shifted gas stream to produce a dehydrated gas stream;
• and
• a purifier configured to receive the dehydrated gas stream and separate hydrogen from the dehydrated gas stream to produce a hydrogen product stream and a recycle stream, the hydrogen product stream comprising a majority of the hydrogen from the dehydrated gas stream, the recycle stream comprising a remainder of the dehydrated gas stream, wherein the combustion reactor is configured to receive the recycle stream.