Hydrogen production from natural gas

After pressurized desulfurization, natural gas is cracked with steam in a special conversion furnace equipped with a catalyst to produce a conversion gas consisting of hydrogen, carbon dioxide, and carbon monoxide. After some of the heat is recovered, medium-temperature shift reaction is used to reduce the CO content in the conversion gas; subsequently, the gas is purified through pressure swing adsorption (PSA) to yield hydrogen. Reaction principle: CH4+H2O→3H2+CO-Q; CO+H2O→H2+CO2+Q

Hydrogen production from natural gas (hydrocarbons such as methane) is mainly carried out through two methods: one is by first producing syngas and then obtaining hydrogen via water-gas shift； Another method is to obtain hydrogen through the direct decomposition of methane or other hydrocarbons. In the process of converting methane into syngas, there are two main reactions: ① steam reforming of methane ② partial oxidation of methane. Water vapor reforming is a highly endothermic reaction, while partial oxidation is a mild exothermic reaction. The reaction equations are as follows: CH4 + H2O → CO + 3H2 △H0= 206 KJ/mol ⑴ CH4 + 1/2O2 → CO + 3H2 △H0=-36 KJ/mol ⑵ A complete oxidation reaction may also occur, with the equation as follows: CH4 + 2O2 → CO2 + 2H2O △H0=-802 KJ/mol ⑶ Synthesis gas must undergo a water-gas shift reaction in order to obtain large amounts of hydrogen; this reaction is also a mild exothermic reaction. The equations are as follows: CO + H2O → CO2 + 2H2 △H0 = -41 KJ/mol. ⑷ When carbon dioxide is present among the reactants, an endothermic reaction of carbon dioxide reforming occurs simultaneously; the equation for this reaction is: CH4 + CO2 → 2CO + 2H2 △H0 = 247 KJ/mol. ⑸ The main side reaction is the formation of carbon deposits, which arise primarily from the decomposition reactions of CO, CO2, and CH4. The equations for these reactions are as follows: CO → C + CO2 △H0 = -172.4 KJ/mol. ⑹ CH4 → C + 2H2 △H0 = 74.9 KJ/mol. ⑺ CO + H2 → C + H2O △H0 = -175.3 KJ/mol ⑻