At present, in order to obtain hydrogen in industrial production, the following methods are usually used:
1. Pass water vapor through hot iron to obtain hydrogen. The purity of the hydrogen obtained in this way will be relatively high, with a purity of about 97%.
2. Hydrogen is extracted from water gas. The purity of the hydrogen obtained in this way is also quite low. Therefore, few people use this method to obtain hydrogen and produce hydrogen through water electrolysis. Electrolytic hydrogen production equipment is currently the most used method in industry, and it is also the method with the highest purity. The purity can reach more than 99%. This is an important method for preparing hydrogen in industry. When electrolyzing sodium (potassium) hydroxide solution, gas is released from the anode and hydrogen is released from the cathode. Hydrogen can also be obtained by electrolyzing sodium chloride aqueous solution to produce sodium hydroxide.
3. Pass water vapor through hot coke to obtain hydrogen, but the hydrogen obtained in this way is usually only 75% pure.
Electrolytic hydrogen production equipment and methods have relatively high requirements for the hydrogen and purity used to cool the generator. Therefore, they are all produced by electrolyzing water.