Main sources of hydrogen

At present, the main hydrogen production methods are coal gasification, natural gas, methanol, industrial by-product and electrolytic water. The purity, impurity types and cost of hydrogen containing feed gas obtained by various methods are shown in Table 1. The purity of hydrogen containing feed gas obtained by one-step electrolysis of water is shown in Table 1 High, and the cost of hydrogen production is relatively high. It is suitable for providing hydrogen sources for industries with relatively small hydrogen consumption but demanding hydrogen purity and impurity content. The cost of hydrogen production from coal, natural gas, methanol, naphtha and other raw materials is relatively low, but the hydrogen content in the feed gas is low, which requires purification, and the process flow is relatively complex, which can provide hydrogen sources for industries with large hydrogen consumption.

Main purification methods of hydrogen

The purity of hydrogen in hydrogen containing feed gas prepared by different methods is generally low. In order to meet the requirements of specific applications for hydrogen purity and impurity content, purification treatment is also required. The process of removing impurities from hydrogen rich gas to obtain hydrogen with purity above 5N (≥ 99.999%) can be roughly divided into three processes.

1、 It refers to the pretreatment of crude hydrogen to remove specific pollutants harmful to the subsequent separation process and convert them into substances easy to separate. The traditional physical or chemical absorption method and chemical reaction method are effective methods to achieve this goal;

2、 It is to remove major and minor impurities to obtain an acceptable level of pure hydrogen (5N and below). Common separation methods include pressure swing adsorption (PSA) separation, low-temperature separation, polymer membrane separation, etc;

3、 Low temperature adsorption, palladium membrane separation and other methods are used to further purify hydrogen to the required index (above 5N).

The above is what I brought to you about hydrogen purification in Chengdu. I hope it will be helpful to you.