Hydrogen impurity components from chlor-alkali production
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I would like to ask the experts: what are the impurity components in hydrogen produced as a by-product of chlor-alkali production, and what are their approximate concentrations? I checked, and there’s methane too. Is methane also produced as a byproduct of hydrogen in the chlor-alkali industry?
How can methane be present in chlor-alkali hydrogen?
The main impurities are water and sodium hydroxide; other gas components have basically not been detected
If it is only hydrogen produced during the electrolysis process in chlor-alkali production, then there will be no methane or other organic gases; the impurities present should be air and moisture that have seeped in, and sometimes a small amount of chlorine as well. The amount of air that has leaked in can generally be determined by analyzing the nitrogen-to-oxygen ratio. If methane impurities are indeed present, it is necessary to evaluate all sources of hydrogen; the factors responsible for the presence of methane or other organic impurities can likely be identified.
The by-product hydrogen from the chlor-alkali industry contains methane. In addition, there are impurity components such as acetylene, carbon monoxide, nitrogen, nitrogen oxides, and free oxygen, whose concentrations depend on the specific manufacturing process. Generally, the methane content is between 1-2%, while the content of other impurity components can reach 0.1-0.5%.
If hydrogen is produced as a by-product through electrolysis, air can penetrate into the system; as for hydrogen produced from other sources, such as methane, it depends on the process used, and usually the amount isn’t very large.
We sent it for analysis earlier, and no organic compounds such as methane were detected; it was mainly water, nitrogen, oxygen, and so on. Water and nitrogen were the most abundant components. However, the hydrogen we sent was hydrogen that had been washed, cooled, and simply dehydrated. After deoxygenation and dehydration, a purity of over 99.95% can generally be achieved; with better treatment, it can reach over 99.99%. In our case, the nitrogen is not subjected to any treatment.