The problem of acidic water in hydrogen production

It mainly refers to hydrogen sulfide and ammonia. Acidic water stripping involves using steam to remove hydrogen sulfide and ammonia vapor; the ammonia extraction via a side stream allows ammonia to be extracted to form ammonia water, while hydrogen sulfide is removed from the top of the tower for further processing. In the case of complete extraction without a side stream, both ammonia and hydrogen sulfide are removed directly from the top of the tower – hydrogen sulfide is sent to a sulfur production furnace to produce sulfur, while ammonia burns at high temperatures in the furnace, turning into nitrogen which is then emitted along with the exhaust gases.

Moderately acidic water refers mainly to carbonates formed when substances such as carbon monoxide and carbon dioxide dissolve slightly in water. The amount of acidic water depends primarily on the amount of steam supplied; less steam means less acidic water, as it is governed by the supply of steam. This portion of acidic water can be used as feedwater for the hydrogenation unit after stripping; if it passes the quality tests, it can also be recycled into the steam generation system.

The acidic water produced in the hydrogen production from natural gas is mainly a carbon dioxide aqueous solution; after stripping and degassing, carbon dioxide can be effectively removed, so there is no need to worry

You are referring to the acidic water from hydrogen production units, right? If hydrogen is produced using natural gas as a raw material, it contains little sulfur and nitrogen

I will answer them one by one: 1. In hydrogen production, medium-acidic water is often mentioned. I would like to ask what exactly are the acidic substances in acidic water? The acidified water after medium-voltage treatment used for hydrogen production is, on the surface, water rich in CO2, as CO is extremely difficult to dissolve in water. However, in domestic medium-shift catalysts, during the medium-shift reaction, not only is CO+H2O converted into CO2 and hydrogen, but there are also numerous side reactions that produce formaldehyde and formic acid, which results in the water becoming acidic. 2 How can the generation of acidic water be reduced in actual production? How to treat acidic water? The amount of acidic water after medium conversion is actually water formed by the condensation of unreacted steam. Reducing this amount means reducing the amount of steam supplied, which in turn lowers the water-to-carbon ratio. However, there is a minimum limit for the catalyst concentration; it must not be exceeded, otherwise it will affect the conversion and medium conversion reactions. Normal CO2-rich water can have its CO2 removed through steam stripping; the temperature at the top of the stripping tower must be above 98°C. However, by-products such as formaldehyde and formic acid are difficult to remove. Imported intermediate-temperature catalysts can effectively suppress side reactions. 3. Can the treatment of acidic water be achieved solely relying on deaerators and acidic water stripping towers? What other functions does acidic water removal have beyond stripping and reduction? The acidic water generated by domestic medium-temperature catalysts is difficult to treat to meet the required standards using deoxidizers or acidic water stripping towers; however, after simple treatment, the steam produced by waste heat boilers can still be used for steam distribution purposes.

The expert upstairs is absolutely right; hydrogen-producing acidic water has a high degree of corrosiveness. When we used carbon steel pipelines, we found severe corrosion, which led us to stop using those pipelines. Last year, the newly installed hydrogen production system used 316L material, which was sent to the circulating water plant for treatment.

Here, after acid water vapor stripping for hydrogen production, the resulting liquid can be used directly as feedwater for the deaerator- -

Acidic water performs well after atmospheric and vacuum distillation with gas feeding