On the role of adding alkali in the reboiler of the methanol regeneration tower
Thread Content
This post was last edited by qihuajingling on 2010-5-12 at 23:49, version 1. According to the operating procedures, adding alkali is intended to prevent polymers from forming and blocking the pipes. I don’t understand what substances polymerize, and what is the mechanism behind using alkali to prevent such polymerization? 2. Some people in the forum say it is used for neutralization to prevent equipment corrosion, so why isn’t alkali added in the previous system, but rather in the pre-washing methanol regeneration system? I would appreciate some advice from those who are more experienced. Thank you in advance!
Regarding addition and subtraction earlier on, in my opinion: bases react with other substances (through ionization); by adding a base to methanol solution, the pH can be adjusted, thereby reducing the formation of high-carbon compounds
It also implies a reaction with HCN; otherwise, there might be concerns that HCN would react with organic substances to form higher-carbon compounds
This is likely intended to prevent corrosion, mainly against HCN. It is very important for processes that do not use complete conversion; such processes can ignore this issue, as HCN generally undergoes hydrolysis in the conversion system, and it cannot be detected when the material passes through the methanol wash stage
The main goal is to reduce the formation of high-carbon products, as large amounts of such products have a significant impact on pipeline transportation
I checked some information, and they said it’s to prevent the equipment from corroding, with only a very small amount of alkali added!
It is to neutralize HCN in the system and reduce corrosion of the equipment……
Reply to the original poster: Alkali was also added to the methanol system earlier! It’s just that you didn’t pay attention! This is a moderately alkaline substance – ammonia!
Is it to add alkali in the reboiler of the methanol regeneration tower?
This issue has been discussed before; the original poster can search using the topic, and there should be what you’re looking for.
Alkali is added to prevent acidic corrosion of the equipment, which occurs under certain conditions – usually when the moisture content exceeds 4%. Under normal circumstances, the moisture level in our methanol circulation system is below 0.1%, so acidic corrosion does not occur. Moreover, all the equipment used in the methanol circulation system is made of stainless steel. However, the methanol water tower is made of carbon steel, and the pH value of the material fed into it is usually around 5; as a result, the equipment is prone to corrosion.