Nitrogen displacement drying using low-temperature methanol washing
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What are the purposes of nitrogen purging after the combined operation of low-temperature methanol washing? What is the required O2 level after replacement? What is the typical water content in methanol when starting a methanol cycle for the first time?
This post was last edited by 654262293 on 2010-10-22 at 13:08. 1. Purpose of displacement: Since air can form explosive mixtures with flammable gases such as carbon monoxide and hydrogen, inert gas, usually nitrogen, should be used to displace all the air from the system before starting up chemical processing operations. 2. After replacement, take samples for analysis; if the oxygen content is <0.5% in two consecutive analyses, it is considered qualified. 3. After water interconnection, there may be dead corners in the system where water can remain during discharge; moreover, the system may not be dried thoroughly. In addition, unstable process conditions at the start of operation, as well as frequent startups and shutdowns, are all factors that contribute to a high water content in the lean methanol at the beginning of operation. The water content in the system at the start was around 3%.
1. Purpose of displacement: Since it is a flammable gas, nitrogen is used to completely displace the air in the system before starting up the chemical plant. 2. After drying and displacement, take samples for analysis; the water content in two consecutive analyses should be <0.5% ； An oxygen content of <0.2% is considered acceptable. 3. When the vehicle is first started, the water content in the system is around 2%.
Reply to 2# 654262293: What should be the acceptable water content after nitrogen displacement? Can’t find this data? Does that mean that once the O2 content is within the acceptable range, the water content becomes less important?
Reply to 3# lwm0987: The O2 content analysis came back as satisfactory, but it’s possible that the water in the system wasn’t completely removed Is the water content ignored then?
This post was last edited by 654262293 on 2010-10-22 at 13:09. Reply to 4# Kuju Kaisshi: Nitrogen drying is deemed successful based on the analysis of the dew point temperature; generally, a dew point of ≤-30°C indicates successful drying.
The water content can be determined using the dew point. The national standard is -20 degrees