The CO2 level in the gas purified by low-temperature methanol washing cannot be reduced
Thread Content
Previously, it was operating at full capacity: the circulation rate was 450,000 KG/H, the circulation temperature was -54°C, the pressure was 3.0 MPA, and the CO2 level in the purified gas could be adjusted to around 2.5. Now the circulation rate has increased to 550,000, the circulation temperature has reached -56°C, and the pressure has risen to 3.2 MPA. The CO2 level in the purified gas remains above 4, and it won’t go down. I don’t know what’s going wrong.
This post was last edited by goldliyang on 2021-10-11 08:18. Hello, where is this located? Could you provide more detailed information? I work in a design institute, and our experienced engineers might be able to help solve this problem. Thank you
Which craftsmanship? It is recommended to proceed according to the process, starting from the following aspects: 1. Check the heat exchangers related to the process gas and feed gas to determine if there are any internal leaks Compare samples taken from the top of the tower with those taken from the boundary area. 2. Check the operation of the thermal regeneration tower – is there sufficient steam supply? Don’t focus only on the operating temperature and pressure of the tower; pay attention to the steam consumption as well ； 3. Inspect the heat exchangers related to lean methanol to check for any internal leaks that could cause CO2-containing methanol to leak into the lean methanol stream.
It’s very likely that there is an internal leak in the heat exchanger; we have replaced both the methanol-rich and methanol-poor heat exchangers
Your reply seems quite poor in quality; it’s a waste of money to turn to you – it only leads to wasted time
This post was last edited by Qingchengjun on 2021-10-9 at 10:57. The person above gave some directions; it’s necessary to conduct experiments and compare test data to find out. Even if academicians come, this is still what needs to be done. Compare the fluctuations in the feed gas, regenerate methanol compared to previous versions, as well as issues such as methanol mixing due to broken heat exchangers and instrument calibration
If there are no issues with the operating temperature, pressure, and flow rate, then follow the suggestions from Building 3 to identify the problem. Pay attention to taking samples of lean methanol from various locations such as before and after the lean/methanol-rich heat exchangers, analyzing them, and comparing the CO2 content in order to verify whether there is any internal leakage in these heat exchangers.
If it is a heat exchanger issue, the CO2 level in the purified gas should also be above the limit at lower loads. It has increased from 450,000 to 550,000, representing a 22% increase in load. Could the original poster please provide more details regarding the design values, operating values, and load conditions?
Is it an alkaline cleaning process? Has it reached maximum adsorption saturation?
1. Changes in gas composition； 2. Detection of internal leaks in heat exchangers ； 3. Methanol component: are there any impurities? ； 4. Regeneration system: whether the methanol leanness meets the requirements.
Judging from the way you respond, even if there are people willing to help you, they won’t do so; be more polite. In a field like this one, it’s best to improve one’s manners (or else it will harm your reputation)