Reasons for the rapid decline in the activity of methanol synthesis catalysts
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The activity of the methanol synthesis catalyst used in our company declines rapidly, as evidenced by the following values at the outlet of the synthesis tower before temperature increase: CO: 4–5.5%, CO2: 6–7%. After increasing by 2°C. The CO content at the exit of the synthesis tower decreased significantly, the amount of vent gas **decreased**, and the daily production increased markedly. After analysis, the CO content at the outlet of the synthesis tower is 3.8~4.2%. CO2: 5~6%. However, after 48–72 hours of operation, the levels of CO and CO2 gradually returned to their levels before the temperature increase. The amount of gas released also gradually increased, and the production dropped back to the level before the temperature increase. Possible causes that can be ruled out at present: 1. Oil contamination (oil-free compressors are used); 2. Sulfur poisoning (tests show no sulfur entering the system); 3. Chlorine poisoning (chlorine content in the steam is zero). I would like to ask experts: what other factors could be responsible for the rapid decline in activity?
There are a few questions: 1. Is the fresh gas used coke oven gas? Gas composition? 2. How do the components of the gas entering the tower change before and after temperature elevation? 3. What are the inlet and outlet temperatures?
It’s not possible to draw any conclusions from such limited information. From your description, it seems that the one-way conversion rate has decreased; this generally reflects the specific surface area and selectivity. By comparing the conversion rate with the yield, as well as the composition of crude methanol and the changes in distillation processes, we can identify potential causes before proceeding with further analysis
I don’t know the exact temperature, so it’s difficult to determine. The possibilities that come to mind are: either there is a problem with the detection system, or 1) the catalyst has been in use for a long time, or 2) during previous production processes, the catalyst was subjected to significant changes in temperature and pressure, which led to its deactivation, or 3) check whether there is a large amount of catalyst powder in the crude methanol – for example, as a result of the catalyst being crushed
I don’t know the exact temperature, so it’s difficult to determine. The possibilities that come to mind are: either there is a problem with the detection system, or 1) the catalyst has been in use for a long time, or 2) during previous production processes, the catalyst was subjected to significant changes in temperature and pressure, which led to its deactivation, or 3) check whether there is a large amount of catalyst powder in the crude methanol – for example, as a result of the catalyst being crushed
Reaction temperature, hotspot temperature, inlet temperature, outlet temperature, gas components entering the tower, gas components leaving the tower, vapor components from flashing, and so on – all of these need to be taken into consideration. Additionally, the service life of the catalyst must also be considered; raising the temperature should not be done lightly
There isn’t much confidence; it’s just a vague sense of warmth.