Methanol synthesis by-products
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For our newly launched methanol project, the catalyst used is also the new C307. However, since operation began, the resistance of the crude methanol filter has remained high; it needs to be replaced once a day under heavy load conditions. What comes out after steam cleaning is wax. The synthesis tower is unable to reach an adequate pressure due to low load levels – the pressure stays between 3.5 and 4.5 MPa, with an inlet temperature of 201°C and an outlet temperature of 224°C. Please analyze what could be causing the high amount of synthesis by-products I would appreciate your advice.
What is the airspeed? What is the particle size of the catalyst?
Air velocity is around 10,000, and the catalyst size is 4.5*5
Does low pressure also have an impact? Additionally, the H2-CO/CO+CO2 ratio in our fresh gas is 2.9
Based on pressure and temperature, everything seems normal. I guess it might be that there are impurities left in the synthesis tower during operation that weren’t completely removed, or perhaps the gas entering the tower contains oil
Based on my experience and relevant information, it is certain that impurities such as rust have entered the catalyst bed, leading to the formation of polycarbonated saturated hydrocarbons； Either the catalyst was not properly controlled during production, resulting in impurities such as iron in its composition.
Incomplete pipeline purging is one of the key factors.
What impact do the gas components have on the by-products?
This kind of situation also occurs in our organization, and the presence of iron is an important factor that leads to the formation of paraffin. Additionally, controlling the catalyst temperature is also very important
If it is due to incomplete purging, there is one issue that is difficult to explain: we did not notice the formation of wax at the beginning of production, and the wax only appeared after a shutdown during which no replacement was carried out. But it’s been a long time, and it’s still extremely congested.
Could H/C be adjusted a bit? Try increasing the CO2 level to see if that makes a difference!