Methanol maintenance
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Methanol – during the initial equipment inspection, some solid wax was found inside the components. I would appreciate it if experts could help analyze what might be causing this
During the operation or shutdown process, there is a change from high temperature to low temperature; the wax produced tends to adhere to the internal components due to cooling and wax formation
Strictly speaking, there is no equipment that does not produce wax. There are many reasons for this; for example, the catalyst may contain impurities, and the gas supply can also have impurities. In particular, iron ions among these impurities can easily cause the reaction to produce wax. There is also the reaction temperature; below 190 degrees, waxing occurs easily.
Many side reactions occur simultaneously during the methanol synthesis process. The formation of paraffin is one of these side reactions, and this is normal. Paraffin has a melting point of around 37°C; it solidifies at temperatures of about 40°C after cooling with water. The alcohol components then adhere to the internal components of the equipment, which is also normal. It’s necessary to clean these components regularly to avoid high or low temperatures inside the synthesis tower, as this can help reduce the formation of paraffin
Many side reactions occur simultaneously during the methanol synthesis process. The formation of paraffin is one of these side reactions, and this is normal. Paraffin has a melting point of around 37°C; it solidifies at temperatures of about 40°C after cooling with water. The alcohol components then adhere to the internal components of the equipment, which is also normal. It’s necessary to clean these components regularly to avoid high or low temperatures inside the synthesis tower, as this can help reduce the formation of paraffin
It’s normal for paraffin to form during alcohol separation; no matter how well you control the methanol synthesis process, side reactions will still result in the formation of paraffin. A thermal wash during major maintenance is sufficient to deal with this issue!
It’s really annoying when wax is formed. I’ve heard of catalysts that produce very little wax; I wonder if that’s true! !
Be careful to melt wax online as well, so as not to affect the water cooling effect and thereby impact the alcohol content
The equipment has been inspected, and the medium-alcohol synthesis tower is now being equipped with a catalyst
In addition to maintaining a bed temperature of at least 210°C under normal operating conditions, during shutdown, the system pressure should be reduced first and nitrogen should be introduced to circulate within the system. At this time, the startup heater should be activated to keep the system warm (it is essential to ensure the bed temperature is maintained) in order to prevent the active gas components from reacting at low temperatures and forming wax. Cool down further after CO+CO2 ≤ 0.5%.
Reply: 10# ZG3316 makes a valid point