Ask for help: Methanol system replacement plan when co-produced methanol is shut down for a long time
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Our company's methanol operation has never been stopped for replacement. Now it needs to be stopped for ten days for maintenance. The transformation of the process requires extensive work. According to the operating procedures, system replacement requires 49% nitrogen. However, our company does not have an air separation unit and cannot produce nitrogen. Is there any other replacement plan? Ask experienced colleagues for help.
In my opinion, small pipes can be replaced with water, and large pipes can be replaced with air, but fire analysis must be strictly carried out.
The catalyst in the methanol synthesis tower is afraid of water and oxygen, and cannot be replaced with water vapor and air. Otherwise, the catalyst will be inactive. Moreover, the catalyst is reduced copper, which will oxidize when it encounters oxygen and water, releasing heat, causing the temperature in the tower to skyrocket. If there are cut-off valves at the front and rear of the tower, you can use bottled nitrogen (more than 99.8%) to replace the synthesis tower from the bottom of the tower after the temperature and pressure are lowered by the open cycle machine to ensure that the synthesis tower is slightly positive and prevent air from entering. The operating procedures for other equipment and piping parts are not very clear. Steam can be used to replace other pipeline equipment. If air is used, attention should be paid to the influence of H2 in the synthesis device. If you want to replace the entire system, you still have to wait until the temperature of the synthesis tower drops, lower the pressure, and replace it with a bottled nitrogen open cycle machine. May I ask what process your company's methanol plant has and what its capacity is?