Issues regarding the operation of methyl acetal catalytic distillation columns
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In the production of methyl acetal, a catalytic tower and a distillation tower are usually two separate units, though they can also be integrated as one unit. In towers that are designed separately, the material in gaseous form at the top of the catalytic tower is fed in from the bottom of the distillation tower; this material then returns to the catalytic tower from there, while the material from the top of the distillation tower returns on its own. I found that in this operation, the material returning to the catalytic tower contains a large amount of methylal, which is undesirable. I think it would be good to add a reboiler to the bottom of the distillation tower to ensure that the material returning to the catalytic tower contains little or no methylal. Does everyone think this approach works? I don’t think there’s any problem.
This post was last edited by cl6119 on 2011-8-30 11:11. There will be problems. Since the vapor feed to the distillation column contains methylal, complete separation in the first stage is not possible. Installing a reboiler in the distillation column does not help much either, unless the feed point of the column is raised as well; to maintain the composition at the top of the column, the number of plates will inevitably need to increase, which may lead to other process problems.
The operation of the methyl acetal distillation tower is simpler compared to that of the catalytic distillation integrated tower.
Adding a reboiler will not enable achievement of the aforementioned objectives. To attain the desired design goals, it is necessary to change the operating conditions of the distillation tower; such changes require a redesign of the entire distillation system, the whole system needs to be replaced, which leads to increased fixed investment. The energy consumption of the distillation tower will definitely rise as well, and it is necessary to conduct a technical and economic analysis to decide whether it is worthwhile to proceed with this approach
In fact, it’s because the tower is too tall; dividing it into two towers makes things easier. If a reboiler is added to the rear tower, it’s equivalent to introducing heat into the tower, which will affect the balance of the entire tower.