汽提法从甲醛水溶液回收甲醇

The Removal of Methanol from Aqueous Formaldehyde by Stripping

通过汽提过程,可以从甲醛溶液中分离回收甲醇。该过程的最佳试验条件是:汽提空气解吸最终平衡温度为70℃,甲醇与空气比为50克∶378—480升,空气流速1.8—2.0升/分,每次试验时间为3.5—4.0小时。汽提后,可得到含甲醇少于1%的55w%浓度的甲醛溶液。甲醇的回收率达95%以上。回收甲醇经过精馏可再用于甲醛生产。

MeOH is removed from aqueous HCHO in a stripping column by a counter-current flow of air at 70℃(head temp.).Maximum recovery of MeOH is obtainedwhen the ratio of MeOH to air is 50(g):378—480(1),the counter-current flow ofair is 1.8—2.0(1/min),and the duration of the process is 3.5—4.0h.After strip-ping,a concentrated aqueous solution of formaldehyde containing >55w% offormaldehyde with only<1% of methanol is obtained.The percentage recovery ofMeOH is>95%.The recovered MeOH can be reutitized after distillation for manufacturingformaldehyde.