乳酸精制新工艺——刮膜蒸发和短程蒸馏联用法

A new refining process for lactic acid by combined wiped film vaporization and short term distillation

2 0 %～ 30 %粗乳酸经刮膜蒸发器 ,在 1 0 0 0～ 70 0 0Pa,60～ 1 0 0℃条件下蒸发 5～ 2 5min ,得到 80 %～ 90 %亚纯乳酸。亚纯乳酸再经短程蒸馏器 ,在 1 0～ 1 0 0Pa ,60～ 90℃条件下蒸馏 0 .5～ 5min得到纯乳酸。这种方法不用活性炭脱色和离子交换 ,仅经过两次减压蒸馏就能得到达到国家标准的纯乳酸。

A new process for refining lactic acid was suggested.The sub pure lactic acid (80%～90%) was obtained by vaporization of the raw lactic acid (20%～30%) at 1 000～7 000 Pa and 60～100℃ in wiped film vaporizer for 5～25 minutes.The pure lactic acid could be obtained by distillation at 10～100 Pa and at 60～90℃ for 0 5～5 minutes.Without using active carbon for decolorization and ion exchange technique,the new process could produce pure lactic acid meeting the specifications of national standard only by vacuum distillation twice.