The invention relates to the field of
chemical industry, and discloses a method for separating and recycling
acrolein in the process of preparing 1,3-
propylene glycol, which comprises the following steps: adding a
polymerization inhibitor into an
acrolein solution to carry out
hydration reaction; making a
reaction product pass through an
acrolein rectifying
tower to separate acrolein from 3-hydroxyl
propionaldehyde; introducing the 3-hydroxyl
propionaldehyde solution into a
hydrogenation reaction unit; after being discharged, mixing the steam with a
polymerization inhibitor solution, atomizing, carrying out two-stage condensation, returning part of condensate to the acrolein rectifying
tower, using part of the condensate for batching, pumping out fixed gas in vacuum, and introducing fixed gas into an acrolein
recovery tower in a
gas phase state; and after steam stripping, continuously discharging and refluxing the acrolein
aqueous solution from the tower kettle for batching, extracting
acetaldehyde liquid from the tower top, condensing and collecting. According to the method, the rectifying tower is adopted to separate the 3-hydroxyl
propionaldehyde, so that the 3-hydroxyl propionaldehyde meets the requirements of subsequent
hydrogenation reaction, a steam stripping method is applied to separation of
acetaldehyde and acrolein, entrained
acetaldehyde can be thoroughly separated, and recycling of the acrolein solution is facilitated.