PROCESS FOR STARTING UP A SEPARATING PROCESS FOR PURIFYING REMOVAL OF ACRYLIC ACID CRYSTALS FROM A SUSPENSIONS OF CRYSTALS THEREOF IN MOTHER LIQUOR

A process for starting up a separating process for purifying removal of acrylic acid crystals from a suspension S of crystals thereof in mother liquor with a hydraulic wash column (0) which has a crystal melt circuit (31) including crystal melt space (C), and a process space (8) and a distributor space (A) which are separated by an end with passages connecting the two spaces, in which the crystal bed (4) is formed for the first time by first filling the crystal melt circuit (31) and, at least partly, the process space (B) with an acrylic acid-comprising startup liquid whose acrylic acid crystal formation temperature is less than or equal to the temperature of the suspension S increased by 15°C., and then continuing the filling of the wash column (0) with the suspension S and optionally with control liquor until the difference between the pressure in the crystal melt space (C) and the pressure in the distributor space (A) falls suddenly, the arithmetic mean of the total waste liquor flow flowing through the filters (7) of the filter tubes (6) of the wash column (0) until this time, based on the area of all filters, being not more than 80 m3/(m2* h).