The present invention relates to a column (1) for thermal treatment of fluid mixtures, having a cylindrical, vertical column body (2) which forms a column cavity (3) and a vertical inner surface (16), a plurality of trays (8) mounted in the column cavity (3) and spaced apart vertically from one another, at least one stub (11) disposed within the column body (2) and extending away from the column body (2), and a closable inspection orifice (9) formed in the stub (11). The characteristic feature of the column of the invention is that in the case of a vertical cross section of the column (1) the surface (15) of the lower line of intersection of the stub (11) directed into the column cavity (3) or a tangent to the surface (15) of the lower line of intersection of the stub (11) at least in sections forms an angle within a range from 210° to 267° with the vertical inner surface (16) of the column body (2) which extends downward from the stub (11).