A method and arrangement for separating tall oil products from a black liquor-containing boiling liquid that has been drained off, was produced within a kraft mill chip digester, and includes a fibrous cellulose material in a mixture with the black liquor and tall oil products, and where the boiling liquid is separated in a separation unit arranged to mechanically separate the boiling liquid into a fibrous cellulose material and a mixture of mixed black liquor and tall oil products, where the mixture of boiling liquid and tall oil products is brought to a separation tank, the separation tank being a gravity separation tank, and adapted to be emptied in a discontinuous manner of the tall oil product collected and concentrated therein, the tall oil products being floated on top of and above a fraction of mixed black liquor, where the tall oil products is brought to a centrifugal separator.