GB170591A - Improvements in or relating to removal of tar from the vapours arising from the distillation of wood - Google Patents

Abstract

170,591. Barbet et Fils et Cie., E. Oct. 21, 1920, [Convention date]. Addition to 120,560. Materials for purifying; condensing processes. -Wood gas &c. is treated for the removal of tar by washing in liquid tar and in condensates from a cooler through which the gases are passed after leaving the tar washer. The crude gases enter a washer A, of the kind described in the parent Specification, through a pipe a and pass at a temperature of about 100‹ C. to a condenser C in which dense vapours of tar, creosote oils, and acetic acid are condensed. The gases at a temperature of about 65‹ to 75‹ C. are then passed through coolers which condense the remainder of the volatiles. The liquid from the condenser C is returned by a pipe d to the upper part of the washer A and the methyl alcohol and acetic acid are re-vaporized from the tar, which is thereby freed from such impurities, a steam coil S immersed in the tar serving to complete the process before the tar is discharged through the overflow B. A sample of the liquid in the pipe d is drawn off through a cock Rand examined, the quality of this liquid being regulated by altering the temperature of the condenser C. The Specification as open to inspection under Sect. 91 (3) (a) describes also a modification, in which the condenser C is worked, at a temperature of 30‹ to 40‹ C., so as to condense nearly all the vapours, and in this case about three-fourths of the condensed liquid would be drawn off from the cock R, only a small quantity thus being used for washing the vapours in the washer A. This subject-matter does not appear in the Specification as accepted.