Abstract: A continuous, low cost method of concentrating dilute streams containing fractions of adsorbable chemicals is disclosed which minimizes heat consumption and provides highly concentrated supplies of valuable chemicals which are suitable for reuse or sale without substantial further processing. The methods hereof are particularly adapted for concentrating waste condensates derived from pulp-making operations such as the Kraft or sulfite processes, but in general are also applicable for treating a wide variety of dilute organic or inorganic adsorbable chemicals.

Abstract: A low cost, two-stage adsorption-desorption method of concentrating dilute supplies of chemicals is provided which uses a minimum of energy in the form of process steam and yields highly concentrated supplies of end products which are suitable for reuse or sale. The methods hereof are particularly adapted for concentrating waste condensates derived from pulp-making operations such as the Kraft or sulfite processes, but in general is also applicable for treating all types of dilute organic or inorganic adsorbable chemicals. The invention involves first adsorbing a chemical fraction from a dilute stream thereof onto activated carbon, followed by regenerating the adsorbed chemicals and concentrating the same by fractional distillation, whereupon the partially concentrated chemicals are again adsorbed, regenerated, subjected to a second fractional distillation concentration step, and recovered.

Abstract: A method of treating waste liquors such as those derived from the sulfite or Kraft pulp making process is disclosed which provides recovered by-products of high purity while moreover decreasing the total amount of process steam required. The method comprises steam stripping the evaporator condensate feed to remove volatile chemical by-products therefrom, and thereafter directing the stripping steam for reuse in concentrating additional volumes of feed in the evaporator. In this manner, the only steam lost during the stripping operation is that used for increasing the sensible heat of the evaporator condensate feed within the steam stripping column. The condensed steam and volatile by-products resulting from evaporator heating operation are then preferably directed to a fractionation column or columns in order to separate and recover the valuable by-products for reuse or sale.