Abstract: The invention relates to a method and apparatus to recover and purify methanol from gases produced in the digester during the kraft pulping process. The gas is typically recovered as a foul gas (called stripper off gas or SOG) comprising methanol, water and various other contaminants. The gas is then treated with successive decanting and distillation steps to remove impurities, thereby producing highly purified methanol.

Abstract: The invention relates to a method and apparatus to recover and purify methanol from gases produced in the digester during the kraft pulping process. The gas is typically recovered as a foul gas (called stripper off gas or SOG) comprising methanol, water and various other contaminants. The gas is then treated with successive decanting and distillation steps to remove impurities, thereby producing highly purified methanol.

Abstract: The invention relates to a method and apparatus to recover and purify methanol from gases produced in the digester during the kraft pulping process. The gas is typically recovered as a foul gas (called stripper off gas or SOG) comprising methanol, water and various other contaminants. The gas is then treated with successive decanting and distillation steps to remove impurities, thereby producing highly purified methanol.

Abstract: The invention relates to a method and apparatus to recover and purify methanol from gases produced in the digester during the kraft pulping process. The gas is typically recovered as a foul gas (called stripper off gas or SOG) comprising methanol, water and various other contaminants. The gas is then treated with successive decanting and distillation steps to remove impurities, thereby producing highly purified methanol.

Abstract: Apparatus (10) for the two stage oxidation of white liquor. The reaction vessel includes a central first stage chamber (24) and a second stage annular outer chamber (26). Heated air is first introduced through the outer second stage chamber (26) by pipes (36) and then directed through elements (38, 40, 44) to the central first stage chamber (24) for completion of the oxidation reaction. Unoxidized white liquor with a small amount of black liquor to catalyze the process is introduced to the first stage of the reaction vessel at a temperature in excess of 185 degrees F. Oxidized white liquor is removed from the second stage chamber and air is venter to atmosphere through the stack at the top of the first stage chamber. The second stage is preferably pressurized for greater efficiency.

Abstract: Method for the recovery of acidic effluent from pulp mill chlorine dioxide generators using the Mathieson or Solvay system. The spent generator acid is directed through a three-stage evaporation/crystallization process in which spent acid from the generator is evaporated and crystallized to produce stage 1 sodium bisulfate crystals. The first stage crystals are then redissolved to form a second solution which is crystallized in order to yield stage 2 sodium sesquisulfate crystals and, finally, the second stage crystals are redissolved in a third stage evaporation/crystallization stage to yield sodium sulfate crystals. Besides salt cake, the system also produces reusable sulfuric acid for the chlorine dioxide generator. No chemicals are added during the recovery steps.