Abstract: First and second indirect contact condensing heat exchangers are used to separate gases from a mixture of condensible and non-condensible gases, such as the vapor from the last stage of a black liquor evaporation plant of a pulp mill. The mixture of gases passes over the first heat exchanger to cool and condense, producing a first condensate and a first remaining gas stream. The condensate is removed from the first remaining gas stream, the gas stream then being passed over the second heat exchanger. A medium for absorbing at least one non-condensible gas in the first gas stream--such as an NaOH liquid solutino--is passed over the surface of the second heat exchanger to absorb gas, and produce a second remaining gas stream (containing primarily air). The second gas stream is separated from the solution with absorbed gas. The solution with absorbed gas may be used as white liquor in kraft pulping in a pulp mill, without concentrating the solution.

Abstract: A continuous method and apparatus for distilling a liquid include conducting the distilling liquid through at least two successive distillation units operating at different temperature levels. The distilling liquid is vaporized in each distillation unit and the obtained vapor condensed into distillate by conducting the vapor into heat exchange relationship with the liquid discharged from the evaporators in a succeeding distillation unit which operates at a lower temperature level. At least one of the distillation units includes a plurality of communicating distillation stages, each distillation stage including an evaporator and a corresponding condenser.

Abstract: A flash evaporator to be used for purposes such as distilling sea water has a series of evaporator stages in which vapor derived from liquid flowing through the successive evaporator stages is condensed to form a distillate. A wall structure situated in each evaporated stage defines therein an elongated narrow gap the length of which is substantially greater than the width of each evaporator stage with this gap forming an orifice through which the liquid is compelled to issue while flowing from an inlet to an outlet of each evaporator stage. Between the inlet and the gap in each evaporator stage the wall structure defines an upstream flow path the cross section of which decreases from the inlet toward the gap. From the gap toward the outlet of each stage the wall structure defines a downstream flow path the cross section of which increases from the gap toward the outlet.

Abstract: A method and apparatus for operating on liquids and gases to perform operations such as altering the extent to which a gas is contained in a liquid and pumping a gas, by means of a liquid, from a lower pressure to a higher pressure. A liquid is drawn upwardly along a suction tube from a first body of the liquid to an elevation substantially higher than this first body so as to reduce the hydrostatic head of the liquid, and from the suction tube the liquid flows back down a delivery tube to a second body of the liquid, an ejector being provided at the upper end region of the delivery tube for increasing the velocity of flow of the liquid while further reducing the pressure thereof. At the ejector a gas is combined with the liquid to be pumped thereby from a lower to a higher pressure, or a gas at a relatively higher pressure than the liquid at the ejector is combined with this liquid at the ejector to be at least partly dissolved into the liquid.