Abstract: A method and an apparatus are provided for controlling crystallization (and thus preventing harmful fouling of heat transfer surfaces) during the treatment of black liquor. The black liquor is concentrated to a high dry solids content (at least about 70%, e.g. about 75-90%) in a falling film crystallizing apparatus (e.g. falling film evaporator). A part of the liquor flowing from the heat transfer surfaces and collected in a retention vessel (e.g. an interior volume of the evaporator) is recirculated to the heat exchange surfaces and a part of the liquor is discharged for further treatment (e.g. combustion in a recovery boiler). A part of the black liquor in the recirculation system is returned directly to the retention vessel in order to facilitate mixing and thus to bring about, in the retention vessel, crystallization of inorganic salts of the black liquor that is as complete as possible.

Abstract: Evaporation of saline water in a desalinization process, or evaporation of other types of liquid such as black liquor from paper pulp processing, is accomplished utilizing a multiple effect evaporator. Each effect includes one or more (e.g. first and second) sets of horizontally elongated dimpled plate evaporator elements. Horizontally flowing heating fluid, such as steam, is introduced to the internal passage of at least the second set in all the effects, and a head of circulation liquid is provided to cause liquid being evaporated to flow downwardly from the head over the external surfaces of the sets of dimpled plates in a thin film. The vapor evaporated is drawn through a demistor and is used as the heating fluid for the next effect. Recirculating liquid that has not evaporated and liquid separated by the demisting process are recirculated to the head associated with each effect. Clean condensate--such as distilled water--is withdrawn from the last effect.

Abstract: An integrated continuous processes for concentrating "weak" nitric acid and concurrently reconcentrating the spent dehydrating agent used to break the nitric acid azeotrope to obtain "strong" nitric acid, the processes involving direct coupling of the nitric acid concentration with the reconcentration of the spent dehydrating agent so that less energy input is required. The major proportion of the feed "weak" nitric acid is vaporized before being fed countercurrently into a column to contact a large volume of the dehydrating agent, this vaporization being one of the two major sources of energy input, the second being through the reboiler at the bottom of the column. Energy input is balanced by energy rejection through condensation of strong nitric acid vapor and water vapor.

Abstract: In the distillation of fresh water from sea water, the sea water is passed ownwardly in a falling film evaporator through a multiplicity of vertical tube evaporator (VTE) stages and multiple stage flash (MSF) evaporators. After the sea water passes through the first VTE stage where it forms a liquid component and a steam component, the liquid component is distributed evenly into the next VTE stage while the steam component enters an adjoining MSF stage. Condensed fresh water flows downwardly from one MSF stage to the next and experiences flash evaporation. The sea water or brine component and the fresh water distillate flow downwardly through the VTE and MSF stages so that the brine component can be removed from the final VTE stage and the fresh water distillate from the final MSF stage.

Abstract: In the distillation of fresh water from sea water, the sea water is passed ownwardly in a falling film evaporator through a multiplicity of vertical tube evaporator (VTE) stages and multiple stage flash (MSF) evaporators. After the sea water passes through the first VTE stage where it forms a liquid component and a steam component, the liquid component is distributed evenly into the next VTE stage while the steam component enters an adjoining MSF stage. Condensed fresh water flows downwardly from one MSF stage to the next and experiences flash evaporation. The sea water or brine component and the fresh water distillate flow downwardly through the VTE and MSF stages so that the brine component can be removed from the final VTE stage and the fresh water distillate from the final MSF stage.

Abstract: A method of utilizing the energy of a high pressure condensate stream including passing steam at an elevated pressure in indirect heat exchange with a material to be heated, collecting a condensate product condensed from the steam of the heat exchange step at an elevated pressure, passing the condensate directly to a steam stripping step at essentially the same pressure at which the condensate was collected and reducing the pressure of the condensate while simultaneously contacting the condensate with a material to be stripped in the stripping step.

Abstract: A flash tank, and method of flashing steam utilizing the tank, result in minimum foam generation so that the outlet steam remains uncontaminated. Feed fluid fed into the interior of the tank is positively prevented from splashing into the liquid seal provided adjacent the liquid outlet from the tank. This may be done by directing the feed fluid upwardly when introduced into the tank, and providing a liquid holding tank externally of the flash tank, feed fluid impacting upon a deflecting member and then the conically downwardly tapering walls of a bottom portion of the tank. Another alternative is to feed the feed fluid downwardly into the tank to impact upon a conical deflecting member so that there is minimum loss of momentum of the feed fluid, and again it impacts upon the conically tapering walls of the tank bottom portion.