Abstract: Mechanical pulp is bleached by a treatment with hydrogen peroxide wherein prior to or simultaneously with said treatment the mechanical pulp is subject to an oxygen pressure.

Abstract: A multiple effect evaporator system and a process for concentrating a process liquid wherein evaporated process liquid from one effect serves as heating fluid in an adjacent effect. Low energy heating fluid in vapor form is fed to an evaporative surface condenser where it is condensed and collected as clean and foul condensate. Coolant for the evaporative surface condenser is provided in the form of process liquid from one of the effects. Prior to passage into the evaporative surface condenser, the process liquid is cooled. In the cooling circuit of the evaporative surface condenser, the process liquid absorbs the heat of condensation of the heating fluid and subsequently rejects the heat into a counter flowing air stream. The process liquid is thereafter heated and returned to another of the multiple evaporator effects.

Abstract: Calcium containing sulphate spent liquor is deactivated by means of heating. Spent liquor is heated by means of direct condensing in a flash-steam-system. Liquor vapors generated during expansion of the already deactivated spent liquor are used for heating the spent liquor. Spent liquor is led to a retention tank through n+1 in series connected direct condensers (DK I-DK V) and from the retention tank through n in series connected flash tanks (FT I-FT IV) disposed counter-currently to the direct condensers. In the last one of the direct condensers (DK V) the liquor is heated by means of externally supplied steam; in all others (DK I-DK IV) by means of expansion vapor.

Abstract: Vapor and liquid contact structure for distillation, fractionation, rectification, absorption, and the refining, in a column, of various liquid materials such as petroleum, chemical, and alcohol solutions. Provision is made for the inclusion of vertically-spaced bubble plate chambers, having respective liquid/vapor contact devices, to accommodate contact of counter-current flows of reflux liquid and vapors. Downcomer means including slanted ramps, disposed outside of the vapor conduit-defining interior, define elongate downcomer structure for liquid flow and thereby, i.e., by such slanted construction, reduce froth or foam passing to a next lower contact device, eliminating unwanted counter-current gas entrainment between contact devices. Liquid flow rates over exit weirs beyond 30 gpm/inch are obtained. Downcomer reflux reservoir depth can be adjusted by an adjustable gate proximate the slot opening to a given contact device.

Abstract: A falling-film process and apparatus for the cocurrent evaporation of a solution is disclosed. The process utilizes a tube-bundle heat exchanger in which the upper ends of the individual tubes of the tube-bundle are closed. Apertures, preferably in the form of slots, are formed adjacent the closed-end of the individual tubes. A liquid heel is maintained above the highest of said apertures and flows into the interior of the tubes through said apertures. Upon entering the tubes the liquid and any vapor released therefrom flows cocurrently in a downward direction. The vapors released from the liquid are recycled to a point above the liquid heel through conduit means separate from the individual tubes.

Abstract: A process for purifying methanol which comprises introducing crude synthetic methanol obtained by catalytic reaction of carbon oxide and hydrogen into a rectifying column either as such or after it is first introduced into a topping column and distilled with or without the addition of water to remove low-boiling components from the top of the topping column, and distilling it in the rectifying column to withdraw purified methanol from the top of the column and mainly water from the bottom of the column; wherein an auxiliary distillation column is provided side by side with the rectifying column, and the rectifying column and the auxiliary distillation column are operated under particular conditions.

Abstract: Method for treating waste slurries containing solid impurities, e.g. in the form of metal chlorides, and silicon tetrachloride and trichlorosilane by evaporation and separation techniques to recover more of the silicon tetrachloride and trichlorosilane.

Abstract: A spray dryer consisting of a tower-like drying container with spraying elements for introducing therein the material to be dried, pipelines and heater for injecting a heated drying gas, and a separator for separating dry fine material and gas. The dry fine material is agglomerated inside the drying tower. The separator consists of porous filter tubes, on which a dust-laden gas stream impinges, which covers the entire flow cross-section of the drying tower. Fine product material deposited on the filter tubes is shaken off by surges of compressed air and drops into a drying zone, a spraying zone, and finally, into a collecting hopper.

Abstract: An aqueous effluent is supplied to a stripping column (total stripping column) from which a mixture that is rich in NH.sub.3, CO.sub.2 and H.sub.2 S is withdrawn as a head product. In at least one additional stripping column the mixture is separated into a mixture which is rich in NH.sub.3 and a mixture which is rich in the sour gaes CO.sub.2 and H.sub.2 S. The mixture which is rich in NH.sub.3 is scrubbed with liquid ammonia. The overhead product from the total stripping column is cooled in a condenser under a pressure of 1 to 7 bars and is thus transformed into a liquid phase to such an extent that the liquid phase contains 70 to 100% of the NH.sub.3 which has been supplied to the condenser. The liquid phase is supplied at a temperature of 30.degree. to 90.degree. C. to a second stripping column (NH.sub.3 stripping column), which is operated under a pressure of 1 to 4 bars and from which a gas mixture that is rich in NH.sub.3 is withdrawn as a head product.

Abstract: Apparatus and method for using a heated waste gas stream to evaporate a volatile component such as water or a solvent from a liquid solution comprises a flue to feed the gas stream from the source of heated gas; a container having an inner chamber to hold the liquid for evaporation of the volatile compound and an outer chamber connected to the flue which forms a gas channel substantially surrounding the inner chamber through which at least a portion of the gas stream flows to supply heat to the inner chamber and evaporate the volatile component of the liquid solution; an inlet to feed the liquid solution into the inner chamber; upper and lower liquid level sensors to control the quantity of liquid solution fed into the inner chamber to establish a liquid level therein; a sparger for agitating the liquid solution in the inner chamber; a sump below the container and connected to the flue to receive any condensate from the gas stream and any liquid leaking from the inner chamber; an outlet to combine, vent and d

Abstract: An evaporator comprises a plurality of substantially parallel plates mounted for rotation about a common axis and in which provision is made for a condensible vapor to flow across a first face of each of said plates and for a liquid, at least a portion of which is to be evaporated, to flow across the second face of each of said plate, which plates are arranged to be rotatable at such a mean acceleration, measured in a radial direction with respect to said axis of rotation, greater than the acceleration due to gravity, said first face of each of said plates has a surface designed to discourage formation of a continuous liquid film thereon. The evaporator may be used to concentrate solutions, e.g. of depleted brine or aqueous caustic soda.

Abstract: An apparatus for desalinating sea water, comprising a distillation unit which includes a porous hydrophobic membrane which is pervious to steam but impervious to water, and a condensation surface arranged at a distance from the membrane, the distillation arrangement also including a first unit for heating and conducting the water to be distilled on one side of the membrane, and a second unit arranged to conduct a liquid which is colder than the water, on the side of the condensation surface remote from the membrane, distilled water being collected and drawn-off between the membrane and the condensation surface.

Abstract: A process for purifying a solvent suitable for use in the polymerization of an olefin in the presence of a Ziegler-Natta catalyst, which comprises feeding the polymerization solvent to a stage lower than a chimney tray of a multi-stage distillation column, said chimney tray being provided at a height between the top and bottom of the column, feeding an organoaluminum compound to a stage higher than the chimney tray, drawing out a condensate from the chimney tray, heating the condensate to produce heated vapor, introducing the heated vapor to the chimney tray or to a stage higher than the chimney tray but lower than the stage to which the organoaluminum compound has been fed, and drawing the solvent in a purified state from the top.

Abstract: Method and apparatus for disposing of waste rinse water used in photographic processes in which the waste rinse water is heated in a dissolution tank to be reduced to a slurry which is accumulated and stored in drums for later processing. The apparatus is compact consisting of separate tanks for the different rinse water, a holding tank to collect the contaminated rinse water and a separate dissolution tank. There is no discharge of any liquid waste products into the environment.

Abstract: A water distiller apparatus for purifying and degassing domestic water supplies is provided which is constructed for easy cleaning of all parts and in which inflowing water is preheated by condensing steam within a condenser which preheating allows dissolved gases to dissipate through a vent before the inlet water reaches an evaporator portion. The rate of inflowing water is controlled by a temperature responsive valve that is in thermal communication with the condenser to maximize heat transfer and minimize heat and water loss.

Abstract: This invention is a process for purifying crude acetone obtained by cleavage of cumene hydroperoxide, said crude acetone containing aldehyde impurities and appreciable amounts of unreacted cumene, by fractionally distilling the acetone in a multiple plate distillation column, said process comprising: continuously feeding crude acetone; continuously feeding a dilute aqueous solution of an alkaline material at a point above the crude acetone feed point; and controlling the temperature profile of the column by adjusting the amount of liquid acetone removed in step (c) to maintain a preselected temperature on a plate in the region between the crude acetone feed point and the alkaline material feed point.

Abstract: Distillative separation of liquid mixtures of one or more water-insoluble substances which have boiling points higher than that of water and one or more substances which have boiling points lower than that of water or which form azeotropes having boiling points lower than that of water, wherein the mixture to be distilled is mixed with a quantity of water such that the boiling point of the water under the pressure applied limits the bottom temperature of the mixture of substances to be separated.

Abstract: An amine is separated from an aqueous solution of amine and volatile organic compounds by distillation in a column. The vapors generated during distillation are condensed. The condensed vapors are then passed into a separating device in which the volatile organic compounds are removed. The liquid remaining in the separating device is then fed to the head of the distillation column. Water is removed from the column in a sidestream and diamine is the residue. This process is particularly effective in recovering aromatic diamines from solutions which accumulate during hydrogenation of dinitro aromatic compounds.

Abstract: A system for diaphragm distillation of a liquid, for example for desalination of salt water, comprising a diaphragm, through which vapor, but not liquid can pass, and a condensation surface for condensing vapor having passed through the diaphragm, and necessary passageways. According to the invention, the system comprises one or several units, each of which comprises a plurality of pipes located one within the other, viz. a first (1) inner pipe, a second (2) pipe located outside thereof and consisting of a diaphragm of the aforesaid kind, and a third (3) pipe located outside the second (2) pipe, which first (1) and third (3) pipes are of a gas-tight material, that said unit is surrounded by a fourth (4) gas-tight pipe, where a first (5) passageway is formed by the first (1) pipe and a second (6), a third (7) and a fourth (8) passageway are formed between said pipes (1,2;2,3;3,4) in successive order in the direction from the inside outward.

Abstract: High purity butene-1, in particular polymerization grade butene-1, is obtained by means of a two-stage fractionation of a C.sub.4 hydrocarbon stream comprising butene-1 which is substantially free from butadiene.The first stage of the fractionation process allows practically all the isobutane contained in the C.sub.4 batch to be separated as the top stream.The bottom phase of the first stage of fractionation is supplied to the second stage of fractionation thus obtaining high purity butene-1 as the top fraction, and the remaining components as the bottom phaseAccording to the process of the invention, vapors of butene-1 obtained as the top stream from the second stage of fractionation are compressed and the resultant heat of condensation is used for operating the reboilers of the two fractionation stages.