Abstract: Hot waste gas is desulfurized in a spray drying-absorption process performed in an absorption chamber wherein a fluidized layer of partially reacted absorbent is maintained in the bottom area. Improved conditions are obtained for the reaction between absorbent and sulfur oxides in the waste gas, whereby the use of inexpensive absorbents of relatively low reactivity, such as limestone, comes into consideration.

Abstract: A calcium sulfate anhydrite material is prepared from a spent absorbent resulting from desulfurization of flue gases. First the sulfite in the spent absorbent is oxidized into sulfate, preferably by heating in an oxygen containing gas, and thereafter the chloride content of the spent absorbent is reduced by heating the spent absorbent at a temperature of 600.degree.-950.degree., preferably 750.degree.-950.degree. C. together with fly ash. Said fly ash may be recovered together with the spent absorbent in the desulfurization process, or it may have been recovered separately and mixed with the spent absorbent.The product may be used as cement additive or for other purposes in which calcium sulfate anhydrite is conventionally utilized.

Abstract: A fluid bed dryer comprises a pre-dryer of the back mixed type and a post-dryer of the plug flow-type. In the pre-dryer the main part of heat is transferred to the product being dried by means of heating panels arranged above the bed plate. A control bed is interposed between the pre-dryer and the post-dryer and includes one or more temperature sensors for sensing the temperature of the product in the control bed. Heat supply to the heating panels is controlled in response to the temperature sensed by the sensor or sensors in order to maintain the product temperature in the pre-dryer at the dew point and so as to ensure that the drying process proceeds within the region of constant drying rate, and that the product contains little or substantially no unbound moisture despite possible changes in product fed to the pre-dryer.

Abstract: An agglomerated powdery milk product is prepared by spraying a concentrate of milk or a fraction thereof into a stream of drying gas directed against the surface of a fluidized layer of already spray dried particles in a conical chamber, thereby obtaining a favorable interaction. Special parameters including temperatures, rates of streams of drying air and residence time are adjusted to obtain an extensively agglomerated product, high production capacity, improved heat economy, low heat damage of the product, and to make possible an easy spray drying of materials, which have hitherto been regarded as unsuitable for spray drying.

Abstract: A process for simultaneous removal of sulfur oxides (SO.sub.x) and nitrogen oxides (NO.sub.x) from gaseous mixtures (such as flue gases and industrial waste gases) containing them which comprises contacting the gaseous mixture with a particulate alkaline earth hydroxide and reaction products of the gaseous mixture and the hydroxide maintained in a moving bed reactor (preferably a fluid bed reactor) at a temperature of about 85.degree. C. to about 150.degree. C. in the presence of water vapor and oxygen and in the substantial absence of liquid water. A baghouse or other particle removal means preferably is employed to extract solid material such as fly ash and reaction products from the gaseous mixture being treated and to further capture unreacted SO.sub.x /NO.sub.x.

Abstract: A process for removal of nitrogen oxides and sulfur oxides from waste gases by contacting the waste gases with a particulate material comprising an alkaline earth based absorbent for sulfur oxides. Essential features are a reaction temperature of 85.degree.-145.degree. C., a maximum value of 3 for the ratio of nitrogen oxides to sulfur oxides, and the presence of oxygen and moisture. In its preferred form the process comprises a spray drying-absorption reaction followed by particle separation in a bag house. Removal efficiency is improved by the presence of minor amounts of sodium sulfite together with the alkaline earth based absorbent. Also a special conveyance of material may be applied to improve efficiency.

Abstract: A process for producing high strength sintered bauxite spheres usable as fracture propping agents in oil or gas wells are produced by continuous spray-granulation of an aqueous binder-containing aluminous ore suspension to form granules which are subsequently sintered. Suitable starting materials include ores of high aluminum silicate content.

Abstract: Strong dense shaped articles such as pellets suitable for use as gravel substitutes are produced by the described method from solid fly ash-containing water materials obtained by a lime based dry scrubbing flue gas desulfurization operation. In this method the dry ash-containing waste powder, which also contains calcium sulfite or sulfate reaction products and unreacted lime, is first uniformly contacted with a critical amount of water and then immediately compacted at a critical compaction ratio to provide a handleable green body in which the fly ash particles are positioned with respect to one another so that the interstitial spaces are sufficient to accommodate the volumetric changes in wthe cementitious materials without any deleterious expansion of the article as the article is cured.

Abstract: In connection with the desulfurization and dedusting of flue gas where use is made of a combined spray drying and absorption and the material produced by this process is filtered off from the gas stream together with fly ash, a heating of the flue gas is performed prior to its discharge into the atmosphere by admixture of hot, non-purified flue gas. This admixture takes place so that the flue gas serving for the reheating passes through only a part of the available filter area, which allows the remaining part of the filter area to be kept at a relatively low temperature. This results in a particularly high sulfur dioxide absorption being achieved during the passage of the flue gas through the filter.A baghouse unit divided up in a special manner can be used in the process.

Abstract: A spray drying apparatus with a drying chamber (10) in which a liquid product is atomized by means of an atomizing wheel (11) and dried by means of warm drying gas or flue gas introduced through a tube (14) which is directed towards the bottom side of the atomizing wheel. In order to avoid adherence of particulate material present within the drying chamber (10) to the bottom side of the atomizing wheel (11) clearing or obstructing gas, preferably atmospheric air, is blown upwardly towards the bottom side of the atomizing wheel from a clearing gas inlet (18).

Abstract: The invention relates to an apparatus for processing a powdered or particulate product forming a vibrating fluidized bed supported by a thin, perforated bed plate which is vibrated while gas is blown upwardly through the perforations of the plate.The bed plate which is made from thin sheet metal is provided with parallel corrugations extending transversely to the direction in which the fluidized product is moved along the plate. The corrugations impart a desired stiffness to the plate and in order to promote removal of residual product from the plate when supply of product to the plate has been terminated, the openings in the plate may be formed so as to direct gas flows supplied therethrough in the same general direction transverse to said corrugations towards an outlet of the apparatus.

Abstract: In an atomizer wheel for the atomization of liquids by ejection through a number of orifices in the side wall of the wheel, whipping-in of air into the atomized liquid is reduced by provision of a protrusion around the leading edge of each orifice relative to the direction of rotation, whereby the liquid flowing backwards relative to the side wall is guided outside the leading edge of the orifice to a liquid inlet passage at the rear part of the ejection orifice relative to the direction of rotation. The protrusion may be formed by a bushing inserted in the ejection orifice and projecting inwardly from the side wall, at the rear side of which relative to the direction of rotation the inlet passage is formed as a slit.

Abstract: A method and system for separating an aqueous suspension containing fibrous particles into fractions of different average characteristics. The suspension to be separated is supplied to a separator disc rotating in a horizontal plane in the upper part of a chamber, in which collecting means are arranged in different zones to receive material dispersed from the disc. The method and system are effective for the separation of paper pulp suspensions such as groundwood pulp, chemical pulp, sediment or waste paper pulp into fractions of different fibre size and for the cleaning of paper pulp suspensions for impurity particles such as sand, shives and splinters. Another field of application is the separation of mineral wool suspensions into fractions consisting mainly of fibrous and spherical particles, respectively.

Abstract: SO.sub.2 is absorbed from hot flue gas by spray drying a Ca(OH).sub.2 -containing suspension in the flue gas. Fly ash is left in the flue gas which is to be treated in the spray absorption process, and the powder which is produced by the spray absorption process and which consequently contains the fly ash and partly reacted Ca(OH).sub.2 is partially recycled. Operation is controlled to obtain a temperature of the flue gas after the treatment which is 8.degree.-20.degree. C. above the saturation temperature of the flue gas at this stage. The process leads to optimum use of the Ca(OH).sub.2 used as absorbent and of the neutralization power inherent in the fly ash. Problems due to sedimentation of the absorbant before its atomization are avoided.

Abstract: Mercury is removed from a stream of hot waste gases by atomizing an aqueous liquid into the hot waste gases in the presence of fly ash suspended in the gas stream. Subsequently the fly ash is separated from the gas stream. A substantial part of the mercury originally present in the gas stream is absorbed or adsorbed by the fly ash so that the stream of the waste gas can safely be discharged to the atmosphere.

Abstract: An aqueous dispersion of polyvinylchloride or vinylchloride copolymerizate is spray dried in a flow of drying air in a drying tower which contains at least one two-fluid nozzle for atomizing the aqueous dispersion and an injection member for pressurized air for providing the atomized particles with a rotary motion, about the longitudinal axis of the drying tower. A controlled rotary motion is imparted to the mixture of sprayed particles and the drying air. The heat economy and product quality are improved since it is possible to use a high drying air inlet temperature and to obtain an easily grindable powder suitable for producing stable, low viscosity plastisols.

Abstract: A processing gas is supplied to the atomizing zone around an atomizing device arranged centrally in an atomizing chamber through a conical guide duct communicating with a horizontal spiral supply duct through an annular mouth. A uniform gas distribution with respect to flow direction and velocity is obtained by means of guide vanes arranged with a small angular spacing in the mouth and comprising two succeeding vane sets, in which the vanes of one set are shaped to deflect the tangential gas stream in the spiral duct to a flow direction, for which the radial velocity component considerably exceeds the tangential component, whereas each vane of the other set positioned at the opening of the mouth towards the conical guide duct projects into the space between neighboring vanes of the first set and extends substantially parallel to tangential planes to said vanes at their internal edges.

Abstract: A processing gas is supplied to the atomizing zone around an atomizing device arranged centrally in an atomizing chamber through a conical guide duct communicating with a horizontal spiral duct through an annular mouth. A gas distribution incorporating a simple and accurate adjustment of the deflection of the gas stream from the spiral duct into the conical guide duct is obtained by means of two separate sets of stationary guide vanes arranged relatively close to and overlying each other in the mouth, one of said sets being constructed to deflect the gas stream stronger than the other set to a direction with a considerably smaller tangential velocity component, a damper being arranged along the mouth to be adjustable in the height direction for controlling the ratio of the portions of the gas stream in the spiral duct conducted into each of the two vane sets.

Abstract: In the chamber of a fluidized bed reactor for processing powdered products, a pneumatic cleansing device is arranged which comprises at least one pipe member mounted to be movable parallel to a perforated powder supporting plate at a small distance from the upper side thereof and having nozzles for ejecting air or gas towards the supporting plate to remove depositions of material from the upper side thereof between the perforations in the plate through which a fluidization gas flows upwardly to form a fluidized powder layer overlying the plate. The cleansing device may comprise additional pipe members with nozzles for ejecting air or gas towards the side wall and ceiling of the chamber and may be constructed for use in a box-shaped chamber as well as a cylindrical chamber for fluidized bed reactors of the plug-flow or spray granulation types.

Abstract: A wear-resistant rotor wheel for use as an atomizer wheel for the atomization of slurries of highly abrasive materials or as a rotor wheel in an agigator or pump of the centrifugal type. The cylindrical side wall of the wheel is formed with ejection orifices and defines together with a body of revolution arranged around the wheel hub a bowl-shaped space which is downwardly limited by an annular plate of wear-resistant sintered material covering the wheel bottom. The annular plate is arranged to be spaced from the wheel bottom with its outer circumference sealingly joining the inner side of the side wall, so that solid particles from a slurry are not allowed to enter between the circumference of the plate and the side wall, while the side wall is allowed to follow deflection of the wheel bottom without subjecting the annular plate to deformation forces.