Abstract: A high strength propping agent for use in hydraulic fracturing of subterranean formations comprising solid, spherical particles having an alumina content of between 40 and 60%, a density of less than 3.0 gm/cc and an ambient temperature permeability of 100,000 or more millidarcies at 10,000 psi.

Abstract: Agglomeration is improved in a straight-through spray drying process by adjusting the location for introduction of recycled fine particles to the atomization zone. The fine particles are dispersed in a minor portion of the drying air and adjustment of the location for the introduction of the fine particles is made so as to change the average distance from the wheel to the area where the fine particles meet atomized droplets or partly dried particles. A spray drying apparatus in which the fine particles are recycled through the use of turnable deflectors, telescopic connections or swivel joints which are suitable for achieving the improved agglomeration.

Abstract: A desulphurization process, in which acid components of waste gas are removed by spray drying absorption, using an aqueous suspension of slaked lime or limestone as absorbent with recycling of part of the reaction product to the absorbent, is controlled on the basis of determination of the chloride content of the aqueous suspension including recycled reaction product.

Abstract: By agglomeration in a high speed mixer spherical granules having a desired granule size distribution are obtained by supplying the agglomeration liquid by means of an atomizer wheel axially positioned in the high speed mixer and by controlling the quantity and evaporation of said liquid in consideration of the changes occurring with respect to water binding ability of the agglomerates during compaction. An apparatus for carrying out the method includes a mixer bowl with an impeller on a central shaft through the bottom of the bowl and an atomizer with an atomizer wheel with its shaft in alignment with the shaft of the impeller.

Abstract: A fluid bed dryer for processing a particulate material includes a series of chambers separated by longitudinally extending common walls and connected by turn-around sections to provide a serpentine path for the material. Each turn-around section is open to adjacent chambers at one end of one of the common walls to receive and turn particulate material distributed across the width of one of the chambers through an arcuate path and deliver the material to the other chamber. Each of the chambers and turn-around sections have a base including a number of gas introduction openings oriented to introduce gas in a specific direction to fluidize and move the particulate material in that direction. The gas introduction openings in the turn-around sections are oriented to successively receive and turn incremental vertical columns of the particulate material in accordance with the distance each incrmental vertical column is spaced from the common wall.

Abstract: An apparatus including an evaporator, a pre-crystallizer, a spray dryer and a fluid bed for drying whey and a rotating disc having a cone-shaped upper surface is provided for receiving partially dried whey from the spray dryer and delivering the whey to the fluid bed while permitting crystallization of the whey as it rests on the surface of the disc.

Abstract: Hygroscopic powders, especially fat-containing milk products, are cooled by being fludized in cooling air. Dehumidification of the drying air is omitted and overdrying prior to cooling to compensate powder rehumidification during cooling is avoided by using a closed cycle cooling in which the spent cooling air after efficient dust removal and re-cooling is used as cooling and fluidizing air. Substantial energy savings are achieved while product quality is maintained or improved.

Abstract: The ability of activated carbon to remove mercury and noxious polyorganic matter, especially chlorodibenzo-dioxins and -furans from incinerator flue gases is utilized in an efficient manner by suspending powdery activated carbon in the flue gas in connection with a conventional spray absorption process in which the acidic components of the flue gas are neutralized by means of basic absorbents. The cooling of the flue gases in the spray absorption process provides an efficient adsorption onto the powdery activated carbon and the separation of said powdery activated carbon from the flue gas is substantially facilitated by the presence of the particulate material formed by the spray absorption process. Also an improved removal of nitrogen oxides is obtained.

Abstract: A fluid bed dryer comprises a bed plate having gas distributing openings in the plate. The gas distributing openings are arranged in pairs of substantially oppositely directed openings, and a depressed portion of the plate extends between the openings of each pair. Throughfall of products through such openings is substantially eliminated, and by suitably choosing the relationship of the effective area of the oppositely directed openings in the pairs of openings it is possible to obtain a desired relationship between the vertical fluidizing component and the horizontal transporting component of the upwardly directed gas flow through the openings of the bridge plate.

Abstract: In a method for cleaning of flue gas derived from waste incineration, of the kind which comprises spray drying a lime slurry in the hot flue gas, the amount of active lime used is from 1.5 to 2.5 times larger than the amount reacting with the acidic components of the flue gas; furthermore, ground blast-furnace slag is incorporated in the lime slurry in an amount that is equivalent to 30 to 100% by weight of the amount of calcium salts generated at the flue gas cleaning. An end-product is hereby obtained, which upon admixing with water, forms a concrete-like material with high mechanical strength and great ability to retain the pollutants present therein so that the product is suited for disposal in nature with a minimum risk of polluting water streams and ground water.

Abstract: A high-gradient magnetic separator is provided for filtrating weakly magnetic particles from a fluid in which they are suspended. The fluid is caused to flow through a separation chamber arranged in a gap in a magnetic circuit which comprises a pair of separate permanent magnetic devices connected by means of yoke members of a magnetic soft material. Permanent magnet devices generate a strong magnetic field in the gap with very small magnetic losses. Each permanent magnetic device comprises a permanent magnetic member with a substantially linear demagnetization curve. A matrix of magnetic soft material is disposed in the gap between pole surfaces of the permanent magnetic devices to create high local magnetic gradients. To facilitate cleaning of the matrix filter material, the separation chamber is formed as a displaceable box-shaped cannister.

Abstract: A high-gradient magnetic separator is provided for filtrating weakly magnetic particles from a fluid in which they are suspended. The fluid is caused to flow through a separation chamber arranged in a gap formed between a pair of opposed pole surfaces of a pair of separate permanent magnetic devices connected with a closed magnetic circuit which includes yoke members. The permanent magnetic devices generate a strong magnetic field in the gap, the magnetic field having a field direction substantially transverse to at least a portion of the flow path of the fluid through the separation chamber. The permanent magnetic devices each include at least one permanent magnetic member having a substantially linear demagnetization curve. A matrix of soft magnetic material is located in the separation chamber to create local magnetic gradients in the magnetic field. The matrix includes strands extending in planes substantially transverse to the magnetic field direction.

Abstract: The ability of a waste gas cleaning spray drying absorber to tolerate substantial variations in the amount of waste gas to be cleaned is enhanced by a system which provides for introduction of any amount of waste gas that would overload the gas disperser(s) of the spray drying absorber, into said absorber via auxiliary apertures in the walls thereof thereby bypassing the gas disperser(s).A plant for cleaning fluctuating amounts of waste gas comprises a control system based on measurement of gas flow to the gas disperser(s).

Abstract: An atomizer wheel for use in a spray drying apparatus comprises an interior annular liquid supply chamber, from which a number of substantially radial ejection ducts extends towards the external surface of the wheel through a length constituting a considerable portion of the radius of the wheel. The ducts discharge into a downwardly open annular discharge slit at a comparatively short distance from an external wall connected with a wheel cover and whose inner wall surface forms an axial-symmetrical surface of revolution with a substantially linear generatrix forming an angle of not more than 15.degree. with the axis of revolution.

Abstract: A process for providing finely divided limestone products. Limestone is abrasively ground in an aqueous media in the presence of added dissolved carbon dioxide or in the presence of a soluble acid-forming compound, the anion of which forms a soluble calcium compound, or in the presence of both dissolved carbon dioxide and an acid-forming compound.A dry flue gas desulfurization process using the finely divided limestone product of the process of the invention is also provided.

Abstract: The atomizer wheel is provided along the circumference of its external wall (3) with a number of ejection apertures, in which wear-resistant ceramic linings (7) are arranged by means of replaceable steel bushings (8). The steel bushings (8) and/or the linings (7) project somewhat into the annular chamber of the atomizer wheel and the bushings are sealed against the external wall (3) with sealing rings (11). Moreover, each bushing (8) is provided in its inner surface facing the associate lining (7) with a flat recess (13) extending on either side of the inner surface of the external wall (3). Thereby, the steel bushings (8) may be resiliently deformed without transferring excessive stresses to the linings (7).

Abstract: A dry particulate sulfite-containing material produced in a flue gas desulfurization process is oxidized and agglomerated in a fluidized bed reactor, wherein the material is fluidized in an oxygen-containing gas. The oxygen-containing gas which is supplied to the fluidized bed has a temperature below the agglomeration temperature of said particulate material. Due to the exothermic character of the oxidation, the temperature of the fluidized bed is maintained above the agglomeration temperature of the particulate material. Gas with entrained particles leaving the fluidzed bed are cooled during its passing through the freeboard of the fluidized bed reactor, whereby problems due to sticking of said entrained particles are avoided. At least a part of said entrained particles are recycled to the fluidized bed reactor.A fluidized bed reactor is provided suitable for performing the combined oxidation and agglomeration.

Abstract: Finely divided limestone is produced by abrasively grinding limestone in an aqueous media in the presence of added dissolved carbon dioxide or in the presence of a soluble acid-forming compound, the anion of which forms a soluble calcium compound, or in the presence of both dissolved carbon dioxide and an acid-forming compound. The finely divided limestone is used in a dry flue gas desulfurization process.

Abstract: Substantially spherical solid particles of a substantially uniform particle size are prepared by dispersing a solution of a polymerizable substance in a first liquid by means of a suitble emulsifier to form droplets of the polymerizable substance of a substantially uniform particle size, which are thereafter poured into a second liquid with which the first liquid is immiscible and which contains a sufficient amount of a reactant to polymerize the polymerizable substance. After the polymerization the substantially spherical particles formed are recovered. In a preferred embodiment, an aqueous solution of an alkaline metal silicate, especially sodium silicate, is dispersed in a coparaffinate by means of a suitable emulsifier, and the emulsion is poured into an aqueous solution of the polymerization reactant to form gelled, substantially spherical hydrated silicate particles.

Abstract: Spent absorbents resulting from desulfurization of flue gas in a spray drying-absorption process contain substantial amounts of sulfite, e.g. calcium sulfite. Said sulfite is oxidized into sulfate by heating of the spent absorbent in the presence of an oxygen-containing gas, preferably at temperatures of 350.degree.-600.degree. C. Thereby the spent absorbents may be converted into materials having industrial utility.