A/s Niro Atomizer

Joy Manufacturing Company

Karsten S Felsvang

Preston L Veltman

Ove E Hansen

Per Morsing

James R Donnelly

Everett L Coe, Jr

Christian Schwartzbach

Karl E Hansen

Ebbe S Jons

Klaus Erik Gude

Erik Liborius

Leif D Caspersen

Stig Rasmussen

Bo Norman

Elisabeth L Rasmussen

Alfonso De Ruvo

Klaus Moller

Geoffrey G Duffy

James R Donelly

Jens Andreasen

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. The chloride content of the absorbent is used as the basis for (a) controlling the amount of chloride in the aqueous suspension to such a value that a specific chloride content of the spray dried product is between 1 and 7% by weight, and, within this range is related to the difference between the temperature of the desulphurized waste gas and the adiabatic saturation temperature thereof, and/or (b) for controlling the quantity of water evaporated by the spray drying, which is also related to the set forth chloride content, to change the difference between the temperature of the desulphurized waste gas and the adiabatic saturation temperature thereof, to provide a minimum temperature difference so as to maximize the acid base reaction yet maintain an actual temperature difference high enough to avoid sticky products.

Method of desulphurizing hot waste gas

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.

Process for flue gas desulfurization

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.

Process for desulfurization of hot waste gas

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.

Fluid bed SOX/NOX process--'hydrated calcine absorption'

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.

Process for removal of nitrogen oxides and sulfur oxides from waste gases

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.

Process for desulfurization, dedusting and discharge of hot fly

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.

Method and a system for separating an aqueous suspension containing

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.

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.

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Allerod, Denmark

Karsten S Felsvang