Abstract: A gas-recycling device according to an embodiment includes a particle remover, a liquid remover, and a supplier. The particle remover brings a mist of liquid into contact with a gas which includes particles and is discharged from an apparatus, to remove the particles from the gas. The liquid remover removes the liquid from the gas having passed through the particle remover. The supplier supplies the gas to the apparatus.

Abstract: Provided are a method and an arrangement for feeding process gases from a suspension smelting furnace into a waste heat boiler. The arrangement comprises a feeding throat for feeding process gas. The feeding throat is connected to an uptake inner space at an exit. The feeding throat is connected to the waste heat boiler at an entrance. The feeding throat having a feeding channel comprising a channel inner roof. At least one of an uptake inner roof of the uptake of the suspension smelting furnace and the channel inner roof of the feeding channel of the feeding throat is provided with an angled and/or curved section that slopes at least partly downwardly in an angled and/or curved manner in the direction towards the entrance.

Abstract: Sulphur oxides are generated from a liquid stream of hydrogen sulphide by feeding the liquid stream to a vacuum stripper where the stream is contacted with a stripping gas including steam under reduce pressure. Hydrogen sulphide is transferred to the stripping gas, whereby a loaded stripping gas is obtained. Water in the loaded stripping gas is condensed producing a H2S rich stream. The H2S is then burned in the stream to produce a stream rich in oxides of sulphur.

Abstract: A process for treating a dust containing, gaseous or liquid feed stream in a reactor containing a plurality of particle beds, which have the capability, once the pressure drop across a bed has reached a maximum allowable level, to distribute most of the feed stream to a point directly upstream of each of the subsequent beds in a series, stepwise manner. The beds contain particles in the form of pellets, cylinders, granules, rings, or mixtures thereof, and at the end of an operation period, the primary fraction of the feed flow is directed through the downstream-most bed in the reactor. By providing for removal of dust in each of the beds, the process enables the reactor to operate with a conventional pressure drop profile, but for an extended on-stream period of time.

Abstract: A method of producing useful products, for example, gypsum and sugar products, from pulp and paper industry wastes.

Abstract: This invention relates to a process for generating recoverable sulfur containing compounds, e.g., sulfur dioxide, from a spent sulfuric acid stream by combusting and/or thermally decomposing the spent sulfuric acid stream in a furnace. The spent sulfuric acid stream is sprayed into the furnace through a spray nozzle designed to minimize the spent sulfuric acid droplet size, e.g., to produce droplets having a Sauter mean diameter of from 200 micrometers to 700 micrometers.

Abstract: A process is provided for the thermal decomposition of contaminated sulfuric acid, which was obtained from the scrubbing of sulfur dioxide contaminated gases created in the pyrometallurgical production of metals. The contaminated sulfuric acid is concentrated to obtain a H2SO4 content of 70% to 80%, wherein, during the concentration step, a portion of the metal components, such as arsenic component, zinc sulfate, cadmium sulfate and copper sulfate, as well as halogens, are removed from the sulfuric acid. The concentrated and purified sulfuric acid is fed into the exhaust shaft of a smelting furnace so that the heat of the smelting furnace exhaust gases thermally decomposes the sulfuric acid into sulfur dioxide, water and oxygen.

Abstract: A process for recovery of substantially all the sulfur in a spent lead-acid battery as Na2SO4 is disclosed. The process comprises (a) breaking the batteries to remove the acid, (b) separating the plastic from the lead bearing materials, (c) smelting the lead bearing materials in a reverberatory furnace in an oxidizing atmosphere to volatilize most of the sulfur in the feed as SO2, (d) scrubbing the SO2 from the off gas stream using a soluble alkaline material such as NaOH, Na2CO3, or KOH to produce a soluble sulfite solution, (e) oxidizing the sulfite solution to sulfate, preferably by turbulent mixing of the solution with air, (f) adjusting the pH by adding the sulfuric acid separated from the batteries, (g) removing the contained heavy metals, (h) crystallizing the sulfate as Na2SO4 or K2SO4, (i) separating a bleed stream from the crystallizer and removing the contained chlorides as a mixed sulfate-chloride product by evaporation of the bleed stream in another crystallizer.

Abstract: A method is disclosed for treating sulfur containing waste streams, comprising:a) injecting said sulfur containing waste streams into a sulfuric acid regeneration unit so as to produce a sulfur dioxide containing effluent;b) passing a portion of said sulfur dioxide containing effluent to a Claus thermal reactor, andc) diverting a portion of said portion of said sulfur dioxide containing effluent of step b to a Claus catalytic reactor that is downstream from said Claus thermal reactor in an amount sufficient to maintain the average temperature in the Claus thermal reactor to be less than 3,250.degree. F.

Abstract: A process and plant for drying and then separating moist salts, such as magnesium sulfite, in which the moist magnesium sulfite is heated to a temperature greater than or equal to about 200.degree. C. in a dryer and the passed through a solid materials lock into a separating plant. The dryer is heated by a circulating stream of exhaust vapors which is heated in a heat exchanger by exhaust gas generated in the separating plant so that the water of crystallization of the magnesium sulfite as well as residual humidity is eliminated during the drying process. Vapor-free acid anhydride, usually sulphur dioxide, is prepared in the separating plant from the dehydrated salt and a metal oxide, e.g., MgO, is recovered or otherwise used. The acid anhydride may be liquified and has a large degree of purity.

Abstract: A process for increasing throughput in a spent sulfuric acid dissociation furnace by injecting dewatered biosolids pre-conditioned to enhance combustion into the furnace while enriching the oxygen content of the air used in the process.

Abstract: In the continuous production of oleum having a concentration of 10 to 45% by weight SO.sub.3 and/or sulfuric acid having a concentration of 94 to 100% by weight H.sub.2 SO.sub.4 by burning sulfur with atomospheric oxygen on the principle of overstoichiometric or understoichiometric burning, cooling the resulting SO.sub.2 -containing gas to 390.degree.-480.degree. C., catalytically reacting the cooled gas to SO.sub.3 -containing gas on a vanadium-containing catalyst on the principle of single- or double-contact catalysis, absorbing the SO.sub.3 -containing gas after cooling and, optionally, separating liquid from the gas after absorption, followed by recovering energy, the improvement which comprises effecting the burning of the sulfur with atomospheric oxygen in the presence of a dry SO.sub.2 -containing gas which contains up to 5,000 ppm (NO).sub.x expressed as NO.

Abstract: An improved process for treating spent alkylation acid to recover a sulfuric acid product suitable for use in wet process phosphoric plants particularly those which recover uranium as a byproduct. The process utilizes heat and agitation to polymerize the liquid, soluble organic impurities normally contained in spent alkylation acid to insoluble, carbonaceous solids. The carbonaceous solids formed are relatively inert in acidic environments, easy to handle and have valuable cation exchange and impurity scavenging properties.

Abstract: A process for removing SO.sub.2 from a fluid containing SO.sub.2 by employing as an absorbent for the SO.sub.2 an admixture of water and a compound represented by Formula I: ##STR1## wherein each R.sup.1, R.sup.2 or R.sup.3 is independently hydrogen; an alkyl group; a carboxylic acid group; a hydroxyalkyl group; an aldehyde group; and alkyl group containing a carboxylic ester, a carboxylic acid or salt, ether, aldehyde, ketone or sulfoxide group; wherein at least one R.sup.1 or R.sup.3 is carboxy methyl group and at least one R.sup.1 or R.sup.3 is hydrogen, preferably at least one R.sup.1 is carboxy methyl and at least one R.sup.3 is hydrogen. The absorbent solution preferably can be thermally regenerated by heating to remove SO.sub.2.

Abstract: A process for the recovery of sulphuric acid from a waste acid stream containing ammonium sulphate comprising vaporizing the waste acid and subsequently converting the ammonia and sulphur dioxide generated to nitrogen and sulphur trioxide, respectively. The process provides an economic method for the regeneration of the waste sulphuric acid from a methyl methacrylate production process.

Abstract: A method for endothermically dissociating contaminated acid wherein high velocity oxidant causes a recirculation flow within a combustion zone and combusts with fuel to release heat and wherein the heat is efficiently applied by the internal recirculation to the acid for endothermic dissociation of the acid.

Abstract: Sodium sulfate-containing residues are worked up by reducing the sulfate by a process in which the sulfate or a mixture or solution of the sulfate is thermally cleaved by adding oxygen, air or oxygen-enriched air at above 1000.degree. C., in particular above 1200.degree. C., under reducing conditions to give gaseous sulfides and oxides of sulfur as well as alkaline slag. The sulfur compounds contained in the gaseous reaction products can be further processed to sulfur, sulfur dioxide and sulfuric acid.

Abstract: A gas mixture including sulphur dioxide is recovered from sulphate waste material by burning a fuel to form a flame zone, introducing sulphate waste material into the zone and introducing pure oxygen or other oxygen-rich gas into the flame zone to support combustion of the fuel and to generate a flame of sufficient temperature to crack solid sulphate waste material and thereby liberate sulphur dioxide therefrom. Solids exiting the flame zone are separated from the gaseous combustion products. The sulphate waste material may be taken from a plant for making titanium dioxide pigment by the sulphate route.

Abstract: A process for decomposing ammonium thiocyanate and equivalent compounds comprising mixing the compounds with molten ammonium sulfate at atmospheric pressure and about 310.degree. C. The compounds decompose giving off carbon dioxide, sulfur dioxide, ammonia and sulfur and leave a residue of ammonia salts but no organic materials.

Abstract: A process and system are set forth for improving an oxygen-enriched Claus process by introducing a sulfuric acid stream into the reaction furnace to moderate oxygen-induced high temperatures which allow oxygen-enrichment and attendant throughput in the Claus process to higher levels than heretobefore practiced.

Abstract: Process for regenerating spent acid is improved by using oxygen-enriched air for combustion, recycling stack gases, and preheating spent acid and air fed to the furnace.

Abstract: A method for treating a waste stream from an alkylation process is disclosed, where the waste stream comprises a fluoride, sulfuric acid, and an acid soluble oil. The method comprises combusting the waste stream, scrubbing the combustion products to remove, fluorine, and recovering sulfur from the combustion products.

Abstract: The invention is a method of treating the distillation residue from the production of phosphorochloridothionates which comprises draining the residue into agitated cold water to form a slurry and contacting the slurry with chlorine gas in a hydrolyzing zone to decompose the residue and produce decomposition gases in controllable amounts having a decreased sulfur content.The novel method would reduce the amount of sulfur in the decomposition gas and make possible the use of less costly abatement facilities.

Abstract: Disclosed are a process and apparatus useful for reclaiming sulfur-containing waste materials such as waste or spent sulfuric acid and acid tars.The sulfur-containing waste material is burned in a multi-stage combustion furnace having, in sequence, a rotary furnace containing heated coke, an intermediate combustion chamber and a secondary combustion chamber. The temperatures, gas flow rates and amount of added air are carefully controlled.A separation gas is produced having a high sulfur dioxide content which can be used in the sulfuric acid contact process. The separation gas is free of nitrous oxides, hydrocarbons and sulfur trioxide.

Abstract: A two-stage process for the catalytic decomposition of H.sub.2 SO.sub.4 wherein H.sub.2 SO.sub.4 in vapor form is contacted in a first stage with a platinum group metal catalyst at temperatures between about 700.degree. K. and 970.degree. K. The platinum group metal catalyst is supported on a substrate of titania, barium sulfate, zirconia, silica, zirconium silicate or a mixture thereof, and at least about 40 percent of the H.sub.2 SO.sub.4 is decomposed to SO.sub.2. Vapors from the first stage enter a second stage where they contact a copper oxide and iron oxide catalyst at a temperature above 970.degree. K. The second stage catalyst is supported on a substrate of barium sulfate, zirconium oxide or titanium oxide.

Abstract: The direct fluid contact heat exchange with H.sub.2 SO.sub.4 at about 330.degree. C. prior to high temperature decomposition at about 830.degree. C. in the oxygen release step of several thermochemical cycles for splitting water into hydrogen and oxygen provides higher heat transfer rates, savings in energy and permits use of cast vessels rather than expensive forged alloy indirect heat exchangers. Among several candidate perfluorocarbon liquids tested, only perfluoropropylene oxide polymers having a degree of polymerization from about 10 to 60 were chemically stable, had low miscibility and vapor pressure when tested with sulfuric acid at temperatures from 300.degree. C. to 400.degree. C.

Abstract: The invention provides a process for thermally decomposing salts, containing mainly ferrous sulfate wherein said feed material is contacted in a single suspension-type exchanger with exhaust gases formed by reaction of the oxygen-containing gases in the fluidized bed reactor, the fluidizing gas and at least a partial stream of the secondary gas stream are heated by an indirect heat exchange in a fuel-heated heat exchanger, and the quantity of oxygen introduced via which consists of the fluidizing gas and the secondary gas, is controlled in dependence on the quantity of fuel in order to receive an exhaust gas from the suspension-type exchanger with a free oxygen content of 1-6% by volume and a temperature of 300.degree.-450.degree. C.

Abstract: In a process for thermally cracking waste sulphuric acid, a combustible material is mixed with such acid and the mixture is supplied to a burner to which a flow of atomizing air is also supplied. A flow of secondary air which is enriched to about 23-40% by volume of oxygen is injected into a flame generated by burning said waste sulphuric acid-combustible material mixture to thereby thermally crack such acid while reducing the production of by-product sulphur trioxide.

Abstract: An improved process for the production of concentrated sulfuric acid from H.sub.2 O- and SO.sub.2 -containing gases by the oxidation of the SO.sub.2 thereof in a plurality of contact stages while lowering the temperature of the gases, thereby condensing the sulfuric acid therefrom, comprises cooling a portion of the sulfur dioxide-containing gases exiting from a combustion or cracking furnace by contacting them with cooling water, the water vapor contained in the gases thereby being partially condensed-out or separated-off. The resulting cooled gases with reduced steam content are recycled into the furnace and, by the selection of the cooling temperature of the recycled gas, the H.sub.2 O/SO.sub.2 mol ratio in the combustion or cracking gases is adjusted within the range of from 1.0 to 1.25, and the remaining portion of the sulfur dioxide-containing gases, i.e., those which are not recycled, is fed to contact oxidation stages.

Abstract: Sulfuric acid of high strength is recovered from spent acids by scrubbing furnace gases with sulfuric acid containing 45 percent to 65 percent H.sub.2 SO.sub.4, removing mist from the gases, cooling the gases and removing water, and pre-drying the gases before final drying and product make-up.

Abstract: Gases containing elemental sulfur are purified therefrom by contact with sulfur trioxide in oleum; additionally the gas may be purified by carbonaceous material. In one embodiment, shown in the drawing, the process is used to remove elemental sulfur from sulfur dioxide produced by reaction of molten sulfur (3) with sulfur trioxide. A portion of the sulfur trioxide is by-passed (6) and introduced into the overhead line (5) of the sulfur dioxide reactor (4). The gases are purified in a second reactor (11) containing a pool of oleum (10).

Abstract: A process for the recovery of sulfuric acid from waste sulfuric acid containing iron sulfate and from solid iron sulfate of high water content of crystallization which consists essentially of:A. concentrating waste sulfuric acid to an acid concentration of 25-55 weight percent, based upon the suspension, by removing water therefrom;B. mixing the concentrated acid of Step A with recycled concentrated sulfuric acid obtained from Step E to form a resultant acid mixture of acid concentration of 30-65 weight percent, based upon the suspension;C. adding said solid iron sulfate of high water content of crystallization to the acid mixture of Step B thereby obtaining iron sulfate of low water content of crystallization;D. separating the iron sulfate of low water content from the resultant sulfuric acid solution of Step C;E. concentrating the separated sulfuric acid solution of Step D to an acid concentration of 45-70 weight percent, based on salt-free acid, and recycling at least a portion thereof to Step B; andF.

Abstract: Spent sulphuric acid, either alongside or mixed with contaminated metal salts such as iron sulphate heptahydrate, is regenerated to fresh acid by countercurrent contact with gases from cleavage of the sulphate salts, such gases containing SO.sub.3 which effects build up of the acid concentration. The built up acid is evaporated in another stage to obtain pure acid. The metal sulphate solids are subjected to high temperature cleavage, generating SO.sub.3 which effects the previous concentration. Cleavage also produces some SO.sub.2 which is converted to SO.sub.3 by wet catalysis.

Abstract: A furnace chamber of substantially circular cross section having a ceiling and a side wall, a burner positioned adjacent said ceiling and substantially evenly spaced from said side wall, a plurality of ultrasonic atomizer assemblies positioned around said burner in a concentric pattern adjacent said ceiling, each of said ultrasonic atomizer assemblies including: (a) means for converting a feed stream of the waste sulfuric acid into a coarse spray, and (b) means for further atomizing the coarse spray by passing it through a field of ultrasonic sound, and a gas flow constricting means transversing said chamber and spaced from said ceiling in a distance of about 1 to 4 times the length of the diameter of said chamber.

Abstract: Improvement in the method for recovering sulfur values in the form of sulfur dioxide from spent sulfuric acid by decomposing the spent sulfuric acid at elevated temperature in the presence of elemental sulfur to generate a sulfur dioxide-containing gas stream, which involves: (a) introducing the spent sulfuric acid into a pool of molten sulfur maintained at temperature of at least about 250.degree. C. to thereby generate a gaseous stream comprising sulfur dioxide, vaporous elemental sulfur, and water; (b) cooling said gaseous stream to temperature above the melting point of the sulfur but below about 160.degree. C. to condense elemental sulfur therefrom, separating the condensed elemental sulfur and returning it to the pool of molten sulfur; followed by (c) further cooling the gaseous stream from which elemental sulfur has been condensed to condense water therefrom, and separating the condensed water from the gaseous stream.

Abstract: Process for recovering sulfur from waste waters containing sulfuric acid, comprising reacting in a first step, the waste water with an aqueous solution of ammonium sulfite, separating the formed sulfur dioxide from the solution, reacting the resulting solution in a second step with calcium oxide to form calcium sulfate and an aqueous ammonia solution, vaporizing ammonia therefrom, reducing the calcium sulfate by means of carbon to form calcium oxide and sulfur dioxide, contacting said vaporized ammonia with said sulfur dioxide and with water, thereby forming an aqueous solution of ammonium sulfite, which is joined to that used in the first step and recycling at least a part of the calcium oxide obtained by reduction of the calcium sulfate to the second step.

Abstract: The effluent streams from utility stack gases containing nitric oxides and sulfur dioxide are sequentially oxidized, absorbed with effluent spent alkylation acid, the unabsorbed remaining gases contacted with carbon monoxide from alkylation units in refinery cracking and other industrial plants to form sulfur, carbon dioxide and nitrogen, the carbon dioxide and nitrogen being vented, the sulfur oxidized to sulfur trioxide and contacting aqueous sulfuric acid therewith to effect concentration of said acid and suitability for recycle to an alkylation unit; the absorbate containing spent alkylation acid sequentially treated with a burning, oxidation, aqueous dilution and carbon monoxide treatment steps to form sulfuric acid for recycle to an alkylation unit and venting formed carbon dioxide and nitrogen.