Abstract: In a hydrocracking unit, the flash gases from the high-pressure separator are fed to the bottom of an absorption zone where the entering gases are counter-currently contacted with a lean solvent. The lean solvent absorbs away the contained methane, ethane, propane, butanes and pentanes (C1+) from the contained hydrogen. The overhead gas stream from the absorption zone typically contains hydrogen at a purity of 90 to 98 mol %, or even higher, which is fed to the recycle gas stream to provide hydrogen purity in the range of 96 to 99 mol %, thereby providing an increase in the overall efficiency of the hydroprocessor unit. The process can also be employed with hydrotreating, hydrodesulfurization, hydrodenitrogenation and hydrodealkylation reactors.

Abstract: A system and method for removing SOx and particulate matter from an emission control device receiving exhaust gases from an engine is provided. The method includes adding a reductant to the exhaust gases to increase a temperature of the emission control device above a threshold temperature. The method further includes ceasing adding the reductant to the exhaust gases to remove particulate matter from the device. The method further includes adding additional reductant to the exhaust gases to remove SOx from the device.

Abstract: Gas streams containing non-condensible gases (NCG's) including reduced sulfur compounds, such as hydrogen sulfide, dimethyl sulfide, dimethyl disulfide and mercaptans, are treated to remove the NCG's from the gas stream. Following an optional initial gas-liquid contact to cool the gas stream to its adiabatic dewpoint and to remove particulates, the gas stream is subjected to an intimate gas-liquid contact with aqueous chlorine dioxide, in one or more contact stages, to oxidize the reduced sulfur compounds and other oxidizable compounds present in the gas stream, and then the gas stream is passed through an entrainment separator to remove entrained liquid droplets.

Abstract: A process and apparatus for removing SO2 from a gas stream having the steps of scrubbing the SO2 with an ammonia scrubbing solution and removing any aerosols generated by the scrubbing in a wet electrostatic precipitator. Ammonium sulfate, a valuable fertilizer, can be withdrawn from the scrubbing solution.

Abstract: The present invention provides an exhaust gas treatment process wherein exhaust gas containing mercury and sulfur dioxide is subjected to a desulfurization treatment in a desulfurizing absorption tower and then passed through a mist eliminator for removing and recovering mist from the desulfurized exhaust gas, the process including the step of removing mercury from the desulfurized exhaust gas by feeding thereto an oxidizing agent such as sodium hypochlorite and an antioxidant such as methanol unreactive with the oxidizing agent at a position upstream of the aforesaid mist eliminator.

Abstract: A process for adjusting the ratio of sulfur dioxide to hydrogen disulfide from the regeneration of a catalytic system of a structured support for example a monolith coated with: (i) a metal oxide sorber component selected from the group consisting of Ti, Zr, Hf, Ce, Al, Si and mixtures thereof, for example Ti2O, (ii) a precious metal component, for example Pt metal and, optionally (iii) a modifier consisting of an oxide Ag, Cu, Bi, Sb, Sn, As, In, Pb, Au or mixtures thereof, such as Cu as copper oxide. The system first captures the gaseous sulfur compounds. Then the captured gaseous sulfur compounds are then desorbed as mainly H2S and SO, in higher concentrations in a separate isolated lower flow stream in a ratio determined by the amount of modifier in the catalyst. The higher concentrations may be processed to less noxious or useful sulfur materials and the catalyst/sorber is regenerated.

Abstract: High quality hydrophilic sulfur is recovered from a biologial conversion zone in which a sulfur containing compound such as a sulfide is converted to elemental sulfur. The sulfur is rendered hydrophilic due to the fine particle size and attachment of biomass to the particles. The sulfur is recovered as an undamaged agglomerate powder after being processed in at least two stages of purification.

Abstract: A feed gas stream containing hydrogen sulphide is subjected in a furnace 6 to reactions in which part of the hydrogen sulphide is burned to form sulphur dioxide, and is which the sulphur dioxide reacts with residual hydrogen sulphide to form sulphur vapor. The sulphur vapor is condensed from the gas stream exiting the furnace 6 in a sulphur condenser 16. Residual sulphur dioxide is reduced back to hydrogen sulphide by hydrogen in a reactor 22. Water vapor is removed from the reduced gas in a quench tower 28 to form a water vapor-depleted gas stream. One part of the water vapor-depleted gas stream is sent to an adsorber vessel 30 in which hydrogen sulphide is absorbed in an absorbent. The resulting hydrogen sulphide-depleted gas stream is vented from the vessel 30 as a purge stream. Another part of the water vapor-depleted gas stream and a hydrogen sulphide-rich gas formed by desorbing hydrogen sulphide from the absorbent in a vessel 38 are returned as recycle streams to the furnace 6.

Abstract: A selected contaminant is removed from a gas stream containing an unselected component that is also absorbed by the solvent, although to a lesser degree than the selected contaminant. In a typical application, hydrogen sulfide is removed from a natural gas stream that contains carbon dioxide as an unselected component. The process employs a solvent absorption/regeneration sequence, carried out in an absorber and regenerator, to remove the selected contaminant (hydrogen sulfide, for example) from the gas stream. The overhead gas from the regenerator has a higher concentration of the selected contaminant than the original gas stream. This contaminant rich overhead gas stream is partially employed as a recycle stream that is combined with the original gas stream, with the resulting combined gas stream being fed to the absorber.

Abstract: A process is provided for the production of hydrogen from hydrogen sulfide by reacting carbon monoxide with hydrogen sulfide to produce hydrogen and carbonyl sulfide, and then reacting the carbonyl sulfide with oxygen to produce carbon monoxide and sulfur dioxide. The carbon monoxide is recycled back to the hydrogen sulfide reaction step. The catalyst used to promote the reaction between carbonyl sulfide and oxygen is an oxide of a metal, such as V, Nb, Mo, Cr, Re, Ti, W, Mn or Ta, which is supported on a support, such as TiO2, ZrO2, CeO2, Nb2O5 and Al2O3.

Abstract: Elemental sulfur is recovered from the hydrogen sulfide present in natural gases and other process gases by treating the hydrogen sulfide-containing gas in a series arrangement of a liquid-phase reactor; a furnace and a sulfur dioxide absorber. The hydrogen sulfide-containing gas and a sulfur dioxide-containing gas are fed into the liquid-phase reactor where they are dissolved into a solvent, such as polyglycol monoethers, diethers of ethylene glycol, diethers of propylene glycol, etc., and react in the presence of a catalyst, such as tertiary amine, pyridine, isoquinoline, etc., to produce elemental sulfur. The feed rates of the hydrogen sulfide-containing gas and the sulfur dioxide-containing gas are selected so that there will be an excess of hydrogen sulfide in the solvent thereby ensuring that the reaction products will include, not only the elemental sulfur, but also residual, unreacted hydrogen sulfide.

Abstract: In general, the invention provides methods and associated apparatuses for removing odorant and sulfur compounds from a gas stream such as natural gas. As an example, such systems are typically required by fuel processor systems adapted to convert natural gas into reformate for use in fuel cell systems, where the odorant and sulfur compounds might otherwise poison the fuel processor and fuel cell catalysts Systems under the present invention are based on the use of at least two filtration stages such that the odorant removal function is segregated from the general removal of H2S.

Abstract: The invention is directed to a process for oxidizing gaseous pollutants in a flue gas stream composed of flue gases, water vapour and one or more gaseous pollutants selected from the group consisting of SO2, NO, NO2, H2S, and mercury vapour, the oxidized form of the pollutants being more readily removable from the flue gas stream by water absorption than the non-oxidized form thereof, comprising: (a) injecting sufficient chlorine in a gaseous form, a liquid form, or as a chlorine water solution, into the flue gas stream while the flue gas stream is at a temperature greater than 100° C.

Abstract: A process is provided to recover residual H2S, SO2, COS and CS2 in the tail gas from a sulphur recovery process. The tail gas is oxidized and hydrolyzed at a temperature of from 180° C. to 700° C. to provide an oxidized and hydrolyzed gas stream containing substantially no COS or CS2 and having a concentration by volume of H2S and SO2 such that the H2S concentration minus twice the SO2 concentration is from 0.25% to 0.5%. Then the gas stream from the hydrolysis is passed over a Claus catalyst, for example based on alumina and/or titanium oxide, for the reaction of H2S with SO2 to form sulphur and provide a gas stream with substantially no SO2.

Abstract: An apparatus and method for sulfur recovery uses a scrubber tower with a plurality of vertically spaced scrubber trays in the tower. Sulfide-lean liquor is supplied to each of the trays and an acid gas is supplied to the tower below the trays. A downcomer extends in the tower and through the trays for accumulating liquid from the trays and moving the liquid to the bottom of the tower. The sulfide-lean liquor and acid gas are selected to form a sulfite-rich or sulfide-rich liquor in each of the trays which are brought to the bottom of the tower through the downcomer for removal from the tower.

Abstract: A method for decomposing nitrogen fluoride or sulfur fluoride, comprising contacting gaseous nitrogen fluoride or sulfur fluoride with a solid reagent comprising elemental carbon, one or more of the alkaline earth metal elements and optionally one or more of the alkali metal elements, to fix the fluorine component in the nitrogen fluoride or sulfur fluoride in said reagent.

Abstract: The present invention relates to a process for the treatment of exhaust gases from internal combustion engines operating with a fuel containing sulphur. This process is characterized in that use is made, as catalyst, of a composition based on a cerium oxide and on a zirconium oxide, in a cerium/zirconium atomic proportion of at least 1, and on at least one oxide chosen from yttrium, lanthanum and praseodymium oxide and which exhibits a specific surface, after calcination for 6 hours at 900 ° C., of at least 35 m2/g.

Abstract: Five combustion exhaust gas treatment systems capable of removing dust and selenium (Se) in combustion exhaust gas and making harmless are proposed: (1) combustion exhaust gas is cooled to 350° C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350° C. or less, dust is separated, Se elution preventive agent is added, and dust is formed into scale; (3) dust in combustion exhaust gas is collected by dust collector, dust is formed into slurry by making use of part of circulation liquid in desulfurization apparatus, and tetravalent Se in dust slurry is transformed into insoluble compound, which is separated into solid and liquid; (4) dust is separated from combustion exhaust gas by dust collector, and it is heated to gasify Se, and is led into desulfurization apparatus, etc.

Abstract: Methods for removing carbonyl sulfide (COS) from a synthesis gas stream are disclosed. The method entails raising the water level of a wet scrubber so that hydrolysis of the COS may occur in the scrubber itself instead of a COS reduction chamber and no additional catalysts other than those naturally occurring in the production of the synthesis gas need be introduced into the scrubber. The water is raised, in one example, to a level such that water within an inner tube of the wet scrubber flows over an upper end of the inner tube. Raising the water level in the scrubber ensures intimate and vigorous interaction between the water, the COS, and the naturally occurring catalyst, and promotes the hydrolysis of the COS. In one example, the naturally occurring catalyst (e.g., alumina oxide) is present in the coal ash produced when coal is the fuel gasified that creates the synthesis gas stream.

Abstract: A method for removing sulfur dioxide out of a gas is provided. The sulfur dioxide contaminated gas is contacted with an aqueous solution or slurry that contains a reagent, such as sodium carbonate or sodium bicarbonate, in a reactor that may be a spray drier or a quench reactor and a gas having a diminished quantity of sulfur dioxide; unreacted reagent; sulfate reaction product, and which is at a temperature in the range of about 130 to 200 ° F. and a humidity in the range of 10 to 70 percent is produced. Particulate calcium hydroxide is blown into this gas through a device, such as dry venturi. The dry venturi removes aerosols out of the gas and helps ensure that the downstream filter cake is porous and non-tacky. The gas is then passed through a filtering device so that solids in the gas accumulate on the filter device, thus forming a filter cake. At least a portion of the sulfur dioxide in the gas is removed via passage of the gas through this filter cake.

Abstract: A highly efficient sulfide catalyst for reducing sulfur dioxide to elemental sulfur, which maximizes the selectivity of elemental sulfur over byproducts and has a high conversion efficiency. Various feed stream contaminants, such as water vapor are well tolerated. Additionally, hydrogen, carbon monoxide, or hydrogen sulfides can be employed as the reducing gases while maintaining high conversion efficiency. This allows a much wider range of uses and higher level of feed stream contaminants than prior art catalysts.

Abstract: Disclosed is a process for the treatment of a plant fluid effluent containing odor compounds including an alkyl mercaptan or an alkyl thiol, an amine compound, ammonia, hydrogen sulfide and mixtures thereof by contacting the plant effluent in either a counterflow or cocurrent flow process. In the process, the effluent is contacted with an aqueous solution comprising a peroxyacid compound and one or more essential oils. When contacted with the peroxyacid, odor compounds in the effluent are oxidized and converted from the gaseous phase into a chemically modified highly aqueous soluble phase in the aqueous treatment. In this way, odor removal from the gas is preferred and odor compounds are efficiently transferred into the aqueous treatment solution. The use of such a process produces a significant improvement in odor quality index as measured by a conventional process using an expert panel when compared to conventional treatment methods.

Abstract: This invention relates to a method for decreasing sulfuric acid and sulfuric anhydride present in combustion exhaust gas which comprises adding an SO3-decreasing agent (hydrogen gas) to combustion exhaust gas and thereby reducing sulfuric acid (H2SO4) and sulfuric anhydride (SO3) present in the combustion exhaust gas, as well as a combustion exhaust gas flow system therefor. Thus, this invention provides a method for decreasing sulfuric acid and sulfuric anhydride present in combustion gas which can prevent the occurrence of troubles (e.g., low-temperature corrosion and ash deposition) arising from H2SO4 and S3 contained in combustion gas.

Abstract: In a process and corresponding device for scrubbing acidic gases out of flue gases using adsorbent-containing suspensions, the flue gases are conveyed into a scrubber with narrowing channels and accelerated in a first stage in a direction opposite to the flow of suspension droplets and in a second stage in the same direction as the flow of liquid droplets, the suspension having already been broken down into droplets before or at the beginning of the acceleration section. Reflux of the suspension into the acceleration section is prevented by the shape of the channels. Flue gas and suspension droplets react and in the connecting first mist precipitator, the droplets are turned around 180° in the direction of gravitational forces.

Abstract: Super clean air having therein chemical components—such as hydrocarbons, organic halogens, acidic gases, basic gases, aldehydes, nitrogen oxides, and H2O (that is, all components other than oxygen, nitrogen, and noble gases—the types of chemical components differ depending on the source of the air)—in concentrations no more than 1 ppb and a dew point lower than −40° C., is obtained from the atmosphere by low-temperature adsorption treatment in stages at temperatures ranging from −40° C. to −180° C. Material air collected from the atmosphere is pretreated in a room-temperature adsorption step to remove moisture and carbon dioxide. The pretreated air is then low-temperature adsorption treated by absorbents in a plurality of steps to adsorb the gaseous chemical components, the treatment temperature being lower in each succeeding step. Treatment at −40° C. may remove, for example, HF, SO2, and/or NH3. Treatment at −100° C.

Abstract: This invention relates to a flue gas treating process including a heat recovery step for recovering heat from flue gas by means of a heat exchanger (4) and thereby cooling the flue gas, and a subsequent absorption step for bringing the flue gas into gas-liquid contact with an absorbing fluid (D) in absorption towers (12, 13) so as to remove at least SO2 present in the flue gas by absorption into the absorbing fluid (D), which is characterized, for example, in that a powder addition step for spraying a powder collectable in the absorption step into the flue gas is provided prior to the heat recovery step. This invention makes it possible to provide a flue gas treating process in which a countermeasure against SO3 present in flue gas can be easily achieved without resorting to ammonia injection and the flue gas can further be purified without the disadvantage of causing the injected substance to remain in the treated flue gas.

Abstract: A composition comprising magnesium sulfite, triple super phosphate, and one of limestone and hydroboracite, useful for heavy metal stabilizing, controlling pH and/or removing acid gas from a solid, semi-solid, liquid or gaseous matrix.

Abstract: A method is provided for removing sulfur dioxide and carbon dioxide out of gases from, for example, the combustion of sulfur containing fossil fuels. The sulfur dioxide and carbon dioxide contaminated gas is first contacted with an aqueous solution containing dimethyl sulfoxide and alkaline earth metal ions, wherein the aqueous solution is at an acidic pH, for example, at a pH of from about 2 to about less than 7, so that the sulfur dioxide in the gas is dissolved in the aqueous solution and, subsequently, reacts with the alkaline earth metal ions to form alkaline earth metal sulfates and alkaline earth metal sulfites. The gas is then contacted with an aqueous solution containing dimethyl sulfoxide and alkaline earth metal ions, wherein this aqueous solution is at a pH that is greater than 7 so that the carbon dioxide in the gas is dissolved in the aqueous solution and, subsequently, reacts with the alkaline earth metal ions to form alkaline earth metal carbonates.

Abstract: Substances to be processed and a hydrogen peroxide aqueous solution are enclosed in a process vessel, and a the process vessel is enclosed in an autoclave together with water. Oxidation processing of the substances is performed by changing the state in the autoclave and the process vessel to a supercritical state which is realized by heating an outer wall of the autoclave with a heater. Further, even if the substances leak from the process vessel, by oxidizing the leaking substances in the autoclave the leaking of the substances to the outside of an oxidation processing apparatus is prevented.