Abstract: A gas refining method for adsorbing a reducing gas obtained by pressure gasification of coal or oil comprises introducing a reducing gas stream into an adsorbing and removing zone where it contacts an adsorbent. Sulfur-containing compounds are adsorbed onto the adsorbent and a first oxygen-containing gas stream is introduced into the adsorbing and removing zone in order to form a regeneration gas containing sulfur dioxide. The regeneration gas is contacted with a second oxygen-containing stream and a calcium-containing liquid slurry to effect absorption of sulfur dioxide by the slurry and precipitation of a gypsum compound. The temperature of the slurry is varied to cause selective precipitation of 60 -gypsum hemihydrate or gypsum dihydrate.

Abstract: This invention relates to a gas refining system wherein sulfur compounds contained in a high-temperature and high-pressure reducing gas obtained by the pressure gasification of coal or heavy oil or the like are adsorbed and removed in the form of a sulfide by an adsorbent, the adsorbent having the sulfide formed thereon is regenerated by roasting it with an oxygen-containing gas, and the regeneration gas containing sulfur dioxide formed by the roasting reaction is introduced into a reactor (50) where, by use of gas blowing means, the regeneration gas and an oxygen-containing gas are blown into a calcium compound-containing slurry fed to the reactor (50), and thereby brought into gas-liquid contact with the slurry to effect the absorption of sulfur dioxide and the precipitation of gypsum within the reactor (50), characterized in that the gas refining system is provided with temperature control means for selectively controlling the temperature of the slurry within the reactor (50) so as to fall within at least

Abstract: After hydrogenation and desulfurization treatment of raw fuel in the desulfurization unit 1, the product is separated in the acidic gas separator 2 into fuel and a hydrogen sulfide-containing gas, and the hydrogen sulfide-containing gas is subjected to combustion together with air in the catalyst converter 3 thereby converting the hydrogen sulfide completely into sulfur dioxide to give a sulfur dioxide-containing gas, and this sulfur dioxide-containing gas is reacted with limestone powder and air in water in the oxidation and neutralization reactor 4, and the resulting slurry is dehydrated in the gypsum slurry solid/liquid separator 5 and then dried in the gypsum heater 6.

Abstract: This invention relates to a gas refining system wherein a high-temperature and high-pressure reducing gas is introduced into a fixed-bed desulfurizer packed with an adsorbent by which sulfur compounds contained in the high-temperature and high-pressure reducing gas are adsorbed and removed in the form of a sulfide, and the adsorbent having the sulfide adsorbed thereon is regenerated by roasting it with a regenerating gas containing oxygen, characterized in that the gas refining system is equipped with oxygen concentration control means for controlling the oxygen concentration in the regenerating gas introduced into the desulfurizer so as to keep the internal temperature of the desulfurizer during the regeneration reaction within the allowable temperature range of the adsorbent.

Abstract: A gas refining system for adsorbing a reducing gas includes a reduced gas stream, a section for adsorbing and removing sulfur-containing compounds in the reducing gas, an adsorbent which contacts the reduced gas stream, an oxygen-gas containing stream which enters the adsorbing and removing section, a calcium-compound containing stream, and a reactor which receives the above streams and allows for the adsorption of sulfur dioxide and precipitation of a gypsum compound.

Abstract: After hydrogenation and desulfurization treatment of raw fuel in the desulfurization unit 1, the product is separated in the acidic gas separator 2 into fuel and a hydrogen sulfide-containing gas, and the hydrogen sulfide-containing gas is subjected to combustion together with air in the catalyst converter 3 thereby converting the hydrogen sulfide completely into sulfur dioxide to give a sulfur dioxide-containing gas, and this sulfur dioxide-containing gas is reacted with limestone powder and air in water in the oxidation and neutralization reactor 4, and the resulting slurry is dehydrated in the gypsum slurry solid/liquid separator 5 and then dried in the gypsum heater 6.

Abstract: The present invention is directed to a method for purifying a high-temperature reducing gas by continuously circulating the processes of reducing a regenerated absorbent with the high-temperature reducing gas, until concentrations of aimed reducing gases have become uniform on upstream and downstream sides of the absorbent, and absorbing sulfur compounds by the use of this absorbent and thereby removing these sulfur compounds therefrom; the aforesaid method being characterized by using at least three reactors filled with the absorbent, by consisting of the four steps of reduction, absorption, SO.sub.2 reduction and regeneration, and by comprising the steps of feeding a circulating gas from the regenerating step to the SO.sub.2 reducing step; converting an SO.sub.2 gas produced in the regenerating step and the SO.sub.2 reducing step into elemental sulfur and recovering the latter as liquid sulfur; and introducing a part of the SO.sub.2 gas into the reducing step and returning the remaining SO.sub.

Abstract: A process for preparing a catalyst for removing nitrogen oxides which comprises sintering orthotitanic acid in coexistence of at least one compound, selected from silicic acid in the form of fine particles, tungsten compounds and molybdenum compounds.

Abstract: A denitration catalyst comprising at least three metal components, (A) titanium, (B) tungsten and/or magnesium, and (C) vanadium, the titanium and tungsten being contained as oxides and the magnesium and vanadium being contained in the form of an oxide or a sulfate or both, said catalyst being composed of a porous molded article of a mixture of an oxide of component A and an oxide and/or a sulfate of component B, the atomic ratio of component B to component A being from 0.01 to 1, and a vanadium compound localized in that area of said molded article which extends from its outermost surface to a depth of 500 microns or less, the content of the vanadium compound in said area being 0.1 to 15% by weight; and a method for removing nitrogen oxides from a waste gas, which comprises contacting a waste gas containing nitrogen oxides, together with ammonia and molecular oxygen, at a temperature of 150.degree. to 650.degree. C., with the aforesaid catalyst.

Abstract: In a process and an apparatus for controlling oxides of nitrogen in exhaust gases from combustion equipment by decomposing the oxides, in the presence of oxygen, with ammonia blown into the equipment and associated ducting at temperatures within the range from 700.degree. to 1300.degree. C., a catalyst assembly is arranged, with the catalytic surfaces of the component units substantially in parallel to the direction of exhaust gas flow, in a region where the temperature of the gas after the decomposing treatment is between 300.degree. and 500.degree. C., and the gas after the decomposing treatment is caused to pass through the catalyst assembly to decompose residual nitrogen oxides and ammonia in the gas to innocuous substances. An additional supply of ammonia, in an amount from 0.5 to 1.

Abstract: A catalyst for the selective catalytic reduction of nitrogen oxides by the use of ammonia as a reducing agent composed of a catalytically active constituent on a carrier having a honeycomb or parallel plate structure, the carrier being prepared from a slurry of crystallized calcium silicate prepared by mixing silicic acid and lime and heating the mixture under pressure, the calcium silicate having the structure of xonotrite and the formula 6 CaO.6 SiO.sub.2. H.sub.2 O.

Abstract: A catalyst for selective catalytic reduction of nitrogen oxides by use of ammonia as a reducing agent is prepared by mixing a silicic acid material with a lime material, heating the mixture under pressure to form a slurry of calcium silicate crystals, forming the slurry into a carrier, and then allowing the carrier to carry a catalytically active ingredient.