Babcock-hitachi Kabushiki Kaisha

Mitsubishi Hitachi Power Systems, Ltd.

Mitsubishi Power, Ltd.

Keiichiro Kai

Yasuyoshi Kato

Naomi Imada

Seiji Ikemoto

Kenichi Arakawa

Kotoe Matsuyama

A used denitration catalyst is regenerated by means of a method comprising bringing the used denitration catalyst comprising titanium oxide as an essential ingredient into contact with a suspension of particles comprising manganese oxide, subjecting the resulting product to a liquid draining, and subjecting the liquid-drained product to a drying process, additionally, further comprising impregnating a solution comprising a compound containing at least one element selected from the group consisting of vanadium, molybdenum and tungsten into the denitration catalyst after the drying process, and subjecting the impregnated product to a drying treatment.

Method of regenerating used denitration catalyst

Provided is a catalyst structure which prevents an increase in pressure loss by a simple construction while the gas flow is efficiently stirred by a structure making contact between adjacent catalyst elements. The catalyst structure is provided with a first flat-plate part and a second flat-plate part which support, on surfaces thereof, a constituent having catalytic activity to an exhaust gas and face each other, and a stirring part which is provided in such a manner as to come into contact first with the first flat-plate part and the second flat-plate part in an extending manner from the first flat-plate part to the second flat-plate part at a prescribed angle with respect to the direction in which the exhaust gas flows.

Catalyst structure

A catalyst structure for exhaust gas cleaning obtained by superimposing flat plate-like catalyst elements composed of a flat part, which is a main structural part, and a linear spacer part composed of raised strips and recessed strips so that a gas flow channel is ensured along the lengthwise direction of the spacer part, wherein the flat part has at least one baffle part composed of a leg plate erectly provided on the flat part with a height that is less than that of the spacer part with reference to the flat part, and a top plate disposed substantially parallel to the flat part from the upper end of the leg plate. Turbulence can be imparted by the baffle part to gas that flows to the gas flow channel.

Catalyst structure for exhaust gas cleaning

An exhaust gas purification catalyst contains titanium oxide as a main component and an oxide of one element or two or more elements selected from the group consisting of tungsten (W), molybdenum (Mo), and vanadium (V) as an active component, wherein the exhaust gas purification catalyst contains phosphoric acid or a water soluble phosphoric acid compound so that the atomic ratio of phosphorus (P) to a catalytically active component represented by the following formula is more than 0 and 1.0 or less; P/catalytically active component (atomic ratio)=number of moles of P/(number of moles of W+number of moles of Mo+number of moles of V).

Exhaust gas purification catalyst suppressing influence of iron compound

A metal substrate for flue gas-denitration catalyst that, like SUS304, can be used without corroding is provided by improving the corrosion resistance of SUS430 substrate that is inexpensive and can easily be supplied stably. A method for producing the metal substrate for flue gas-denitration catalyst, wherein the method comprising the steps of: lath-processing a band-shaped steel plate made of ferrite stainless steel into a band-shaped metal lath; (1) degreasing process oil adhering to the metal lath; (2) passing the metal lath through a solution containing phosphoric acid and surfactant to load the solution; (3) draining off the excess solution; and (4) drying and heating the solution-loaded metal lath to react the phosphoric acid with the substrate, in which respective steps are carried out sequentially to form a film of phosphate compound on a surface of the substrate.

Method for producing metal substrate for flue gas denitration catalyst

Provided is a method for cleaning a used denitration catalyst, which prevents release of mercury to the atmosphere by collecting and removing mercury which would have been released to the atmosphere in the process of cleaning the used denitration catalyst. The method comprises immersing the used denitration catalyst mainly composed of titanium oxide and having been used in exhaust gas containing mercury in a cleaning liquid, and stirring the cleaning liquid to dissolve and remove catalyst poisons including the mercury from the used denitration catalyst, wherein a waste gas generated in the step of stirring the cleaning liquid is conducted to a flue having a mercury removal device so as to remove the mercury, and then vented to the atmosphere.

Method for cleaning used denitration catalyst

An exhaust gas purification catalyst is made as a composition comprising titanium oxide (TiO), aluminum sulfate (Al(SO)), an oxide of vanadium (V), and an oxide of molybdenum (Mo) and/or tungsten (W), wherein on titanium oxide having sulfate ions and aluminum ions adsorbed thereon obtained by making contact with aluminum sulfate at more than 1 wt % and not more than 6 wt % relative to titanium oxide in the presence of water, an oxo acid salt of vanadium or a vanadyl salt and an oxo acid or an oxo acid salt of molybdenum and/or tungsten are supported in a proportion of more than 0 atom % and not more than 3 atom %, respectively. By this, the degradation of catalyst performance can be suppressed even with exhaust gas containing potassium compounds at a high concentration in combustion ash.

Exhaust gas purification catalyst and production method therefor, and method for purifying nitrogen oxide in exhaust gas

To overcome the problem of a conventional catalyst and to provide an exhaust gas purifying catalyst that meets the requirement concerning Hg oxidation activity and SOoxidation activity; i.e., an exhaust gas purifying catalyst which specifically reduces percent SOoxidation, while maintaining percent Hg oxidation at a high level. The invention provides an exhaust gas purifying catalyst which comprises a composition containing oxides of (i) titanium (Ti), (ii) molybdenum (Mo) and/or tungsten (W), (iii) vanadium (V), and (iv) phosphorus (P), wherein the catalyst contains Ti, Mo and/or W, and V in atomic proportions of 85 to 97.5:2 to 10: 0.5 to 10, and has an atomic ratio of P/(sum of V and Mo and/or W) of 0.5 to 1.5, and an exhaust gas purifying method comprising exposing an exhaust gas containing a nitrogen oxide (NO) and metallic mercury (Hg) to the catalyst in the presence of ammonia as a reducing agent, to thereby perform reduction of NOcontained in the exhaust gas and oxidation of metallic mercury (Hg) contained in the exhaust gas.

Exhaust gas purifying catalyst

To overcome the problem of a conventional catalyst and to provide an exhaust gas purifying catalyst that meets the requirement concerning Hg oxidation activity and SOoxidation activity; i.e., an exhaust gas purifying catalyst which specifically reduces percent SOoxidation, while maintaining percent Hg oxidation at a high level. The invention provides an exhaust gas purifying catalyst which comprises a composition containing oxides of (i) titanium (Ti), (ii) molybdenum (Mo) and/or tungsten (W), (iii) vanadium (V), and (iv) phosphorus (P), wherein the catalyst contains Ti, Mo and/or W, and V in atomic proportions of 85 to 97.5:2 to 10:0.5 to 10, and has an atomic ratio of P/(sum of V and Mo and/or W) of 0.5 to 1.5, and an exhaust gas purifying method comprising exposing an exhaust gas containing a nitrogen oxide (NO) and metallic mercury (Hg) to the catalyst in the presence of ammonia as a reducing agent, to thereby perform reduction of NOcontained in the exhaust gas and oxidation of metallic mercury (Hg) contained in the exhaust gas.

A method for removing mercury in a combustion exhaust gas includes injecting ammonia or urea as a reducing agent into a combustion exhaust gas containing nitrogen oxides, sulfur dioxide, metallic mercury, and hydrogen halides, and then introducing the combustion exhaust gas to a denitration apparatus filled with a denitration catalyst to cause a denitration reaction and oxidize the metallic mercury to produce mercury halide; and introducing the combustion exhaust gas through an air preheater and an electric dust collector to a wet desulfurization apparatus, thereby removing sulfur dioxides and the mercury halide, wherein the ammonia concentration of the combustion exhaust gas at an exit of the denitration apparatus is maintained at 5 ppm or higher, and the mercury halide is adsorbed or precipitated onto combustion ash and collected by the electric dust collector to discharge the mercury halide out of a system.

Method of mercury removal from combustion exhaust gas and combustion exhaust gas purification apparatus

A catalyst is provided having higher mercury oxidation performance than a conventional catalyst without increasing catalyst quantity or enhancing SOoxidation performance and constitutes an oxidation catalyst for metal mercury, which contains a molybdenum and vanadium complex oxide, for example, MoVO, as a main component having a catalytic activity and is formed by placing the molybdenum and vanadium complex oxide in layers only on the surface of a plate-like or honeycomb-like porous carrier. The porous carrier contains Ti and W and has a function of an NOx removal catalyst as a whole.

Growing community of inventors

Kure, Japan

Keiichiro Kai