Mitsubishi Jukogyo Kabushiki Kaisha

Other

The Kansai Electric Power Co., Inc.

Central Research Institute of Electric Power Industry

Toru Seto

Shigeaki Mitsuoka

Mitsuyasu Honda

Masaki Iijima

Kenji Inoue

Shigeru Shimojo

Kenji Kobayashi

Kunihiko Yoshida

Masao Hino

Mutsunori Karasaki

Taiichiro Suda

Masumi Fujii

Yoshitsugu Hotta

Mitsugi Suehiro

Kazuhiro Matsumoto

Makoto Kobayashi

Naohiko Ukawa

Norihisa Kobayashi

Yoshiaki Obayashi

Kozo Iida

Atsushi Morii

Masumi Atsukawa

Toshikuni Sera

Yoshihiro Shiraishi

Hiromi Shirai

Takeji Tanaka

Toshio Nakayama

A process is provided for removing carbon dioxide out of combustion exhaust gas by scrubbing the exhaust gas with an aqueous solution of monoethanolamine in a scrubber, and regenerating the carbon dioxide-loaded aqueous solution of monoethanolamine in a regenerator. The process is provided with means for replenishing the aqueous solution of monoethanolamine with a stock, aqueous solution containing from about 70% to about 75% by weight of monoethanolamine. By providing a stock, aqueous solution containing from about 70% to about 75% by weight of monoethanolamine, which is injected into the carbon dioxide-loaded aqueous solution of monoethanolamine being transferred from the scrubber to the regenerator, the entire carbon dioxide recovery system is free from flammables, rendering fire-fighting precautions unnecessary.

Recovery of carbon dioxide from combustion exhaust gas

Disclosed are, in a method for purifying a high-temperature reducing gas in which sulfur compounds present in a high-temperature reducing gas are absorbed and removed by an absorbent according to a dry method, a method for purifying a high-temperature reducing gas which is characterized in that a reducing gas is supplied into a gas containing sulfur dioxide gas which is discharged from a regeneration system for regenerating the absorbent which system forms a system together with an absorption system in which the sulfur compounds are absorbed with the absorbent, a resulting gas mixture is led through a reactor filled with a catalyst, the sulfur dioxide gas and the reducing gas are let react with each other under pressurization so that elemental sulfur is directly produced and recovered as liquid sulfur; and the above method which is further characterized in that catalyst layers in the reactor in which the sulfur dioxide gas and the reducing gas react with each other are divided into parts or made to have a plurality of stages, a heat exchanger and a sulfur condenser are disposed between these parts or stages, and the temperature control of these gases and the removal of sulfur produced in the reaction are carried out during the reaction.

Method for purifying high-temperature reducing gas

An electric generating power plant and a method of operation thereof wherein the boiler (1) produces steam to a turbine driven-generator (2), carbon dioxide from combustion exhaust gas emitted from the boiler is simultaneously absorbed in an absorbing solution in an absorber (7), the absorbing solution with the absorbed carbon dioxide is passed through a regenerator (10) where the carbon dioxide is stripped from the absorbing solution, the regenerated absorbing solution is returned to the absorber (7), and steam from either the boiler (1) or turbine of the turbine-driven generator (2) is supplied to a reboiler (13) to provide heat for operation of the regenerator (10). During periods of high demand for electric power steam extraction from the boiler or turbine is discontinued, operation of the regenerator (10) is discontinued and the absorbing solution from the absorber (7) is stored in a first storage unit (15). During periods of low power demand steam is supplied to the reboiler (13) from the boiler (1) or turbine and absorbing solution from the first storage unit (15) is fed to the regenerator (10) for operation thereof, and absorbing solution stripped of carbon dioxide from the regenerator (10) is stored in a second storage unit (16). Absorbing solution from the second storage unit (16) is fed to the absorber (7) during periods of high power demand.

In a method for absorbing and removing sulfur compounds such as hydrogen sulfide and carbonyl sulfide present in a high-temperature reducing gas using an absorbent, disclosed is a method for purifying a high-temperature reducing gas which is characterized in that: said method uses at least four towers of reactors filled with an absorbent and comprises four steps which are an absorption step for absorbing and removing sulfur compounds with an absorbent, a regeneration step for regenerating said absorbent using a gas containing oxygen, a cooling step after the regeneration step, and a reduction step for reducing said regenerated and cooled absorbent with a high-temperature reducing gas until the concentration of the reducing gas becomes uniform before and after passing through the absorbent; heat is continuously recovered from the high-temperature gas at the outlet of the regeneration reactor in said regeneration step; and the regeneration and absorption performance is thus stabilized. Also disclosed is a method for purifying a high-temperature reducing gas which is characterized in that this method uses as least four towers filled with an absorbent as in the above method; and an additional preliminary regeneration step is provided besides the above four steps in order to make possible a smooth operation when switching to the regeneration step and the continuous recovery of sulfur.

Disclosed is a catalyst for removing nitrogen oxides from exhaust gases from internal combustion devices such as boilers, gas turbine and diesel engines which is characterized in that the catalyst contains Component A comprising type II anhydrous gypsum (insoluble anhydrite) and Component B comprising titanium oxide, the sum of the weights of Components A and B is equal to or more than 80 weight % of the total weight of the catalyst, the weight ratio of Component B to (Component A+Component B) is between 0.05 and 0.3, and the catalyst contains at least one or more of the oxides of vanadium, tungsten, molybdenum, iron, copper, chromium and manganese.

Catalysts for the removal of nitrogen oxides

The present invention is directed to a method for treating an exhaust gas containing dust composed of a glassy material and a sticky material consisting principally of CaO in a gas parallel flow type solid-gas contact reactor, the aforesaid method being characterized by including the step of forcing the dust to collide with a solid surface on the upstream side of the reactor in order to separate the dust into the glassy material and the sticky material consisting principally of CaO; and the present invention is also directed to an apparatus for the above method, the apparatus being characterized by including a collision device for colliding with the dust which is disposed in an exhaust gas flow path on an upstream side of the reactor.

Apparatus for treating exhaust gas

A method for reactivating catalysts which comprises the steps of:

Method for reactivating catalysts used for removing nitrogen oxides with

A solid-gas contact reactor for dirty exhaust gas is characterized by a first dust-proof plate provided on contact areas between a lower surface of a support base for supporting packages of catalyst layers in each stage and a reactor wall so that the first dust-proof plate makes an angle equal to or larger than the rest angle of dust in the exhaust gas with respect to the support base. Second dust-proof plates are provided on contact areas between adjacent ones of the packages of catalyst layers in each stage and contact areas between the reactor wall and frames of the packages of catalyst layers and the second dust-proof plates make the same angle with respect to the frame structure.

Solid gas contact reactor

A rectangular-solid packaged catalyst assembly made up of a plurality of rectangular-solid unit catalysts stacked and assembled together, the unit catalysts having a honeycomb structure with a multiplicity of gas passages each. Heat-resistant packings are used to cover at least the vertices and the neighboring areas of the faces of the unit catalysts other than the gas-passage faces and also to cover the edges of the gas-passage faces surrounding the gas passages, the packings being integrally secured to the unit catalysts and packaged together in a rectangular-solid housing. Retaining strips are placed over the packings on the edges of the gas-passage faces on at least either the gas inlet or outlet ends of the unit catalysts and are securely attached to the housing.

Rectangular-solid packaged catalyst assembly

A method for treating an exhaust gas containing nitrogen oxides, oxygen and soot, in which the nitrogen oxides are selectively reduced into nitrogen by adding ammonia to the exhaust gas as a reducing agent under existence of a catalyzer, is improved in that the nitrogen oxide is removed by introducing the exhaust gas into a denitration reactor in which a plurality of planar catalyzer packs or catalyzer packs having gas passage holes are arrayed in parallel to a gas flow and a linear velocity of the gas through the reactor is selected at 4-15 m/s. In one preferred mode of the method, soot having a relatively large particle diameter is preliminarily removed by a dust remover disposed upstream of the reactor, while most of the remaining soot is removed by a high performance dust collector disposed downstream of the reactor. Denitration reactor structures suitable for the improved method for treatment are also disclosed herein.

Method and apparatus for treating an exhaust gas

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 1.5 times equivalent (in molar ratio) to the amount of nitrogen oxides in moles in the gas is introduced into the space immediately upstream of the catalyst assembly, thereby to accelerate the decomposition of the oxides in the gas to make it harmless.

Growing community of inventors

Hiroshima, Japan

Toru Seto