Mitsubishi Heavy Industries Limited

Other

Mitsubishi Jukogyo Kabushiki Kaisha

Kikuo Tokunaga

Yuichi Fujioka

Toshiaki Ohkubo

Akira Hashimoto

Shozo Kaneko

Toshihiko Setoguchi

Toshimitsu Ichinose

Osamu Naito

Nobuaki Murakami

Masakazu Tateishi

Katsuyuki Ueda

Yoshihisa Arakawa

Shuya Nagayama

Takayuki Maeda

Yoshiyuki Wakabayashi

Masashi Hishida

Michimasa Yagi

Takashi Ohnishi

Yasuo Katsuki

An ammonia generating method characterized by generating ammonia by the contact hydrolysis of urea by contacting at 200&deg; C. or more an aqueous solution of urea with a contact hydrolysis catalyst containing at least one selected from the group consisting of hydroxides, carbonates, and silicates of alkaline metals as the main component, and a combusted exhaust gas processing method using the ammonia generated by the method.

Exhaust gas processing method

This invention relates to a method for decreasing sulfuric acid and sulfuric anhydride present in combustion exhaust gas which comprises adding an SO,-decreasing agent (hydrogen gas) to combustion exhaust gas and thereby reducing sulfuric acid (H,SO,) and sulfuric anhydride (SO,) 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 H,SO,and S,contained in combustion gas.

Method for decreasing sulfuric acid and sulfuric anhydride present in combustion exhaust gas

A dust collecting apparatus and method for dedusting a Ca-containing gas using a ceramics filter is provided, in which a filter differential pressure elevation rate is suppressed. A desulferizing agent,and a mineral,containing MgO are supplied via a hopper,a valve,and a feeder,into a pressurized fluidized-bed combustion furnace,together with coal,and air,. A combustion gas,is dedusted by a cyclone,to become a combustion gas,, the combustion gas,enters a filter container,having a ceramics filter,and is further dedusted. A combustion gas,which is dedusted is supplied into a gas turbine,to generate power, and combustion gas,heats a waste heat recovery boiler,which in turn drives a steam turbine,. The mineral,containing MgO is added in the combustion gas,which flows in the ceramics filter,. Thereby MgO is added to the combustion gas so that the filter differential pressure elevation rate can be suppressed. The more MgO that is supplied, the greater the effect becomes, and an operation stop due to the differential pressure elevation is eliminated.

Dust collecting method

This invention relates to a process for removing sodium chloride and potassium salts, which are impurities concentrated and accumulated in pulp digesting chemicals, from ash collected from a soda recovery boiler. This process comprises the steps of (a) mixing ash collected from the combustion exhaust gas of the soda recovery boiler with water to form a slurry, adjusting the pH of the slurry to 10 or less by the addition of sulfuric acid, adjusting the temperature of the slurry to 20.degree. C. or above, and holding the slurry at that temperature for a sufficient time to cause sodium chloride and potassium salts present in the collected ash to be dissolved in the water; (b) cooling the slurry to a temperature below 20.degree. C. by the addition of ice and/or water so as to precipitate solid matter therefrom; and (c) separating the slurry into solid and liquid components and recovering the solid component while discharging the liquid component out of the system.

Process for removing sodium chloride and potassium salts from ash

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Nagasaki, Japan

Kikuo Tokunaga