Hitachi, Ltd.

Babcock-hitachi Kabushiki Kaisha

Babcock-hitachi, Ltd.

Teruo Kumagai

Tomoichi Kamo

Toshikatsu Mori

Fumito Nakajima

Tatsuo Horiba

Shinpei Matsuda

Seiji Takeuchi

Shimpei Matsuda

Kazuo Iwamoto

Kunko Kitami

Takaaki Suzuki

Akira Kato

Kunihiro Maeda

Akira Yoshinari

Yukio Hishinuma

Katsuya Ebara

Kohki Tamura

Kazutoshi Higashiyama

Hideyo Kodama

Yasuyuki Nishimura

Hidetoshi Akimoto

Yoshimi Yanai

Tsukasa Nishimura

Akira Okayama

Atsuko Soeta

Tsuneyuki Kanai

Kouki Tamura

A method of producing a high-temperature oxide superconducting material, which comprises the steps of (a) preparing a material corresponding to an oxide superconductor of the perovskite type structure consisting essentially of a first member selected from the group consisting yttrium, lanthanoids, thallium and bismuth; at least one alkaline earth metal; copper; and oxygen and (b) heating the material in the presence of an alkali metal selected from the group consisting of potassium, sodium, rubidium and cesium to a temperature around the melting point of the alkali metal or to a higher temperature for a time sufficient to effect grain growth in the superconductor material, thereby to produce the superconductor containing the alkali metal in an amount not larger than 4 mole % based on the first member.

Oxide high-temperature superconducting material, method of preparing

A fuel cell electrode having a catalyst layer comprising electroconductive particles carrying a catalytically active component and a binder on a water-repellent baked plate comprising a carbon paper comprising carbon fiber and an organic binder and polytetrafluoroethylene infiltrated into voids of said carbon paper, characterized in that the carbon fiber of said baked plate has at least 20 cutting edges per square millimeter, and said polytetrafluoroethylene is infiltrated into at least one of said cutting edges to render the plate flexible.

Flexible, water-repellent baked carbon plate, its production, fuel cell

In a fuel cell having a fuel electrode, an oxidant electrode, and an electrolyte which is located between both the electrodes, a methanol concentration control device is disposed, at a pipe which supplies the fuel to the fuel cell for controlling the amount of the methanol in the pipe by detecting the open-circuit voltage of the unit cell or the open-circuit potential of the oxidant cell at the methanol concentration control device.

Fuel cell comprising a device for detecting the concentration of methanol

A coal or petroleum combustion flue gas containing sulfur oxides and dust is treated by contacting the flue gas with a sulfur dioxide-oxidizing catalyst, thereby converting sulfur dioxide to sulfur trioxide, allowing the resulting sulfur trioxide to react with components of dust, absorbing the trioxide into the dust as a sulfate, and removing the dust. Catalytic oxidation of sulfur dioxide can be efficiently carried out at a low temperature and sulfur oxides can be efficiently removed from the flue gas.

Process for treating flue gas

There is provided a method for converting sulfur dioxide in an exhaust gas to sulfur, which comprises the reduction step of reducing sulfur dioxide in an exhaust gas containing water vapor to hydrogen sulfide in the presence of carbon, a part of the exhaust gas is caused to bypass the reduction step and the remainder of the exhaust gas is fed to the reduction step to convert sulfur dioxide in the exhaust gas to hydrogen sulfide; the gas from the reduction step is mixed with the exhaust gas bypassing the reduction step while controlling the amount of the bypassing exhaust gas so that the ratio of hydrogen sulfide to sulfur dioxide in the mixed gas is maintained at 2; the mixed gas is fed to the Claus reaction step; and the Claus reaction step of reacting hydrogen sulfide formed at the reduction step with sulfur dioxide to convert hydrogen sulfide to sulfur.

Method and apparatus for converting sulfur dioxide in gas to sulfur

An improved process for desulfurizing combustion exhaust gases of mainly coal containing sulfur oxides, HF and dust containing Al is provided, which process consists of four steps; a first step of contacting the gases with calcium carbonate or hydroxide in the form of slurry to convert the sulfur oxides into CaSO.sub.3 ; a second step of contacting O.sub.2 with the resulting slurry to convert CaSO.sub.3 into CaSO.sub.4 ; a third step of separating CaSO.sub.4 and mother liquor from the resulting slurry; and a fourth step of preparing a slurry of calcium carbonate or hydroxide to be employed in the first step, from the mother liquor, the pHs of the slurry and the mother liquor in the first and fourth steps being adjusted to 5 or higher by adding alkali such as sodium carbonate. According to the present process, it is possible to prevent hindrance of HF and Al contained in dust to the reaction of SO.sub.2 -absorbent (CaCO.sub.3 or Ca[OH].sub.2) with SO.sub.2 gas, and thereby improve percentage desulfurization and also obtain a high quality gypsum.

Process for desulfurizing combustion exhaust gases

Growing community of inventors

Hitachi, Japan

Teruo Kumagai