Hitachi, Ltd.

Hitachi Metals, Ltd.

Ken Yasuda

Shigeru Azuhata

Hisao Yamashita

Shin Tamata

Shuichi Kanno

Kazuyoshi Irie

Toshiaki Arato

Shinzo Ikeda

Hiroyuki Doi

Yutaka Fukui

Tetsuo Kashimura

Koji Sato

Akira Yoshinari

Takehiro Ohno

Hideki Tamaki

A gas stream containing at least one fluorine compound selected from the group consisting of compounds of carbon and fluorine, compounds of carbon, hydrogen and fluorine, compounds of sulfur and fluorine, compounds of nitrogen and fluorine and compounds of carbon, hydrogen, oxygen and fluorine is contacted with a catalyst comprising at least one of alumina, titania, zirconia and silica, preferably a catalyst comprising alumina and at least one of nickel oxide, zinc oxide and titania in the presence of steam, thereby hydrolyzing the fluorine compound at a relatively low temperature, e.g. 200&#xb0;&#x2013;800&#xb0; C., to convert the fluorine of the fluorine compound to hydrogen fluoride.

Process for treating fluorine compound-containing gas

A gas stream containing at least one fluorine compound selected from the group consisting of compounds of carbon and fluorine, compounds of carbon, hydrogen and fluorine, compounds of sulfur and fluorine, compounds of nitrogen and fluorine and compounds of carbon, hydrogen, oxygen and fluorine is contacted with a catalyst comprising at least one of alumina, titania, zirconia and silica, preferably a catalyst comprising alumina and at least one of nickel oxide, zinc oxide and titania in the presence of steam, thereby hydrolyzing the fluorine compound at a relatively low temperature, e.g. 200&#xb0;-800&#xb0; C., to convert the fluorine of the fluorine compound to hydrogen fluoride.

A superalloy having more excellent hot corrosion resistance than conventional single crystal alloys, oxidation resistance levels as high as that of conventional single crystal alloys, high strength, and creep rupture strength; single crystal members used for a blade or a nozzle produced by utilizing such an alloy; and a combined cycle power generation system produced by utilizing such members. A highly hot corrosion resistant and high-strength superalloy consisting essentially of, by weight, 6-12% Cr, 4.5-6.5% Al, 2-12% W, 2.5-10% Ta, not more than 5.8% Mo, 0.1-3% Co, 0.2-3% Nb, 0.1-4% Re, not more than 0.3% Hf, and the balance being Ni and unavoidable impurities; single crystal members used for a blade or a nozzle produced utilizing such an alloy; and a combined cycle power generation system produced by utilizing such members.

High corrosion resistant high strength superalloy and gas turbine

A Ni-base superalloy consisting essentially of, by weight: 0.05 to 0.20% C, 20 to 25% Co, 15 to 25% Cr, 1.0 to 3.0% Al, 1.0 to 3.0% Ti, 1.0 to 3.0% Nb, 5 to 10% W, and at least 55% Ni, the combination of the [Al+Ti] and tungsten contents being determined as shown in FIG. 5. This superalloy has a high thermal-fatigue resistance, a great high-temperature strength, particularly, a great creep rupture strength, and a good weldability. The superalloy is used to form gas turbine nozzles, which are employed in a gas turbine. Using such a gas turbine, a combined power generating system is built.

Gas turbine and gas turbine nozzle

A Ni-base superalloy consisting essentially of, by weight: 0.05 to 0.20% C, 20 to 25% Co, 15 to 25% Cr, 1.0 to 3.0% Al, 1.0 to 3.0% Ti, 1.0 to 3.0% Nb, 5 to 10% W, and at least 42.5% Ni, the combination of the [Al+Ti] and tungsten contents being determined as shown in FIG. 5. This superalloy has a high thermal-fatigue resistance, a great high-temperature strength, particularly, a great creep rupture strength, and a good weldability. The superalloy is used to form gas turbine nozzles, which are employed in a gas turbine. Using such a gas turbine, a combined power generating system is built.

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Hitachi, Japan

Ken Yasuda