Chiyoda Corporation

Nippon Furnace Kogyo Kabushiki Kaisha

Ryosuke Shimizu

Ryoichi Tanaka

Mamoru Matsuo

Nobuo Moriya

Yasumasa Morita

Masao Kawamoto

Hitoshi Kaji

Hiroshi Yagi

Tetsuhiko Ohki

Hiroshi Miyama

Hirokuni Kikukawa

Takao Kawai

A reformed gas composed mainly of hydrogen and carbon monoxide to be used for a fuel cell is produced by using a multi-tubular reformer provided with bayonet type double-wall catalyst tubes and feeding hydrocarbon gas such as natural gas and steam to the reformer. Porous media of a ceramic material are arranged in such a manner in a shell side flue gas inlet part of the interior of the reformer as to envelop the leading end parts of the catalyst tubes. The transfer of heat from the flue gas to the catalyst tubes is enhanced because the porous media accumulate the heat from the flue gas and radiate the accumulated heat in the direction of the walls of the outer tubes of the catalyst tubes. The otherwise possible uneven transfer of heat to the catalyst tubes is prevented because the wall effect and the channelling of the flue gas are repressed. This invention, therefore, permits effective utilization of the thermal energy of the flue gas for the reforming reaction and enables the reformer to be stably operated.

Method of heat transfer in reformer

A tubular furnace uses a fluid to be heated which is prevented from coking or a heating tube which is prevented from burning. Heat is provided through a smaller heat transfer area and problems of corrosion at low temperature of the heating pipe in the tubular furnace due to sulfur content in the fuel are solved, to thereby achieve a high efficiency. A coil path(3) is divided into a plurality of zones(2a,2b,2c,2d), each with at least one regenerative-heating-type alternate combustion system(4). The system supply combustion air to burners(5,6) through regenerative beds(7,7) and the discharge of combustion gas therefrom. Combustion is independently controlled in each zone to create a desired heat flux pattern such that a boundary layer temperature of the fluid to be heated in the zones(2a,2b,2c,2d) of the coil path(3) is lower than a coking temperature or lower than an allowable maximum temperature to be determined by the material of the heating pipe.

Tubular furnace and method of controlling combustion thereof

Growing community of inventors

Yokohama, Japan

Ryosuke Shimizu