Nippon Furnace Kogyo Kabushiki Kaisha

Nippon Furnace Kogyo Kaisha, Ltd.

Toyota Jidosha Kabushiki Kaisha

Nkk Corporation

Chiyoda Corporation

Japan & Nippon Furnace Kogyo Kaisha, Ltd.

Nippon Furnace Koayo Kabushiki Kaisha

Mamoru Matsuo

Ryoichi Tanaka

Hitoshi Yahara

Yosuke Kataoka

Kazuhisa Mitani

Jun Sudo

Makoto Miyata

Hiroaki Sato

Toshio Ishii

Shunichi Sugiyama

Tomohiko Nishiyama

Masao Kawamoto

Hitoshi Kaji

Tsutomu Yasuda

Toshikazu Akiyama

Ryosuke Shimizu

Tetsuhiko Ohki

Hiroshi Miyama

By Hiroko Tanaka

Ryoichi Tanaka, Deceased

Kanako Maehara

By Rie Oshima

By Shinichi Tanaka

Yoshiki Fujii

Shigeo Kurioka

Akinori Hokabori

Hirokuni Kikukawa

Gas flow furnace

Deodorizing system

Radiant tube burner

Gas flow circulation type tubular heating equipment

A combustion method in an industrial combustion system is provided, in which a low temperature combustion air to be fed to a combustion zone of the combustion system is preheated through a high-cycle regenerative combustion system. The high-cycle regenerative combustion system includes a pair of regenerators of honeycomb structure having a plurality of fluid passages defined by honeycomb walls thereof. Either of the combustion air and an exhaust gas generated in the combustion zone is adapted to selectively flow through the fluid passages, and the high-cycle regenerative combustion system has a switching cycle time set to be 60 seconds at the longest, so that the regenerator is alternately in heat-transferable contact with the combustion air flow and the exhaust gas flow to perform heat exchange therebetween. The regenerator has a temperature efficiency greater than 0.7 and the combustion air flow is preheated by the exhaust gas through the regenerator in the high temperature efficiency, whereby the combustion air is continuously preheated up to a temperature range above 800.degree. C. The high temperature air flow is continuously introduced into the combustion zone and a combustion fuel is fed to the air flow, so that a combustion reaction is generated and maintained in the combustion zone by the preheated air flow and the combustion fuel.

Combustion method of industrial combustion system

A boiler is provided with a radiation heat transfer section in its combustion chamber, which has therein, at least one regenerative-heating burner system including a pair of burners each with a regenerative bed. The burners receive combustion air and exhaust combustion gas which passes through the regenerative beds. Combustion is alternately effected in one of the burners and combustion gas is passed into the other burner, and exhausted through the corresponding regenerative bed of this other burner. Surplus thermal energy which is not completely consumed in the radiation heat transfer section is recovered in the regenerative bed. Combustion air than passes through the heated regenerative bed to heat the air. The boiler temperature is kept flat across the boiler. That is, the temperature is kept almost constant across the combustion chamber. This is done by maintaining a high rate of forced supply of more than 60 m/s for the combustion air. Also, the combustion air is heated to above the ignition point of the fuel, that is, about 800.degree. C. These two factors increases thermal efficiency while reducing NO.sub.x emissions.

Boiler

Regenerative burner and regenerative heat exchange system applicable

Low-NOx burner

A small once-through boiler can avoid burning caused due to excessive heating of water pipes and burning around a fire hole of a burner in particular and heighten the heat load of a combustion chamber to further reduce the size of the system as compared with a prior art boiler. In the small once-through boiler, at least one regenerative burner system 20 is provided in a combustion chamber 1, the regenerative burner system 20 carrying out supply of combustion air A and exhaust of combustion gas E through a regenerator 22 and relatively changing flows of the combustion gas E and the combustion air A with respect to the regenerator 22 so as to supply the combustion air A via the regenerator 22 heated by heat of the combustion gas. Water pipe group 4 is provided apart from the combustion chamber wall surface 3 to form a passage 12 between the rear surface of the water pipe group 4 and the combustion chamber wall surface 3. Communicating openings 10 and 11 through which the combustion gas C passes are formed between adjacent water pipes at upper and lower ends of the water pipe group 4 so that a part of the combustion gas C can pass through the passage 12 provided at the rear of the water pipe group 4, whereby a part of the combustion gas C flows from the lower communicating openings 11 into the passage 12 to move upward and again flows from the upper communicating openings 10 into the combustion chamber 1.

Small once-through boiler

A high-cycle regenerative combustion system has first and second regenerative heat exchanger units. A four-way valve is provided for alternately bringing the heat exchanger units into contact with a low temperature fluid and a high temperature fluid. The valve is switched at a switching cycle time not longer than 60 seconds. Each heat exchanger unit has a void ratio .epsilon. which substantially provides the maximum value (Q/V)max of the volumetric efficiency (Q/V). The temperature efficiency .eta. t is preset to be a value in a range between 0.7 and 1.0. The heat transmission coefficient h and the heat transmission area A of the heat exchanger unit are determined such that the temperature efficiency, which is calculated in accordance with a specific equation as being a function of the heat transmission coefficient, the heat transmission area and the switching cycle time .tau., falls under the preset value within the range mentioned above. Each of the first and second heat exchanger units has the cell pitch P and the cell wall thickness b, which provide the above-mentioned values of the void ratio, heat transmission coefficient and heat transmission area. Thus, a compact and high-performance regenerative heat exchanger can be obtained, which has a reduced overall volume while exhibiting the large heat transmission rate and high temperature efficiency.

High-cycle regenerative heat exchanger

Four-port valve

A boiler is provided with a radiation heat transfer section in its combustion chamber, which has therein, at least one regenerative-heating burner system including a pair of burners each with a regenerative bed. The burners receive combustion air and exhaust combustion gas which passes through the regenerative beds. Combustion is alternately effected in one of the burners and combustion gas is passed into the other burner, and exhausted through the corresponding regenerative bed of this other burner. Surplus thermal energy which is not completely consumed in the radiation heat transfer section is recovered in the regenerative bed. Combustion air then passes through the heated regenerative bed to heat the air. The boiler temperature is kept flat across the boiler. That is, the temperature is kept almost constant across the combustion chamber. This is done by maintaining a high rate of forced supply of more than 60 m/s for the combustion air. Also, the combustion air is heated to above the ignition point of the fuel, that is, about 800.degree. C. These two factors increases thermal efficiency while reducing NO.sub.x emissions.

Boiler with increased flame temperature and output

A method of low-NOx combustion and a burner device for effecting the same, in which a primary fuel is injected in a direction from tile periphery of stream of a combustion air towards that same combustion air, effecting a first combustion, so as to create a generally cylindrical primary flame covering the combustion air, whereby a secondary fuel injected towards the combustion air is shielded or intercepted by such primary flame from the combustion air, while causing NOx in tile primary flame to be reduced by the secondary fuel, after which, a second combustion is effected by bringing the secondary fuel to contact with a portion of the combustion air penetrating through the primary flame, at a downstream side. This arrangement permits more positive decrease of NOx density in an exhaust gas.

Method of low-NOx combustion and burner device for effecting same

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

Mamoru Matsuo