摘要:
A regenerative heat exchange system performs heat exchange by alternately passing combustion exhaust gas as high-temperature fluid and combustion air as low-temperature fluid through a fixed regenerator. A regenerative burner carries out combustion using preheated air from the exchange system. The regenerative heat system comprises: a permeable regenerator partitioned into three or more chambers in the circumferential direction; a double-pipe outlet/inlet partitioned into a supply chamber and an exhaust chamber; and changeover member which isolates the regenerator from the outlet/inlet and by which the regenerator selectively communicates with the outlet/inlet by a supply communicating hole and an exhaust communicating hole which are provided with such a positional relation that the supply communicating hole and the exhaust communicating hole do not simultaneously lie in any of the partitioned chambers.
摘要:
In combustion using air preheated by regenerative direct heat exchange between exhaust gas and the combustion air using a regenerator as a heat exchange medium, the present invention relates to a low-NOx burner that is effective for reduction in NOx in a mid-temperature range which has been conventionally difficult to be realized and improves stability of the flame. According to this low-NOx burner, at an outlet of an air throat 24 for flowing a full quantity of the combustion air is disposed a burner tile 22 having an enlarged diameter portion 23 thereof whose diameter is larger than that of the outlet, and a fuel nozzle 19 for injecting the fuel from the enlarged diameter portion 23 of the burner tile is also provided. Further, a flow of the combustion air injected from the air throat 24 produces a negative pressure at a secondary combustion chamber 25 surrounded by the enlarged diameter portion 23 of the burner tile around the air throat 24 to cause a strong furnace exhaust gas recycle to occur, and a flame holding area X1, a furnace exhaust gas recycle combustion area X2 and a slow combustion area X3 are formed.
摘要:
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.
摘要:
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 the 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 the 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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
With respect to a radiant tube burner to be used for heating a heating furnace or the like, to suppress the generation of NOx accompanying combustion, to make the structure thereof fit for a radiant tube burner equipment, to simplify the control of a fuel supply system and an air supply system, and to prevent the coking. Furthermore, to provide a combustion control scheme appropriate to a radiant tube burner. For these purposes, the present invention placed the respective tips of a fuel nozzle, e.g., pilot burner joint-use nozzle (11), and an air throat (13) in the end of a radiant tube (3) and moreover has a combustion air injection port (33) of the air throat (13) provided to be deviated in contact with or near to the inner circumferential wall surface of the radiant tube (3). In addition, a control device (307) for making a burner burn alternately.
摘要:
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.