JP4096016B2 - Combustion method of regenerative radiant tube burner - Google Patents

Description

  The present invention relates to a combustion method for a regenerative radiant tube burner.

  In the burner apparatus, as a technique for improving the heating efficiency, a pulse combustion method is known in which the flow rate is increased and the heat transfer coefficient is increased by pulsating the combustion exhaust gas in the heat transfer tube.

  However, conventionally, in order to perform pulse combustion, it is necessary to provide a mechanism for generating pressure fluctuations in a very short cycle on the fuel and combustion air supply side. However, when this mechanism is applied to a regenerative radiant tube burner, the ignition and extinguishing of the burner are performed intermittently and while the two burners are alternated, so that it is based on unstable combustion and poor detection of the flame detector. Combustion is interrupted, and there is an anxiety factor in the followability of the controller that controls ignition and extinguishing of the burner, and pulse combustion cannot be applied to the regenerative radiant tube burner.

  Accordingly, an object of the present invention is to provide a combustion method for a regenerative radiant tube burner that improves the thermal efficiency by pulsating the pressure in the radiant tube by simple means, as in the case of pulse combustion.

The present invention, in order to achieve the object, along with arranging the regenerator to the outer peripheral portion of the lever of the burner body provided bar burner body in both ends of the radiant tube, the radiant tube positioned in the regenerator rear in regenerative radiant tube burner with a combustion air supply port and an exhaust gas outlet, the regenerative radiant combustion gas exhaust system tube burner providing a pulsating flow generation mechanism consisting of the rotary valve, the valve of the rotary valve during burner combustion a shall by burning regenerative radiant tube burner by pulsing the exhaust gas pressure in the radiant tube by rotating the body.

As is apparent from the above description, according to the present invention, the generation of the pulsating flow of the combustion exhaust gas necessary for improving the heating efficiency of the burner is performed by the pulsating flow generation mechanism comprising a rotary valve provided in the combustion exhaust gas exhaust system . Since the combustion is performed by rotating the valve body and the burner is normally combusted, the heating efficiency can be improved without causing any trouble to other mechanisms unlike the pulse combustion of the burner.

  Next, an embodiment of the present invention will be described with reference to FIG.

  Reference numeral 10 denotes a radiant tube. Fuel supply pipes 11a and 11b are provided at both ends of the radiant tube, and outer cylinders 13a and 13b are provided on the outer periphery of the inner cylinders 12a and 12b provided outside the fuel supply pipes 11a and 11b. The space formed by the inner cylinders 12a, 12b and the outer cylinders 13a, 13b is filled with, for example, heat storage bodies 14a, 14b made of ceramic balls or ceramic honeycomb bodies. In addition, many opening 15a, 15b is provided ahead of the thermal storage body 14a, 14b.

  Further, a gap A is formed between the outer cylinders 13a and 13b and the radiant tube 10, and this gap A is divided into two in the longitudinal direction by the partition plates 16a and 16b.

  Furthermore, combustion air supply / exhaust ports 17a, 17b are provided behind the partition plates 16a, 16b of the radiant tube 10, and cooling air supply / exhaust ports 18a, 18b are provided in the front.

The fuel supply pipes 11a and 11b are connected to a fuel supply line via fuel cutoff valves V _1a and V _1b , and the combustion air supply and exhaust ports 17a and 17b are connected to exhaust gas cutoff valves V _2a and V _2b . Combustion air is communicated with the exhaust gas suction fan F ₁ and between the exhaust gas cutoff valves V _2a and V _2b and the combustion air supply / exhaust ports 17a and 17b via combustion air cutoff valves V _3a and V _3b. and it communicates with the supply blower F _2.
Moreover, the cooling air supply and exhaust ports 18a, 18b are cooling air shut-off valve V _4a, communicates with the said combustion air supply blower F ₂ via the V _4b, the cooling air shut-off valve V _4a, V _The space between _4b and the cooling air supply / exhaust ports 18a and 18b is connected to cooling air shutoff valves _V5a and _V5b .

Further, an exhaust gas cutoff valve V ₆ is provided in the exhaust gas line downstream of the exhaust gas junction point a downstream of the exhaust gas cutoff valves V _2a and V _2b , and an adjustment valve V ₇ and a motor drive are provided in the bypass line of the exhaust gas cutoff valve V _6. rotary valve V ₈ is open, closes pulsating flow generation mechanism are installed by.

As shown in FIG. 2, the rotary valve V ₈ includes a valve box 20 having a flow path P and a shaft 22 that rotates the valve body 21, and opens and closes the flow path P by driving a motor M. . In addition, 23 is a seal packing and 24 is a gland.

Next, the regenerative radiant tube burner B having the above configuration first opens the fuel cutoff valve V _1a , the exhaust gas cutoff valve V _2b , the combustion air cutoff valve V _3a and the exhaust gas cutoff valve V ₆ , and the other cutoff valves. Is closed, the combustion air supply blower F ₂ and the exhaust gas suction fan F ₁ are driven, and the fuel gas is supplied from the fuel supply line to one burner body _Bra . The combustion air passes through the heat accumulator 14a and is ejected from the opening 15a, while the fuel gas is ejected from the tip opening of the fuel supply pipe 11a. Then, combustion air and fuel gas are mixed in the flame-stabilization portion 19a which is formed between the tip opening portion of the opening 15a and the fuel supply pipe 11a, complete with ignition burner body B _ra by spark of the ignition plug (not shown) Burn. The combustion exhaust gas passes through the radiant tube 10, heats the inside of the furnace T by the radiant heat transfer, passes through the heat storage body 14 b, heats the heat storage body 14 b to 800 to 900 ° C., and the combustion gas itself is about The temperature is lowered to 200 ° C. and exhausted from the exhaust gas suction fan F ₁ .

Thereafter, after a predetermined time has elapsed, the other shut-off valves other than the cooling air shut-off valves V _4a , V _4b , V _5a , V _5b are switched in the opposite directions, that is, the burner body B _rb burns and the burner body B _Ra extinguishes fire.

In this case, the combustion air supplied to the burner body B _rb passes through the heat storage element 14b that has already become high temperature, is preheated to high temperature (700 to 800 ° C.), and is ejected from the opening 15b. It ejects from the tip opening of the supply pipe 11b. The combustion air and the fuel gas are mixed in a flame holding portion 19b formed between the front end opening of the fuel supply pipe 11b and completely burned. This combustion exhaust gas is then exhausted through the heat accumulator 14a by preheating the heat accumulator 14a to 800-900 ° C.

Thereafter, when a predetermined time elapses, each shut-off valve is switched to the original state contrary to the above, and the burner bodies B _ra and B _rb sequentially perform alternating combustion.

Next, in order to pulsate the combustion exhaust gas in the radiant tube 10, as described above, the burner main bodies B _ra and B _rb are alternately combusted, the exhaust gas cutoff valve V ₆ is closed, and the adjustment valve V ₇ is radiant. After adjusting the pressure P ₁ in the tube 10 to be a positive pressure , the rotary valve V ₈ , which is a pulsating flow generation mechanism, is operated by driving the motor M to open and close the flow path P in a cycle of several tens Hz to 100 Hz. Let As a result, the pressure in the radiant tube 10 fluctuates as P ₁ and P _max as shown in FIG. 3, that is, the combustion exhaust gas is exhausted as a pulsating flow, and the heating efficiency in the radiant tube 10 is increased. Will be improved.

Next, when it is necessary to lower the furnace temperature by changing the heat cycle, the fuel cutoff valves V _1a and V _1b , the exhaust gas cutoff valves V _2a and V _2b , and the combustion air cutoff valves V _3a and V _3b are set. For example, the cooling air shut-off valve V _4a is opened, V _4b is closed, the cooling air shut-off valve V _5a is closed, V _5b is opened, and the exhaust gas suction fan F ₁ is stopped.

Then, the cooling air is supplied from the combustion air supply blower F ₂ from the cooling air supply / exhaust port 18a, and this cooling air does not pass through the high-temperature heat storage body 14a, that is, the remainder It is supplied to the radiant tube 10 without raising the temperature, and after the radiant tube 10 is effectively cooled, it is exhausted from the cooling air cutoff valve V _5b .

  The cooling air supply / exhaust port for supplying the cooling air may be either 18a or 18b. However, if it is supplied from a low-temperature side heat accumulator, for example, the burner main body side that has been in a combustion state until now, the radiant tube The cooling air that has been heated through 10 passes through the outer periphery of the high-temperature side heat accumulator, so that there is little loss of the heat stored in the heat accumulator, and the combustion air is preheated from the beginning of burner ignition at the next burner combustion. Can do.

The figure which shows the thermal storage type radiant tube burner concerning the present invention, and its piping system. Sectional drawing of a rotary valve. The graph which shows the relationship between a rotary valve opening / closing period and a furnace pressure. The figure which shows the conventional heat storage type radiant tube burner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Radiant tube, 11a, 11b ... Fuel supply pipe, 12a, 12b ... Inner cylinder, 13a, 13b ... Outer cylinder, 14a, 14b ... Heat storage body, 15a, 15b ... Opening, 16a, 16b ... Partition plate, 17a, 17b ... combustion air supply and exhaust ports, 18a, 18b ... cooling air supply and exhaust ports, 19a, 19b ... flame stabilizing portion, A ... gap, B _ra, B _rb ... burner body, F ₁ ... an exhaust gas suction fan, F ₂ ... Combustion air supply blower, V _1a , V _1b ... Fuel shut-off valve, V _2a , V _2b ... Exhaust gas shut-off valve, V _3a , V _3b ... Combustion air shut-off valve, V _4a , V _4b ... Cooling air shut-off valve, V _5a, V _5b ... cooling air shut-off valve, V ₆ ... gas shutoff valve, V ₇ ... control valve, V ₈ ... rotary valve (pulsating flow generation mechanism), a ... exhaust confluence point, T ... furnace.

Claims (1)

A regenerative radiant in which a burner body is provided in both ends of the radiant tube, a heat storage body is disposed on the outer periphery of the burner body, and a radiant tube located at the rear of the heat storage body has a combustion air supply port and an exhaust gas discharge port. in tube burner, the pulsating flow generation mechanism consisting of the rotary valve to the flue gas exhaust system of the regenerative radiant tube burner is provided, pulsating exhaust gas pressure in the radiant tube by rotating the valve body of the rotary valve during burner combustion A method for burning a regenerative radiant tube burner, characterized in that:

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