JPH0816529B2 - Furnace temperature control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace temperature control method.
More specifically, the present invention relates to a furnace temperature control method capable of rapid furnace temperature adjustment.

[0002]

2. Description of the Related Art As a furnace temperature adjusting means in a conventional heating furnace, changing the combustion amount of a burner is the most common.
Further, as an additional furnace temperature adjusting means, it is general to adjust the air ratio.

[0003]

However, although the combustion temperature can be adjusted most reliably by adjusting the combustion amount,
In the case of a furnace whose purpose is to combust like an incinerator (incinerator), that is, incineration itself, the adjustment of the combustion amount is an adjustment of the treatment amount, which is extremely inconvenient in the case of an incinerator that requires a total treatment. Also, in the case of adjusting the furnace temperature by adjusting the combustion amount in a general heating furnace, if this is suddenly performed, misfire or an air ratio error will occur, so it can only be gradually changed and the responsiveness Is bad. In addition, even in reheating for burning a fuel that cannot self-combust, such as low-calorie gas, adjusting the combustion amount may make combustion itself unstable. Furthermore, when the amount of combustion is adjusted, the flame length generally changes, so the heat transfer mechanism in the furnace changes, and in most cases adversely affects uniform heating in the furnace.

When changing the air ratio, it is impossible to control the furnace temperature beyond the stable combustion range of the burner. In addition, since the air ratio range in which the most stable combustion is performed is generally narrow, the adjustment range is considerably narrowed.

It is an object of the present invention to provide a furnace temperature control method capable of reliably and quickly responding to the furnace temperature control without controlling the combustion amount.

[0006]

In order to achieve such an object, the furnace temperature control method of the present invention is a heating furnace using a burner as a heat source, which is provided with a regenerator and supplies and burns combustion air through the regenerator. A first exhaust means for installing a heat storage type burner for discharging gas in at least one assembled furnace body, and for alternately burning these burners to discharge combustion gas from the burner which has not been burned through the heat storage body; Second exhaust means for discharging the combustion gas to the outside of the furnace without passing through the burner, and by operating the second exhaust means, the amount of the combustion gas passing through the burner is changed. I try to control the temperature.

[0007]

Therefore, when it is necessary to adjust the furnace temperature, the second exhaust means is operated to directly change the amount of the combustion gas discharged to the outside of the furnace, thereby changing the amount of the combustion gas supplied to the heat storage body of the heat storage type burner. Change. As a result, the preheating temperature of the combustion air is changed, and the flame temperature is changed regardless of the amount of combustion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings. This embodiment is applied to an open frame burner.

FIG. 1 shows an embodiment of the furnace structure when the furnace temperature control method of the present invention is applied to a heat storage type heating furnace. In this furnace, a furnace body 1 is provided with at least one set of regenerative burners 2 and 3. The heat storage type burners 2 and 3 are not particularly limited in their structure and combustion method, but in the present embodiment, the combustion air supply system 7 for supplying combustion air to the wind box 4 and the combustion gas are discharged. The combustion gas exhaust system 8 is selectively connectable to the combustion gas exhaust system 8 and is provided so as to supply combustion air and discharge combustion gas through the heat storage body 5. Fuel nozzles 6 and 6 for injecting fuel are embedded in a burner throat portion of the wind box 2 near the furnace body 1. The fuel nozzles 6 and 6 are provided so as to inject fuel from the inner peripheral surface of the refractory material forming the burner throat, and are installed so that the fuel intersects the flow of combustion air flowing in the burner throat. Has been done. It is sufficient if at least one fuel nozzle 6, 6 is buried,
By arranging two or more pieces at equal intervals in the circumferential direction, the occupied area ratio in the burner throat can be adjusted to change the mixing characteristics of fuel and air, and a flame is formed in the center of the burner throat. Is provided. Further, the flame length can be changed by changing the mixing speed of the fuel and air by changing the angle formed by the flow of the fuel injected from the fuel nozzles 6 and 6 and the air flow.

The combustion gas exhaust system 8 and the combustion air supply system 7 are selectively connected by a four-way valve 11 to the wind box 4 of one of the burners 2 and 3, and are supplied by, for example, a pushing fan 9. At the same time that the combustion air is supplied to the wind box 4, for example, the induction fan 1
By 0, combustion gas is sucked from the wind box 4 and discharged into the atmosphere. Further, the fuel is selectively supplied to either one of the burners 2 and 3 via the three-way valve 13.
The combustion gas exhaust system 8 and the induction fan 10 form a first exhaust means.

The furnace body 1 is usually made of a refractory material such as refractory bricks, and carries in / out a heated object (not shown).
In addition to the above, a second exhaust means 16 is provided. This second
As the exhaust means 16, the duct 14 having the opening / closing damper 15 is adopted. If necessary, an induction fan (not shown) is provided in the duct 14 to perform induction exhaust, or a chimney is connected to the duct 14 to provide exhaust by a tunnel effect. The second exhaust means 16 of the present embodiment can change the opening degree by operating the damper 15 to adjust the exhaust amount.

With the above-mentioned structure, the pair of regenerative burners 2 and 3 are alternately burned, and the burned gas exhaust system 8 of the burner which does not burn the burned gas, that is, the first exhaust means. The exhaust heat of the combustion gas is recovered in the heat storage body 5. Therefore, the temperature in the furnace depends on the preheating temperature of the combustion air when the amount of combustion is constant. Therefore, for example, when the temperature inside the furnace becomes so high that the furnace wall, the chimney, etc. may be burned out, the duct 14 serving as the second exhaust means 16 is opened to remove the combustion gas in the furnace 1 from the second exhaust means 16. The amount of combustion gas discharged from the heat storage body 5 of the first exhaust means is reduced. As a result, when the combustion is switched, the temperature of the combustion air supplied through the heat storage body 5 decreases, so that the flame temperature decreases even if the combustion amount is constant. Further, when the combustion is further switched because a part of the lowered combustion gas is discharged from the first exhaust means through the heat storage body 5 of the burner on the opposite side, the flame temperature becomes further lower. Therefore, the temperature inside the furnace drops sharply.

This relationship is clear from the relationship between the hot air temperature and the exhaust gas recovery rate shown in FIG. This figure shows the combustion air preheating temperature and the combustion gas sensible heat recovery rate when it is assumed that the heat radiation is 0 and the heat exchange rate between the combustion gas and the heat storage body 5 is 100% for the sake of explanation. Thus, it can be understood that the combustion gas temperature decreases as the recovery rate decreases.

It should be noted that the above-mentioned embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, although an example in which the present invention is applied to the open frame burner has been described, the present invention is not particularly limited to this, and the present invention can be applied to a radiant tube burner. For example, although not shown, if a bypass path that opens and closes the heat storage body is provided and that can be opened and closed, and if the second exhaust means is configured to discharge the combustion gas by bypassing the heat storage body by opening and closing the bypass path, good. In this case, the amount of combustion gas discharged through the bypass without passing through the heat storage body can be controlled by adjusting the opening degree of the bypass passage.

[0015]

As is apparent from the above description, the furnace temperature control method of the present invention includes at least one heat storage burner for supplying combustion air and discharging combustion gas through the heat storage body.
Installed in the assembled furnace body, the first exhaust means for alternately burning these burners and discharging the combustion gas from the burner that is not burning through the heat storage body, and discharging the combustion gas outside the furnace without passing through the burners. And a second exhaust means for
Since the furnace temperature is controlled by changing the amount of the combustion gas that passes through the burner by operating the exhaust means, the temperature inside the furnace can be rapidly changed while the combustion amount is constant. Moreover, since the furnace temperature control method of the present invention allows the furnace temperature to be adjusted while the combustion amount remains constant, when the furnace is intended for combustion itself such as an incinerator or a low-calorie gas combustion device, the combustion amount can be adjusted. Only the furnace temperature can be adjusted while continuously burning without changing.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a furnace for carrying out a furnace temperature control method of the present invention.

FIG. 2 is a graph showing a relationship between a temperature of combustion air and a combustion gas recovery rate in the burner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2 Heat storage type burner 3 Heat storage type burner 5 Heat storage body 8 Combustion gas exhaust system which constitutes first exhaust means 10 Induction fan which constitutes first exhaust means 16 Second exhaust means

Claims (1)

[Claims] 1. A heating furnace using a burner as a heat source, wherein at least one heat storage type burner is provided in the furnace body, the heat storage burner having a heat storage body and supplying combustion air and discharging combustion gas through the heat storage body. And a second exhaust means for discharging the combustion gas from the burner, which is not combusted, through the heat storage body, and the combustion gas is discharged outside the furnace without passing through the burner. Means for controlling the furnace temperature by changing the amount of combustion gas passing through the burner by operating the second exhaust means.