JP3373303B2 - Operating method of regenerative heat storage combustion system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a heat storage regeneration combustion system that utilizes the heat of exhaust gas after combustion for preheating combustion air. 2. Description of the Related Art Conventionally, a thermal storage regeneration type combustion system shown in FIG. 2 is known. The regenerative combustion system 50 includes a regenerative burner device 51 composed of a burner 54 and a regenerator 56 and a regenerative burner device 52 composed of a burner 55 and a regenerator 57 arranged in a furnace 53 as a pair. ing. The burners 54 and 55 are respectively provided with fuel supply valves 58 and
It is connected to a fuel supply device 60 via 59. The regenerator 56 includes a combustion air supply fan 61.
And an exhaust gas fan 62 via an air supply valve 63 and an exhaust gas discharge valve 64, respectively. Similarly, the regenerator 57 includes a combustion air supply fan 61 and an exhaust gas fan 62.
Are connected via an air supply valve 65 and an exhaust gas discharge valve 66, respectively. Further, pilot burners 67 and 68 are provided near the burners 54 and 55, respectively, and the burners 54 and 55 and / or the pilot burners 67 and 68 are provided.
68 is provided with flame detectors 69 and 70. [0004] The heat storage regeneration combustion system 50 having the above-described configuration.
Then, the fuel supply valve 58, the air supply valve 63, and the exhaust gas discharge valve 66 are opened, and the fuel supply valve 59, the air supply valve 65, and the exhaust gas discharge valve 64 that are paired with these valves are closed. Thus, the fuel and the combustion air are supplied to the burner 54, and the fuel burns. Exhaust gas generated by combustion is burner 5
After passing through the regenerator 57 from the heater 5 and heating the regenerator 57, the exhaust gas is discharged by the exhaust gas fan 62 through the exhaust gas discharge valve 66. After a certain period of time, the valves 58, 63, and 66 are closed to stop burning the fuel in the burner 54. Further, the valves 59, 65 and 64 are opened, and the fuel and the combustion air preheated by the regenerator 57 are supplied to the burner 55 to burn the fuel. Exhaust gas generated by the combustion is supplied to a burner 54.
After passing through the heat accumulator 56 and heating the heat accumulator 56, the heat is discharged by the exhaust gas fan 62 through the exhaust gas discharge valve 64. Thereafter, the heat storage regeneration combustion by the burners 54 and 55 is alternately repeated at regular intervals. As described above, in the heat storage regeneration combustion system 50, the heat contained in the exhaust gas after combustion is recovered by the heat storage devices 56 and 57, and this heat is used for preheating the combustion air, thereby improving the combustion efficiency. be able to. [0006] By the way, in order to perform safe combustion with a burner, it is generally necessary that the flow ratio between fuel and air be stable. However, the valve is activated immediately after the burner is ignited. Depending on the speed, the flow rate ratio may not be optimized and ignition failure may occur. In particular, in the regenerative regenerative combustion system 50 having the above-described configuration, the burners 54 and 55 alternately repeat ignition and extinguishing frequently, and thus have a high probability of misfire. For this reason,
The pilot burners 67, 68 are located near the burners 54, 55.
, Whereby the burners 54 and 55 are reliably ignited. [0007] The pilot burners 67 and 68
To ignite 4,55, pilot burners 67,68
The pilot burners 67 and 68 are ignited immediately before the burners 54 and 55 are ignited, and the pilot burners 67 and 68 are extinguished when the burners 54 and 55 are ignited. . However, in the method in which the pilot burners 67 and 68 are continuously burned, the flame detectors 69 and 70 are connected to the pilot burner 6.
There is a case where the flame of 7, 68 is erroneously detected as the flame of the burners 54, 55, and there is a risk that the fuel is continuously supplied even when the burners 54, 55 are misfired. In the method of igniting and extinguishing the pilot burners 67 and 68, the erroneous detection of the flame detectors 69 and 70 as described above can be prevented.
Since igniting and extinguishing of 7,68 are frequently repeated, it is necessary to use a highly reliable control device for controlling the pilot burners 67,68, so that the equipment of the regenerative combustion system 50 becomes complicated. There was a problem. SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has a non-combustion regenerative burner device in which combustion is alternately performed by a pair of regenerative burner devices. In a regenerative regenerative combustion system in which exhaust gas is sucked from and the heat of the exhaust gas is recovered to be used for preheating combustion air, the furnace temperature is lower than the ignition temperature of a mixed gas of fuel and combustion air. When the temperature inside the furnace is equal to or higher than the ignition temperature of the gas mixture of the fuel and the combustion air, combustion is performed alternately by the pair of regenerative burners. It is characterized by performing. Here, the ignition temperature of the gas mixture of fuel and combustion air refers to a temperature at which stable combustion can be started, and includes a case where a slight temperature is added or subtracted from the theoretical ignition temperature. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing a piping system and a control system of a regenerative combustion system according to the present invention. A regenerative combustion system 1 includes a pair of regenerative burner devices 2 and 3, and these regenerative burners are used. The burner devices 2 and 3 include burners 4 and 5 and heat accumulators 6 and 7, respectively. The burners 4 and 5 have pilot burners 8 and 9 respectively.
Is provided. The burners 4 and 5 are provided, for example, in the furnace 10 so as to face each other, and are connected to a fuel supply source 13 via fuel supply valves 11 and 12, respectively. Heat storage 6,7
Has a heat storage medium, such as alumina balls, housed therein, and is provided in gas supply pipes 18 and 19 connected to the burners 4 and 5 in this embodiment. The gas supply pipe 18 is provided with a combustion air supply pipe 20.
The end of the combustion air supply pipe 20 is connected to a combustion air supply fan 22, and the end of the exhaust gas discharge pipe 21 is connected to an exhaust gas fan 23. The combustion air supply pipe 20 and the exhaust gas discharge pipe 21 are provided with a combustion air supply valve 24 and an exhaust gas discharge valve 25, respectively. Similarly, the other gas supply pipe 19 branches into a combustion air supply pipe 26 and an exhaust gas discharge pipe 27, and an end of the combustion air supply pipe 26 is connected to a combustion air supply fan 22 to discharge the exhaust gas. The end of the pipe 27 is connected to the exhaust gas fan 23. Further, the combustion air supply pipe 26 and the exhaust gas discharge pipe 27 are provided with a combustion air supply valve 28 and an exhaust gas discharge valve 29, respectively. The furnace 10 has a thermometer 30 for measuring the temperature inside the furnace.
And flame detectors 31, 3 for detecting the flames of the burners 4, 5
1 '. An exhaust pipe 32 is connected to the furnace 10, and an end of the exhaust pipe 32 is connected to a smoke exhaust device 33. The smoke exhaust device 33 includes an exhaust gas fan 34 and a chimney 35.
The exhaust gas in the furnace 10 is discharged from the chimney 35 by opening and closing an exhaust valve 36 provided in the exhaust pipe 32. In some cases, the exhaust gas in the furnace 10 may be discharged from the chimney 35 by natural ventilation using the chimney wind power without providing the exhaust gas fan 34. All the valves 11, 12, 24, 2 described above
5, 28, 29, 36, pilot burners 8, 9
The flame detectors 31, 31 'are connected to the sequencer 37. The thermometer 30 is connected to a sequencer 38, and the sequencer 38 and the sequencer 37 are connected. The operation of the heat storage regeneration combustion system 1 having the above configuration will be described. In the heat storage regeneration combustion system 1, when the internal temperature of the furnace 10 is lower than the ignition temperature of the gas mixture of the fuel and the combustion air based on the measurement result of the thermometer 30, the fuel is supplied to the burners 4 and 5 with the fuel. When the combustion air is supplied to perform continuous combustion and the internal temperature of the furnace 10 is equal to or higher than the ignition temperature, the burners 4 and 5 are alternately burned to perform heat storage regeneration combustion. Hereinafter, the continuous combustion and the heat storage regeneration combustion will be described in detail. The temperature inside the furnace 10 is measured by a thermometer 30, and the measurement result is output to a sequencer 38. If the measured temperature is lower than the ignition temperature, a signal for performing continuous combustion is output from the sequencer 38 to the sequencer 37. The sequencer 37 controls the fuel supply valves 11 and 12 and the combustion air supply valves 24 and
28 and the exhaust valve 36 is opened. And the exhaust gas discharge valve 2
5 and 29 are closed, and fuel and combustion air are supplied to both burners 4 and 5 to perform continuous combustion. The exhaust gas generated by the above-described continuous combustion is discharged from a chimney 35 by an exhaust gas fan 34.
When the heat storage regeneration combustion system 1 is switched from the non-combustion state to the combustion state, the pilot burners 8 and 9 are supplied from a fuel supply device and a combustion air supply device (not shown) based on a signal from the sequencer 37. Combustion of fuel and combustion air. The burners 4 and 5 are ignited by this combustion, and after the burners 4 and 5 are ignited, the flame detectors 31 and 31 '.
Operates. At this time, when the flame detector 31 or 31 'does not operate, the fuel supply valves 11 and 12 are immediately closed by a signal from the sequencer 37. When the temperature in the furnace rises and the temperature measured by the thermometer 30 becomes equal to or higher than the ignition temperature of the gaseous mixture of fuel and combustion air, the sequencer 38 switches to the sequencer 3
A signal for performing heat storage regeneration combustion is output to 7. Specifically, when burning with the burner 4 of one regenerative burner device 2, the fuel supply valve 11 and the combustion air supply valve 24 are opened, and fuel and combustion air are supplied to the burner 4. Further, the exhaust gas discharge valve 29 is opened, the exhaust valve 36 is throttled or closed, and the fuel supply valve 12, the combustion air supply valve 28, and the exhaust gas discharge valve 25 are closed. The fuel and combustion air supplied to the burner 4 ignite spontaneously because the furnace temperature is higher than the above-mentioned ignition temperature.
Therefore, the burner 4 reliably burns without misfire. On the other hand, the exhaust gas generated by the regenerative combustion passes through the regenerator 7 from the burner 5 and heats the regenerator 7.
3 to be discharged. After a lapse of a predetermined time, the fuel supply valve 1 is used to set the burner 4 of one regenerative burner device 2 to a non-combustion state and burn the burner 5 of the other regenerative burner device 3.
1. The combustion air supply valve 24 and the exhaust gas discharge valve 29 are closed,
The fuel supply valve 12, the combustion air supply valve 28, and the exhaust gas discharge valve 25 are opened. Then, the fuel and the combustion air preheated by the regenerator 7 are supplied to the burner 5 and burn by spontaneous ignition as described above. The exhaust gas generated by the heat storage regeneration combustion passes through the regenerator 6 from the burner 4, heats the regenerator 6, and then passes through the exhaust gas discharge valve 25 to the exhaust gas fan 2.
3 to be discharged. Thereafter, the combustion of the burners 4 and 5 alternately is repeated. As described above, in the heat storage regeneration combustion system 1, at the time of heat storage regeneration combustion, the burners 4, 5 are ignited without depending on the pilot burners 8, 9, and burn reliably without misfiring. When the temperature in the furnace becomes lower than the ignition temperature of the gas mixture of fuel and combustion air, the heat storage regeneration combustion system 1 is switched to continuous combustion by signals from the sequencers 37 and 38. In the above description, the regenerative combustion system 1 is provided with only one pair of regenerative burner devices 2 and 3. However, if necessary, a plurality of pairs of regenerative burner devices may be provided. Is also good. The above-mentioned ignition temperature differs depending on the type of fuel. For example, when using by-product gas in a steel mill, the set temperature of the sequencer 38 is about 800 ° C.
Set to. Further, the temperature at which transition from continuous combustion to regenerative heat storage combustion can be set in the sequencer 38 is set to a temperature + α at which the regenerative heat storage combustion is switched to continuous combustion + α. To prevent. As is clear from the above description, in the heat storage regeneration combustion system according to the present invention, when the furnace temperature is lower than the ignition temperature of the mixed gas of fuel and combustion air, each heat storage type Since the fuel and the combustion air are supplied to the burner of the burner device to continue the continuous combustion, it is possible to prevent a misfire caused by repeated ignition and extinguishing of the burner. Further, when the temperature in the furnace is equal to or higher than the ignition temperature of the gas mixture of fuel and combustion air, combustion is reliably performed by spontaneous ignition, so that one of the pair of regenerative burner devices from the other burner or the other burner. Even if the combustion is alternately switched from one burner to one burner, the combustion is surely performed without misfire, so that the heat storage regeneration combustion with high thermal efficiency is reliably performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a piping diagram of a heat storage regeneration combustion system according to the present invention. FIG. 2 is a piping diagram of a conventional heat storage regeneration combustion system. [Description of Signs] 1 ... regenerative combustion system, 2, 3 ... regenerative burner device, 4, 5 ... burner, 6, 7 ... regenerator, 11, 12 ... fuel supply valve, 30 ... thermometer, 37, 38 ... sequencer.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Toki 2-4-7 Kyomachibori, Nishi-ku, Osaka-shi, Osaka Inside Chugai Furnace Industry Co., Ltd. (72) Inventor Katsuaki Nishi 2-chome, Kyomachibori, Nishi-ku, Osaka-shi, Osaka No. 4-7 Inside Chugai Furnace Industry Co., Ltd. (72) Inventor Yoji Fujimoto 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Pref. Kawasaki-dori 1-chome (without address) Kawasaki Steel Corporation Mizushima Works (72) Inventor Kazuhiro Yahiro 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Prefecture (address-less) Kawasaki Steel Corporation Mizushima Works (72) Inventor Fukui Masayasu 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. (Without address) Kawasaki Steel Corp. Mizushima Works (56) References: Japanese Utility Model 7-41240 (JP, U) (58)査the field (Int.Cl. ^7, DB name) F23L 15/00 F23C 7/06 F23D 14/66

Claims (1)

(57) Claims 1. Combustion is alternately performed by a pair of regenerative burner devices, and exhaust gas is sucked from a non-combustion regenerative burner device and heat of the exhaust gas is converted to combustion air. In a regenerative regenerative combustion system designed to be recovered for use in preheating, when the temperature in the furnace is lower than the ignition temperature of a gas mixture of fuel and combustion air, combustion is performed by both regenerative burner devices forming a pair. When the temperature in the furnace is equal to or higher than the ignition temperature of the gas mixture of fuel and combustion air, the heat storage regeneration combustion system is characterized by alternately performing heat storage regeneration combustion by a pair of heat storage burners. .