JPS61264127A - Heater for furnace - Google Patents

Abstract

PURPOSE:To assure the uniformity of temp. by opening plural pieces of high- speed jet burners which make full-load operation with good combustion efficiency and constant air-fuel ratio during firing into a furnace chamber and executing alternate combustion with the firing burners with the predetermined sequence so that wake gases are stirred in the furnace. CONSTITUTION:For example, 6 pieces of the high-speed jet burners 1-6 which make full-load operation with the good combustion efficiency and constant air-fuel ratio during firing are successively staggered laterally and are disposed along the longitudinal direction of a heating furnace 9. The combustion rate is made controllable stepwise by the firing number of the burners. The firing burner gases are determined by the predetermined firing combination and the combination is periodically and successively changed over. At least part of the burners under firing are turned on and off at the time intervals determined according to the required quantity of heat in the cold season.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a furnace heating device that efficiently heats a furnace used for heat treatment of iron, steel, etc. and reduces harmful components in exhaust gas.

In the case of a batch-type heating furnace, the amount of combustion is at its maximum at the beginning of heating, and a large amount of combustion gas circulates in the furnace, but after that, the amount of combustion gradually decreases, and during soaking heating, the amount of combustion is 1/1 of the initial heating. 1
It requires only 0 to 1/100 of the amount of heat. As a method for reducing the amount of heat, a constant air-fuel ratio combustion system that throttles both air and fuel has already been used, but as the amount of combustion decreases, problems arise in maintaining temperature uniformity. Furthermore, constant air combustion systems have already been used in which the amount of air is fixed at the maximum combustion level and only the amount of fuel is reduced, but this system has poor combustion efficiency during uniform heating. Furthermore, impulse combustion systems in which all burners are turned on and off at the same time are already in use, but the burner off time during soaking heating is long (and the gas in the furnace is not circulated during this off time). It is difficult to equalize the temperature inside the furnace.Furthermore, a special system is known that uses a special nozzle and combines a constant air combustion system and a constant air fuel ratio combustion system, but the structure is There is a feeling that there is still a step forward in improving the combustion efficiency at times of complicated combustion and low combustion.The present invention was made to solve these problems.

The first embodiment of this invention will be explained based on FIGS. 1 to 8.

9 is the heating furnace, 10 is the furnace chamber of the heating furnace 9, and 1, 2° 3 is the first
The high-speed jet burner 4.5.6, which is installed on the right side of the furnace chamber 10 in FIGS. 1 and 2, is the high-speed jet burner installed on the left side of the furnace chamber 10 in FIGS. The left and right burners are sequentially staggered along the direction. These burners are designed to perform constant air-fuel ratio combustion with the maximum air jetting amount and maximum fuel jetting amount during combustion in the on state, and so that neither air nor fuel is jetted out in the off state. It has become. Hereinafter, such burners will be referred to as on-off operating burners. In this embodiment, there are six on-off operating burners 1 to 6, which open into the furnace chamber 10, and are controlled in five steps. ' Figure 3 is a graph showing the state of the first control stage, with time plotted on the horizontal axis and each burner plotted on the vertical axis. The lined portion indicates ignition combustion. T is one unit, 6 units is one cycle, and each burner is designed to ignite one unit each. Each burner tends to have its own share of time,
It is designed to be turned on and off. If you shorten the on time and lengthen the off time, the amount of heat generated during the shared time will decrease even if the size of the burner frame is the same (for example, position A in Figure 8), and if you lengthen the on time, , if the off time is shortened, the amount of heat generated during the shared time will increase (for example, position B in Figure 8).
. In this first control stage, heat is generated from 0 to 1/6 of the maximum heat generation amount.

Figure 4 is a graph showing the state of the second control stage, where 6 units T are
Each unit has a set of two burners, and one burner in the set remains on (hereinafter referred to as the "on-keeping burner"), and the other burner changes the off time ratio as it turns on and off. This adjusts the amount of heat generated. In this case, each burner is responsible for one continuous turn-on and one turn-off during one cycle. In this second control stage,
Generates 1/6 to 2/6 of the maximum calorific value.

FIG. 5 is a graph showing the state of the third control stage, where 2 units T is 1
Each unit has two keep-on burners and one
The amount of heat generated is adjusted by the on/off operation of the burner. In this third control stage, 2/6 to 3/6 of the maximum calorific value
generates fever.

FIG. 6 is a graph showing the state of the fourth control stage, where 2 units T is 1
Each unit has 3 on burners and 1
This fourth control stage adjusts the amount of heat generated by the on/off operation burner.
generates fever.

FIG. 7 is a graph showing the state of the fifth control stage, where 1 unit T is 1
Each unit has 4 burners to keep it on and 2
The amount of heat generated is adjusted by the on/off operation of the burner. In this fifth control stage, 4/6 to 6/6 of the maximum calorific value
(This control stage generates heat from 4/6 to 5/6 and 5/6.
It can be divided into two stages: /6 to 6/6).

FIG. 8 is a graph showing the relationship between the control stage and the combustion amount, with the horizontal axis representing the control stage and the vertical axis representing the combustion amount. 1. 2.
3. 4. 5 indicates the number of control stages, the area surrounded by diagonal lines represents the combustion by the on-maintenance burner, and the area between the diagonal dotted line and the area surrounded by the diagonal line represents the combustion part by the on-off operating burner. ing.

A second embodiment of the present invention will be explained based on FIGS. 9 to 17.

In this embodiment, the left ceiling burner 17 of the furnace chamber 10. Right side wall burner 11. Left side wall burner 13. Right ceiling burner 15. Left ceiling burner 18. Right side wall burner 12. The left wall burner 14 and the right ceiling burner i6 are
They are arranged to be sequentially shifted along the longitudinal direction of the furnace chamber 10. The side wall burners 11.12 and 13.14 are set to output half the capacity of the ceiling burners 15.16 and 17.18.

FIG. 11 is a graph showing the state of the first control stage, with 4 units T7
! J (This is one cycle, and the amount of heat generated is adjusted by sequentially turning on and off the four side wall burners for each unit one by one. In this first control stage, the amount of heat generated is adjusted from 0 to 1/12 of the maximum amount of heat generated.
generates fever.

Figure 12 is a graph showing the state of the second control stage, with 6 units T in one cycle, 4 sidewall burners, 1 keep-on sidewall burner for each unit, and 1 on/off operation sidewall burner. The amount of heat generated is adjusted by In this second control stage, heat is generated between 1/12 and 2/12 of the maximum heat amount.

Figure 13 is a graph showing the state of the third control stage, in which two units T make one cycle, four side wall burners are connected to each unit, two keep-on side wall burners and two on/off operating side walls. The amount of heat generated is adjusted by the burner. In this third control stage, heat is generated from 2/12 to 4/12 of the maximum heat amount.

FIG. 14 is a graph showing the state of the fourth control stage, where two units T correspond to one cycle, and the amount of heat generated is adjusted by two on/off operating side wall burners and two on-maintaining ceiling burners. In this fourth control stage, 4/12 to 6/6 of the maximum calorific value is
Perform 12 fevers.

Fig. 15 is a graph showing the state of the fifth control stage, where two units T make one cycle, each unit has two sidewall burners kept on, two sidewall burners operating on/off, and two sidewall burners kept on. The amount of heat generated is adjusted using the ceiling burner.

In this fifth control stage, heat is generated from 6/12 to 8/12 of the maximum heat amount.

FIG. 16 is a graph showing the state of the sixth control stage, in which the amount of heat generated is adjusted by four on-off operating side wall burners and four on-maintaining ceiling burners.

In this sixth control stage, 8/12 to 12/12 of the maximum calorific value
generates fever.

FIG. 17 is a diagram corresponding to FIG. 8 of the first embodiment, in which the area surrounded by solid lines represents the area covered by the ceiling burner, and the other areas represent the area covered by the side wall burner.

As described above, the furnace heating device according to the present invention opens a plurality of high-speed jet burners in the furnace chamber that operate at a constant air-fuel ratio with high combustion efficiency and at full load during ignition, and the combustion amount is adjusted in stages according to the number of ignited burners. In addition to making it possible to control
The ignition burners are determined by a predetermined ignition combination, and the combinations are periodically and sequentially switched as necessary, and during each cycle, at least some of the burners being ignited are determined according to the required amount of heat. On/off at time intervals
It was designed to be turned off.

Combustion is performed at the air-fuel ratio with the highest combustion efficiency over the entire combustion range, and since the burner used is a high-speed jet burner, a large amount of wake gas stirs the inside of the furnace, ensuring uniform temperature throughout the heating and scorching periods. You can. In addition, since the ignition burner performs alternating combustion according to a predetermined order, there is no localized heating, and energy-saving operation and low-pollution operation (particularly low NOx generation) is possible over the entire range.

[Brief explanation of the drawing]

1 to 8 show a first diagram of a furnace heating device according to the present invention.
Fig. 1 is a schematic front view of the furnace, Fig. 2 is a plan view of the same, Fig. 3 is a graph showing the operating state of the first control stage, and Fig. 4 is a graph showing the operating state of the second control stage. A graph showing the operating state of the control stage, Fig. 5 a graph showing the operating state of the third control stage, Fig. 6 a graph showing the operating state of the fourth control stage, and Fig. 7 a graph showing the operating state of the fifth control stage. FIG. 8 is a graph showing the relationship between the control stage and the combustion amount. Figures 9 to 1
FIG. 7 is for explaining a second embodiment of the furnace heating device according to the present invention, FIG. 9 is a schematic front view of the furnace, and FIG. 10 is a schematic front view of the furnace.
Figure 11 is a graph showing the operating state of the first control stage, Figure 12 is a graph showing the operating state of the second control stage, and Figure 13 is a graph showing the operating state of the third control stage. , Fig. 14 is a graph showing the operating state of the fourth control stage, Fig. 15 is a graph showing the operating state of the fifth control stage, and Fig. 16 is a graph showing the operating state of the fifth control stage.
A graph showing the operating state of the control stage, and FIG. 17 is a graph showing the relationship between the control stage and the combustion amount. 1 Burner 2 Burner 3 Burner 4 Burner 5 Burner 6 Burner 9 Heating furnace 10 Furnace chamber 11 Burner 12 Burner 13 Burner 14 Burner 15 Burner 16 Burner 17 Burner 18 Burner

Claims (1)

[Claims] During ignition, multiple high-speed jet burners that operate at a constant air-fuel ratio with good combustion efficiency and at full load are opened in the furnace chamber, and the combustion amount can be controlled in stages by the number of burners ignited. The ignition combination is determined by a predetermined ignition combination, and the ignition combinations are periodically switched in sequence, and during each cycle, at least some of the burners that are igniting are turned on and off at time intervals determined according to the amount of heat required. Furnace heating device characterized by being turned off.