JP4385454B2 - Atmospheric gas heating temperature adjustment method and heating temperature adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas heating method and apparatus for heating an atmospheric gas for heating supplied to a heating furnace or the like, and more particularly includes three or more regenerative heaters, which are in a combustion state, an atmospheric gas heating state, and an atmospheric gas. The present invention relates to a method for adjusting the temperature of an atmospheric gas in a regenerative gas heating apparatus that sequentially switches the order of suction and continuously supplies heated atmospheric gas, and an adjustment / control device thereof.
[0002]
[Prior art]
As heating methods for heating steel materials, etc. in a non-oxidizing or reducing atmosphere, methods such as a radiant tube method, a direct flame reduction heating method, and a two-layer atmosphere combustion method have been proposed and adopted depending on the application. In recent years, a method has been proposed in which a heated atmosphere gas is directly supplied to a heating furnace, whereby the steel material is efficiently heated under a desired atmosphere. A typical example is the means proposed in International Publication No. WO98 / 38344.
[0003]
This means is a regenerative atmospheric gas heating method in which the atmospheric gas is heated using three or more regenerative heaters including a burner device and a heat storage chamber provided in the exhaust passage of the combustion exhaust gas from the burner device. In at least one or more regenerative heaters among the three or more regenerative heaters, the burner device is burned, and only the combustion exhaust gas or only the combustion exhaust gas is exhausted through the heat storage chamber. A combustion state in which heat is stored in the heat storage chamber, and an atmosphere gas supply state in which the atmosphere gas is heated and supplied through the atmosphere gas in at least one other heat storage heater, and at least one other heat storage heater is used. In the regenerative heater, the atmospheric gas is sucked in, and each of these regenerative heaters is sequentially switched in the order of the combustion state, the atmospheric gas heating state, and the atmospheric gas suction state. Instead it is a means to keep continuously supplying heated ambient gas.
[0004]
[Problems to be solved by the invention]
By the above proposal, it is possible to continuously supply the heated atmospheric gas and to continuously recover the surplus atmospheric gas and reuse it for the next atmospheric gas heating supply, thereby improving the thermal efficiency. There are advantages such that heating at a low running cost is possible by improving the temperature and reusing resources (atmospheric gas).
[0005]
However, when the atmospheric gas is heated and supplied using the above means, the temperature of the atmospheric gas supplied to the heating furnace is a period during which the atmospheric gas is heated and supplied through the atmospheric gas into the heat storage chamber of one regenerative heater. Decreases gradually. Next, when the heating of the atmospheric gas is switched as in another heat storage chamber, it rises again, but it falls again as time passes. Since such a cycle is repeated, when the cold-rolled steel sheet is continuously heated by the above means, the steel sheet temperature varies in the conveying direction (longitudinal direction) of the steel sheet, and thus it is difficult to obtain a steel sheet having uniform characteristics. There was.
[0006]
The present invention comprises three or more heat storage heaters as described above, which are sequentially switched in the order of the combustion state, the atmospheric gas heating state, and the atmospheric gas suction state, and continuously supply the heated atmospheric gas. The objective is to solve the problem of gas heating devices, that is, the problem that the temperature of the heated atmospheric gas fluctuates in time series, thereby suppressing the time series variation of the heating temperature in continuous heating of steel strips, etc. The purpose is to do.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have conceived of adjusting the temperature of the atmospheric gas supplied to the heating furnace by mixing the cooling gas with the atmospheric gas discharged from the heat storage chamber in the atmospheric gas heating state. The present invention has been completed. Specifically, the present invention includes a first heat storage chamber that is heated and stored by combustion exhaust gas from a burner device and a second heat storage chamber that is provided in the suction path for the atmosphere gas, as a method for adjusting the heating temperature of the atmosphere gas. Use three or more regenerative heaters, and heat each of the regenerative heaters in order to continuously supply heated atmospheric gas by sequentially switching the combustion state, the atmospheric gas heating state, and the atmospheric gas suction state. In the supply method, the cooling gas is mixed with the atmospheric gas discharged from the first heat storage chamber of the regenerative heater in the atmospheric gas heating state.
[0008]
Further, the present invention provides a heat storage type atmospheric gas heating temperature adjusting device for carrying out the above atmospheric gas heating temperature adjusting method, a combustion burner, and a first heat storage chamber provided in an exhaust path of combustion exhaust gas from the burner. And three or more regenerative heaters each including a second heat storage chamber provided in the atmospheric gas suction path, and each of the regenerative heaters is in order of a combustion state, an atmospheric gas heating state, and an atmospheric gas suction state. In the regenerative atmospheric gas heating apparatus that continuously supplies the atmospheric gas heated by switching sequentially, a cooling gas supply port is provided in a passage from the first thermal storage chamber of the regenerative heater to the heating facility. .
[0009]
Further, in the above-mentioned apparatus, the atmosphere is first regenerator outlet side gas temperature measuring device placed in the gas passage, a first regenerator gas flow control valve is installed in the atmospheric gas supply path to the first heat storage chamber, and A cooling gas flow rate adjustment valve is installed in the cooling gas supply path leading to the cooling gas supply port provided in the atmospheric gas passage ,
Based on the temperature signal of the first heat storage chamber outlet gas temperature measuring device,
_{Q t · T g · Cp g} = Q r · T r · Cp r + Q c · T c · Cp c
Q _t = Q _r + Q _c
As the gas flow rate control device for controlling the first regenerator gas flow control valve and the cooling gas flow rate control valve so as to satisfy is installed, always maintained at the target temperature feed gas temperature to the heating furnace or the like It is preferable to provide a control mechanism that performs this.
Here Q _t: flow rate of the mixed gas T _g: mixed gas temperature Cp _g: mixed gas pressure specific heat Q _r: first regenerator outlet side gas flow T _r: first regenerator outlet side gas temperature Cp _r: first regenerative chamber out-side gas specific heat at constant pressure Q _c: cooling gas flow rate T _c: cooling gas temperature Cp _c: cooling gas specific heat at constant pressure [0010]
This invention replaces with the said control method, and is mixed gas which measures the temperature of the mixed gas of the atmospheric gas supplied from the said 1st thermal storage chamber to the said atmospheric gas channel, and the cooling gas supplied from the said cooling gas supply port A cooling gas which is provided with a temperature measuring device, a first heat storage chamber gas flow rate adjustment valve is installed in the atmosphere gas supply path to the first heat storage chamber , and reaches the cooling gas supply port provided in the atmosphere gas passage A cooling gas flow control valve is installed in the supply path ,
A gas flow rate control device that controls the first heat storage chamber gas flow rate control valve and the cooling gas flow rate control valve based on the temperature measurement result of the mixed gas temperature measuring device so as to maintain the temperature based on the measurement result at a target value. It can also be installed .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a regenerative atmosphere gas heating apparatus for carrying out the atmosphere heating method according to the present invention.
[0012]
As apparent from FIG. 1, three regenerative heaters 1 </ b> A to 1 </ b> C are attached to the heating furnace 20 as one set. Each of these regenerative heaters 1A to 1C has first heat storage chambers 3A to 3C and second heat storage chambers 4A to 4C. Each of the heat storage chambers 3A to 3C and 4A to 4C is filled with a spherical or cylindrical heat storage body made of, for example, ceramics.
[0013]
One of the first heat storage chambers 3 </ b> A to 3 </ b> C is opened inside the furnace 20, thereby forming atmospheric gas passages 22 </ b> A to 22 </ b> C. The other one is connected to the exhaust path via the exhaust valves 7A to 7C and the exhaust fan 11, and is also connected to the atmospheric gas supply source 15 as will be described later.
[0014]
On the other hand, the second heat storage chambers 4A to 4C are connected to the atmospheric gas supply source 15 via the atmospheric gas recovery valves 9A to 9C and the atmospheric gas recovery fan 13, respectively, and the air valves 10A to 10C and the air fan 14 are connected. Via the air supply path.
[0015]
Burner devices 2A to 2C are attached to the first heat storage chambers 3A to 3C, respectively, and the burner devices 2A to 2C supply combustion gas via combustion gas control valves 6A to 6C for controlling supply of combustion gas. Connected to a source (not shown). In addition, the combustion chambers 5A to 5C of the burner devices 2A to 2C communicate with the inside of the heating furnace 20 through the atmospheric gas passages 22A to 22C.
[0016]
The atmospheric gas supply source 15 includes a common atmospheric gas tank 16. The atmospheric gas tank 16 is connected to the second heat storage chambers 4A to 4B via the atmospheric gas recovery valves 9A to 9C, the atmospheric gas recovery fan 13, and the CO ₂ removal device 19. The atmosphere gas tank 16 is connected to the first heat storage chambers 3A to 3C of the heat storage heaters 1A to 1C via the O ₂ removal device 17, the atmosphere gas blowing fan 12, and the atmosphere gas blowing valves 8A to 8C. ing. Further, an atmospheric gas supply path for supplementing the exhaust gas from the heating furnace 20 is connected to the atmospheric gas tank 16.
[0017]
The regenerative atmospheric gas heating device further branches from the atmospheric gas tank 16, the O ₂ removing device 17, the path from the atmospheric gas blowing fan 12 to the atmospheric gas blowing valves 8A to 8C, and passes through the cooling gas blowing valves 21A to 21C. The first heat storage chambers 5 </ b> A to 5 </ b> C are connected to the atmospheric gas passages 22 </ b> A to 22 </ b> C that reach the furnace 20.
[0018]
An outline of the operating state of the equipment will be described below. The state shown in FIG. 1 is that the leftmost regenerative heater (hereinafter referred to as the first regenerative heater) 1A system is in a combustion state, and the central regenerative heater (hereinafter referred to as the second regenerative heater) 1B. The system is in the atmospheric gas heating state, and the rightmost regenerative heater (hereinafter referred to as the third regenerative heater) 1C is in the atmospheric gas suction state. Here, the combustion state is a state where the burner devices 2A to 2C are combusted, and the atmospheric gas heating state is a state where the atmospheric gas is heated and supplied to the furnace, and the atmosphere A gas suction-like body means a state where atmospheric gas is sucked from the inside of the heating furnace.
[0019]
In this state, in the first heat storage heater 1A system, the burner device 2A is in the combustion state, and the first heat storage chamber 3A is in the heat storage state. At that time, the air preheated by the second heat accumulator 4A is supplied to the burner device 2A. In the second regenerative heater 1B system, the atmospheric gas is supplied from the atmospheric gas supply source 15 to the first heat storage chamber 3B that has been in the combustion state so far, and is heated and supplied to the heating furnace 20. In the regenerative heater 1C system in the atmosphere gas suction state, the sensible heat is stored in the second heat storage chamber 4C through the atmosphere gas in the heating furnace. The first heat storage chamber 3C and the second heat storage chamber 4B are on standby.
[0020]
If this state is continued, the atmospheric gas temperature supplied into the heating furnace 20 from the second first regenerative heater 1B in the atmospheric gas heating state gradually decreases. On the other hand, the temperature of the first heat storage chamber 3A of the first heat storage heater 1A in the combustion state gradually increases. Therefore, when the temperature reaches a certain limit value or when a predetermined time has elapsed, the first regenerative heater 1A system that has been in the combustion state until then has been heated to the atmospheric gas heating state. The second regenerative heater 1B system is switched to the atmospheric gas suction state. Further, the third regenerative heater 1C system is switched to the combustion state. Thereby, it becomes possible to supply the high-temperature atmosphere gas into the heating furnace 20 again. After the above state is continued, for example, when the ambient gas temperature supplied to the heating furnace 20 is lower than the limit value, the first regenerative heater 1A system is brought into the suction state, and the second regenerative heater 1B system is The 3rd heat storage type heater 1C system is made into a heating state in the combustion state.
[0021]
The atmospheric gas heated continuously can be supplied into the heating furnace 20 by repeating the above operations periodically at predetermined timing. However, as is clear from the above description, the temperature of the atmospheric gas supplied into the heating furnace 20 periodically varies with a certain width. In the present invention, in order to solve this problem, a low-temperature cooling gas for temperature adjustment is mixed with the atmospheric gas discharged from the first heat storage chamber of the regenerative heater in the atmospheric gas heating state.
[0022]
The temperature control of the atmospheric gas supplied from the regenerative heater 1B system in the heated state to the furnace 20 will be described as an example with reference to FIG. 1, and the high temperature atmospheric gas supplied from the first heat storage chamber 3B to the heating furnace 20 will be described. In addition, the cooling gas is blown into the atmospheric gas passage 22B from the atmospheric gas tank 16 via the cooling gas injection valve 21B, and the amount of the atmospheric gas supplied to the heating furnace 20 is adjusted so as to be kept substantially constant. This operation is performed on the regenerative heater in a heated state every time the switching operation is performed. Therefore, the ambient gas passages 22A to 22C of each of the regenerative heaters 1A to 1C are cooled from the ambient gas tank 16. Cooling gas supply ports 23A to 23C for bypassing and flowing the gas are provided.
[0023]
Various adjustments of the temperature adjusting gas can be performed by using various known means, but it is preferable to use the feed forward system shown in FIG. 2 or the feedback system shown in FIG. Alternatively, these methods can be used in combination.
[0024]
FIG. 2 is a conceptual view showing a control system for a heating atmosphere gas temperature by a feed-forward method for the regenerative heater 1B. As shown here, a measuring device for measuring the temperature of the first heat storage chamber outlet gas is provided in the atmosphere gas passage 22B of the first heat storage chamber 3B constituting the heat storage heater 1B, and the measurement result Is input to the gas flow rate adjusting device 34B. The gas flow rate adjusting device 34B calculates the gas amount and the temperature adjustment gas amount from the first heat storage chamber 3B based on the temperature and amount of the gas to be supplied to the heating furnace 20, and the first heat storage chamber gas flow rate adjustment valve 31B and the cooling gas. The opening degree of the flow control valve 32B is adjusted and controlled.
[0025]
In that case, the gas flow rate (Q), the gas temperature (T) and between the specific heat _{(Cp) Q t · T g} · Cp g = Q r · T r · Cp r + Q c · T c · Cp c
Q _t = Q _r + Q _c
It is preferable that the heating gas having a constant temperature and flow rate flows into the heating furnace.
Where Q _t : mixed gas flow rate T _g : mixed gas temperature Cp _g : mixed gas constant pressure specific heat Q _r : second heat storage chamber outlet side gas flow rate T _r : second heat storage chamber outlet side gas temperature Cp _r : second heat storage chamber exit-side gas pressure specific heat Q _c: cooling gas flow T _c: cooling gas temperature Cp _c: a cooling gas specific heat at constant pressure.
[0026]
FIG. 3 is a conceptual diagram showing the control system for the heating atmosphere gas temperature by the feedback method for the regenerative heater 1B. As shown here, the atmospheric gas supplied to the furnace 20 to the atmospheric gas passage 22B from the regenerative heater 1B to the furnace 20, that is, from the high temperature gas and cooling gas supply port discharged from the heat storage chamber 3A A measuring device for measuring the temperature of the mixed gas of the cooling gas to be input is provided, and the measurement result is input to the gas flow rate adjusting device 34B. The gas flow rate adjusting device 34B calculates the gas amount and the temperature adjustment gas amount from the first heat storage chamber 3B based on the temperature and amount of the gas to be supplied to the heating furnace 20, and the first heat storage chamber gas flow rate adjustment valve 31B and the cooling gas. The opening degree of the flow control valve 32B is adjusted and controlled.
[0027]
Conventionally, the temperature of the gas supplied from the regenerative heater has periodically fluctuated, and has reached about 200 ° C. at the maximum. However, according to the present invention, the fluctuation range is remarkably reduced. When the control format was properly taken, the fluctuation range was approximately ± 5 ° C.
[0028]
As mentioned above, although embodiment of this invention was described about the most typical form, application of this invention does not stop in this, For example, it does not prevent using reducing gas about atmospheric gas. As for the supply of the cooling gas, instead of branching from the heating gas path as in this example, a gas whose temperature has been adjusted in advance may be supplied from a cooling gas supply path provided separately and independently. Moreover, in this example, although the heated atmospheric gas is supplied to the heating furnace, the application is not particularly limited, and for example, it may be used for tundish heating for steel making.
[0029]
【The invention's effect】
In the present invention, as described above, the gas temperature discharged from the regenerative heater is adjusted to the temperature by the cooling gas and supplied to the heating furnace or the like, so that it is supplied to the heating furnace or the like while maintaining high thermal efficiency. The atmospheric gas temperature can be made extremely uniform.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a regenerative atmosphere gas heating apparatus for carrying out an atmosphere heating method according to the present invention.
FIG. 2 is a conceptual diagram of a heating gas temperature control system using a feed-forward method.
FIG. 3 is a conceptual diagram of a heating gas temperature control system using a feedback method.
[Explanation of symbols]
1A to 1C: Regenerative heaters 2A to 2C: Burner devices 3A to 3C: First heat storage chambers 4A to 4C: Second heat storage chambers 5A to 5C: Combustion chambers 6A to 6C: Combustion gas control valves 7A to 7C: Exhaust valves 8A to 8C: Atmospheric gas blowing valves 9A to 9C: Atmospheric gas recovery valves 10A to 10C: Air valve 11: Exhaust fan 12: Atmospheric gas blowing fan 13: Atmospheric gas recovery fan 14: Air fan 15: Atmospheric gas supply source 16: Atmospheric gas tank 17: O ₂ removing device 19: CO ₂ removing device 20: heating furnaces 21A to 21C: cooling gas injection valves 22A to 22C: atmospheric gas passages 23A to 23C: cooling gas supply port 31B: first heat storage chamber gas flow rate adjustment Valve 32B: Cooling gas flow rate adjusting valve 33B: First heat storage chamber gas outlet temperature measuring device 34B: Gas flow rate adjusting device 35B: Mixed gas temperature measuring device

Claims (4)

Three or more regenerative heaters having a first heat accumulator heated and stored by combustion exhaust gas from a burner device and a second heat accumulator provided in an atmosphere gas suction path are used to burn each of the regenerator heaters. In the method for heating and supplying the atmospheric gas, the heated atmospheric gas is continuously switched by sequentially switching the state, the atmospheric gas heating state, and the atmospheric gas suction state in this order.
A method for adjusting a heating temperature of an atmospheric gas, wherein a cooling gas is mixed with the atmospheric gas discharged from the first heat storage chamber of the regenerative heater in the atmospheric gas heating state. Three or more regenerative heaters comprising a combustion burner, a first heat storage chamber provided in the exhaust path of the combustion exhaust gas from the burner, and a second heat storage chamber provided in the suction path for the atmospheric gas, In the regenerative atmospheric gas heating device that continuously supplies the heated atmospheric gas by sequentially switching the respective regenerative heaters in the order of the combustion state, the atmospheric gas heating state, and the atmospheric gas suction state,
An apparatus for adjusting a heating temperature of a regenerative atmospheric gas, wherein a cooling gas supply port is provided in an atmospheric gas passage extending from a first thermal storage chamber to a heating facility of the regenerative heater. A first heat storage chamber outlet gas temperature measuring device is installed in the atmosphere gas passage, a first heat storage chamber gas flow rate control valve is installed in the atmosphere gas supply path to the first heat storage chamber , and the atmosphere gas passage is provided in the atmosphere gas passage. A cooling gas flow rate adjustment valve is installed in the cooling gas supply path to the provided cooling gas supply port ,
Based on the temperature signal of the first heat storage chamber outlet gas temperature measuring device,
_{Q t · T g · Cp g} = Q r · T r · Cp r + Q c · T c · Cp c
Q _t = Q _r + Q _c
3. The heating temperature of the regenerative atmospheric gas according to claim 2, wherein a gas flow rate control device for controlling the first heat storage chamber gas flow rate control valve and the cooling gas flow rate control valve is installed so as to satisfy Adjustment device.
Here Q _t: flow rate of the mixed gas T _g: mixed gas temperature Cp _g: mixed gas pressure specific heat Q _r: first regenerator outlet side gas flow T _r: first regenerator outlet side gas temperature Cp _r: first regenerative chamber exit-side gas pressure specific heat Q _c: cooling gas flow T _c: cooling gas temperature Cp _c: cooling gas specific heat at constant pressure A mixed gas temperature measuring device for measuring the temperature of the mixed gas of the atmospheric gas supplied from the first heat storage chamber and the cooling gas supplied from the cooling gas supply port is installed in the atmosphere gas passage, and the first heat storage A first heat storage chamber gas flow rate adjustment valve is installed in the atmosphere gas supply path to the chamber , and a cooling gas flow rate adjustment valve is installed in the cooling gas supply path leading to the cooling gas supply port provided in the atmosphere gas passage And
A gas flow rate control device that controls the first heat storage chamber gas flow rate control valve and the cooling gas flow rate control valve based on the temperature measurement result of the mixed gas temperature measuring device so as to maintain the temperature based on the measurement result at a target value. The apparatus for adjusting a heating temperature of a regenerative atmosphere gas according to claim 2, wherein the apparatus is installed .

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