JP4033851B2 - Furnace gas circulation unit - Google Patents

Description

  The present invention relates to an in-furnace gas recirculation unit, and more particularly, to an in-furnace gas that can be disposed at any position of the furnace body and can control the in-furnace circulation or stirring of the in-furnace gas. It relates to a gas circulation unit.

  In general, a combustion furnace such as a tubular heating furnace, a metal heating furnace, a ceramic firing furnace, a metal melting furnace, a gasification melting furnace, or a boiler is provided with a combustion facility, and the combustion facility is a fuel supply device that supplies hydrocarbon fuel. An air supply device that supplies combustion air, a burner device that mixes fuel and combustion air, and burns the fuel. The fuel mixed with the burner device and the combustion air generate a flame by diffusion combustion in the in-furnace combustion zone. Premixing of fuel and combustion air before supplying the burner apparatus is concerned about causing an unexpected flashback phenomenon, and is not generally employed.

  In order to achieve complete combustion of fuel in a general combustion apparatus, it is necessary to set the actual air amount of the combustion air to an excessive air ratio exceeding the theoretical air amount of the fuel. The mixing ratio (air fuel consumption) is set to approximately 14 to 15. For example, the fuel volume of methane fuel supplied to the combustion device is set to about 1/15 of the required air amount. Many combustion facilities include a flame holder such as a swirling flow type or a flame holding plate type in order to mix the fuel injection flow and the air flow having such a flow rate difference as desired. The flame holder is disposed in a mixed region of fuel and air to form a high-temperature circulating flow that can be ignited, thereby preventing the flame from blowing out and ensuring the stability of the flame.

In such a conventional combustion method, a large amount of air flow is blown into the furnace as compared with the fuel flow rate. Therefore, the characteristics of the flame formed in the furnace, the characteristics of gas circulation in the furnace, etc. It is generally determined by control of temperature, flow rate, flow rate, directionality, etc., and limits are inherently imposed on the control of the furnace gas circulation and flame characteristics. In order to improve the control of the gas circulation in the furnace and the flame characteristics, the present inventors have mixed the combustion gas derived from the furnace (in-furnace gas) or the fuel mixed with water vapor and injected into the furnace. momentum and the combustion method or the fuel supply method for increasing (momentum) already proposed (JP 2001-124329, JP-see JP 2001-124 3 05 No.).
JP 2001-124329 A JP 2001-124305 A

  However, the conventional combustion method is based on the premise that the positions of the fuel supply port, the combustion air supply port, and the combustion exhaust gas exhaust port in the furnace are specified. It is designed after specifying the positions of these supply ports and exhaust ports. Therefore, the gas circulation in the furnace cannot be controlled without being subjected to positional restrictions of the fuel supply port, the combustion air supply port, and the combustion exhaust gas exhaust port.

  On the other hand, a stirrer that stirs the gas in the furnace can be arranged in the furnace and the gas in the furnace can be forcibly stirred. However, in this case, the drive unit or the driving force transmission mechanism of the stirrer is installed in the furnace. Therefore, the stirrer must be designed with a special heat-resistant material and a heat-resistant mechanism, and the initial equipment cost of the stirrer is increased. In reality, it is difficult to ensure the heat resistance and durability of the stirring device itself, and even if this can be overcome, the stirring gas is controlled when the furnace gas is controlled by direct stirring of the furnace gas. It is difficult to predict the characteristics of the circulation flow caused by the above, the action of the circulation flow acting on the flame, and the like.

  Conventionally, the oxygen partial pressure (oxygen concentration) of the gas in the furnace is the injection state of air and fuel by the burner device, the combustion reaction of the flame, the circulation of the combustion gas in the furnace, the oxidation or combustion reaction of the object to be heated or combustible However, it is difficult to positively control the oxygen partial pressure in the furnace. If a large amount of air or oxygen is supplied into the furnace, the oxygen partial pressure in the furnace increases rapidly, and the oxidation or combustion reaction is likely to change rapidly. When oxygen is blown into the furnace, changes in the furnace temperature field that are difficult to predict can occur. On the other hand, when a large amount of the in-furnace gas is recirculated to the burner device, the combustion reaction is suppressed, and there is a possibility that a change in the combustion atmosphere, for example, a change from the oxidation combustion atmosphere to the reduction combustion atmosphere may occur.

  The present invention has been made in view of such circumstances, and the object thereof is not subject to positional restrictions related to the positions of the fuel supply port, the combustion air supply port, and the combustion exhaust gas exhaust port, An object of the present invention is to provide an in-furnace gas circulation unit that can be disposed at any position of the furnace body and can control the in-furnace circulation or stirring of the in-furnace gas.

  Another object of the present invention is to provide an in-furnace gas circulation unit that can variably control the combustion atmosphere in the furnace without affecting the in-furnace temperature field.

In order to achieve the above object, the present invention includes a supply / exhaust port that functions as a discharge port for deriving the gas in the furnace to the outside of the furnace and also functions as an injection port for injecting a reintroduction flow of the gas in the furnace into the furnace. First and second heat storage devices,
A circulating fan that pressurizes the gas in the furnace led out of the furnace and sends the gas in the furnace to the supply / exhaust port via the heat storage device;
A first position where the gas in the furnace is led out of the furnace through the first heat storage device, and the reintroduced gas is injected into the furnace through the second heat storage device, and the gas in the furnace is passed through the second heat storage device. A supply / exhaust switching valve device that is led out and can be switched to a second position for injecting reintroduced gas into the furnace via the first heat storage device;
Each of the first and second heat storage devices receives heat by heat transfer contact with the furnace gas, cools the furnace gas, and dissipates heat by heat transfer contact with the reintroduction flow. A heat storage body for heating
Each supply / exhaust port of the first and second heat storage devices is parallel to the inner wall surface of the furnace body and close to each other so as to continuously inject the reintroduction flow in the same direction to a specific portion of the furnace interior region. It is arranged to provide an in-furnace gas circulation unit characterized in that the supply / discharge switching valve device is alternately switched to the first position and the second position.

  The in-furnace gas circulation unit of the present invention has a structure independent of the combustion equipment of the furnace, and is not subject to positional restrictions due to the positions of the fuel supply port, the combustion air supply port, and the combustion exhaust gas exhaust port. It can be placed anywhere on the body. The high-temperature furnace gas is cooled by the heat storage body, and the supply / discharge switching valve device and the circulation fan are disposed outside the furnace. Therefore, excessive thermal stress does not act on the supply / discharge switching valve device and the circulation fan, and the circulation fan does not suffer from adverse effects due to thermal degradation. The cooled in-furnace gas is reheated by the heat accumulator and reintroduced into the furnace at a temperature equivalent to the in-furnace gas. The flow rate and flow rate of the reintroduction flow can be variably controlled by setting the flow rate and pressure of the circulation fan.

The present invention also provides an in-furnace gas circulation unit characterized in that the in-furnace gas circulation unit further includes an adding device for adding an additional fluid to the cooled in-furnace gas.
The additional device adds an oxidizer, water vapor, or inert gas that adjusts the combustion atmosphere in the furnace to the cooled furnace gas, and the heat storage device heats the furnace gas containing the additional fluid and re-enters the furnace. Introduce. The combustion atmosphere in the furnace is adjusted by the reintroduction flow, and since the reintroduction flow is heated by the heat storage device and then injected into the furnace, the change in the furnace temperature field hardly occurs. Therefore, according to the in-furnace gas circulation unit, the combustion atmosphere in the furnace can be controlled without substantially affecting the in-furnace temperature field.

The present invention further provides an in-furnace combustion method using the in-furnace gas circulation unit configured as described above.
(1) Injecting the reintroduction flow into the furnace gas to activate the furnace gas circulation,
(2) Injecting the reintroduction flow toward the furnace flame to control the reach distance, direction and / or flame volume of the flame;
(3) Control the combustion reaction of the fuel and combustion air by injecting the reintroduction flow into the furnace so as to mix and collide with the fuel jet and air jet of the combustion facility, or
(4) A furnace combustion method characterized by injecting a reintroduction flow to which the additional fluid has been added into the furnace, and controlling the properties of the furnace flame formed by the furnace combustion equipment or the furnace combustion atmosphere. To do.

  According to the above configuration of the present invention, it is possible to dispose the fuel supply port, the combustion air supply port, and the combustion exhaust gas exhaust port in any position of the furnace body without being subjected to positional restrictions. An in-furnace gas circulation unit capable of controlling the in-furnace circulation or stirring of gas is provided.

  Further, according to the present invention, there is provided an in-furnace gas circulation unit capable of variably controlling the combustion atmosphere in the furnace without affecting the in-furnace temperature field by further providing the additional fluid addition device in the in-furnace gas circulation unit. Is done.

  According to a preferred embodiment of the present invention, the in-furnace gas circulation unit further includes a support substrate that is integrated with the furnace body to form the inner wall surface of the furnace, and the heat storage device includes a casing that houses the heat storage body. . The casing is integrally supported by the support substrate. The supply / discharge switching valve device is connected in series to each heat storage device, and a control device for adjusting the switching timing of each supply / discharge switching valve device is further provided in the in-furnace gas circulation unit. The reintroduction flow is, for example, injected into a portion of the furnace region where the action of the flame or its radiant heat is difficult to reach, a portion of the furnace region where gas circulation in the furnace is difficult to occur, or a region where the gas in the furnace stays Or it injects into a dead water area | region and improves the heating effect | action of a combustion furnace by the convection heat transfer in a furnace. The re-introduction stream also collides with the flame, combustion gas stream, fuel jet or combustion air jet and changes the properties of the flame or combustion gas.

The relative angle between the central axes of each reintroduction flow (or the angle formed by the central axis of each heat storage device) is such that a reintroduction flow in the same direction is continuously injected into a specific part of the furnace area. Preferably, it is limited within the range of 20 ° to −20 °, more preferably within the range of 10 ° to −10 °, and the distance between the centers of the supply / discharge ports is preferably relative to the diameter D of the supply / discharge ports. 5D or less, more preferably 3D or less.

  Preferably, the in-furnace gas circulation unit further includes a third heat storage device, and the supply / discharge switching valve device injects reintroduced gas into the furnace from the supply / discharge port of any one of the heat storage devices, and the other Switching control is performed so that the gas in the furnace is led out from the supply / discharge port of the two heat storage devices. More preferably, the in-furnace gas circulation unit further includes a fourth heat storage device, and the supply / discharge switching valve device injects reintroduced gas into the furnace from the supply / discharge port of any one of the heat storage devices, and the other Switching control is performed so as to derive the gas in the furnace from the supply / exhaust port of the three heat storage devices. The flow rate of the in-furnace gas flow sucked from the supply / exhaust port is reduced to 1/2 or less of the flow rate of the reintroduction flow injected from the supply / exhaust port, and the short path of the gas flow between the supply / exhaust ports is suppressed Is done.

  According to another preferred embodiment of the present invention, the in-furnace gas circulation unit further includes an adding device for adding an additional fluid to the cooled in-furnace gas. Preferably, as additional fluid, air, oxygen, water vapor and / or inert gas is added to the reintroduction stream. More preferably, the in-furnace gas circulation unit further includes an exhaust means for exhausting a part of the in-furnace gas after cooling out of the system.

  FIG. 1 is a longitudinal sectional view of a furnace gas circulation unit showing a preferred embodiment of the present invention. FIG. 1 (A) shows a first operating state of the in-furnace gas circulation unit, and FIG. 1 (B) shows a second operating state of the in-furnace gas circulation unit.

  The in-furnace gas circulation unit 1 includes a heat storage device 2 (2A: 2B), a supply / discharge switching valve device 3 (3A: 3B) and a circulation fan 4, and the heat storage device 2 and the supply / discharge switching valve device 3 are located in the furnace region. 9 is disposed in a furnace body 91 that divides 9. The heat storage device 2 has a structure in which the heat storage body 21 is accommodated in the heat storage body case 22, and the heat storage body case 22 penetrates the support substrate 23. The support substrate 23 is made of the same heat and fire resistant material as the furnace body 91. The support substrate 23 is integrated with the furnace body 91 and forms a furnace inner wall surface 92 facing the furnace inner region 9 together with the furnace body 91.

  Each heat storage body 21 is made of a ceramic structure heat storage body having a honeycomb structure having a cylindrical outer shape, and has a large number of narrow flow paths. Each flow path of the heat storage body 21 penetrates the heat storage body 21 in the axial direction of the heat storage device 2. The heat storage body 21 constitutes a regenerator type heat exchanger and exhibits a temperature efficiency of 0.9 or more. The structure of this type of heat exchanger is disclosed in detail in, for example, Japanese Patent Application No. 5-6911 (Japanese Patent Laid-Open No. 6-213585) by the applicant of the present application, and further detailed description is omitted. To do.

  The heat storage case 22 is made of a metal cylindrical member that penetrates the support substrate 23 and is integrally supported by the support substrate 24. The front end portion of the heat storage body case 22 extends further from the front end surface of the heat storage body 21 to the inside of the furnace, and is slightly reduced in diameter and opened to the in-furnace region 9. The circular opening at the front end of the heat storage body case 22 constitutes the furnace gas supply / exhaust port 20. The supply / discharge port 20 functions as an in-furnace gas suction port for sucking the in-furnace gas in the in-furnace region 9 and also functions as an in-furnace gas injection port for injecting the pressurized in-furnace gas into the in-furnace region 9. .

  Each supply / discharge switching valve device 3 corresponding to each heat storage device 2 is aligned coaxially with the heat storage device 2 and projects out of the furnace from the support substrate 23. Each valve device 3 includes a valve mechanism 30, a furnace gas inlet 31, a furnace gas outlet 32, and a valve driving device 33. The valve drive device 33 drives the valve mechanism 30 to switch the valve mechanism 30 to the lead-out position or the introduction position. The valve mechanism 30 functions as a two-position control valve capable of selectively opening and closing the introduction port 34 or the derivation port 35.

  An in-furnace gas introduction pipe 41 is connected to the discharge port of the circulation fan 4. The in-furnace gas introduction pipe 41 branches into introduction pipes 42 and 43, and the introduction pipes 42 and 43 are in-furnace gas of each valve device 3. Each is connected to the inlet 31. On the other hand, an in-furnace gas outlet pipe 46 is connected to the suction port of the circulation fan 4. The in-furnace gas outlet pipe 46 branches into outlet pipes 44 and 45, and the outlet pipes 44 and 45 are connected to the valve devices 3. Each is connected to the furnace gas outlet 32. The suction pressure of the circulation fan 4 acts on one supply / exhaust port 20 via the in-furnace gas outlet pipes 46, 45, 44, the valve device 3 and the heat storage device 2, and the supply air pushing pressure of the circulation fan 4 is introduced. It acts on the other supply / exhaust port 20 through the pipes 41, 42, 43, the valve device 3 and the heat storage device 2.

  In the first operating state shown in FIG. 1 (A), the valve mechanism 30 of the first valve device 3A is located at the lead-out position where the furnace gas introduction port 34 is closed and the furnace gas lead-out port 35 is opened. The valve mechanism 30 of the two-valve device 3B is located in the introduction position in which the introduction port 34 is opened and the outlet port 35 is closed. The in-furnace gas flows into the first heat storage device 2A from the supply / discharge port 20 of the first heat storage device 2A and passes through the flow path of the heat storage body 21 under the suction pressure of the circulation fan, as indicated by the arrows. 1 flows into the switching valve 3A. The high temperature in-furnace gas is radiated by heat transfer contact with the heat storage body 21 and the temperature is lowered. At the same time, the heat storage body 21 receives the sensible heat held in the furnace gas and raises the temperature. The in-furnace gas cooled by heat exchange with the heat storage body 21 is sucked into the circulation fan 4 through the outlet 32 and the outlet pipes 45 and 46 of the first valve device 3A. The circulation fan 4 pressurizes a relatively low temperature in-furnace gas and supplies it to the inlet 31 of the second valve device 3B via the inlet pipes 41 and 42. The in-furnace gas flows into the second heat storage device 2B from the second valve device 3B, and makes heat transfer contact with the heat storage body 21. The heat storage body 21 dissipates heat by heat exchange with a relatively low temperature in the furnace gas and cools it. At the same time, the in-furnace gas receives the sensible heat held by the heat storage body 21 and rises in temperature, and is blown out from the supply / discharge port 20 of the second heat storage device 2B to the in-furnace region 9 as a high-temperature reintroduction gas. The in-furnace gas after the temperature rise has a temperature substantially equal to the in-furnace gas flowing into the first heat storage device 2.

  The temperatures Ti, To, T1, and T2 of the gas circulating through the gas circulation circuit including the heat storage device 2, the valve device 3, the circulation fan 4, the outlet pipes 44, 45, and 46 and the introduction pipes 41, 42, and 43 are, for example, It is set as follows.

Furnace gas temperature at the time of derivation (supply / discharge port 20) Ti = 1200 ° C.
Gas temperature in the furnace after passing through the heat storage body (valve device 3) T1 = 200 ° C.
Gas temperature when introducing the valve device (inlet 31) T2 = 100 to 150 ° C.
Gas temperature at re-introduction (supply / discharge port 20) To = 1150 ° C
Note that the difference (temperature drop) between the gas temperature T1 after passing through the heat storage body 21 and the gas temperature T2 introduced into the valve device 3 is mainly the pipes of the outlet pipes 44, 45, 46 and the inlet pipes 41, 42, 43. Due to heat dissipation from the wall surface.

  In the second operating state shown in FIG. 1 (B), the valve mechanism 30 of the second valve device 3B is located at the lead-out position where the introduction port 34 is closed and the lead-out port 35 is opened, and the first valve device 3A is The inlet port 34 is opened by the valve mechanism 30 and the outlet port 35 is closed. The gas in the furnace flows into the supply / exhaust port 20 of the second heat storage device 2B under the attraction pressure of the circulation fan 4 as shown by the arrow, and passes through the heat storage body 21, the second valve device 3B, and the outlet pipes 44 and 46. Then, the air is sucked into the circulation fan 4 and pressurized by the circulation fan 4, and is supplied from the inlet / outlet 20 of the first heat storage device 2A through the introduction pipes 41 and 43, the first valve device 3A and the first heat storage device 2A. Blow out to the inner area 9. In this circulation circuit, the furnace gas is cooled by exchanging heat with the heat storage body 21 of the second heat storage device 2B, and is heated by exchanging heat with the heat storage body 21 of the first heat storage device 2A. The supply / discharge port 20 of the first heat storage device 2A injects a reintroduction gas having the same temperature as the furnace gas flowing into the supply / discharge port 20 of the second heat storage device 2B into the furnace region 9.

  The circulation circuit also includes an exhaust pipe 47 (shown by a broken line) for exhausting a part of the furnace gas to the outside of the system. The exhaust pipe 47 is connected to the introduction pipe 41. An exhaust control valve 48 is interposed in the exhaust pipe 47, and the exhaust control valve 48 exhausts about 5 to 10% of the in-furnace gas to the atmosphere or the like as desired in order to prevent the heat storage body 21 from being overheated.

  The in-furnace gas circulation unit 1 includes a valve drive device 33, an exhaust control valve 48, and a control unit C / U (illustrated only in FIG. 1A) for controlling the operation of the circulation fan 4. The control unit C / U controls the switching timing of each valve drive device 33 in a coordinated manner, and sets the phase (derived position or introduction position) of each valve device 3 to an opposite phase. The valve drive device 33 switches the valve position of the valve device 3 every predetermined time under the control of the control unit C / U, and the in-furnace gas circulation unit 1 has the first operating state shown in FIG. The 2nd operation state shown to 1 (B) is repeated alternately every predetermined time.

  The valve device 3 and the circulation fan 4 are only in contact with the in-furnace gas cooled by the heat storage device 2 in any operating state. Therefore, excessive thermal stress acts on the valve device 3 and the circulation fan 4. And the problem of thermal degradation associated with this does not occur.

  2 and 3 are sectional views showing the structure of each part of the supply / discharge switching valve device 3. FIG. 2 shows the lead-out position of the valve device 3, and FIG. 3 shows the introduction position of the valve device 3. It is shown.

  The supply / discharge switching valve device 3 has a structure in which a supply / discharge pipe 61, a valve housing 51, and a valve drive device 33 are connected in series. The valve driving device 33 includes an actuator 50 that is integrally attached to the valve housing 51 by a support member 58. The supply / discharge pipe 61 is hermetically connected to the flange portion of the heat storage body case 22, and forms the supply / exhaust flow path 6 for the in-furnace gas in the in-pipe region. An elbow pipe 36 having a lead-out port 35 is disposed in the supply / discharge passage 6, and the elbow pipe 36 penetrates the pipe wall of the supply / exhaust pipe 61 and projects out of the pipe. The connecting flange portion formed at the protruding end of the elbow pipe 36 forms the furnace gas outlet 32 to which the outlet pipes 44 and 45 can be connected.

  The valve housing 51 is hermetically connected to the end of the supply / exhaust pipe 61, and the supply region 5 for the in-furnace gas recirculation flow is formed in the housing 51. The valve housing 51 includes a rod insertion part 52 and a valve seat part 55. The piston rod 53 of the actuator 50 penetrates the rod insertion part 52 so that sliding is possible. A valve element 54 fixed to the tip of the piston rod 53 is seated on the valve seat 55. The supply / discharge pipe 61, the lead-out port 35, the valve body 54, the introduction port 34, the valve seat portion 55, the actuator 50, the rod insertion portion 52, and the piston rod 53 are concentric about the central axis CL of the supply / discharge switching valve device 3. Placed in. The lead-out port 35, the valve body 54, the introduction port 34, and the valve seat 55 constitute the valve mechanism 30 shown in FIG.

  A circular contour introduction port 34 is formed at the center of the valve seat 55, and the piston rod 53 passes through the center of the introduction port 34. An annular seating member 56 capable of airtight contact with the valve body 54 is attached to the valve seat portion 55. The seating member 56 is disposed on the surface of the valve seat portion 55 facing the supply / discharge flow path 6. A drive side portion of the piston rod 53 extends through the rod insertion portion 52 to the outside of the valve housing 51 and extends into the actuator 50. The actuator 50 comprises a fluid pressure actuated cylinder device (pneumatically actuated cylinder device in this example), and a working fluid circuit (not shown) is connected to the actuator 5 and a control signal line of the control unit C / U. 59 is connected to a working fluid supply / discharge control unit (not shown) of the actuator 50. The supply / discharge control unit of the actuator 50 expands and contracts the piston rod 53 in response to the control signal input via the control signal line 59, and controls the valve device 3 in two positions as described above.

  In the lead-out position of the valve device 3 shown in FIG. 2, the actuator 50 pulls the piston rod 53 into the actuator 50, the valve body 54 is seated on the valve seat portion 55, and the valve body 54 and the seating member 56 are The supply area 5 and the supply / exhaust flow path 6 are isolated so as not to be ventilated. The valve body 54 completely opens the outlet port 35, and the supply / exhaust flow path 6 communicates with the in-furnace gas outlet 32. The first valve device 3A shown in FIG. 1A and the second valve device 3B shown in FIG. 1B are in this derived position.

  In the introduction position of the valve device 3 shown in FIG. 3, the actuator 50 extends the piston rod 53 from the actuator 50, and the valve body 54 is separated from the valve seat portion 55 and seated on the outlet port 35. The valve body 54 and the outlet port 35 isolate the supply / exhaust flow path 6 and the in-furnace gas outlet 32 so that they cannot be vented. The introduction port 34 is completely opened, and the supply region 5 communicates with the supply / discharge channel 6. The second valve device 3B shown in FIG. 1 (A) and the first valve device 3A shown in FIG. 1 (B) are in this introduction position.

  FIG. 4 is a longitudinal sectional view of the in-furnace gas circulation unit showing another embodiment of the present invention. FIG. 4 (A) shows a first operating state of the in-furnace gas circulation unit, and FIG. B) shows the second operating state of the in-furnace gas circulation unit. In addition, in each figure after FIG. 4, the same referential mark is attached | subjected about the component which is substantially the same as that of the component shown in FIG.

  The in-furnace gas circulation unit 1 shown in FIG. 4 includes a valve body 65 having a pivotal on-off valve structure in the supply / discharge passage 6. The on-off valve 65 is fixed to a rotatable support shaft 66, and the support shaft 66 is rotated by the power of the actuator 50. The on-off valve 65 selectively opens / closes the outlet 31 or the inlet 32 according to the rotation of the support shaft 66. The positions of the on-off valves 65 of the first and second valve devices 3A: 3B are set in opposite phases. For example, when the first valve device 3A is in the derived position, the second valve device 3B takes the introduction position. (FIG. 4A), when the second valve device 3B is in the lead-out position, the first valve device 3A takes the introduction position (FIG. 4B). The actuator 50 switches the position of the on-off valve 65 every predetermined time under the control of the control unit C / U, and the in-furnace gas circulation unit 1 operates in the first operating state shown in FIG. ) And the second operating state shown in FIG. 6 are repeated alternately at predetermined time intervals.

  The valve device 3 having the structure shown in FIG. 4 can be advantageously used for downsizing and simplifying the device structure as compared with the valve structure shown in FIGS. The other structure of the in-furnace gas circulation unit 1 shown in FIG. 4 is substantially the same as the structure of each part of the in-furnace gas circulation unit shown in FIG. 1 to FIG. To do.

FIG. 5 is a longitudinal sectional view of an in-furnace gas circulation unit showing still another embodiment of the present invention.
The in-furnace gas circulation unit 1 shown in FIG. 5 includes a heat storage device 2 and a supply / discharge switching valve device 3 having the same structure as the in-furnace gas circulation unit shown in FIG. 1 to FIG. These are substantially the same as the in-furnace gas circulation unit 1 shown in FIGS. However, the in-furnace gas circulation unit 1 of the present embodiment further includes an additional fluid addition device 7 for adding an additional fluid to the in-furnace gas in the circulation circuit. The addition device 7 is interposed in the furnace gas introduction pipe 41. The additional fluid supply pipe 71 is connected to the addition device 7, and the control valve 72 is interposed in the supply pipe 71.

  As an additional fluid, air, oxygen, or water vapor is supplied from the supply pipe 71 to the adding device 7. The in-furnace gas sucked by the in-furnace gas circulation unit 1 generally has only a residual oxygen concentration in the range of 0% to 10%, and the temperature of the in-furnace gas is substantially equal to the temperature of the combustion zone. Equally (Ti = 1200 ° C.) and still quite hot. The in-furnace gas is cooled by heat exchange with the heat storage body 21 (T1 = 200 ° C.), further lowered in temperature by heat radiation from the outlet pipes 44, 45, and 46, and sucked into the circulation fan 4 as a relatively low-temperature in-furnace gas. Is done.

  The circulation fan 4 pressurizes the in-furnace gas, and the in-furnace gas is sent to the introduction pipe 41 under the supply air pressure of the circulation fan 4. The addition device 7 adds an additional fluid (air, oxygen, or water vapor) to the furnace gas. The addition amount of the additional fluid is set within a range of 5 to 50% (weight ratio) of the in-furnace gas flow rate circulating in the circulation circuit of the in-furnace gas circulation unit 1, and the control valve 72 variably controls the addition amount. . If desired, a part of the in-furnace gas is exhausted out of the system through an exhaust pipe 47 (shown by a broken line) under the control of the exhaust control valve 48.

  The reintroduced gas is injected into the in-furnace region 9 from the supply / exhaust port 20 of the heat storage device 2 in a state in which the amount of oxygen, the amount of air, or the amount of water vapor is adjusted by adding the additional fluid. By injecting the reintroduced gas whose oxygen amount or air amount is adjusted into the in-furnace region 9, the oxygen partial pressure or the air amount in the in-furnace region 9 can be variably controlled. Further, by directing the jet of reintroduced gas to the flame, the position, volume, directionality, or combustion reaction itself of the flame zone in the in-furnace region 9 can be changed. On the contrary, by increasing the water vapor amount of the reintroduced gas, the oxygen partial pressure or the air amount in the in-furnace region 9 is reduced, or the reintroduced gas is mixed and collided with the fuel injected into the furnace. The hydrocarbon can be reformed, thereby changing the characteristics of the in-furnace combustion reaction.

6 to 8 are a front view and a cross-sectional view showing a supply / discharge pattern of the in-furnace gas circulation unit 1.
The in-furnace gas circulation unit 1 shown in FIG. 6 is the same as the in-furnace gas circulation unit shown in FIGS. 1 to 3, and as shown in FIGS. 6B and 6D, a pair of upper and lower heat storage devices 2A: 2B and supply / discharge switching valve device 3A: 3B. 6 (A) and 6 (C) are front views of the in-furnace gas circulation unit 1 viewed from the in-furnace region, and the in-furnace gas circulation unit 1 shown in FIGS. 6 (B) and 6 (D). Corresponds to each of the operating states.

  In the first operating state of the in-furnace gas circulation unit 1 shown in FIGS. 6 (A) and 6 (B), the supply / exhaust port 20 of the heat storage device 2A functions as an outlet for deriving the in-furnace gas to the outside of the furnace. The supply / discharge port 20B of the heat storage device 2B functions as an injection port for injecting the reintroduced gas into the in-furnace region 9. On the other hand, in the second operating state of the in-furnace gas circulation unit 1 shown in FIGS. 6 (C) and 6 (D), the supply / exhaust port 20 of the heat storage device 2A injects the in-furnace gas into the in-furnace region 9. The supply / exhaust port 20B of the heat storage device 2B functions as an outlet for deriving the furnace gas to the outside of the furnace.

  The control unit C / U controls the operation of the actuator 50, and the supply / discharge switching valve device 3 performs switching between the lead-out position and the introduction position at predetermined time intervals under the control of the control unit C / U. In such a configuration of the heat storage device 2 and the valve device 3, the derivation (suction) flow rate and the injection flow rate of each supply / discharge port 20 are substantially equal. In FIG. 6, the difference between derivation (suction) and injection of the supply / exhaust port 20 is indicated by the brightness of the supply / exhaust port 20, and the supply / exhaust port 20 on the derivation side (suction side) is shown in dark color. The supply / discharge port 20 on the injection side is shown in a bright color.

  The in-furnace gas circulation unit 1 shown in FIG. 7 is provided with three supply / discharge ports 20 and three heat storage devices 2A: 2B: 2C and supply / discharge switching valve devices 3A corresponding to these supply / discharge ports 20: 3B: 3C is provided. The structures of the heat storage devices 2A: 2B: 2C and the supply / discharge switching valve devices 3A: 3B: 3C are substantially the same as those shown in FIGS. The valve devices 3A: 3B: 3C are controlled such that only a single valve device is located at the injection position and the other two valve devices are located at the lead-out position. Accordingly, of the three supply / discharge ports 20, the only supply / discharge port functions as an injection port for injecting the reintroduction gas, and the other two supply / discharge ports guide the gas inside the furnace to the outside. Act as an exit. The valve devices 3A: 3B: 3C are also switched to the injection positions in the order 3A → 3B → 3C. Accordingly, in the in-furnace gas circulation unit 1, in the first operating state shown in FIG. 7A, the supply / discharge port 20 of the heat storage device 2A functions as an injection port, and the supply / discharge port 20 of the heat storage device 2B: 2C is guided. In the second operating state shown in FIG. 7 (B), which functions as an outlet, the supply / discharge port 20 of the heat storage device 2B functions as an injection port, and the supply / discharge port 20 of the heat storage device 2A: 2C functions as a discharge port, Further, in the third operating state shown in FIG. 7C, the supply / discharge port 20 of the heat storage device 2C functions as an injection port, and the supply / discharge port 20 of the heat storage device 2A: 2B functions as a discharge port.

  In this configuration, the opening area of the suction side (outflow side) opening that opens in the in-furnace region 9 (FIG. 1) is set to be twice the opening area of the injection side (introduction side) opening that opens in the in-furnace region 9. Therefore, the flow rate of the in-furnace gas passing through the injection side opening is increased to about twice the flow rate of the in-furnace gas passing through the suction side opening. By such an increase in the injection flow rate, the amount of gas in the furnace attracted by the reintroduction gas flow increases, and the gas circulation action in the furnace is further activated. Moreover, the short path | pass (short circuit) effect | action by which an injection flow is attracted | sucked by the suction side opening by the flow velocity reduction of a suction flow can be suppressed.

  The in-furnace gas circulation unit 1 shown in FIG. 8 includes four supply / discharge ports 20 and four heat storage devices 2A: 2B: 2C: 2D and supply / discharge switching valve devices corresponding to these supply / discharge ports 20. 3A: 3B: 3C: 3D. The structures of the heat storage devices 2A: 2B: 2C: 2D and the supply / discharge switching valve devices 3A: 3B: 3C: 3D are substantially the same as those shown in FIG. The valve devices 3A: 3B: 3C: 3D are controlled such that only a single valve device is located at the injection position and the other three valve devices are located at the outlet position. Accordingly, of the supply / discharge ports 20, the only supply / discharge port functions as an injection port for injecting the reintroduction gas into the in-furnace region 9, and the other three supply / exhaust ports lead out the discharge gas from the furnace. Function as. The valve devices 3A: 3B: 3C: 3D are switched to the injection positions in the order of 3A → 3B → 3C → 3D. Accordingly, in the in-furnace gas circulation unit 1, in the first operating state shown in FIG. 7A, the supply / discharge port 20 of the heat storage device 2A functions as an injection port, and the supply / discharge port 20 of the heat storage device 2B: 2C: 2D. 7B functions as the outlet, and in the second operating state shown in FIG. 7B, the supply / discharge port 20 of the heat storage device 2B functions as the injection port, and the supply / discharge port 20 of the heat storage device 2A: 2C: 2D is the discharge port. In the third operating state shown in FIG. 7C, the supply / discharge port 20 of the heat storage device 2C functions as an injection port, and the supply / discharge port 20 of the heat storage device 2A: 2B: 2D serves as a discharge port. Further, in the fourth operating state shown in FIG. 7D, the supply / discharge port 20 of the heat storage device 2D functions as an injection port, and the supply / discharge port 20 of the heat storage devices 2A: 2B: 2C functions as a discharge port. To do.

  In this configuration, the opening area of the suction side (outflow side) opening that opens in the in-furnace region 9 (FIG. 1) is three times the opening area of the injection side (introduction side) opening that opens in the in-furnace region 9. The flow rate of the in-furnace gas passing through the injection side opening is increased to about 3 times the flow rate of the in-furnace gas passing through the suction side opening. For this reason, the gas circulation action in the furnace is activated, and the above-mentioned short path action can be reliably prevented.

Hereinafter, an embodiment of a combustion furnace provided with the in-furnace gas circulation unit 1 having the above configuration will be described.
FIG. 9 is a cross-sectional view showing the configuration of a combustion furnace provided with the in-furnace gas circulation unit 1 shown in FIG.

  The combustion furnace has a combustion region 9 formed in the furnace body 91, and an object to be heated 95 is disposed in the combustion region 9. In the combustion furnace, a burner 8 is disposed as combustion equipment for heating the article 95 to be heated. The burner 8 is a conventional burner for a combustion furnace including a fuel supply facility, a combustion air supply facility, a pilot burner, a flame holding mechanism, a combustion control device, and the like. The fuel and combustion air of the burner 8 are ejected from the burner tile portion 81 to the in-furnace region 9 to form a flame zone in the in-furnace region 9. As the burner 8, an alternate combustion type heat storage type (regenerator type) burner provided with a heat storage body such as a honeycomb type heat storage body or a pellet type heat storage body may be adopted.

  The flame formed by the fuel and combustion air of the burner 8 is determined by the directionality of the burner 8, the fuel injection speed, the air injection speed, the air ratio, the shape of the burner tile portion 81, the position of the combustion exhaust gas outlet, and the like. There is a limit to controlling the in-furnace gas circulation, the flame position, the flame properties, and the like only by the burner 8. For this reason, the in-furnace gas circulation unit 1 </ b> A: 1 </ b> B is disposed at an appropriate position of the furnace body 91. In this example, the in-furnace gas circulation unit 1A is disposed at a position (diagonal position) symmetrical to the burner 8 with respect to the center of the combustion furnace, and the in-furnace gas circulation unit 1B is a furnace in which the burner 8 is disposed. It is arranged on the furnace wall orthogonal to the wall.

  The in-furnace gas circulation unit 1A: 1B sucks in-furnace gas from one supply / exhaust port 20, cools it by the heat storage device 2, pressurizes the cooled furnace gas by the circulation fan 4, and the other heat storage device 2 Then, it is reheated and injected into the in-furnace region 9 from the supply / discharge port 20. The injection flow of the in-furnace gas circulation unit 1A energizes the high-temperature in-furnace gas, and directs the in-furnace gas flow so that the in-furnace gas flow is directed to the back side region of the object to be heated 95 located on the opposite side of the flame. Works. The jet flow of the in-furnace gas circulation unit 1 </ b> B energizes the in-furnace gas so that the in-furnace gas directed to the back side region of the article to be heated 95 is turned toward the flame base of the burner 8. As a result, the in-furnace circulation of the in-furnace gas is activated, the in-furnace gas retention region or the dead water region is eliminated, and the temperature field in the in-furnace region 9 is leveled over the entire region.

  The in-furnace gas circulation units 1 </ b> A and 1 </ b> B also add an oxidizing agent (air or oxygen) by the addition device 7 to the sucked and cooled in-furnace gas. A part of the in-furnace gas is exhausted from the exhaust pipe 47 to the outside of the system. While the oxygen concentration of the in-furnace gas is generally 0% to 10%, the oxygen concentration of the in-furnace gas jet injected by the in-furnace gas circulation unit 1A: 1B is, for example, 5 to 50% (weight ratio). To increase. The addition amount of the oxidizing agent with respect to the furnace gas is controlled by the addition device 7. Unburned fuel contained in the in-furnace gas circulating in the in-furnace region 9 mixes and collides with the in-furnace gas jet of the in-furnace gas circulation unit 1A: 1B, and burns and generates heat. Further, the oxygen partial pressure of the in-furnace gas is increased by the addition of the oxidizing agent in the adding device 7, and the combustion reaction in the furnace is promoted. Thus, the in-furnace gas circulation units 1A: 1B function as in-furnace circulation promotion means, combustion promotion means, and oxygen partial pressure control means.

FIG. 10 is a cross-sectional view showing a modification of the combustion furnace shown in FIG.
The form of the article to be heated 95 differs depending on the purpose of use and design conditions of each combustion furnace. As shown in FIG. 10, when heating the deformed article to be heated 95, it is desirable that the shape of the flame zone of the burner 8 be changed to a shape suitable for the contour of the article to be heated 95. In the case of the conventional burner structure, by arranging a plurality of burners at appropriate positions, it is only possible to adjust the action of the flame on the object to be heated 95. For this reason, from the relationship with the fuel pipe and the combustion air supply path, Difficulties occurred in the arrangement of various pipes and equipment, and the design flexibility was restricted. However, the in-furnace gas circulation unit 1 has relatively few design restrictions in relation to the arrangement of piping or equipment in such a system, and can be arranged at an arbitrary position.

  In the combustion furnace shown in FIG. 10, the in-furnace gas circulation unit 1 </ b> A is disposed on the furnace wall orthogonal to the furnace wall in which the burner 8 is disposed, and the jet of fuel and combustion air injected by the burner 8 is heated 95. The flame shape is deformed so as to correspond to the shape of the object to be heated 95. The in-furnace gas circulation unit 1B is disposed at a position (diagonal position) symmetrical to the burner 8 with respect to the center of the combustion furnace, energizes high-temperature in-furnace gas, and is placed on the opposite side of the flame. It acts to direct the gas flow in the furnace to the back side region of the heated object 95. Thereby, while optimizing the flame | frame action with respect to the to-be-heated material 95, the gas circulation in a furnace can be activated and the temperature level of a furnace temperature field can be achieved. If desired, an oxidant or the like may be added to the reintroduced gas by the addition device 7 to promote the combustion reaction in the furnace, or the oxygen partial pressure in the furnace atmosphere may be variably controlled.

FIG. 11 is a cross-sectional view showing another embodiment of the combustion furnace provided with the in-furnace gas circulation unit.
The combustion furnace shown in FIG. 11 includes a combustion region 9 and a burner 8 as in the combustion furnace shown in FIG. The furnace wall portion 92 of the furnace body 91 adjacent to the burner 8 is inclined at a predetermined angle with respect to the burner tile portion 81 of the burner 8, and the furnace wall portion 92 includes a furnace having the structure shown in FIG. An internal gas circulation unit 1 is provided.

  The burner 8 ejects fuel and combustion air from the burner tile portion 81 to the in-furnace region 9, and the in-furnace gas circulation unit 1 sucks in-furnace gas from one supply / discharge port 20 and cools it by the heat storage device 2. Then, the cooled furnace gas is pressurized by the circulation fan 4, reheated by the other heat storage device 2, and injected from the supply / exhaust port 20 into the furnace area 9.

  In the present embodiment, the in-furnace gas circulation unit 1 increases the momentum increase that increases the combustion gas momentum of the burner 8 in addition to the functions as the in-furnace circulation promotion means, the combustion promotion means, and the oxygen partial pressure control means as described above. Works effectively as a means. That is, the fuel and combustion air injected by the burner 8 are mixed and collided in the in-furnace region 9 to burn and generate heat, but the in-furnace jet of the in-furnace gas circulation unit 1 further collides with the fuel and combustion. The working air momentum increases. The in-furnace jet of the in-furnace gas circulation unit 1 collides with the direction of the fuel and air jets of the burner 8 at an angle Θ, and the fuel and air jets increase their momentum and flame. Increase the reach of.

  The in-furnace gas circulation unit 1 also injects a high-temperature in-furnace gas in which an oxidant (air or oxygen) is adjusted by the addition device 7, and mixes and collides with the fuel injection flow and the air injection flow of the burner 8. The in-furnace gas flow of the in-furnace gas circulation unit 1 dilutes the combustion air of the burner 8 and lowers the oxygen concentration of the combustion air, so that the flame is a relatively low temperature flame due to slow combustion in the in-furnace region 9. To generate. Such a flame is not only advantageous for suppressing the formation of nitrogen oxides (NOx), but also diffusion of combustion reaction, expansion of flame volume, reduction and leveling of flame temperature, prevention of local high temperature of flame. This is advantageous for the purpose.

  If desired, the in-furnace gas circulation unit 1 may mix 5 to 50% air or a larger amount of air with respect to the sucked in-furnace gas. It is injected into the in-furnace region 9 as an oxygen partial pressure oxidizing agent. The in-furnace gas injected by the in-furnace gas circulation unit 1 collides with the jet of fuel and air supplied to the in-furnace region 9 by the burner 8 and promotes combustion and heat generation of the fuel.

  As a modification, the in-furnace gas circulation unit 1 may add water vapor to the sucked in-furnace gas. The water vapor mixed with the furnace gas is heated by a heat storage device and heated to a high temperature of 800 ° C. or higher. Hydrocarbons and unburned components in the furnace gas react with steam and are reformed, and the combustion reaction can be changed or optimized by setting appropriate conditions.

  FIG. 12 is a cross-sectional view showing an embodiment of a combustion furnace including an in-furnace gas circulation unit and a high-temperature air injection device having a structure substantially similar to the in-furnace gas circulation unit.

  A combustion furnace burner 8 shown in FIG. 12 includes a fuel injection nozzle 87 connected to a fuel supply pipe 89 and an air supply device 88 connected to a combustion air supply pipe 74. The air supply pipe 74 is connected to an air supply main pipe 73, and the main pipe 73 is connected to an air supply fan 75. An additional fluid supply pipe 71 branches from the main pipe 73 and is connected to the addition device 7 of the in-furnace gas circulation unit 1. The in-furnace gas circulation unit 1 is disposed on the furnace wall where the burner 8 is disposed, and is positioned symmetrically in pairs on both sides of the burner 8.

  As described above, the in-furnace gas circulation unit 1 promotes the circulation of the in-furnace gas, promotes the combustion reaction, and functions as a means for controlling the oxygen partial pressure of the in-furnace atmosphere. As described above, the reintroduction gas injected by the in-furnace gas circulation unit 1 assists the combustion gas injected by the burner 8 to control the ejection momentum and the flow direction, or promote mixing.

  The combustion furnace of this example further includes a high-temperature air injection device 80 disposed on the furnace wall facing the burner 8. The high-temperature air injection device 80 has a structure very similar to the in-furnace gas circulation unit 1, and includes a heat storage device 82 that stores a heat storage body having a honeycomb structure, and a switching valve device 83 that is connected in series to the heat storage device 82. The structures of the heat storage device 82 and the switching valve device 83 are substantially the same as the structures of the heat storage device 2 and the valve device 3 described above. Air supply pipes 76 and 77 branched from the air supply main pipe 73 are connected to the air supply port of the valve device 83, and exhaust pipes 78 and 79 connected to the suction port of the exhaust fan 94 are connected to the exhaust port of the valve device 83. Connected.

  In the operating state of the valve device 83 shown in FIG. 12, combustion air is introduced from the air supply pipe 76 into the air supply region 85 in the valve device 83, and is in heat transfer contact with the heat storage body of the heat storage device 82 so as to have a high temperature of 800 ° C. or higher. And is injected into the in-furnace region 9 as high-temperature combustion air. At the same time, the in-furnace gas passes through the heat storage body of the heat storage device 82 under the exhaust attraction pressure of the exhaust fan 94 and comes into heat transfer contact with the heat storage body to be cooled. The lowered in-furnace gas is sucked into the exhaust fan 94 via the supply / exhaust region 86 of the valve device 83 and the exhaust pipe 79 and exhausted outside the system.

  The position of the valve device 83 shown in FIG. 12 is switched after a predetermined time, and the combustion air is introduced from the air supply pipe 77 into the air supply region 85 and is in heat transfer contact with the heat storage body of the heat storage device 82 to be 800 ° C. or higher. Injected into the furnace region 9 as high-temperature combustion air, the gas in the furnace passes through the heat storage body of the heat storage device 82 under the exhaust attraction pressure of the exhaust fan 94, contacts the heat storage body, cools, and supplies and discharges The air is sucked into the exhaust fan 94 via the region 86 and the exhaust pipe 78 and exhausted out of the system.

  The position of the valve device 83 is alternately switched every predetermined time set to 60 seconds or less, and the high-temperature air injection device 80 injects high-temperature combustion air from any one of the heat storage devices 82 into the in-furnace region 9. Then, the in-furnace gas is exhausted out of the system from the other heat storage device 82.

  The in-furnace gas circulation unit of the present invention may be used as such a high-temperature air injection device 80. In this case, the in-furnace gas circulation unit exhausts the entire amount of the in-furnace gas out of the system and discharges the in-furnace gas. Is completely replaced with additional fluid (air).

FIG. 13 is a cross-sectional view showing an embodiment of a tubular heating furnace provided with the in-furnace gas circulation unit 1.
13 includes a first in-furnace region 9 ′ and a second in-furnace region 9 ″ defined by a partition wall 93, and the in-furnace region 9′9 ″ is continuous through a communication portion. To do. Heated pipes 96 and 97 through which the fluid to be heated flow are arranged in the in-furnace region 9′9 ″, and vertically penetrate the in-furnace region 9′9 ″. Examples of such a tubular heating furnace include a steam reforming furnace or an ethylene decomposition furnace.

  A burner 8 is disposed on the furnace wall of the in-furnace region 9 ′, forms a flame zone in the in-furnace region 9 ′, and the flame is composed of heated tubes 96 arranged in the in-furnace region 9 ′ along the flame direction. The heated fluid flowing through the pipe is heated. The combustion gas in the in-furnace region 9 ′ flows to the in-furnace region 9 ″ through the communication portion, and is exhausted outside the furnace through the exhaust gas passage 98 of the exhaust port 99.

  An in-furnace gas circulation unit 1A: 1B is arranged on the furnace wall of the in-furnace region 9 ″. The unit 1A: 1B sucks and cools the in-furnace gas, pressurizes it, reheats it, and reheats it. ” In the in-furnace region 9 ″, the heated tubes 97 are arranged in a plurality of rows in parallel to the injection direction of the in-furnace gas circulation units 1A: 1B, and the heated fluid flows in the vertical heated tubes 97. The in-furnace gas flowing into the in-furnace region 9 ″ actively circulates in the in-furnace region 9 ″ by the circulation action of the in-furnace gas circulation units 1A: 1B, and uniformly heats the respective heated tubes 97.

  The in-furnace gas circulation unit 1A: 1B also prevents the hot in-furnace gas flowing into the in-furnace region 9 ″ from flowing into the exhaust port 99 in a short circuit, and the hot in-furnace gas is effectively covered. The furnace gas circulation is activated and the furnace temperature field is leveled so as to heat the heating tube 97. This improves the density of the tube 97 to be heated and the degree of freedom in design of the arrangement, and the tube heating furnace. In addition, the in-furnace gas circulation unit 1 may be further provided on the furnace wall of the in-furnace region 9 ′.

  FIG. 14 is a conceptual diagram for explaining the directionality and the relative position of each supply / exhaust port 20 of the in-furnace gas circulation unit 1.

  FIG. 14A shows the in-furnace gas circulation unit 1 including the heat storage device 2 in which the central axis is oriented in the α direction and the β direction, respectively. As described above, one of the supply / exhaust ports 20 of each heat storage device 2 sucks in-furnace gas, and the other injects in-furnace gas after pressurization and reheating into the furnace. In order to simplify the above, a state is shown in which the supply / exhaust port 20 simultaneously injects furnace gas into the furnace.

The expansion angle (half angle) θ ₂ of the free jet G at the supply / discharge port 20 is normally considered to be about 10 °. If the relative angle θ ₁ of each central axis (direction α, β) of the heat storage device 2 is 20 ° or less, the jet of the supply / discharge port 20 forms at least a partially parallel jet. Therefore, the angle theta ₁ of the central axis of the supply-discharge port 20 (direction alpha, beta) is set in the range of 20 ° ~-20 °, supply-discharge port 20 is for a particular portion of the furnace area Inject reintroduction flow in the same direction. Preferably, the angle θ ₁ is set within a range of 10 ° to −10 °.

  FIG. 14B shows a schematic side view showing the properties of the free jet G of the supply / exhaust port 20.

  When the diameter of the supply / discharge port 20 is a dimension value D, the central portion F of the jet G is in a region where the distance measured from the supply / discharge port 20 to the downstream side along the central axis α: β is about 4D to 5D. A portion called a potential core is formed. In this region, the central portion F maintains a flow rate substantially the same as the outlet flow rate of the supply / exhaust port 20. A region in the range up to about 10D with a distance from the supply / discharge port 20 exceeding about 5D is a region called a transition region, and a region having a distance over about 10D from the supply / discharge port 20 is a region called a development region It is. In general, the flow velocity of the jet G is considerably attenuated in the development region. Therefore, if each supply / discharge port 20 is arranged so that it merges for the first time in the development region when parallel jets G are injected at the same time, the jets G are jets that do not interfere with each other's motion, that is, independent separate It is grasped as a jet.

  Assuming that each supply / discharge port 20 simultaneously injects the jet G with respect to the supply / discharge ports 20 arranged close to each other, the distance (x + D) between the central axes shown in FIG. If y ≦ 5D), the merging of the regions forming the potential core in the central portion F occurs at least partially, and the distance (x + D) between the central axes is in the range of about 3 to 5D (5D <y ≦ 10D), the merging of the transition regions occurs at least partially. In any case, unlike the case of the first merging in the development region, it can be considered that the influence of the jet G on the surroundings is equivalent to the influence of the jet injected from the single supply / discharge port. Accordingly, the center-to-center distance (x + D) of the supply / discharge port 20 is preferably set to 5D or less, more preferably 3D or less, for example, within a range of 3D to 5D.

Note that the geometric relationship between the distances x and y shown in FIG. 14C is as follows.
(i) When y = 5D
5D / 0.5x = tan (90 ° −θ ₂ ) = tan 80 ° = 5.6713
x = (5D / 5.6713) /0.5=1.763D
x + D = 2.763D = about 3.0D

(ii) When y = 10D
10D / 0.5x = tan80 ° = 5.6713
x = (10D / 5.6713) /0.5=3.47D
x + D = 4.47D = about 5D

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and is within the scope of the present invention described in the claims. Various modifications or changes are possible, and it goes without saying that these modifications or modifications are also included in the scope of the present invention.

  For example, the in-furnace gas circulation unit may be used in a steel heating furnace that performs annealing or the like, or a ceramic firing furnace such as a tunnel kiln. In this case, the in-furnace gas circulation unit can be used not only for activation of the in-furnace circulation and leveling of the in-furnace temperature field, but also for introduction of inert gas into the furnace, adjustment of the firing atmosphere, etc. As described above, the present invention can be applied to an application corresponding to the purpose of use of the combustion facility.

  Moreover, in the said Example, although the in-furnace gas circulation unit is arrange | positioned at the side wall of the furnace, you may arrange | position an in-furnace gas circulation unit in the bottom wall or top wall of a furnace body.

  Further, the heat storage body and the supply / discharge switching valve device are not limited to four or less, and the in-furnace gas circulation unit may include five or more heat storage bodies and supply / discharge switching valve devices as necessary. good.

  The in-furnace gas circulation unit of the present invention is preferably used for a combustion furnace such as a tubular heating furnace, a metal heating furnace, a ceramic firing furnace, a metal melting furnace, a gasification melting furnace, or a boiler. The in-furnace gas circulation or agitation or the combustion atmosphere in the furnace is controlled.

FIG. 1 is a longitudinal sectional view of a furnace gas circulation unit showing a preferred embodiment of the present invention. It is sectional drawing which shows each part structure of the supply / discharge switching valve apparatus shown in FIG. 1, and the derivation position of the valve apparatus is shown. Like FIG. 2, it is sectional drawing which shows each part structure of a supply / discharge switching valve apparatus, and the introduction position of the valve apparatus is shown. It is a longitudinal cross-sectional view of the in-furnace gas circulation unit which shows other embodiment of this invention. It is a longitudinal cross-sectional view of the in-furnace gas circulation unit which shows other embodiment of this invention. It is the front view and sectional drawing which show the supply / discharge pattern of the gas circulation unit in a furnace. It is the front view and sectional drawing which show the other supply / discharge pattern of the gas circulation unit in a furnace. It is the front view and sectional drawing which show another supply / exhaust pattern of the gas circulation unit in a furnace. FIG. 6 is a cross-sectional view illustrating a configuration of a combustion furnace including the in-furnace gas circulation unit illustrated in FIG. 5. FIG. 10 is a transverse sectional view showing a modification of the combustion furnace shown in FIG. 9. It is a cross-sectional view showing another embodiment of the combustion furnace provided with the in-furnace gas circulation unit shown in FIG. It is a cross-sectional view showing an embodiment of a combustion furnace provided with an in-furnace gas circulation unit and a high-temperature air injection device having a structure substantially similar to the in-furnace gas circulation unit. It is a cross-sectional view showing an embodiment of a tubular heating furnace provided with an in-furnace gas circulation unit. It is a conceptual diagram for demonstrating the directionality and relative position of each supply / exhaust port of a gas circulation unit in a furnace.

Explanation of symbols

1 In-furnace gas circulation unit 2 Heat storage device 3 Supply / exhaust switching valve device 4 Circulating fan 9 In-furnace region 20 In-furnace gas supply / exhaust port 21 Heat storage body 22 Thermal storage body case 23 Support substrate 30 Valve mechanism 31 In-furnace gas introduction port 32 Furnace Inner gas outlet 33 Valve drive unit 34 Inlet port 35 Outlet ports 41, 42, 43 Inlet pipes 44, 45, 46 Outlet pipe 47 Exhaust pipe 48 Exhaust control valve 91 Furnace body 92 Furnace wall surface

Claims (16)

First and second heat storage devices each having a supply / discharge port functioning as an outlet for deriving the gas in the furnace to the outside of the furnace and functioning as an injection port for injecting the reintroduction flow of the gas in the furnace into the furnace;
A circulating fan that pressurizes the gas in the furnace led out of the furnace and sends the gas in the furnace to the supply / exhaust port via the heat storage device;
A first position where the gas in the furnace is led out of the furnace through the first heat storage device, and the reintroduced gas is injected into the furnace through the second heat storage device, and the gas in the furnace is passed through the second heat storage device. A supply / exhaust switching valve device that is led out and can be switched to a second position for injecting reintroduced gas into the furnace via the first heat storage device;
Each of the first and second heat storage devices receives heat by heat transfer contact with the furnace gas, cools the furnace gas, and dissipates heat by heat transfer contact with the reintroduction flow. A heat storage body for heating
Each supply / exhaust port of the first and second heat storage devices is parallel to the inner wall surface of the furnace body and close to each other so as to continuously inject the reintroduction flow in the same direction to a specific portion of the furnace interior region. The in-furnace gas circulation unit, wherein the supply / exhaust switching valve device is alternately switched to the first position and the second position.   The heat storage device further includes a support substrate that is integrated with the furnace body to form a furnace inner wall surface, and the heat storage device includes a casing that houses the heat storage body, and the casing is integrally supported by the support substrate. The in-furnace gas circulation unit according to claim 1.   The supply / discharge switching valve device further injects reintroduced gas into the furnace from the supply / exhaust port of any one of the heat storage devices, and supplies the other two heat storage devices. The in-furnace gas circulation unit according to claim 1, wherein the switching is controlled so as to derive the in-furnace gas from the furnace.   And a supply / exhaust switching valve device that injects reintroduced gas into the furnace from the supply / exhaust port of any one of the heat storage devices, and the other three heat storage device supply / exhaust ports. 4. The in-furnace gas circulation unit according to claim 3, wherein the switching is controlled so as to derive the in-furnace gas from the furnace.   The said supply / exhaust switching valve apparatus is connected in series with each said thermal storage apparatus, and the control apparatus which adjusts the switching timing of each supply / exhaust switching valve apparatus is further provided. The in-furnace gas circulation unit according to item 1.   The in-furnace gas circulation unit according to any one of claims 1 to 5, further comprising an addition device for adding an additional fluid to the cooled in-furnace gas.   The in-furnace gas circulation unit according to any one of claims 1 to 6, further comprising exhaust means for exhausting part of the in-furnace gas after cooling out of the system. In the furnace combustion method using the furnace gas circulation unit according to any one of claims 1 to 7,
An in-furnace combustion method characterized by injecting the reintroduction flow into an in-furnace region to activate in-furnace gas circulation.   Injecting the reintroduction flow into a portion of the furnace area formed around the object to be heated arranged in the furnace and where the action of the flame or its radiant heat does not directly affect the object to be heated. The in-furnace combustion method according to claim 8, which is improved. In the furnace combustion method using the furnace gas circulation unit according to any one of claims 1 to 7,
An in-furnace combustion method characterized by injecting the reintroduction flow toward an in-furnace flame and controlling an arrival distance, a direction, or a flame volume of the flame. In the furnace combustion method using the furnace gas circulation unit according to any one of claims 1 to 7,
The reintroduction flow is injected into the furnace so that the combustion equipment for forming the furnace flame mixes and collides with the fuel and combustion air injected into the furnace, and the combustion reaction of the fuel and the combustion air is controlled. An in-furnace combustion method. In the furnace combustion method using the furnace gas circulation unit according to claim 6 or 7,
An in-furnace combustion method characterized by injecting a reintroduction flow to which the additional fluid has been added into the furnace to control the properties of the in-furnace flame or the in-furnace combustion atmosphere formed by the combustion equipment of the furnace. The furnace combustion method according to claim 12, wherein air, oxygen, water vapor, or an inert gas is added to the reintroduction flow as the additional fluid. In the furnace combustion method using the furnace gas circulation unit according to claim 3 or 4,
The flow rate of the in-furnace gas flow sucked from the supply / discharge port is reduced to 1/2 or less of the flow rate of the reintroduction flow injected from the supply / discharge port, and the gas flow between the supply / discharge ports is short-circuited. A furnace combustion method characterized by preventing a pass.   The in-furnace gas circulation unit according to any one of claims 1 to 7, wherein a relative angle of a central axis of the reintroduction flow is limited to a range of 20 ° to -20 °. .   The in-furnace gas circulation according to any one of claims 1 to 7 or 15, wherein a distance between centers of the supply and discharge ports is set to 5D or less with respect to a diameter D of the supply and discharge ports. unit.

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