JPH0711389B2 - How to operate the sweep fire furnace - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a method for operating a sweep fire furnace.

(Prior Art) The strength of the burner frame provided opposite to the both side walls of the furnace has a complementary relationship such that when one becomes stronger, the other becomes weaker and when one becomes weaker, the other becomes stronger. Furnaces that are arranged to change cyclically while being maintained are known to those skilled in the art under the name Sweepfire furnace.

Such a furnace, as shown in FIG. 4, uses combustion air supplied from the blower (4) and tertiary air, which is diffusion air, to the burners (2) and (3) on both side walls of the furnace (1). The sweep control was simultaneously performed by the valve (6) with the motor (5), and such sweep operation was performed from beginning to end during the operation of the furnace. However, in a sweep fire furnace in which sweep operation is performed from beginning to end in this way, since the stirring flow inside the furnace becomes an alternating flow, the fibers are easily cut and scattered in the furnace where the fiber is lined in the furnace, Since radiative heat transfer occupies the main position rather than convective heat transfer, in the high temperature region the movement of the flame inside the furnace hinders soaking and rather temperature control and diffusion air amount control are a series. Therefore, there has been a problem that it is difficult to adjust the low range of the diffused air amount for the purpose of energy saving.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, prevents damage to the furnace material in a high temperature range, eliminates scattering of fibers, and makes uniform heating and energy saving. It has been completed to provide a method for operating a sweep fire furnace capable of achieving the following.

(Means for Solving the Problems) The first invention made to solve the above problems is to increase the strength of the frame of the burner provided so as to face both side walls of the furnace when the other becomes stronger. When operating a sweep fire furnace that changes periodically while maintaining a weakening relationship, only the intensity of the tertiary air for diffusion is changed while keeping the fuel and combustion air supplied to each burner constant. It is characterized in that the sweep control is performed by.

A second invention is to operate a sweep fire furnace in which the strength of a burner frame provided opposite to both side walls of the furnace is periodically changed while maintaining the relationship that when one becomes stronger, the other becomes weaker. In this case, the sweep control for changing the strength of the burner flame is suppressed or stopped when the temperature in the furnace reaches a high temperature.

A third aspect of the present invention is to operate a sweep fire furnace in which the strength of a burner frame provided opposite to both side walls of the furnace is periodically changed while maintaining the relationship that when one becomes stronger, the other becomes weaker. When the temperature inside the furnace is low, the intensity of the tertiary air for diffusion is changed to perform sweep control.
As the temperature inside the furnace becomes higher, the tertiary air is throttled to suppress or stop the sweep control.

(Example) Hereinafter, the present invention will be described in more detail with reference to the illustrated example.

In the system shown in FIG. 1, a combustion line (7) for supplying combustion air to each burner (2), (3) and each burner (2), (3)
The diffusion line (8) that supplies the tertiary air for diffusion is connected to the blower (4) in a separate system, and only the diffusion line (8) has a motor (5) and valve (6) for sweep control. And are connected. The fuel and combustion air supplied to the burners (2) and (3) are kept substantially constant under the control of the temperature control line (9), but only the tertiary air for diffusion is supplied to the motor (5). Valve (6)
Sweep control is performed by and to change its strength periodically.

If only the tertiary air is swept in this way, the sweep operation can be performed in the furnace independently of the calorific value of the burners (2) and (3) that determine the temperature in the furnace. When the temperature reaches a high temperature, the tertiary air can be freely throttled to reduce or stop the stirring air flow in the furnace.

Next, in the system shown in FIG. 2, the system of FIG. 1 is simplified, and the fuel supplied to each burner (2), (3) is the combustion air pressure from the combustion line (7). Proportional control is performed according to. And only the tertiary air is the motor
Sweep control is performed by (5) and the valve (6).

Also in this case, when the temperature in the furnace reaches a high temperature, the tertiary air can be freely throttled to suppress or stop the sweep operation.

Next, the system shown in FIG. 3 corresponds to the second aspect of the invention, and the conventional system shown in FIG. 4 is used as it is to change only the operation method.
In this case, not only the tertiary air is swept controlled, but also the combustion air is swept controlled together with the tertiary air. However, when the temperature in the furnace reaches a high temperature, the sweep control motor
By (5), the opening / closing operation range of the valve (6) is changed or stopped at a position of a certain opening degree to suppress or stop the sweep operation.

In addition, the valve that sends the diffused air among the three valves that control the air sent from the valve (6) shown in FIGS. 3 and 4 performs the opposite operation to the other two series of valves. . That is, the two series of valves are set so that the flow rate works in the opening direction and the flow rate increases, while the flow rate works in the opening direction and the flow rate decreases.

(Operation) As described above, according to the second and third aspects of the invention, when the temperature in the furnace is low, the conventional sweep operation is performed to positively form an alternating flow in the furnace, and heat transfer by convection is performed. It is possible to suppress the sweep operation and stop it when the temperature inside the furnace becomes high. For this reason, the direction of the stirred flow in the furnace in the high temperature region can be made constant, and the cutting and scattering of the fiber lined in the furnace can be prevented. Further, according to the second and third aspects of the invention, the movement of the burner frame can be stopped in a high temperature region where radiant heat transfer is the main, and soaking in the furnace can be achieved. Further, according to the first and third aspects of the invention, the amount of the tertiary air for diffusion can be freely reduced in the high temperature region, so that large energy saving can be achieved.

Although all of the drawings relate to the shuttle kiln, it goes without saying that the present invention can be applied to other than the shuttle kiln.

(Effect of the Invention) As described above, the present invention succeeds in preventing damage to the inner wall of the furnace, soaking the heat, and conserving energy by changing the operation method of the conventional sweep fire furnace. Therefore, as a method of operating a sweep fire furnace that solves the conventional problems, it greatly contributes to industrial development.

[Brief description of drawings]

1, 2, and 3 are all piping system diagrams for explaining an embodiment of the present invention, and FIG. 4 is a piping system diagram for explaining a conventional example. (1): Furnace, (2): Burner, (3): Burner, (4): Blower,
(5): Motor for sweep control, (6): Valve for sweep control, (7): Combustion line, (8): Diffusion line.

Claims (3)

[Claims] 1. When operating a sweep fire furnace in which the strength of a burner frame provided opposite to both side walls of the furnace is periodically changed while maintaining the relationship that when one becomes stronger, the other becomes weaker, A method for operating a sweep fire furnace, wherein sweep control is performed by changing only the intensity of tertiary air for diffusion while keeping the fuel and combustion air supplied to each burner constant. 2. When operating a sweep fire furnace in which the strength of a burner frame provided opposite to both side walls of the furnace is periodically changed while maintaining the relationship that when one becomes stronger, the other becomes weaker, A method for operating a sweep fire furnace, which comprises suppressing or stopping the sweep control for changing the strength of the burner flame when the temperature in the furnace reaches a high temperature. 3. When operating a sweep fire furnace in which the strength of a burner frame provided opposite to both side walls of the furnace is periodically changed while maintaining the relationship that when one becomes stronger, the other becomes weaker, 3 for diffusion when the temperature inside the furnace is low
A method for operating a sweep fire furnace, characterized in that the strength of secondary air is changed to perform sweep control, and the tertiary air is throttled to suppress or stop the sweep control as the temperature inside the furnace rises.