JPH0553535B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a combustion control method for a tunnel kiln equipped with an oxidizing flame zone and a reducing flame zone.

(Conventional technology) A tunnel kiln used for firing ceramics or glazed tiles, etc. is equipped with an oxidation flame zone and a reduction flame zone sequentially from the entrance side, and the gas in the furnace is directed from the reduction flame zone to the oxidation flame zone. A burner is installed at the boundary to blow in excess air to completely burn the CO gas and other gases. However, in such a tunnel kiln, not only the temperature inside the furnace but also the atmosphere must be properly controlled, so conventionally a CO meter was installed at the boundary between the oxidation flame zone and the reduction flame zone.
A method was used to control the reduction flame zone burner and the burner for blowing in excess air so that the CO concentration in this area was zero. However, when these burners are controlled, the temperature inside the furnace changes accordingly, so it is not easy to judge the fluctuations in both the atmosphere inside the furnace and the temperature inside the furnace. However, in many cases, it was not possible to take timely measures in response to changes.

(Problems to be Solved by the Invention) The present invention solves the above conventional problems and appropriately controls the temperature and atmosphere of a tunnel kiln equipped with an oxidation flame zone and a reduction flame zone. This was completed with the aim of creating a combustion control method for tunnel kilns that would enable combustion.

(Means for solving the problem) The present invention measures the furnace temperature near the air-only burner provided at the boundary between the oxidation flame zone and the reduction flame zone, and ensures that the furnace temperature in this area is constant. This is characterized by adjusting the output of the fuel-dedicated burner at the rear of the reduction flame zone so that

The present invention will be described in more detail below with reference to the drawings. Reference numeral 1 denotes a furnace body of a tunnel kiln, the inlet of which is an oxidation flame zone 2, and the central part an oxidation flame zone 3. is equipped with a normal burner, but the reducing flame zone 3 is equipped with a number of air-fuel mixture burners 4, and by adjusting the air-fuel ratio, the CO concentration as shown in the figure is created. ing. As mentioned above, in the tunnel kiln, a flow occurs in the furnace body 1 that is not opposite to the direction of movement of the materials to be fired, so there is a risk that reducing gas may flow from the reducing flame zone 3 toward the oxidizing flame zone 2. There is. Therefore, an air-only burner 5 is provided at the boundary between the oxidizing flame zone 2 and the reducing flame zone 3 to completely burn the reducing gas.

Conventionally, a CO meter was installed in the reduction flame zone 3 to control combustion so that the CO concentration remained constant, but in the present invention, a CO meter is not used, and instead, a CO meter is installed in the air-only burner 5. A thermometer 6 is installed nearby to measure the temperature of this part. The measured temperature value is then taken into a controller 7 such as a microcomputer, and if the temperature is lower than the set value, the output of the fuel burner 8 installed at the rear of the reduction flame zone 3 is increased; When the measured value of the thermometer 6 is higher than the set value, control is performed to reduce the output of the fuel-only burner 8. In other words, an increase in the CO concentration at the boundary between the oxidation flame zone 2 and the reduction flame zone 3 means that the ratio of fuel in the reduction flame zone 3 has increased, and as a result, the thermometer 6 has reached the set value. It should measure a higher temperature. Therefore, in this case, by reducing the output of the fuel-only burner 8, not only the temperature but also the CO concentration will return to the set value. Conversely, a decrease in CO concentration means a lack of fuel supply, so the thermometer 6 should measure a temperature lower than the set value, so in this case, the output of the fuel-only burner 8 should be increased. If so, both the temperature and CO concentration will rise and return to the set values.

In this way, in the present invention, the reduced flame zone 3
Focusing on the relationship with CO concentration, combustion control is performed simply based on the temperature at the boundary between oxidation flame zone 2 and reduction flame zone 3, without measuring CO concentration as in conventional methods, making control easy. It is possible to control the system with no room for individual differences among operators, and it is also easy to achieve automation. As a result, the temperature and atmosphere inside the tunnel furnace can be controlled extremely stably, which is also effective in stabilizing the quality of fired products.

(Effects of the Invention) As is clear from the above description, the present invention is capable of easily and reliably controlling the temperature and atmosphere of a tunnel kiln equipped with an oxidation flame zone and a reduction flame zone. As a combustion control method for tunnel kilns that eliminates the problems of conventional methods, it will greatly contribute to the development of industry.

[Brief explanation of the drawing]

The drawings are plan views illustrating embodiments of the present invention. 2: Oxidation flame zone, 3: Reduction flame zone, 5: Air-only burner, 8: Combustion-only burner.

Claims (1)

[Claims] 1. Measure the furnace temperature near the air-only burner 5 provided at the boundary between the oxidation flame zone 2 and the reduction flame zone 3, and adjust the temperature at the rear of the reduction flame zone 3 so that the temperature inside the furnace in this area is constant. A method for controlling combustion in a tunnel kiln, the method comprising: adjusting the output of a burner 8 dedicated to fuel.