JPS635646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for supplying different types of fuel in a combustion furnace.

In addition to the main fuel as gas fuel, an auxiliary fuel that has not been used in the past because the supply amount is not constant is used, and this is added to the main fuel to reduce the amount of main fuel used and increase the effect of energy saving. is planned.

Conventionally, when two types of gas fuels are used as described above, these fuels are mixed before combustion, and the mixed gas fuel is supplied to a burner of a fuel furnace and combusted.
However, as mentioned above, the supply amount of the auxiliary fuel is not constant, and the supply sometimes stops, which makes the combustion flame of the burner unstable and even causes the flame to go out.

The present invention has been made in view of the above-mentioned circumstances, and provides a dissimilar fuel supply device configured to continuously perform combustion regardless of fluctuations in the supply amount or supply stoppage of the auxiliary fuel. The purpose is to provide

The dissimilar fuel supply device according to the present invention includes a main fuel supply line disposed in a plurality of burners, a sub fuel supply line disposed in the same burners, and a pressure maintaining system connected to the sub fuel supply line and having a control valve. an inert gas supply line, and a pressure detection valve control device that detects the mixed gas pressure on the downstream side of the connection point between the auxiliary fuel supply line and the inert gas supply line and controls the control valve. The pressure of the detection valve control device is set so that the flow rate of the mixed gas supplied to the burner is higher than the combustion rate.

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

Embodiment In the accompanying drawings, a plurality of branch parts 4 of a main fuel supply line 3 and a plurality of branch parts 6 of a sub-fuel supply line 5 are arranged in a plurality of burners 2 provided on a front wall 1 of a heating furnace, respectively. has been done. A control valve 7 is provided in the auxiliary fuel supply line 5, and a flow rate detection valve control device 8 detects the flow rate at a point A on the upstream side of the control valve 7 to control the valve 7. Further, an on-off valve 9 is provided in each of the plurality of branch portions 6 of the auxiliary fuel supply line 5.

An inert gas supply line 10 for pressure maintenance is connected to the auxiliary fuel supply line 5 on the downstream side of the control valve 7.
The same line 10 is provided with an on-off valve 11 and a control valve 12 on the downstream side thereof. Then, the pressure detection valve control device 13 detects the pressure of the mixed gas of the auxiliary fuel and the inert gas at a point on the downstream side of the gas mixture point B, that is, a pressure detection point C, and controls the control valve 12. There is. Nitrogen gas is used as the inert gas.

In the fuel supply system configured as described above, the main fuel and the auxiliary fuel are supplied to the burner 2. The amount of supplementary fuel supplied is not constant, and the supply may sometimes stop. Therefore, if the flow rate of the auxiliary fuel supplied to the burner 2 becomes lower than the combustion rate, there is a risk of flashback occurring.
Therefore, in order to prevent backfires as described above, perform the following operations.

The main fuel is supplied to the burner 2 at a predetermined flow rate and burned. The set pressure of the pressure detection valve control device 13 is set to a pressure at which the supply flow rate of the mixed gas of the auxiliary fuel and nitrogen gas in the burner 2 is equal to or higher than the combustion rate. Next, the on-off valve 11 is opened to allow nitrogen gas to pass through the supply line 10.

As a result, the pressure detection valve control device 13 opens the control valve 12 to a required angle so that the detected pressure at the pressure detection point C is maintained at the set pressure of the device 13, and nitrogen gas flows through the valve 12. The fuel then enters the auxiliary fuel supply line 5.

In this state, the control valve 7 is opened to a required angle, and the auxiliary fuel is passed through the supply line 5 and mixed with nitrogen gas at the gas mixing point B. The mixed gas is supplied to the burner 2 via the pressure detection point C, and is ignited and burned by the spark of the main fuel.

In the above fuel supply system, the pressure of the mixed gas at the pressure detection point C is kept constant regardless of fluctuations in the supply amount of the auxiliary fuel by the pressure setting of the pressure detection valve control device 12 as described above. Therefore, the flow velocity of the mixed gas in the burner 2 never becomes lower than the combustion velocity. Therefore, there is no risk of backfire occurring in the burner 2.

When the control valve 7 is opened to a larger angle, the pressure at the pressure detection point C becomes higher, and as a result, the control valve 1
The second valve opening angle is made small by the pressure detection valve control device 13.

When the supply amount of the auxiliary fuel increases further and the pressure at the pressure detection point C becomes equal to or higher than the set pressure of the pressure detection valve control device 13, the control valve 12 is completely closed by the pressure detection valve control device 13. As a result, only the auxiliary fuel is supplied to the burner 2.

When stopping the supply of auxiliary fuel, the operation is the reverse of the above, and the control valve 7 is gradually closed. As a result, as the supply amount of auxiliary fuel decreases, the pressure at the pressure detection point C falls below the set pressure of the pressure detection valve control device 13, and the valve opening angle of the control valve 12 is gradually controlled by the device 13. Made big. When the control valve 7 is completely closed, only nitrogen gas is passed through the auxiliary fuel supply line 5. As a result, the flame caused by the auxiliary fuel in burner 2 is completely extinguished, and no backfire occurs.

Reference Example In this example, no pressure-maintaining gas supply line is provided in the attached drawings. In the case of a fuel supply system having this configuration, the following operation is performed to prevent backfire.

Main fuel is supplied to a plurality of burners 2 and burned. The control valve 7 is opened to a required opening degree, and the pressure from the auxiliary fuel supply source to the on-off valve 9 is maintained at a pressure at which the flow rate of the auxiliary fuel supplied to the burner 2 is equal to or higher than the combustion speed. Then, the plurality of on-off valves 9 are sequentially opened and ignition is performed. Moreover, when stopping the supply of auxiliary fuel, the on-off valves 9 are sequentially closed in the opposite manner to the above, and then the flow rate control valve 7 is closed.

Therefore, in this case, it is necessary to repeat the above operation from the beginning every time the supply amount of the auxiliary fuel changes, making the valve operation extremely complicated.

Since the dissimilar fuel supply device according to the present invention is configured as described above, it is possible to perform combustion continuously and with a stable flame regardless of fluctuations in the supply amount or stoppage of supply of the subfuel. It is possible to reliably prevent backfire due to a decrease in the amount of fuel supplied or a stop in the supply.

[Brief explanation of the drawing]

The drawing is a flow line diagram showing an embodiment of the present invention. 2...Burner, 3...Main fuel supply line, 5...
...Auxiliary fuel supply line, 10...Inert gas supply line, 12...Control valve, 13...Pressure detection valve control device.

Claims (1)

[Claims] 1 A main fuel supply line arranged in a plurality of burners, an auxiliary fuel supply line arranged in the same burner, an inert gas supply line for pressure maintenance connected to the auxiliary fuel supply line and having a control valve, The pressure detection valve control device detects the mixed gas pressure on the downstream side of the connection point between the fuel supply line and the inert gas supply line and controls the control valve, and the pressure detection valve control device detects the mixed gas pressure in the burner. A device for supplying different types of fuel in a combustion furnace, the pressure of which is set so that the supply flow rate is higher than the combustion rate.