JPH0331763B2 - - Google Patents

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Application Field The present invention relates to a combustion control method for a hot-blast stove, and more specifically, a combustion control method for a hot-blast stove that performs combustion control by controlling the calories of combustion gas. Pertains to.

BACKGROUND TECHNOLOGY Usually, two or more hot blast furnaces are installed per blast furnace, but in general, the thermal efficiency of each combustion chamber 1 in the hot blast furnace combustion chamber 1 is different, and the heat load is applied at the early stage of combustion. In order to increase this, a so-called two-stage combustion method is used. Therefore, the mixing ratio of low calorie gas (hereinafter referred to as B gas) and high calorie gas (hereinafter referred to as C gas) is changed for each combustion chamber 1 or according to the combustion state of each combustion chamber 1, and the mixed gas (hereinafter referred to as M gas) calorie control has become common.

FIG. 3 shows an example of a conventional M gas calorie control flow. In the figure, B from the B gas main 20
The gas and C gas from the C gas primary side pipe 9 branched from the C gas main pipe 8 are mixed to become M gas, which is then passed through the M gas main pipe 7 and then from the M gas branch pipe 6 to the hot blast furnace combustion chamber. 1. In addition, the calorie control of M gas is performed using the C gas 2 branched from the C gas main pipe 8.
It passes through each C gas branch pipe 14 from the next side pipe 10, and is connected to the M gas branch pipe 6 by a C gas branch pipe valve 15, a C gas branch pipe butterfly valve 16, and a C gas branch pipe orifice 17 provided on the C gas branch pipe 14. By controlling the amount of C gas supplied, the calorie amount of M gas is controlled according to the combustion state of each hot blast furnace combustion chamber 1. The combustion method of a hot blast furnace is shown in Figure 4. Generally, in the case of a blast furnace having four hot blast furnaces, a stacked/parallel method of two combustion and two blowing blasts is used.
For example, in the case of the combination of combustion shown in sections A and B in FIG. 4, the calorie control of the M gas is performed by increasing the heat of the hot-blast stove 1a in the first half and the hot-blast stove 1b in the second half to enhance the combustion state.

In this case, in the conventional method, as shown in FIG. 16 and a C gas branch pipe orifice 17 for flow rate measurement, and these generally have large diameters, which have disadvantages such as high equipment costs, complicated control methods, and increased maintenance costs. Ta.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned problems, and specifically, an orifice 18 and a flow rate regulating valve 19 are provided in the C gas secondary piping 10 to increase the C gas flow rate. In addition, a cutoff valve 15 is installed on the C gas branch pipe 14.
The purpose of this system is to control the calorie content of M gas and reduce equipment costs, control-related costs, and maintenance costs.

<Structure of the Invention> Means for Solving the Problems and Their Effects The present invention provides a combustion method for a hot air stove that uses a mixed gas of a low calorie gas and a high calorie gas as combustion gas for the hot air stove. inside,
A high calorie gas whose flow rate is controlled by a high calorie gas primary side flow regulating valve is introduced to form a mixed gas, and a high calorie gas secondary side is branched from the upstream side of the high calorie gas primary side flow regulating valve. The high calorie gas whose flow rate is adjusted by the high calorie gas secondary flow regulating valve provided in the piping is introduced into the branch pipe for the hot blast furnace of the mixed gas through the cutoff valve, thereby producing a mixed gas for each hot blast stove. It is characterized by controlling the calories of.

Hereinafter, the structure and operation of the means of the present invention will be explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing the calorie control of combustion gas according to the present invention, FIG. 2 is a process diagram showing the combustion method of the present invention, and FIG. 3 is a diagram showing the calorie control of combustion gas according to the conventional method. It is an explanatory diagram, and FIG. 4 is a process diagram showing the combustion method of the hot air stove.

That is, the present invention provides (1) an orifice 18 and a flow rate adjustment valve 19 common to each hot-blast stove in the C-gas piping 10 for M-gas calorie control, and (2) a C-gas piping 14 for blowing C gas into each hot-blast stove. (3) A combination of the flow rate adjustment valve 19 and the cutoff valve 15 is used to arbitrarily control the M gas calorie for each hot blast stove.

In FIG. 1, M gas, which is a mixture of B gas from the B gas main pipe 20 and C gas from the C gas primary side pipe 9 branched from the C gas main pipe 8, passes through the M gas main building 7. From the M gas branch pipe 6, a branch pipe orifice 5, a flow rate adjustment valve 4, a gas main valve 3, and a gas valve 2 are connected.
It is the same as in the conventional case that the air is supplied to the hot blast furnace combustion chamber 1 through the air.

In the case of calorie control of M gas, C gas passes through an orifice 18 and a flow rate adjustment valve 19 provided in a C gas secondary pipe 10 that branches on the upstream side of an orifice 11 of the C gas main pipe 8 to a C gas branch pipe 14. It is supplied to the M gas branch pipe 6 via the inlet cutoff valve 15. Therefore, the amount of C gas mixed with M gas is controlled by C gas 2.
This is performed by the next-side orifice 18 and the C gas secondary-side flow rate adjustment valve 19.

Therefore, compared to the conventional example shown in FIG. 3, the number of orifices and regulating valves is greatly reduced, which simplifies the control method and reduces equipment and maintenance costs.

Hereinafter, as shown in Fig. 2, four hot air stoves 1a,
In the blast furnace having 1b, 1c, and 1d, the case of two combustion units and two blast furnaces will be specifically explained as follows.

For example, a case will be described in which the hot-blast stoves 1a and 1b are burning, with the hot-blast stove 1a in the final stage of combustion and the hot-blast stove 1b in the early stage of combustion, that is, section B in FIG. 3.

Here, the shaded area Qcb is an increased calorie area due to M gas calorie control, and the white area Q1b is an area where calorie control is not performed. Specifically, the part Q1b is the flow rate from the M gas main pipe 7 through the M gas branch pipe 6b and enters the hot air stove 1b, and the part Qcb is the flow rate from the orifice 18 and the flow rate adjustment valve in the C gas secondary pipe 10. 19, and the hot blast stove 1b is
is the flow rate entering the In the hot stove 1a at the final stage of combustion,
Since C gas is not injected, the C gas cutoff valve 15a is closed, and the M gas main pipe 7 is disconnected from the M gas branch pipe 6a.
Only the flow rate Q1a of the M gas that enters the hot air stove 1a through the hot air stove 1a is sent. In addition, the hot air stoves 1c and 1 are blowing air.
In d, gas valves 2c and 2d, gas main valves 3c and 3d, and C gas branch pipe cutoff valves 15c and 15d.
All are closed.

In this way, in the hot air stove 1a during combustion, the flow rate of M gas is maintained at a constant value by the flow rate from the M gas main pipe 7, and in the hot air stove 1b, which requires calorie control, the flow rate of M gas is maintained at a constant value by the flow rate from the M gas main pipe 7. By opening the valve 15b, it is possible to perform arbitrary flow rate control using the flow rate adjustment valve 19 provided in the C gas secondary side piping 10.

<Effects of the Invention> As explained above, the present invention provides a combustion method for a hot-air stove that uses a mixed gas of a low-calorie gas and a high-calorie gas as the combustion gas for the hot-air stove.
A high calorie gas whose flow rate is controlled by a high calorie gas primary side flow rate regulating valve is introduced into the low calorie gas to form a mixed gas, and the high calorie gas is branched from the upstream side of the high calorie gas primary side flow rate regulating valve. By introducing the high calorie gas whose flow rate is regulated by a high calorie gas secondary side flow regulating valve provided in the high calorie gas secondary side piping into the branch pipe of the mixed gas going to the hot blast furnace through the cutoff valve. This hot blast furnace combustion control method is characterized by controlling the calorie content of the mixed gas for each hot blast stove.Compared to the conventional method, the number of orifices and regulating valves used is greatly reduced, and as a result, the combustion Gas calorie control becomes simple and easy, and the effects are extremely large, such as reducing equipment costs and maintenance costs.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing calorie control of combustion gas according to the present invention, FIG. 2 is a process diagram showing the combustion method of the present invention, and FIG. 3 is an explanatory diagram showing calorie control of combustion gas according to the conventional method. Figure 4 is a process diagram showing the combustion method of a hot air stove. Code 1...Hot stove combustion chamber, 2...Gas valve, 3...
...Gas main valve, 4...M Gas flow rate adjustment valve, 5...M
Gas branch pipe orifice, 6...M gas branch pipe, 7...
M gas main, 8...C gas main, 9...C gas 1
Next side piping, 10...C gas primary side piping, 11...
C gas primary side orifice, 12...C gas primary side butterfly valve, 13...C gas primary side valve, 14...
...C gas branch pipe, 15...C gas branch pipe cutoff valve, 16
...C gas branch pipe flow rate adjustment valve, 17...C gas branch pipe orifice, 18...C gas secondary side orifice,
19...C gas secondary side flow rate adjustment valve, 20...B gas main pipe.

Claims (1)

[Claims] 1. In a hot blast furnace combustion method in which a mixed gas of low calorie gas and high calorie gas is used as the combustion gas in the hot blast stove, a high calorie gas whose flow rate is controlled by a high calorie gas primary side flow regulating valve is added to the low calorie gas. A calorie gas is introduced to form a mixed gas, and a high calorie gas secondary flow rate adjustment valve provided in a high calorie gas secondary side pipe branched from the upstream side of the high calorie gas primary side flow rate adjustment valve is used. The high calorie gas whose flow rate is adjusted is passed through a shutoff valve.
A combustion control method for a hot blast stove, characterized in that the calorie of the mixed gas is controlled for each hot blast stove by introducing the mixed gas into a branch pipe going to the hot blast stove.