JP2008050636A - Oxygen-enriched blasting method into blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen-enriched blasting method into a blast furnace with which returning compressed oxygen quantity in an oxygen compressor is reduced and energy efficiency can be improved. <P>SOLUTION: The returning compressed oxygen quantity flowing through a returning piping 17 for returning the compressed oxygen to the sucking side from the spouting side in the oxygen compressor 2 is measured, and in the case of exceeding the returning compressed oxygen quantity to a pre-decided prescribed quantity, the opening degree of a second flowing-rate adjusting valve 22 is made to large and the compressed oxygen quantity flowing through the compressed oxygen supplying pipe 16 is increased and also, the opening degree of a first flowing rate adjusting valve 21 is made to little by the increasing quantity of this compressed oxygen to reduce the oxygen quantity for flowing through the oxygen supplying pipe 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an oxygen-enriched air blowing method for a blast furnace, which is performed in order to increase oxygen production in blown air to the blast furnace and increase the production amount of pig iron.

  Conventionally, in an ironworks, oxygen-enriched air obtained by mixing oxygen in blown air is guided to a blast furnace in order to increase the amount of blast furnace output.

At that time, an oxygen supply pipe is connected to the suction pipe on the suction side of the blast furnace blower, oxygen (eg, gauge pressure 0.1 kg / cm ² ) is mixed in the blown air, and the oxygen-enriched air is mixed with the blast furnace blower ( For example, a method of blowing air to a blast furnace by increasing the gauge pressure to 4 kg / cm ² ) and connecting a compressed oxygen supply pipe pressurized (compressed) by an oxygen compressor to a discharge pipe of the discharge side of the blast furnace blower into the blown air A method is known in which compressed oxygen (for example, a gauge pressure of 20 kg / cm ² ) is mixed and the oxygen-enriched air is blown into a blast furnace (see, for example, Patent Documents 1 and 2).

In addition, by combining both of the above, an oxygen supply pipe is connected to the blower piping on the suction side of the blast furnace blower to mix oxygen in the blown air, and the oxygen compressor is used to boost the blower piping on the discharge side of the blast furnace blower. There is a method of connecting compressed oxygen supply pipes, mixing compressed oxygen in blown air, and blowing the oxygen-enriched air to a blast furnace.
JP-A-6-306431 JP-A-10-245812

  Usually, in steelworks, oxygen is separated from air by an air separation device, and the separated oxygen is supplied to a converter, etc. in addition to the above blast furnace. Is supplied. At that time, the required amount of oxygen in the blast furnace is substantially constant, whereas the required amount of oxygen in the converter or the like varies depending on the operation status.

  Therefore, oxygen is mixed in the blast air on the suction side of the blast furnace blower described above, and the compressed oxygen boosted by the piping oxygen compressor is mixed in the blast air on the discharge side of the blast furnace blower, and the oxygen-enriched air is mixed. In the method of blowing air to the blast furnace, when the required amount of compressed oxygen decreases depending on the operation status in the converter, etc., and surplus occurs in the compressed oxygen from the oxygen compressor, the excess compressed oxygen is discharged from the oxygen compressor. The operation of returning from the suction side to the suction side (return operation) is performed.

  However, when such a return operation is performed, the amount of compressed oxygen amount (return compressed oxygen amount) returned from the discharge side of the oxygen compressor to the suction side is unnecessarily increased, and energy loss is reduced. Will occur.

  The present invention has been made in view of the circumstances as described above, and mixes oxygen in the blown air on the suction side of the blast furnace blower and boosts the pressure in the blown air on the discharge side of the blast furnace blower by a piping oxygen compressor. In the oxygen-enriched air blowing method in which the compressed oxygen is mixed and the oxygen-enriched air is blown to the blast furnace, the oxygen to the blast furnace that can reduce the amount of return compressed oxygen in the oxygen compressor and improve the energy efficiency It aims at providing the enrichment ventilation method.

  In order to solve the above problems, the present invention has the following features.

  [1] An oxygen supply pipe is connected to the suction pipe of the blast furnace blower to mix oxygen in the blown air, and the compressed oxygen supply pipe is pressurized by the oxygen compressor to the blow pipe of the discharge side of the blast furnace blower In the oxygen-enriched air blowing method in which compressed oxygen is mixed in the blown air and the oxygen-enriched air is blown to the blast furnace, the compression flowing through the return pipe that returns the compressed oxygen from the discharge side to the suction side of the oxygen compressor When the amount of oxygen is measured and the amount of compressed oxygen exceeds a predetermined amount, the amount of compressed oxygen flowing through the compressed oxygen supply pipe is increased and the amount of oxygen increased by the amount of increase in compressed oxygen. An oxygen-enriched air blowing method for a blast furnace characterized by reducing the amount of oxygen flowing through a supply pipe.

  In the present invention, the amount of return compressed oxygen in the oxygen compressor can be reduced, and the energy efficiency can be improved.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram of an oxygen-enriched blower facility for a blast furnace used in an embodiment of the present invention.

As shown in FIG. 1, this oxygen-enriched blower equipment includes an air separation device 1 that separates oxygen from air, and an oxygen compressor 2 that boosts the oxygen sent from the air separation device 1 (power consumption 0.18 kWh / Nm ³ ), a blast furnace blower 4 (power consumption 0.08 kWh / Nm ³ ) for blowing air to the blast furnace 31, and suction of the blast furnace blower 4 to mix oxygen sent from the air separation device 1 into the blown air And a mixer 3 provided on the side.

  An oxygen supply pipe 11 for supplying oxygen from the air separation apparatus 1 to the oxygen compressor 2 and an oxygen supply branched from the oxygen supply pipe 11 for supplying oxygen from the air separation apparatus 1 to the mixer 3 The pipe 12, the suction pipe 13 on the suction side of the blast furnace blower 4 (the blow pipe 13 a on the upstream side of the mixer 3, and the blow pipe 13 b between the mixer 3 and the blast furnace blower 4), and the discharge on the discharge side of the blast furnace blower 4 In order to guide the compressed oxygen from the piping 14, the compressed oxygen supply pipe 15 for supplying the compressed oxygen from the oxygen compressor 2 to the converter 32, and the discharge side blowing pipe 14 of the blast furnace blower 4. The compressed oxygen supply pipe 16 branched from the compressed oxygen supply pipe 15 and the compressed oxygen supply pipe 15 branched from the discharge side of the oxygen compressor 2 to return the compressed oxygen from the discharge side of the oxygen compressor 2 to the suction side. The oxygen supply on the suction side of the oxygen compressor 2 The return pipe 17 is provided which is connected to 11.

  A first flow rate adjustment valve 21 is attached to the oxygen supply pipe 12, a second flow rate adjustment valve 22 is attached to the compressed oxygen supply pipe 16, and a third flow rate adjustment valve 23 is attached to the return pipe 17.

Using the oxygen-enriched blower equipment configured as described above, oxygen (here, gauge pressure 0.1 kg / cm ² ) from the air separation device 1 is guided to the mixer 3, and the suction side of the blast furnace blower 4 Oxygen is mixed in the blown air flowing through the blower pipe 13 (here, the gauge pressure is 8 kg / cm ² ) and compressed from the oxygen compressor 2 into the blown air flowing through the blower pipe 14 on the discharge side of the blast furnace blower 4. Oxygen (here, gauge pressure 18 kg / cm ² ) is mixed, and the oxygen-enriched air is blown to the blast furnace 31. Further, the compressed oxygen from the oxygen compressor 2 is also supplied to the converter 32.

  When the amount of compressed oxygen required decreases depending on the operation status in the converter 32 and surplus occurs in the compressed oxygen from the oxygen compressor 2, conventionally, the surplus compressed oxygen is simply discharged from the oxygen compressor 2. In this embodiment, the return operation for returning the compressed oxygen from the discharge side of the oxygen compressor 2 to the suction side is performed (return operation for returning from the suction side to the suction side). When the return compressed oxygen amount exceeds a predetermined amount (return compressed oxygen amount upper limit value), the opening of the second flow rate adjustment valve 22 is increased and compressed. While the amount of compressed oxygen flowing through the oxygen supply pipe 16 is increased, the amount of oxygen flowing through the oxygen supply pipe 12 is reduced by reducing the opening of the first flow rate adjustment valve 21 by the amount of increase in the compressed oxygen.

  As a result, in this embodiment, it becomes possible to suppress the return compressed oxygen amount to be equal to or lower than the predetermined return compressed oxygen amount upper limit value, and it is possible to reduce the return compressed oxygen amount and improve the energy efficiency. Become.

That is, the amount of oxygen boosted by the blast furnace blower 4 (power consumption 0.08 kWh / Nm ³ ) is reduced by the reduced amount of return compressed oxygen (the amount of increase in compressed oxygen supplied to the blast furnace side), thereby Thus, the amount of return compressed oxygen is 0.08 kWh / h per 1 Nm ³ / h.

Incidentally, in the above, the upper limit value of the return compressed oxygen amount is set to 0 Nm ³ / h, that is, when the return compressed oxygen is generated, the opening amounts of the second flow rate adjustment valve 22 and the first flow rate adjustment valve 21 are adjusted immediately. May be.

For example, compressed oxygen amount flowing compressed oxygen supply pipe 16 is 1000 Nm ³ / h, amount of oxygen flowing through the oxygen supply pipe 12 is 1000 Nm ³ / h, the compression amount of oxygen flowing through the return pipe 17 (return compressed oxygen amount) is 1000 Nm ³ / If h, the opening amount of the second flow rate adjustment valve 22 is increased so that the amount of compressed oxygen flowing through the compressed oxygen supply pipe 16 is 2000 Nm ³ / h, and the opening amount of the first flow rate adjustment valve 21 is decreased. Thus, the amount of oxygen flowing through the oxygen supply pipe 12 is set to 0 Nm ³ / h. As a result, the amount of compressed oxygen flowing through the return pipe 17 (return compressed oxygen amount) becomes 0 Nm ³ / h.

  In the above, when the required compressed oxygen amount is recovered (increased) depending on the operation status in the converter 32, the amount of compressed oxygen flowing through the compressed oxygen supply pipe 16 is reduced by reducing the opening of the second flow rate adjustment valve 22. While decreasing, the opening amount of the 1st flow regulating valve 21 is enlarged by the amount of the amount of compressed oxygen reduction, and the amount of oxygen which flows into the oxygen supply pipe 12 is increased.

  In the above embodiment, as shown in FIG. 1, the number of oxygen compressors 2 is one. However, when one oxygen compressor cannot cope with the capacity when the required amount of compressed oxygen is maximized. Therefore, a plurality of oxygen compressors are often installed in parallel on the downstream side of the air separation device 1 so as to correspond to the maximum value of the required compressed oxygen amount. In that case, when the required amount of compressed oxygen increases or decreases depending on the operation status of the converter, the number of oxygen compressors to be operated will be increased or decreased as necessary, but the total capacity of the oxygen compressors to be operated will be increased. When the amount of compressed oxygen does not match the required amount of compressed oxygen, surplus is generated in the compressed oxygen from the operated oxygen compressor, and an operation (return operation) for returning surplus compressed oxygen from the discharge side of any oxygen compressor to the suction side is performed. Will do.

  Therefore, even when such a plurality of oxygen compressors are installed, as in the above embodiment, when the return compressed oxygen amount exceeds a predetermined return compressed oxygen amount upper limit value, The opening amount of the second flow rate adjustment valve 22 is increased to increase the amount of compressed oxygen flowing through the compressed oxygen supply pipe 16, and the opening amount of the first flow rate adjustment valve 21 is decreased by the amount of increase in the compressed oxygen amount. The amount of oxygen flowing through the oxygen supply pipe 12 may be reduced.

  Accordingly, the return compressed oxygen amount can be suppressed to be equal to or lower than a predetermined return compressed oxygen amount upper limit value, and the return compressed oxygen amount can be reduced and the energy efficiency can be improved.

  First, as a conventional example, when excess compressed oxygen is generated in the oxygen-enriched blower facility shown in FIG. 1, oxygen-enriched air is blown into the blast furnace while simply performing a return operation.

In contrast, as an example of the present invention, oxygen-enriched air was blown into the blast furnace based on the above-described embodiment of the present invention. At that time, the upper limit value of the return compressed oxygen amount was set to 0 Nm ³ / h.

As a result, return compressed oxygen content was 1000 Nm ³ / h in the conventional example, in the present invention example, it reduced to approximately ^{0 Nm} 3 / h, thereby, 80kWh / h (1000Nm ³ /h×0.08kWh/Nm ³ ) Power saving effect was obtained.

It is explanatory drawing of the oxygen enriched ventilation equipment used in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air separation apparatus 2 Oxygen compressor 3 Mixer 4 Blast furnace blower 11 Oxygen supply pipe 12 Oxygen supply pipe 13, 13a, 13b Blower pipe 14 Blower pipe 15 Compressed oxygen supply pipe 16 Compressed oxygen supply pipe 17 Return pipe 21 First flow rate adjustment Valve 22 Second flow control valve 23 Third flow control valve 31 Blast furnace 32 Converter

Claims (1)

  The oxygen supply pipe is connected to the air supply pipe on the suction side of the blast furnace blower to mix oxygen in the air, and the air supply pipe on the discharge side of the blast furnace blower is connected to the supply pipe for compressed oxygen boosted by the oxygen compressor. In the oxygen-enriched air blowing method in which compressed oxygen is mixed in the blown air and the oxygen-enriched air is blown to the blast furnace, the amount of compressed oxygen flowing through the return pipe that returns the compressed oxygen from the discharge side of the oxygen compressor to the suction side is determined. When the amount of compressed oxygen exceeds a predetermined amount, the amount of compressed oxygen flowing through the compressed oxygen supply pipe is increased and the oxygen supply pipe is increased by the amount of increase in the compressed oxygen. An oxygen-enriched air blowing method for a blast furnace, characterized by reducing the amount of flowing oxygen.

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