JP5392319B2 - Coke oven fuel gas mixing device - Google Patents

Description

  The present invention relates to an apparatus for mixing blast furnace gas (hereinafter referred to as B gas) and coke oven gas (hereinafter referred to as C gas), and more particularly to an apparatus for mixing C gas into a flow of B gas to obtain a uniform fuel gas.

A coke oven is a device that produces coke that is carbonized to charge coal into the blast furnace as a reducing agent. The coke oven is equipped with multiple carbonization chambers, combustion chambers, and heat storage chambers, and M gas preheated in the heat storage chamber is combusted in the combustion chamber. By doing this, the coal in the carbonization chamber is carbonized.
In the operation of the coke oven, it is important to produce coke with uniform quality, and temperature distribution adjustment between a plurality of carbonization chambers and in each carbonization chamber is performed by combustion control of M gas. Recently, a reduction in energy consumption is required from the viewpoint of the global environment, and further higher accuracy in combustion control is required.

  The fuel gas combustion control is an M gas calorie control having two control systems: an M gas flow constant control system and an M gas calorie constant control system for adjusting the C gas flow rate and burning the M gas at a constant calorie. Combustion control is performed by the method.

  In the M gas calorie control method, the component is obtained from the sampled C gas, and when the C gas calorie fluctuates, it is necessary to change the B gas flow rate and the C gas flow rate so that the M gas calorie becomes constant. It has been pointed out that it takes time until stable combustion occurs because the M gas flow rate constant control system and the M gas calorie constant control system interfere.

  The control method described in Patent Document 1 sets the input heat amount to the coke oven, detects the calorific value of each of the B gas and C gas supplied to the coke oven, and sets the set input heat amount and the respective heat amount. Based on the calorific value of the fuel gas, the amount of heat supplied to the coke oven for the B gas and / or C gas is controlled so that an input heat amount substantially equal to the set input heat amount can be stably obtained. .

Specifically, the input heat amount E is used, and the flow rate ratio of the B gas and the C gas is calculated using a relational expression from the set M gas calorific value Q _M and the detected calorific values Q _B and Qc of the B gas and C gas. The necessary B gas flow rate and C gas flow rate are controlled using γ (C gas flow rate / B gas flow rate).

  Patent Document 2 improves the technology described in Patent Document 1, changes the input heat amount based on the calorific values of B gas and C gas that change over time, and the M gas flow constant control system and the M gas calorie constant control system mutually It is characterized by suppressing fluctuations in the amount of input heat due to interference.

  Further, a control system shown in FIG. 3 has been studied as a control system that stabilizes the constant gas calorie combustion of M gas. When setting the amount of heat supplied to the coke oven 100, component analysis is performed for both B gas and C gas with a gas chromatograph, the gas density is obtained from the obtained analysis value, and the density correction of the orifice of the M gas flow path is performed. It is characterized by performing.

  A gas chromatograph device 200 is disposed downstream of the flow meter 60 and the flow meter 70 in the flow path of B gas and C gas, and each gas density is obtained from the analysis value.

After mixing B gas and C gas in the mixer 110, the flow rate of the M gas adjusted by the flow control valve 90 corrects the density of the measured value in the flow meter 80, so the supply heat amount (the product of the M gas heat amount and the flow rate). ) Can be set accurately. Since highly accurate combustion control is possible, the stability of NO _X guarantee is improved.

JP-A-60-71685 JP 7-19453 A

  However, according to the inventions described in Patent Documents 1 and 2, the stability of the furnace temperature is improved, but calorimeters are arranged in the respective flow paths of B gas and C gas, and based on the measured values of M gas Since the calorific value is obtained, the M gas calorie value is a calculated value based on the calorie measurement values of the B gas and the C gas, and produces a difference from the true M gas calorie. In addition, the flow rate control method is complicated, and stabilization of combustion control is not sufficient.

  Further, the method described in FIG. 3 requires a plurality of expensive gas chromatographic analyzers for component analysis of B gas and C gas, so that the equipment cost is increased and the density correction itself of the flow meter is not easy.

  Accordingly, an object of the present invention is to provide an apparatus for accurately controlling the gas calorie of M gas when the gas calorie of B gas or C gas fluctuates.

The object of the present invention can be achieved by the following means.

1. A mixing device that is attached to a blast furnace gas supply pipe and mixes the coke oven gas with the blast furnace gas to form a fuel gas for the coke oven,
A pipe part, a nozzle part for supplying coke oven gas to the peripheral part of the blast furnace gas, and a nozzle part for supplying coke oven gas to the center part of the blast furnace gas,
The pipe portion has the same diameter as the blast furnace gas supply pipe, and has a plurality of slits for blowing the coke oven gas as a swirl flow along the inner wall of the pipe in a part of the pipe axis direction. The pipe part is a double pipe structure provided with an outer pipe having a nozzle part for supplying coke oven gas to the peripheral part of the blast furnace gas,
The nozzle part for supplying coke oven gas to the central part of the blast furnace gas has a nozzle opening that opens conically, and a conical member that is coaxially disposed in front of the nozzle opening, and the conical member is located at the center thereof Having an opening communicating with the nozzle opening in the part,
The coke oven fuel gas mixing device according to claim 1, wherein the nozzle port is arranged so as to blow coke oven gas from the upstream side of the pipe portion into a central portion of a radial section of the conical member .

  According to the present invention, the amount of heat supplied to the coke oven can be accurately controlled by a simple method, exhaust gas loss can be reduced, and this is extremely useful industrially. In addition, since the calories of M gas are detected after B gas and C gas are uniformly mixed, the detected gas calories become true values, the input heat amount is stable, the furnace temperature is unstable, and the coke quality is degraded. And prevent an increase in energy intensity.

The control flow figure which shows the control structure of the combustion control method of the coke oven which concerns on this invention. It is sectional drawing which shows an example of the mixing apparatus which concerns on this invention, (a) is a side view, (b) is a front view. Conventional example (coke oven combustion control system). Conventional example (mixing device). Conventional example (mixing device).

  The present invention relates to an M gas calorie control method having two control systems, an M gas flow constant control system and an M gas calorie constant control system for adjusting the C gas flow rate and burning M gas with a constant calorie. The calorimeter is arranged in the path of the M gas, the calorie of the M gas is directly obtained, and the calorimeter is arranged in the gas path after the B gas and the C gas are uniformly mixed.

  FIG. 1 is a control flow diagram showing a control configuration of a combustion control method for a coke oven according to the present invention, wherein 1 is a coke oven, 2 is a calorimeter, 3 is an analyzer for performing exhaust gas analysis, and 4 is an M for the coke oven 1 A calculation device for setting the input heat amount of gas, 5 is a flow meter for measuring the B gas flow rate, 6 is a flow meter for measuring the C gas flow rate, 7 is a flow meter for measuring the M gas flow rate, and 8 is a flow control for the M gas. Valve 9, pressure control valve for exhaust gas, 10 a mixing device for mixing B gas and C gas, 11 for a chimney (exhaust gas tower), e for the distance between the mixing device 10 and the calorimeter 2 mounting position.

  In the combustion control method according to the present invention, the input heat amount of the M gas supplied to the coke oven 1 is obtained by the calculation device 4 from the target furnace temperature and the actual furnace temperature range so that the input heat amount of the M gas becomes constant during combustion. The M gas is controlled using the M gas flow meter 7 and the M gas flow control valve 8, and the exhaust gas from the coke oven is pressure-controlled by the pressure control valve 9 and then discharged from the chimney 11.

  The input heat amount of the M gas is obtained by the product of the M gas heat amount and the flow rate, and the M gas heat amount is directly measured by the calorimeter 2 attached to the fuel gas path on the downstream side of the mixing apparatus 10. Further, the M gas calorie is detected by the calorimeter 2, and the B gas flow meter 5 and the C gas flow meter 6 are used to correct the B gas flow rate and the C gas flow rate ratio.

  The calorimeter 2 has a position where B gas and C gas mixed by the mixing device 10 are uniformly distributed in the radial cross section of the M gas path (indicated as an interval e in the figure), that is, M gas. It is preferable to attach to the downstream side from the position where the difference in C gas concentration distribution is eliminated because the measurement accuracy of the M gas calorific value is improved.

  In the present invention, the B gas and the C gas are mixed in the central portion and the peripheral portion of the gas flow of the B gas by using the mixing device 10 so that the gas gas is uniformly distributed in the radial cross section of the fuel gas path.

  The uniformity in the M gas is performed by adjusting the ratio of the C gas amount in the central portion and the peripheral portion in the cross section perpendicular to the flow direction of the B gas, but the flow rate when the C gas is allowed to flow into the B gas can also be controlled. preferable. The flow rate at the time of inflow is preferably set so that the uniformity is improved by making the flow rate difference within 10% between the central part and the peripheral part.

  FIG. 2 is a cross-sectional view showing an example of a mixing apparatus according to the present invention, where (a) shows a side view and (b) shows a front view. In the figure, 12 is the entire mixing apparatus, 13 is a nozzle for supplying C gas to the central part of B gas, 14 is a nozzle for supplying C gas to the peripheral part of B gas, 15 is attached with nozzles 13 and 14 and B gas A pipe part inserted between the supply pipe 20 and the M gas supply pipe 21, 151 is an outer pipe of the pipe part 15, 16 is a swirl vane that swirls C gas supplied by the nozzle 14, and 17 is a front part of the nozzle 13. A conical member disposed at the center, 18 is an opening provided in the central portion of the conical member 17, and a plurality of 19 are provided on the inner wall of the tube portion 15 to blow C gas into the peripheral portion of the tube portion 15 as a swirling flow. Therefore, a slit 20 is a B gas supply pipe, and 21 is an M gas supply pipe for supplying M gas obtained by mixing C gas to B gas to the coke oven.

  The mixing device 12 includes a pipe portion 15 and nozzles 13 and 14 and is coaxially mounted on the B gas supply pipe 20. The pipe portion 15 has the same diameter as the M gas supply pipe 21, and a plurality of slits 19 for blowing C gas as a swirling flow along the inner wall of the pipe are provided in a part of the pipe axis direction. The provided pipe portion has a double pipe structure having an outer pipe 151 provided with a nozzle 14 for supplying C gas.

  The shape of the slit 19 is not particularly limited as long as the C gas is smoothly fed into the pipe as a swirling flow, but is desirably provided at equal intervals in the circumferential direction of the inner wall of the pipe portion 15.

  The nozzle 13 has a conical opening and a conical member 17 disposed coaxially in front of the nozzle opening. The conical member 17 has an opening 18 communicating with the nozzle opening at the center thereof. Provide. With such a structure, C gas can be stably blown into the central portion of B gas.

  Therefore, the nozzle 13 has a shape in which the nozzle opening opens in the tube portion 15, for example, an L shape, and the conical member 17 also has the C gas in the tube portion 15 in the center of the radial section of the tube portion 15. Arrange to blow into the part.

  The C gas supplied to the nozzle 13 is blown from the gap between the nozzle opening and the conical member 17 and the opening 18 of the conical member 17. The nozzle 13 is attached to the tube portion 15 with a support member a, and the conical member 17 is attached to the tube portion 15 with a support member b. The support members a and b are preferably rod-shaped members so as not to disturb the gas flow.

  On the other hand, the C gas supplied to the nozzle 14 follows the inner wall of the tube portion 15 from the outer tube 151 having the nozzle 14 attached therein and having the swirl vanes 16 therein by the slit 19 provided on the inner wall of the tube portion 15. It becomes a swirl flow and is supplied to the periphery of the B gas.

  According to the present invention, the fuel gas calorie constant control is more accurate and more responsive than the case where the M gas calorific value is directly measured and obtained by calculation using the C gas component and B / C gas ratio by sampling. It is possible to construct a system.

In the mixing apparatus shown in FIG. 2, a B gas supply pipe 1350Φ and a C gas supply nozzle diameter 300Φ are used, and the flow rates during M gas combustion are B gas: 51940 (Nm ³ / H) and C gas: 4500 (Nm ³ / H). The mixing length was around 44 m and the difference in C gas concentration distribution was as good as 1% or less.

  Further, at a position 60 m from the C gas mixing portion, the C gas concentration distribution difference was about 0.3%, while the conventional method in which only the peripheral gas was blown was about 6%.

  In the M gas supply method of the present invention, a well-known M gas flow rate control system is used, and the two control systems of the M gas flow rate constant control system and the M gas calorie constant control system are also controlled by known methods. The effects of the present invention will be described below with reference to examples.

C gas was blown into the B gas supply pipe using mixing devices having various structures, and the mixed state was investigated.
In the example of the present invention, the mixing apparatus shown in FIG. 2 was used. Sixteen nozzles having a central nozzle diameter of 350 mm and peripheral slits having a rectangular opening of 80 × 50 mm were provided at equal intervals in the circumferential direction of the inner wall of the tube. The B gas supply pipe had a diameter of 1350 mm.

  The comparative example is a mixing apparatus having the structure shown in FIGS. 4 and 5, and C gas is supplied from the C gas supply nozzle 400 only to the periphery of the B gas supply pipe 300. 4, the B gas supply pipe 300 has a diameter of 1350 mm, the C gas supply nozzle 400 has a diameter of 400 mm, and in FIG. 5, the B gas supply pipe 300 has a diameter of 1350 mm, the C gas supply nozzle 400 has a diameter of 500 mm, and three C gas supply nozzles 400 The ring tube 500 connecting the two is 400A.

  Table 1 shows the test conditions and mixing properties. Mixability was measured at a cross section 60 m downstream from the mixing position. Invention Example No. Nos. 1 to 4 show a good difference in C gas concentration distribution of 1% or less, whereas Comparative Example 5 and 6 were inferior at around 6%.

  In the example of the present invention, the C.sub.gas velocities blown from the central nozzle and the peripheral slit are substantially equal. 2 is 0.21%. No. 4 is 0.17%, and the C gas velocity blown from the peripheral slit is about 4 times that of the central nozzle. No. 1 is 0.26%, and the C gas velocity blown from the peripheral slit is about 0.5 times that of the central nozzle. 3 was inferior at 0.30%. In each of the inventive examples, the NOx concentration in the exhaust gas was lower than that of the comparative example.

DESCRIPTION OF SYMBOLS 1 Coke oven 2 Calorimeter 3 Analyzer which analyzes exhaust gas 4 Calculation device which sets the heat input of M gas to coke oven 5 Flow meter which measures B gas flow rate 6 Flow meter which measures C gas flow rate 7 M gas flow rate Flow meter 8 for measuring M gas flow control valve 9 Exhaust gas pressure control valve 10, 12 Mixing device 11 Exhaust gas tower 13, 14 Nozzle 15 Pipe part 151 Outer pipe 16 Swivel blade 17 Conical member 18 Opening 19 Slit 20 B Gas supply pipe 21 M Gas supply pipe a, b Support member e Interval between mixing apparatus and calorimeter 60, 70, 80 Flow meter 90 Flow control valve 100 Coke oven 110 Mixing apparatus 200 Gas chromatograph apparatus 300 B Gas supply pipe 400 C Gas supply nozzle 500 Ring tube

Claims (1)

A mixing device that is attached to a blast furnace gas supply pipe and mixes the coke oven gas with the blast furnace gas to form a fuel gas for the coke oven,
A pipe part, a nozzle part for supplying coke oven gas to the peripheral part of the blast furnace gas, and a nozzle part for supplying coke oven gas to the center part of the blast furnace gas,
The pipe portion has the same diameter as the blast furnace gas supply pipe, and has a plurality of slits for blowing the coke oven gas as a swirl flow along the inner wall of the pipe in a part of the pipe axis direction. The pipe part is a double pipe structure provided with an outer pipe having a nozzle part for supplying coke oven gas to the peripheral part of the blast furnace gas,
The nozzle part for supplying coke oven gas to the central part of the blast furnace gas has a nozzle opening that opens conically, and a conical member that is coaxially disposed in front of the nozzle opening, and the conical member is located at the center thereof Having an opening communicating with the nozzle opening in the part,
The coke oven fuel gas mixing device according to claim 1, wherein the nozzle port is arranged so as to blow coke oven gas from the upstream side of the pipe portion into a central portion of a radial section of the conical member .

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