JPS5882925A - Method of controlling distribution of flow of particulate material - Google Patents

Abstract

PURPOSE:To equally distribute particulate material without directly measuring the flow of the material, by utilizing such a fact that the flow in each branch pipe varies in dependence upon the outlet pressure of each branch pipe but the solid-gas ratio is substantially equal, when the two-phase fluid of solid and gas having a sufficiently high velocity is distributed. CONSTITUTION:When the two-phase fluie of solid and gas having a velocity relatively higher than the falling velocity of a particulate material is distributed to a plurality of branch pipes, the flow of the two-phase fluid of solid and gas in each branch pipe varies in dependence upon the outlet pressure of each branch pipe, but the solid-air ratio in each branch pipe is substantially equal. Perceiving this fact, pressure loss across a predetermined length in the straight part of each branch pipe is calculated in case of equally distributing the two-phase fluid of solid and gas to a plurality of branch pipes on account of the solid-gas ratio which is obtained by the calculation of total flows of particulate material and gas, and as well of the pressure of the two- phase fluid of solid and gas in each branch pipe so that the pressure loss is controlled to be made equal to the pressure loss in the same part of each branch pipe after the two-phase fluid of solid and gas is distributed.

Description

[Detailed description of the invention] Zero shot'! A relates to a flow source control method when distributing powder or granular material to a plurality of destinations in a vapor phase.

In the past, the only fuel used in blast furnaces was coke, but with the development of blast furnace technology, heavy oil was injected into the blast furnace from the tuyere as an auxiliary fuel. Attempt to use pulverized coal instead75
;It is actively practiced.

When blowing pulverized coal into the blast furnace from the tuyere, it is necessary to stabilize the total amount of pulverized coal being blown into the blast furnace and to adjust the amount of pulverized coal blown into each tuyere to stabilize the blast furnace condition. Uniformity is required.

However, in the conventional method of injecting pulverized coal into the blast furnace using a carrier gas, there is no established method for measuring the flow rate of solid-gas two-phase fluid, so it is difficult to control the blowing mixing of each tuyere force. The reality is that this is not the case. Venturi differential pressure type, #J pressure type, Coriolis type, capacitance type, etc. are known flowmeters for measuring the flow value of solid-gas two-phase fluid. Flowmeters that separate the flow rate from the solids flow rate to identify the solids flow have poor measurement accuracy and stability, and cannot be used to control the amount of injection.

The present invention was made against this background,
Two methods are proposed that allow granular material to be distributed into a mass without directly measuring the flow rate of a solid-gas two-phase fluid or a solid.

In the method of the present invention, when a solid-gas two-phase fluid having a flow rate sufficiently higher than the one-year sedimentation rate of powder and granules is distributed, the flow rate of the solid-gas two-phase fluid in each distribution branch pipe varies depending on the outlet pressure of each distribution branch pipe. However, noting that the solid-air ratio in each distribution branch pipe is almost equal, the solid-air ratio is calculated from the gold powder flow and the total gas flow rate, and the solid-air ratio and the solid-air two-phase in each distribution branch pipe are calculated. From the pressure of the fluid, calculate the pressure loss (hereinafter referred to as pressure loss) in a fixed length section of the straight pipe section of the distribution branch pipe when the solid-gas two-phase fluid is equally distributed to each distribution branch pipe, and calculate this pressure loss as the solid-gas 2 phase fluid. Control the pressure drop to be equal to the pressure drop in the same part of each distribution branch pipe after distributing the phase fluid.
It is something that does.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing an embodiment in which fine powder is distributed and supplied to each wall of a blast furnace. The drawing is a schematic diagram showing the implementation state of the method of the present invention, and pulverized coal obtained by pulverizing coal is transported and stored in a tank 1. A load bearing cell 2 is provided in the load bearing portion of the tank 1, and the weight of the pulverized coal is weighed. A cutting device 3 is provided at the lower outlet of the tank 1, and the necessary fine pulverized coal is supplied to the supply pipe 52 by the cutting device 3.

On the other hand, a carrier gas such as nitrogen gas or air is supplied to the supply pipe 52 from a gas tank (not shown) through a carrier gas supply pipe 51, and the pulverized coal cut from the tank 1 to the supply pipe 52 is transported by this carrier gas. It becomes a solid-gas two-phase fluid and is distributed by the distributor 7 to a plurality of distribution branch pipes 6, 6, . . . . A known flow meter 4 such as a Venturi differential pressure type is installed in the carrier gas supply pipe 51 and measures the flow rate of the carrier gas inside the carrier gas supply pipe 51 . The distributor 7 is, for example, a distributor having a conical cone, and is capable of uniformly distributing the fluid to each distribution branch pipe 6, 6, . . . .

Each distribution branch pipe 6.6 immediately after the distributor 7...K is the flow rate 1i
jJ Both valves 8.8... are treated with dogs, and will be described later /j! The flow rate is controlled by a computer control device 10. Flow control valve 8 for each distribution branch pipe 6.6...
．． A measuring device 9.9 for measuring the pressure loss of each distribution branch pipe of the fluid is interposed in a portion of the straight pipe +5-8, 6t. This measuring device 9.9...#
This is a differential pressure oscillator in which two measurement tube sections are connected in communication at two locations separated by a fixed length of straight tube sections 6a, 6m, . . .

Furthermore, pressure gauges 11.
11... are interposed to measure the pressure of the fluid within each distribution branch pipe 6, 6.... And each pressure gauge 11.11...
The solid-gas two-phase fluid whose pressure has been measured is fed to each tuyere of the blast furnace (not shown).

On the other hand, load cell 2. Flowmeter 4. Measuring device 9.9...,
Furthermore, each measurement signal of the pressure gauges 11, 11... is input to the arithmetic and control unit IO, where the arithmetic processing described later is performed, and the opening of the flow rate control valves 8,8... is determined based on the arithmetic results. It is designed to adjust. Therefore, in this invention, the flow rate of solid, ie, powder, granular material is not measured while it is flowing, but is determined by capturing the weight change of tank 1 by load cell 2. The differential value of the weight-reduced sunset view corresponds to the hourly flow rate.

Other flowmeter 4 measures carrier gas flow rate, and 1-E
The point that the IE force in each distribution branch pipe 6,6, . . . is obtained by the force 11, 11, . When the solid-gas two-phase fluid is evenly distributed to each distribution branch pipe 6.6 by using these solid flow rate, carrier gas flow rate, and distribution branch pipe internal pressure, the straight pipe portion 6a in each distribution branch pipe 6.6... The pressure drop is calculated, and the flow rate control valve 8 is controlled so that the calculated result matches the measurement results obtained by each measuring device 9.9.

This flow rate control method will be explained in more detail.

The pressure loss ΔP+ in the straight pipe portions 6a, 6a... of the distribution branch pipes 6, 6... (however, the subscript it/i is the number representing the distribution branch pipe) is the pressure drop IPf when only gas is flowing, and the addition of pulverized coal. It is the sum of the pressure loss jP. If a sufficient feeding distance (run-up distance 8) to the straight pipe portion 6a is taken so as not to cause acceleration loss of the pulverized coal in the straight pipe portion 6a, the additional pressure loss ΔPs will mainly be a friction pressure loss. Now, let us assume that the fluid flow rate in each distribution branch pipe is Vt (m/8), the solid-air ratio in each distribution branch pipe 6, 6... is mI, and the pressure in each distribution branch pipe 6, 6... is P. Pressure drop ΔP in each distribution branch pipe.

is expressed by the following formula.

Δpi = ΔPs + 1Pf = 4(Pt) mt vl”+ K2(Pt
)vt”−(K+(Pt)mt+Kt(Pt
)) vt” −(1) (However, + (
Pl), K2(P>) is the pressure P in each distributor pipe
(constant determined by 1) If pulverized coal is flowed at a speed sufficiently faster than its settling speed, and if the flow velocity is uniform in the distribution branch pipe over a sufficiently long feeding distance, the Each distribution branch pipe 6.6...
・Flow is carried out so that the solid-air ratio of each is equal.

Therefore, the solid-air ratio m of the solid-gas two-phase fluid is calculated from the change value of the load cell 2 and the measured value of the flow meter 4, and this is set as the solid-air ratio m of each distribution branch pipe 6, 6... Solid-gas ratio IIJ, pressure Pi of each distribution branch pipe 6, 6... measured by pressure gauge 11, 11..., gas flow rate measured by flow meter 4, and load cell 2
Each distribution branch pipe 6, 6... calculated from the pulverized coal electricity value by
The pressure drop jPi of the above equation (1) can be obtained from the respective flow velocities v1 and K when the fluid is evenly distributed to the two. Note that the constants +(Pt) and Kt(Pt) are determined using solid lines.

The arithmetic and control device 10 performs the above-mentioned arithmetic processing to determine the pressure loss Δ.
Pi is calculated, and each flow rate control valve 8 degree is By adjusting the flow rate of 8, pulverized coal will be evenly distributed to each distribution branch pipe 6, 6, .

Note that in the above method, when the temperature change is large, the accuracy of equal distribution is improved by temperature-correcting the calculated pressure loss ΔPI.

When pulverized coal is blown into the valley tuyere of a blast furnace using the apparatus configured as described above, the pulverized coal cut out from the tank 1 is supplied with nitrogen gas from the carrier gas supply pipe 51.

By supplying a carrier gas such as air, it becomes a solid-gas two-phase fluid, which is distributed by the day distributor 7.
The flow rate control valve 8゜8... installed immediately after is used to calculate the pressure drop when pulverized coal is evenly distributed, which is determined from the powder flow rate, gas flow rate, ', and the pressure in each distribution branch pipe, as described above. Since the measuring device 9 is controlled by the arithmetic and control unit 1O to eliminate the cliff loss, the flow rate of the pulverized ash flowing through each distribution branch pipe 6, 6, etc. becomes uniform, and therefore the blast furnace The Kin 8 translation can be evenly injected into each separate mouth.

In the above embodiment, the flow rate of pulverized coal is measured by the load cell 2, but the flow rate is not limited to this, and it can also be determined by measuring the flow rate of the cutting device 3, for example.

As described in detail above, zero-start #iA is a method for distributing a solid-gas two-phase fluid of powder and carrier gas to multiple branch pipes, and the The pressure of the gas two-phase fluid is measured, and based on this measurement result, the solid gas two-phase fluid is
While calculating the pressure loss at a specific part of the branch pipe when the phase fluid is distributed equally to each distribution branch pipe, the pressure drop in the part related to the specific part is measured, and the calculated pressure loss and the measured pressure loss are calculated. Since the flow rate of the solid-gas two-phase fluid in the branch pipes is controlled by comparing the ratio of When feeding pulverized coal to each tuyere of the cJT, stable operation of the blast furnace can be ensured and fuel costs can be reduced.

Note that the part for calculating pressure loss and the part for measuring pressure loss are not limited to the same parts as in the embodiment of the drawings, nor are they limited to the same shape.

[Brief explanation of the drawing]

The drawings are schematic diagrams showing an embodiment of the method of the present invention. 1... Tank 2... Load cell 3... Cutout 1114... Flowmeter 6... Distributor 1! F7...
・Distributor 8...Flow rate 11i1J control valve 9...Measuring device 10...Arithmetic and control unit 11...Pressure gauge Patent Applicant Agent: Sumitomo Metal Industries, Ltd.
Patent Attorney Noboru Kono

Claims (1)

[Claims] 1. In the method of distributing a solid-gas two-phase fluid of powder and carrier gas to branch pipes for 4I, the powder and granular flow rate, the carrier gas flow rate, and the pressure of the solid-gas two-phase fluid in each branch pipe are measured. , Based on this measurement result, calculate the pressure loss at a specific part of each distribution branch pipe when the solid air, two chloride fluid is equally distributed to each distribution branch pipe, and measure the pressure loss at a part related to the specific part. A current distribution control method for powder and granular material, characterized in that the flow rate of the solid-gas two-phase fluid in the branch pipe is controlled by comparing the calculated pressure loss and the measured pressure loss.