CN1049046C - Measuring method of powder flow in pipeline - Google Patents

Abstract

The present invention relates to a method for measuring the flux of pipeline powder in the fields of steel, metallurgy, thermal power, cement industry, etc. The difference of the powder weight of an initial time and a final time in unit time is firstly taken, multi-time measurement is carried out according to the unit time on capacitive sensors of pipelines, and average values of pipeline capacitance are obtained. All the average values are summed, the weight difference of the powder and the sum quantity of the average values are compared, a capacitance change ratio is obtained, and the flux of each pipeline is obtained by that the ratio and the average values of pipeline capacitance are multiplied.

Description

Measuring method of powder flow in pipeline

The present invention relates to the method for measuring channel powder flow in the fields such as a kind of iron and steel, metallurgy, thermoelectricity, cement industry, glass furnace.

At present, in fields such as iron and steel, metallurgy, cement industry and glass furnace, all use powdery coal to act as a fuel, the method that relies on strength to carry is sent in the special-purpose kiln and is burnt.For the CONTROL PROCESS process, improve technical economical index, to improve the quality of products, energy efficient all needs the ducted pulverized coal flow that is sent to kiln is detected.The most frequently used both at home and abroad at present, the most representative is electric capacity coherent detection method.This method is that the capacitive transducer of being made up of pole plate and isolated pipe is set in tested pipeline, make in fuel delivery event, what flow through capacitive transducer does not flow the dielectric that just becomes between capacitor plate with the pressurized air of coal dust or the powder of band coal dust, according to the different media or the variable concentrations of same medium, sensor just reflects different capacitances, with secondary instrument to the capacitance variations of sensor measure, record, pass through again that injecting coal quantity---capacitance is demarcated, just draw pipeline powder coal at difference instantaneous value constantly.But still there is very big problem in this method, because the size of the capacitance that capacitive transducer reflects is not only with to flow through the concentration of coal dust relevant in the pipeline, also the moisture with temperature, the particularly coal dust of the ash of coal dust itself, coal dust has much relations, sometimes coal dust moisture increases one of percentage, the capacitance of capacitive transducer can increase by 10 to tens, drifted about the zero point of secondary instrument, and measurement result loses meaning.Therefore the measurement result of this method is extremely inaccurate, does not have practical value.For addressing this problem, some researcher's employing is demarcated in advance the above-mentioned influence factor beyond the coal powder density and is revised.Come revisal as the numerical value of measuring with electronic scale that always is blown into the coal dust amount.But the thing followed is too frequent demarcation can make the flow measurement recording curve become desultory dotted line, and this brings a lot of difficulties, uncontrollable technological process for the technological operation personnel.

Purpose of the present invention is exactly in order to address the above problem, and it is accurate to propose a kind of measurement, stable and reliable for performance, measuring method of powder flow in pipeline and sensor thereof with practical value.

Technical solution of the present invention:

A kind of measuring method of powder flow in pipeline is characterized in that:

A, in unit interval t, carry out initial time and twice weighing constantly that end to spraying into coal dust total amount in the kiln, obtain initial time coal dust total amount G respectively with electronic scale _oWith the coal dust total amount G constantly of ending _k, get its difference: Δ G=G _k-G _o

B, on each pipeline of transporting to kiln with fuel point (fuel point is two at least), the capacitive transducer of its first pipeline carries out (m is the integer greater than 1) measured capacitance value m time in same unit interval t, obtain each time measurement capacitance 1C _o, 1C _l1C _mThe capacitive transducer of its second pipeline also carries out m time in same unit interval t measures, and obtaining measurement capacitance is 2C _o, 2C _l2C _mAnd the like, the measurement capacitance of n pipeline is nC _o, nC _lNC _m

C, to m the capacitance that each pipeline records in unit interval t, the mean value of getting separately is: $1C=\frac{{1C}_o+{1C}_l+{\…\…1C}_m}{m}$ $2C=\frac{{2C}_o+{2C}_l+{\…\…2C}_m}{m}$ $\mathrm{nC}=\frac{{\mathrm{nC}}_o+{\mathrm{nC}}_1+{\…\…\mathrm{nC}}_m}{m}$

D, with above-mentioned each mean value 1C, 2C ... the nC summation, that is:

∑＝1C+2C+…+nC。

E, coal dust total amount difference DELTA G that a step is obtained just obtain the ratio of coal dust total flow and capacitance variations than the mean value summation ∑ that last d step obtains: $Z=\frac{\mathrm{\ΔG}}{\mathrm{\Σ}}$

The condenser paper average that f, the ratio Z that the e step is obtained and each pipeline record multiplies each other, and just obtains the desired pulverized coal flow Q of each pipeline in unit interval t, i.e. the first pipeline powder coal flow Q ₁=Z * 1C, the second pipeline powder coal flow Q ₂=Z * 2C ..., n pipeline powder coal flow Q _n=Z * nC.

The present invention will be blown into the coal dust total amount of kiln first and the condenser paper average of each pipeline capacitive transducer organically combines together, can obtain the moment flow and mean value and accumulated value of the coal dust of each pipeline rapidly by data acquisition unit and computing machine.The inventive method is simple, practical, measurement result is accurate, accuracy can reach 2%, can satisfy the requirement of technological operation personnel CONTROL PROCESS process, at any time control and adjust the fuel coal dust operational throughput of each pipeline, reach energy savings, improve the quality of products, improve the purpose of technical economical index, have very high popularizing value.The inventive method is not only applicable to the Coal powder spray of steel plant's blast furnace, Coal powder spray and the Coal powder spray of metallurgical furnace and the coal-burning installation of heat power plant boiler of steelmaking converter, is applicable to the coal combustion equipment of cement and glass yet.

Below in conjunction with the description of drawings concrete course of work of the present invention.

Fig. 1 is that the present invention is used for coal powder injection blast furnace technology process flow diagram;

Fig. 2 is a coal powder injection jar weight voltage signal data acquisition circuit electrical schematic diagram of the present invention;

Fig. 3 is pipeline capacitive transducer of the present invention and data acquisition circuit electrical schematic diagram thereof.

The present invention is an example with steel plant's coal powder injection blast furnace 1, as Fig. 1, supposes that coal powder injection blast furnace 1 has ten coal powder injection air ports 2, then with ten pipelines 3 of each coal powder injection air port 2 corresponding connection separately capacitive transducer 4 is housed respectively all.

The variation of coal powder injection jar 5 coal dust weight measures by electronic scale 6.Electronic scale 6 is according to the coal dust weight change of coal powder injection jar 5, its bridge circuit output current signal.When coal powder injection jar 5 is filled coal dust, obtain current maxima i _Max, when coal dust has sprayed in the coal powder injection jar 5, obtain current minimum i _Min, these two current signal i _Max, i _MinInput coal powder injection jar weight voltage signal data acquisition circuit is as Fig. 2.Because the coal dust in the coal powder injection jar 5 constantly sprays its current maxima i _MaxBecome minimum value i _MinBe a continuous change procedure, then the current signal that should change is by amplifier IC ₁Obtain a correspondent voltage variable signal and send into analog to digital converter IC ₂Voltage input end V _x, IC ₂The digital signal of output is from data output end D ₀-D ₇Deliver to device for digit-displaying IC ₃Show in real time, be sent to the input/output port I/O of main frame simultaneously again.

Separately capacitive transducer 4 is and is connected to each self-corresponding data acquisition circuit on ten pipelines 3, as Fig. 3.Their principle of work is identical, is example with arbitrary road, and when having coal dust to flow in a certain pipeline 3, then the capacitive transducer 4 of this pipeline reflects a relevant capacitance value C _x, this capacitance C _xBe an amount that changes with coal powder density in the pipeline, it sends into amplifier IC ₄Obtain the magnitude of voltage of a variation after the amplification, deliver to analog to digital converter IC again ₅Voltage input end V _x, IC ₅Digital signal from output terminal D ₀-D ₇Export device for digit-displaying IC to ₅Show in real time, deliver to the input/output port I/O of main frame simultaneously.In like manner, the input/output port I/O of main frame also delivered to the capacitance variations signal in this pipeline by the capacitive transducer 4 of other pipeline 3.

When carrying out the detection of pipeline powder flow, getting a certain initial moment is t _o, unit interval t was made as one minute, and then main frame will be selected its t by the weighing-up wave that coal powder injection jar weight voltage signal data acquisition circuit is sent here _oCoal dust gravimetric value G constantly _oAnd t _o+ 1 minute coal dust gravimetric value G constantly _k, obtain the weight difference △ G=G of coal dust in a minute _k-G _oSimultaneously, main frame is still from t _oBe the initial moment constantly, with the capacitive transducer 4 of ten pipelines 3 carry out six values (be per 10 second value once).Obtain the measurement capacitance of ten pipelines 3 respectively:

1C ₀、1C ₁……1C ₆，

2C ₀、2C ₁……2C ₆，

·

·

·

10C ₀、10C ₁……10C ₆。

So just can obtain the mean value of each pipeline 3 six measurement capacitances in a minute: $1C=\frac{{1C}_o+{1C}_l+\…\…{1C}_6}{6}$ $2C=\frac{{2C}_o+{2C}_l+{\…\…2C}_6}{6}$ $6C=\frac{{6C}_o+{6C}_l+{\…\…6C}_6}{6}$

With above-mentioned each mean value summation, obtain mean value summation ∑=1C+2C+ ... + 6C.

Coal dust weight difference DELTA G is compared with mean value summation Σ, just obtains the ratio of pulverized coal flow and capacitance variations: $Z=\frac{\mathrm{\ΔG}}{\mathrm{\Σ}}.$

The condenser paper average that this ratio Z and each pipeline 3 are recorded multiplies each other, and promptly obtains each pipeline 3 with t _oFor initial time plays pulverized coal flow Q in 1 minute, that is:

Q ₁＝Z×1C

Q ₂＝Z×2C

Q ₁₀＝Z×10C

Above-mentioned mean value calculation, summation operation, ratio calculating and flow rate calculation etc. are finished according to special software design automatically by main frame.

The present invention is a benchmark with the loss of weight of coal powder injection jar 5 in the unit interval, is assigned on the n root pipeline.The capacitor averaging value representation that separately capacitive transducer 4 recorded in the unit interval on the n root pipeline amount that coal dust distributes in each pipeline in this time, and the summation of sendout should match with the loss of weight of coal powder injection jar 5 in the same time in the n root pipeline 3.Like this, when moisture in the coal dust increased or reduce, it is the also corresponding increase of condenser paper average or the minimizing of pipeline 3 separately, but their ratio Z is constant.In like manner, on the capacitive transducer 4 that the increase of the ash in the coal dust (or factors such as temperature of coal dust) or minimizing are reflected to each pipeline 3, also corresponding increase of the condenser paper average of its each pipeline 3 or minimizing, ratio Z is still constant.Therefore the various up to now measuring method of powder flow accuracy far-reaching disadvantages of various factors such as body water content, powder ash, powder temperature of being pollinated have just been solved, have wide practical value or promotional value, be convenient to operating personnel and control the powder flow of adjusting each pipeline at any time, reach the purpose of optimised process control.

Claims (1)

1, a kind of measuring method of powder flow in pipeline is characterized in that:

A, in unit interval t, carry out initial time and twice weighing constantly that end to spraying into coal dust total amount in the kiln, obtain initial time coal dust total amount G respectively with electronic scale _oWith the coal dust total amount G constantly of ending _k, get its difference: Δ G=G _k-G _o

B, on each pipeline of transporting to kiln with fuel point (fuel point is two at least), the capacitive transducer of its first pipeline carries out (m is the integer greater than 1) measured capacitance value m time in same unit interval t, obtain each time measurement capacitance 1C _o, 1C _l1C _mThe capacitive transducer of its second pipeline also carries out m time in same unit interval t measures, and obtaining measurement capacitance is 2C _o, 2C _l2C _mAnd the like, the measurement capacitance of n pipeline is nC _o, nC _lNC _m

C, to m the capacitance that each pipeline records in unit interval t, the mean value of getting separately is: $1C=\frac{{1C}_o+{1C}_l+\…\…{1C}_m}{m}$ $2C=\frac{{2C}_o+{2C}_l+{\…\…2C}_m}{m}$ $\mathrm{nC}=\frac{{\mathrm{nC}}_o+{\mathrm{nC}}_l+{\…\…\mathrm{nC}}_m}{m}$

D, with above-mentioned each mean value 1C, 2C ... the nC summation, that is:

∑＝1C+2C+…+nC。

E, coal dust total amount difference △ G that a step is obtained just obtain the ratio of coal dust total flow and capacitance variations than the mean value summation ∑ that last d step obtains: $Z=\frac{\mathrm{\ΔG}}{\mathrm{\Σ}}$

The condenser paper average that f, the ratio Z that the e step is obtained and each pipeline record multiplies each other, and just obtains the desired pulverized coal flow Q of each pipeline in unit interval t, i.e. the first pipeline powder coal flow Q ₁=Z * 1C, the second pipeline powder coal flow Q ₂=Z * 2C ..., n pipeline powder coal flow Q _n=Z * nC.

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