JP2949096B1 - Method and apparatus for measuring unburned carbon content of fly ash - Google Patents

Abstract

[PROBLEMS] To provide a method and an apparatus for measuring unburned carbon content of fly ash which require only a small capital investment, are easy to maintain, have a high operation rate, and are easy to perform online measurement and maintenance of the apparatus. That is the task. SOLUTION: Based on a measured value of a reflected light amount of fly ash measured by using a reflected light amount measuring device using a blue light emitter as a light source, based on a calibration curve which previously associates the reflected light amount with the unburned carbon amount, The fly ash is configured to determine the unburned carbon amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for continuously measuring the unburned carbon content of fly ash used as a cement admixture, an artificial lightweight aggregate or the like. About.

[0002]

2. Description of the Related Art Conventionally, the unburned carbon amount of fly ash is
Sampling a small amount of fly ash and manually analyzing the ignition loss method (combustion method) manually in the analysis building (actual measurement)
In order to efficiently and more efficiently collect high-quality fly ash and fly ash, it is necessary to manage the amount of unburned carbon continuously day and night. In some places, it has become difficult due to the increase in size, the use of various types of coal, and the boiler load fluctuation several times a day.

[0003] As a measure for improving this point, a method of automatically sampling fly ash, putting it in a capsule, conveying the air to an analysis building, and automatically analyzing unburned carbon by an analyzer (Japanese Patent Publication No. 5-63239), The flue gas was collected from the flue gas using a sampling tube, and fly ash was sampled on the filter paper inserted in the measurement cell.
A method of estimating and calculating the amount of unburned carbon from the reflection intensity of fly ash under a constant light source (JP-A-62-217143,
JP-A-2-130453 and JP-A-5-322718).

[Problems] However, all of them have the following problems. There are many ancillary facilities, and high investment is required for the entire facility. Maintenance is labor-intensive. If even one of the incidental facilities breaks down, the entire facility will not be able to operate, so there will be many non-operational hours.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the problems in the prior art, and an object specifically set to solve the problems is a small capital investment. , Easy maintenance, high availability,
Another object of the present invention is to provide a method and an apparatus for measuring the unburned carbon content of fly ash, which facilitate online measurement and maintenance of the apparatus.

[0006]

Means for Solving the Problems Claim 1 of the present invention
The method for measuring the unburned carbon amount of fly ash according to the present invention is based on the reflected light amount and unburned carbon amount created in advance from the measured value of the reflected light amount of fly ash measured using a reflected light amount measuring device using a blue light emitter as a light source. Based on the calibration curve that corresponds to
It is characterized in that the unburned carbon content of fly ash is obtained.

According to a second aspect of the present invention, there is provided an apparatus for measuring the amount of unburned carbon in fly ash, comprising a sampling device branched from a conveying path and a probe for measuring the amount of reflected light provided at a rear end of the sampling device. A light source composed of a blue light emitter for obtaining a reflected light amount, an amplifier for amplifying an output signal from the reflected light amount measuring probe, and a reflected light amount and an unburned carbon amount prepared in advance from the output of the amplifier. And a computer for continuously calculating the unburned carbon amount based on the corresponding calibration curve.

[0008]

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. However, this embodiment is specifically described for better understanding of the gist of the present invention.
The contents of the invention are not limited unless otherwise specified.

The following three factors affect the amount of reflected fly ash in measuring the unburned carbon content of fly ash. In other words, the fineness of fly ash The unburned carbon content of fly ash Others Among these factors, the effect of the unburned carbon content of fly ash is strong, and the reflected light quantity decreases as the unburned carbon content increases. Utilizing this point, from the measured value of the reflected light amount of fly ash, the amount of unburned carbon is determined based on a calibration curve that associates the amount of reflected light with the amount of unburned carbon created in advance. is there.

As shown in FIG. 1, an unburned carbon measuring apparatus to which this method is applied is a fly ash storage silo 11.
Pre-conveyance path 13 from ash to fly ash classification equipment 12
A sampling device 1 that branches off from the front conveyance path 13 and connects to the rear conveyance path 14 between the first and second conveyance paths 14 to facilitate measurement of the amount of reflected fly ash; A light source 2 for obtaining the reflected light amount of the fly ash supplied to the sampler 1, a reflected light amount measuring probe 3 for measuring the reflected light amount of the fly ash supplied to the sampling device 1, and a reflected light amount measuring probe 3
(Amplifier) 4 for amplifying and transmitting the output signal from
And a calculator 5 which receives an output signal of the amplifier and obtains the unburned carbon amount based on a calibration curve which previously associates the reflected light amount with the unburned carbon amount.

As shown in FIG. 2, the sampling device 1 includes a branch chute 15 branched from the preceding conveyance path 13,
A screw conveyor 16 that is installed horizontally to increase the density of fly ash that has been diverted and conveyed, and to convey the flow at a flow rate of 1 m / min or less;
Outlet pipe 17 that connects from the outlet to the downstream conveyance path 14
Consists of The screw conveyor 16 is provided with a motor 16b for driving the screw 16a and a probe insertion port 16c for measuring the amount of reflected light at the outlet of the screw conveyor 16.

In order to obtain the unburned carbon amount of fly ash by the unburned carbon amount measuring apparatus thus configured, a calibration curve is set and a light source is selected in advance. [Setting of calibration curve] Regardless of the fluctuation of quality such as fineness of fly ash,
Using the fact that the amount of reflected light and the amount of unburned carbon have a fixed relationship (FIG. 3), a calibration curve for determining the amount of unburned carbon is given by the following equation (1). That is, if the output voltage based on the amount of reflected light is L and the coefficients a and b are, the unburned carbon amount Y is

[0014]

Y = a · L + b (1) Therefore, the amount of unburned carbon can be accurately obtained from the amount of reflected fly ash using this calibration curve.

[Selection of Light Source] The light sources and peak wavelengths for obtaining the reflected light amount of fly ash are as follows: red light emitter 660 nm, green light emitter 560 nm, blue light emitter 450
The output voltage based on the amount of reflected light obtained by the light source having peak wavelengths of 570 nm and 570 nm, respectively, is LR; the amount of reflected light at a light source peak wavelength of 660 nm LG; the amount of reflected light at a light source peak wavelength of 560 nm LB; Reflected light quantity LY: The reflected light quantity at the light source peak wavelength of 570 nm, the coefficient of the calibration curve at each light source is determined, and the deviation between the unburned carbon measured value Y from each calibration curve and the unburned carbon quantity by manual analysis (actual measurement) The optimal light source that minimizes the blue light is the blue light emitter, and its peak wavelength is 450 nm (Table 1). It has been found that the use of this light source can minimize the effect of the other factors on the amount of reflected light among the three factors that affect the amount of reflected fly ash.

[0016]

[Table 1]

The specific values of the coefficients a and b of the calibration curve obtained from the output voltage L based on the amount of reflected light collected over several days and the unburned carbon amount by manual analysis (actual measurement) are as follows. Was.

## EQU2 ## a = −0.234 (2)

## EQU3 ## b = 3.160 (3)

[Measurement Accuracy] The correlation between the measured value obtained from the obtained calibration curve and the unburned carbon amount by manual analysis (actual measurement) is strong as shown in FIG. It was confirmed that the amount of carbon was required.

[Operation and Effect] As described above, the sampling device provided on the transport path, the reflected light amount measuring probe provided at the rear end of the sampling device,
A light source for obtaining the reflected light amount and an amplifier for amplifying the output signal from the reflected light amount measuring probe constitute a reflected light amount measuring device of fly ash,

As a light source for obtaining a reflected light amount that minimizes a deviation between the measured value of the unburned carbon amount and the measured value of the measured amount of unburned carbon, taking into account that the influence of other components on the total reflected light amount is small. Using a blue light emitter with a peak wavelength of 450 nm,

The amount of unburned carbon of fly ash is obtained from the measured value of the amount of reflected light of fly ash based on a calibration curve prepared in advance, which associates the amount of reflected light with the amount of unburned carbon. Is measured online, and the unburned carbon content of the fly ash is accurately obtained from the result.

As a result, the following effects can be obtained. From the measured value of the reflected light amount of the fly ash, the unburned carbon amount of the fly ash can be accurately obtained based on a calibration curve which previously associates the reflected light amount with the unburned carbon amount.

The number of incidental equipment is small, the equipment does not require a large investment, the maintenance is not required, the downtime is reduced, and the unburned carbon content of the fly ash can be easily and continuously reduced in real time. You can ask.

By accurately determining the unburned carbon content of fly ash, among the quality standards of fly ash for concrete (JIS A 6201), the ignition loss related to the unburned carbon content is one of the quality standards. , The standard value is 5.0
%, And quality control for this standard can be strictly performed at low cost.

Therefore, at present in the construction field, for ready-mixed concrete or cast-in-place concrete, it is indispensable to use a chemical admixture such as an AE agent (air entraining agent), a water reducing agent, a fluidizing agent, and a retarder. Has become
At this time, in concrete using fly ash cement or concrete containing fly ash as an admixture, unburned carbon in the fly ash adsorbs the chemical admixture like activated carbon, and the effect of the admixture is impaired. Therefore, it is possible to solve the quality problem due to the unburned carbon content of fly ash such that the concrete of the desired quality cannot be obtained, and the concrete or fly ash using fly ash cement is mixed. Effective utilization of concrete mixed as a material is promoted.

[0026]

As described above, according to the present invention, in the method for measuring the unburned carbon content of fly ash according to claim 1, the reflected light quantity of fly ash measured using a reflected light quantity measuring device using a blue light emitter as a light source. By determining the unburned carbon amount of fly ash based on the calibration curve that previously associates the reflected light amount with the unburned carbon amount from the measured values, the influence of other components on the total reflected light amount is reduced. Since the amount of reflected fly ash is measured, the amount of unburned carbon can be accurately obtained.

According to a second aspect of the present invention, there is provided an apparatus for measuring the amount of unburned carbon in fly ash, comprising a sampling device branched from a conveying path and a reflected light amount measuring probe provided at a rear end of the sampling device. A light source composed of a blue light emitter for obtaining a reflected light amount, an amplifier for amplifying an output signal from the reflected light amount measuring probe, and a reflected light amount and an unburned carbon amount prepared in advance from the output of the amplifier. Since it consists of a computer that continuously calculates the amount of unburned carbon based on the corresponding calibration curve, the effect of other components on the total reflected light amount is reduced, and the measured value of the unburned carbon amount in fly ash and the actual measurement Since the deviation from the value can be minimized, the unburned carbon content of fly ash can be obtained easily, quickly and continuously with high accuracy, minimizing capital investment and simplifying maintenance. And, it is possible to improve the operating rate of the equipment.

[0028]

[Brief description of the drawings]

FIG. 1 is a system configuration diagram according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a sampling device according to an embodiment.

FIG. 3 is a graph showing the relationship between the amount of reflected light from fly ash and the measured value of unburned carbon in the embodiment.

FIG. 4 is a graph showing a relationship between an estimated value and an actually measured value of the unburned carbon amount of fly ash in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sampling apparatus 2 Light source 3 Probe 4 Amplifier (Amplifier) 5 Computer 11 Fly ash storage silo 12 Fly ash classification equipment 13 Front stage transporter 14 Rear stage transporter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-55696 (JP, A) Proceedings of the Annual Conference of the Japan Society of Finishing Engineers, Vol. 1996, Vol. 1, pp. 237-240 (1996) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 21/00-21/01 G01N 21/17-21/61

Claims (2)

(57) [Claims] 1. A method for measuring the amount of reflected light of fly ash, which is measured using a reflected light amount measuring device using a blue light-emitting body as a light source, based on a calibration curve which previously associates the amount of reflected light with the amount of unburned carbon. And measuring the amount of unburned carbon in fly ash. 2. A sampling device branched from a transport path, a probe for measuring a reflected light amount provided at a rear end of the sampling device, and a blue light emitting device for obtaining a reflected light amount.
A light source comprising a body, an amplifier for amplifying an output signal from the reflected light amount measuring probe, from the output of the amplifier,
A computer that continuously calculates the amount of unburned carbon based on a previously created calibration curve that associates the amount of reflected light with the amount of unburned carbon.
An apparatus for measuring unburned carbon content of fly ash, comprising: