JP2889640B2 - Method and apparatus for measuring adhesion of powder and granular material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for measuring an adhesive force, which is an important property in handling a granular material.

[Conventional technology]

Conventionally, as shown in FIG.
1) and (22) are filled with the sample powder (23), and the case (2
1) and (22) are divided and the packed layer of the sample powder in the cases (21) and (22) is broken, and the maximum stress at that time is measured with a measuring instrument (2
The adhesive force between the particles of the sample powder (23) was determined based on the maximum stress measurement value measured in 4).

[Problems to be solved by the invention]

 However, the above prior art has the following disadvantages.

(A) When the sample powder (23) is filled into the cases (21) and (22), the compacted state tends to vary, and the reproducibility is poor.

(B) Sample powder with a large particle size of about 40 to 50 μm or more (23)
In case of sample powder (23) with too good fluidity, the case (2
Since the sample-granule-packed layer collapses with the division of 1) and (22), no fracture surface is formed and measurement is impossible.

(C) When measuring the adhesion between particles in high-temperature treatment such as drying, granulation, and coating, accurate measurement is difficult because it is difficult to uniformly heat the packed layer of sample powder and granules. . Further, it is difficult to measure the adhesive force of the granular material under wet powder and high humidity, and under various gas atmospheres.

An object of the present invention is to reliably perform interparticle adhesion measurement with good reproducibility irrespective of the physical properties of the granular material, and
An object of the present invention is to ensure that the measurement of adhesion between particles under high temperature, high humidity, and various gas atmospheres can be performed with high accuracy.

[Means for solving the problem]

The characteristic means of the method for measuring the adhesive force of the granular material according to the present invention includes: forming a fluidized bed of the sample granular material by supplying a fluidizing gas; measuring a differential pressure ΔP between the upstream side and the downstream side of the fluidized bed;
Determine the correlation between the superficial velocity U of the fluidized bed and the differential pressure ΔP,
Based on the U-ΔP correlation, an actually measured minimum fluidizing speed Uobs is obtained. On the other hand, a minimum fluidizing speed calculated value Ucal is calculated by the following equation (1). φc: Kalman's shape factor F (εmf): porosity function at the beginning of fluidization ρp: density of sample powder ρf: gas density χsv: body area average diameter (particle diameter) g: gravity coefficient μ: gas The measured minimum fluidization speed Uobs and the calculated minimum fluidization speed
Based on Ucal, the adhesive force Fc between particles of the sample powder is expressed by the following equation (2). m: mass of the sample powder (per piece) g: Gravity coefficient The effect is as follows.

[Action]

Various examinations and experiments were conducted on techniques for measuring the adhesive force of the granular material capable of solving the above-mentioned disadvantages of the prior art, and it was confirmed by experiments that the superficial velocity U obtained by forming a fluidized bed of the sample granular material and the differential pressure ΔP And the minimum fluidization velocity calculated value Uc determined by the above equation (1).
Based on al, it was newly found that it is effective to calculate the adhesive force Fc of the granular material by the above equation (2).

In other words, since the correlation between the superficial velocity U and the differential pressure ΔP is determined by using the sample powder as a fluidized bed, a factor of a large measurement error such as the adverse effect due to the variation in the consolidation state in the prior art is eliminated, and the reproducibility is reduced. Good measurement can be performed.

In addition, even if the particle size of the powder is large or the fluidity is good, accurate measurement can be reliably performed without being adversely affected as in the above-described related art.

In addition, since the temperature and humidity of the fluidizing gas can be adjusted to the desired temperature and humidity throughout the fluidized bed of the granular material, the measurement of the adhesion at high temperature and high humidity can be easily and reliably performed with high accuracy. it can. In addition, since any gas can be used as the flowing gas, the measurement of the adhesive force under various gas atmospheres can be easily, reliably, and accurately performed.

〔The invention's effect〕

As a result, highly reproducible measurements can be reliably performed regardless of the physical properties of the powder and granules, and the adhesion can be measured easily and reliably under high temperature, high humidity, or any gas atmosphere. A completely new method for measuring the adhesion of powders was established.

By providing the adhesion measuring device according to the second aspect, the above-described excellent measurement can be automatically and easily performed.

〔Example〕

 Next, an embodiment will be described with reference to FIGS.

 First, an apparatus for measuring the adhesion of a granular material will be described.

As shown in FIG. 1, a vessel (2) for forming a fluidized bed (1) of sample powders is provided with a flow path (4) for supplying a flowing gas provided with a flow meter (3). Connect and channel (4)
Flow control means (5) for changing the gas supply amount by means of
And a differential pressure measuring means (6) for measuring the pressure difference ΔP between the upstream side and the downstream side of the fluidized bed (1).

Computer (C) that executes automatic operation of the flow rate adjusting means (5) and measurement of the adhesion of the granular material based on information from the input device (7), the flow meter (3), and the differential pressure measuring means (6). ,
In addition, an indicator (8) for displaying the adhesive force calculated by the computer (C) is provided, and as shown in FIG. 2, the computer (C) is provided with the following various means.

(A) Flow rate adjusting means (9) for automatically operating the flow rate adjusting means (5) to change the gas supply amount of the flow path (4) based on the measurement start instruction from the input device (7).

(B) U operation for obtaining the superficial velocity U of the fluidized bed (1) by the following equation U = F / A based on the measured flow rate F of the flow meter (3) and the fluidized bed cross-sectional area A from the input device (7). Means (10).

(C) U-ΔP correlation storage means (11) for storing the correlation between the superficial velocity U of the fluidized bed (1) and the pressure difference ΔP based on information from the U calculation means (10) and the differential pressure measurement means (6). ).

That is, the U-ΔP correlation becomes the state shown in FIG. 3A when the superficial superficial velocity U increases, and the state shown in FIG. 3B when the superficial superficial velocity U decreases. Become.

(D) Uobs determination means (1) for obtaining the actual measured minimum fluidization speed Uobs based on information from the U-ΔP correlation storage means (11)
2).

That is, as shown in FIGS. 3 (a) and (b), the U-ΔP correlation is a correlation (straight line A) in which the superficial velocity U and the differential pressure ΔP are represented by a linear function in a low superficial velocity U. In the range where the superficial velocity U is high, even if the superficial velocity U changes, the differential pressure ΔP
Becomes constant (straight line B), and the superficial velocity corresponding to the intersection of the straight lines A and B is determined as the actually measured minimum fluidizing velocity Uobs.

(E) The following set values from the input device (7) φc: Kalman's shape factor F (εmf): void fraction function at the beginning of fluidization ρp: density of sample powder ρf: gas density χsv: body area average Diameter (particle diameter) g: Gravity coefficient μ: Minimum fluidization velocity calculated value Ucal based on gas viscosity Ucal calculation means (13) obtained by:

Note that the gas density ρf is set by actually measuring in advance by a liquid immersion method (pycnometer method or the like).

If the average particle diameter is 40 to 50 μm or more, the body area average diameter χsv is measured and set in advance by a microscopic method, or measured and measured in advance by a known method such as a gravity sedimentation method, a Coulter counter, and a sieving method.

The shape factor φc of Kalman is a volume average value Dpv previously measured by the same method as the body area average diameter χsv, and a particle unit determined in advance by a Blaine air permeation apparatus and by the Kozeny-Carman equation (air permeation method). Based on the specific surface area per volume Sv, the following formula Is set in advance by calculation.

The porosity function F (εmf) at the start of fluidization is given by the following Erugun
It is calculated and set in advance by the equation or Kozeny-Carman equation.

Here, εmf is a space ratio at the start of fluidization, and is calculated in advance as follows. That is, a fluidized bed having a cross-sectional area A is formed by a granular material having a density ρp and a weight W, and the height Lb of the fluidized bed at the time of fluidization is actually measured. Calculate and set.

(F) Measured minimum fluidization speed Uo from Uobs determination means (12)
bs and the minimum fluidization velocity calculation value Uc from the Ucal operation means (13)
The adhesive force Fc between particles of the sample powder based on al m: Mass of the sample powder (per piece) g: Fc calculation means (14) obtained from the gravity coefficient.

Next, a measuring method using the above-mentioned adhesive force measuring device will be described.

(A) An appropriate amount of sample powder is charged into the container (2).

(B) A, φc, Lb, W, ρp, ρ
f, χsv, g, μ, and Dpv are set.

(C) The start of measurement is instructed by the input device (7).

(D) The superficial velocity U of the fluidized bed (1) is automatically changed by the flow rate change executing means (9).

(E) U operation means (10), U-ΔP correlation storage means (1
1), the minimum fluidization speed U measured by the operation of the Uobs determination means (12)
obs is automatically requested.

(F) Calculated minimum fluidization velocity by Ucal determination means (13)
Ucal is calculated automatically.

(G) The inter-particle adhesion Fc of the sample powder is automatically calculated by the Fc calculation means, and the calculated inter-particle adhesion Fc is displayed on the display (8).

(Another embodiment)

 Next, another embodiment will be described.

In carrying out the method of the present invention, some or all of the following items (a) to (e) may be artificially performed.

(B) Changing and calculating the superficial velocity U.

(B) Record of correlation between superficial velocity U and differential pressure ΔP.

(C) Determination of the measured minimum fluidization speed Uobs.

(D) Calculation of minimum fluidization speed calculation value Ucal.

(E) Calculation of adhesive force Fc.

In order to determine the superficial velocity U, the flow velocity of the vessel (2) may be measured directly by a flow meter, in which case the U calculation means (10) can be omitted.

To measure the differential pressure ΔP, the differential pressure may be directly measured by a differential pressure gauge, or the difference between the pressures measured by the two pressure sensors may be determined artificially or automatically by the differential pressure calculating means.

 The fluidizing gas can be selected from air, nitrogen and other suitable ones.

When calculating the minimum fluidization velocity calculation value Ucal, the specific surface area Sv and the volume average value Dpv are used instead of the Kalman shape factor φc.
May be used, and instead of the porosity function F (εmf) at the start of fluidization, the cross-sectional view A of the fluidized bed, the density ρp of the sample particles, the height of the fluidized bed at the time of fluidization An arithmetic expression in which Lb and the weight W of the sample powder are substituted may be used, and these substitution expressions are equivalent to the expression (1) in claim 1 and claim 2 corresponding thereto.
Is included.

Fc / mg may be indicated on the display (2).
Instead of c, Fc / mg may be calculated artificially, and this case is included in the expression (2) of claim 1.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure shown in the attached drawings.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a conceptual diagram of the apparatus, FIG. 2 is a block diagram, FIG.
(B) is a graph illustrating Uobs determination. FIG. 4 is a conceptual diagram of a conventional device. (1) ... fluidized bed, (2) ... container, (3) ... flow meter, (4) ... flow path, (5) ... flow rate adjusting means, (6)
... Differential pressure measurement means, (7) ... Input device, (8) ... Display device, (9) ... Flow rate change execution means, (10) ... U calculation means, (11) ... U-ΔP Correlation storage means, (12) ... Uobs
Judgment means, (13) Ucal calculation means, (14) Fc calculation means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01N 11/00 G01N 19/00 G01N 33/24 B01J 4/00 B01J 8/00-8/46 JICST file ( JOIS) Patent file (PATOLIS) Practical file (PATOLIS)

Claims (2)

(57) [Claims] 1. A fluidized bed of a sample granule is formed by supplying a fluidizing gas, and a pressure difference ΔP between an upstream side and a downstream side of the fluidized bed is measured. The correlation of the pressure ΔP is obtained, and the measured minimum fluidization speed Uobs is obtained based on the U-ΔP correlation. On the other hand, the minimum fluidization speed calculation value Ucal is calculated by the following equation (1). φc: Kalman's shape factor F (εmf): porosity function at the beginning of fluidization ρp: density of sample powder ρf: gas density χsv: body area average diameter (particle diameter) g: gravity coefficient μ: gas The measured minimum fluidization velocity Uobs and the minimum fluidization velocity calculated value Uc
Based on al, the interparticle adhesion Fc of the sample powder is expressed by the following equation (2). m: Mass of sample granules (per piece) g: Method for measuring adhesion of granules obtained by gravity coefficient 2. A flow path (4) for supplying a flowing gas, which is provided with a flow meter (3), is connected to a vessel (2) for forming a fluidized bed (1) of sample powder and granules, A flow rate adjusting means (5) for changing a gas supply amount by the flow path (4) is provided, and a differential pressure measuring means (6) for measuring a pressure difference ΔP between an upstream side and a downstream side of the fluidized bed (1) is provided. A flow rate change executing means (9) for automatically operating the flow rate adjusting means (5) to change the gas supply amount of the flow path (4) based on the measurement start support from the input device (7); The superficial velocity U of the fluidized bed (1) is determined based on the measured flow rate F of the flow meter (3) and the cross-sectional area A of the fluidized bed from the input device (7).
Is provided by the following formula U = F / A, and the superficial velocity of the fluidized bed (1) is determined based on information from the U calculating means (10) and the differential pressure measuring means (6). U-ΔP correlation storage means (11) for storing the correlation between U and the pressure difference ΔP, and Uobs determination means for obtaining the actual measured minimum fluidization speed Uobs based on information from the U-ΔP correlation storage means (11) (12) is provided, and the following set values from the input device (7) φc: Kalman shape factor F (εmf): void fraction function at the start of fluidization ρp: density of sample powder ρf: gas density χsv: Body area average diameter (particle diameter) g: Gravity coefficient μ: Minimum fluidization velocity calculated value Ucal based on gas viscosity The Ucal calculation means (13) for obtaining the measured minimum fluidization speed Uobs from the Uobs determination means (12) is provided.
And the minimum fluidization velocity calculation value from the Ucal operation means (13)
Based on Ucal, the adhesive force Fc between particles of the sample powder m: Mass of the sample powder (per piece) g: Fc calculation means (14) obtained by the gravity coefficient is provided, and the interparticle adhesion force Fc obtained by the Fc calculation means (14)
An adhesion measuring device for a granular material, which is provided with a display (8) for displaying the following.