CN104849079A - Method for measuring mixing effect of mixing equipment by measuring mixing uniformity of alcohol solution - Google Patents

Abstract

The invention discloses a method for measuring the mixing effect of mixing equipment by measuring the mixing uniformity of alcohol solution. The mixing features of different mixing equipment cannot be described and measured in a unified way. The method comprises the following steps: machining m small circular holes in the cross section of the pipe wall of a mixer to be measured near the outlet; feeding alcohol aqueous solution into the mixer; evenly dividing the cross section with the small circular holes into m fan-shaped sampling areas; dividing each fan-shaped sampling area into k fan-shaped sampling blocks; selecting a sampling point in each fan-shaped sampling block; measuring the alcohol relative density of each sampling point by a density meter; inversely calculating the alcohol concentration of each sampling point according to a mapping table of alcohol relative density and alcohol concentration of alcohol aqueous solution; measuring the flow velocity of each sampling point; and calculating the mixing uniformity of anhydrous alcohol and pure water at the cross section of the outlet. According to the invention, the mixing uniformity at the outlet of mixing equipment is calculated by measuring the mixing uniformity of alcohol solution, so that methods for measuring the mixing effect of different mixing equipment are unified.

Description

The method of mixing apparatus mixed effect is surveyed by measuring and calculating alcoholic solution mixture homogeneity

Technical field

The invention belongs to field of measuring technique, the mixed effect relating to mixing apparatus detects, and is specifically related to a kind of method being surveyed mixing apparatus mixed effect by measuring and calculating alcoholic solution mixture homogeneity.

Background technology

Mixing apparatus is that the industrial circles such as chemical industry, environment, water treatment are commonly used, and the quality of mixed process directly has influence on the consumption of starting material, medicament, the energy etc. in follow-up each technique and final product quality.

Mixability is through mixing the tolerance of the degree of uniformity of the dispersion blending reached with different material; In a lot of industry, need intermixture to mix fully with liquid, ensure that follow-up operation is more effectively carried out.

To the evaluation of mixing apparatus mixed effect, the degree of mixing of mixed liquor in certain incorporation time will be determined in theory, should calculate or measure the degree of uniformity of each component in each moment mixer outlet cross section, because the kind of mixing apparatus is varied, the physical difference of fluid-mixing is wherein also larger.In some mixers there is phase transformation in fluid, there is complicated physics, chemical reaction in some fluids, due to the difference of the service condition of mixer, makes to there is certain difficulty to the measurement of mixture homogeneity each other, at present, about the measurement of mixing uniformity does not have a unified standard.

Measuring method adopts trace particle photographic process comparatively accurately, the trace particle concentration in mixer outlet cross section, this method equipment is complicated, expensive, data processing speed is slow, be unsuitable for on-line continuous and measure, and the fluid line of measured place must do the transparent form of squarely, so that ray cast mistake, and do not produce deflection.Wang Zong bravely waits in people's " study on determination method of static mixer mixed effect " literary composition in Shenyang Institute of Chemical Technology journal in 2006, and the concentration proposed by measuring immiscible oil and water measures the method for static mixer mixed effect.

And mixed process is first from large-scale convection campaign, spread and molecular diffusion by vortex, what finally reach on molecular level is even.Main body convection current constantly can only be moved fluid-mixing, be out of shape and be divided into larger drop " micelle ".Vortex diffusion is out of shape larger drop micelle length by length, is divided into less micelle, by the diffusion between little micelle interface, degree of irregularity is reduced to the size of vortex itself.Eddy size is continually varying, maelstrom splits into the vortex compared with small scale under turbulent flow stretching, shear action, energy is delivered to little vortex from maelstrom, until the vortex of smallest dimension and wide Lip river husband (Kolmogoroff) microscale of Ka Erma, finally because the effect of viscous stress dissipates as heat.Vortex diffusion can only be reduced to Kolmogoroff yardstick micelle size, and can not reach Homogeneous phase mixing completely, its final realization can only lean on the molecular diffusion in smallest dimension micelle, and what finally reach on molecular level is even.Because molecular diffusion rates is much larger than vortex rate of propagation, vortex diffusion couple incorporation time plays a leading role.So adopt two kinds of immiscible fluids and adopt two kinds of fluids dissolved each other to go the result measuring mixed effect differ also not quite, what it really played a decisive role to mixed effect is that fluid flows through mixing apparatus and the hydraulics that formed.

In addition, because oil is different from the density of water, make fluid in mixing apparatus, occur the situation of profit layering, test measurement result and actual mixed process can be made to there is larger difference.And for different mixing apparatus, to the mixing of profit, there is different behavioral traits, be difficult to carry out Unify legislation and measurement to its mixed characteristic.In addition, in sampling process, because oil and water are comparatively large by the resistance to flow difference of relatively thin stopple coupon, will certainly cause, the water percentage of institute's sample thief is greater than local actual water percentage.

And alcohol and water can now dissolve each other, and its properties of Aqueous Solution is stablized, and its density-concentration exists clear and definite corresponding relation.And existing densimeter measurement precision reaches 0.0001 [g/cm3], as plum Teller-Tuo benefit DM40, measurement range is 0.0000-3.0000 [g/cm3], temperature range is 0.0-91.0 DEG C, so from principle and feasibility, by adopting the mixed effect of anhydrous alcohol and water, the mixed effect of various mixing apparatus can be weighed completely.

Summary of the invention

The object of the invention is for the deficiencies in the prior art, a kind of method being calculated mixture homogeneity by measurement alcohol and water hybrid density is provided, water and alcohol is utilized infinitely to dissolve each other, and there is the corresponding relation of approximately linear in the alcohol concentration of alcohol and aqueous mixtures and alcohol relative density, adopt high-precision densitometer to the sampling of difference position on same xsect, measure the alcohol relative density of alcohol water blend sample, its alcohol concentration of anti-release, calculate each mixing apparatus outlet mixture homogeneity, make the balancing method of different mixing apparatus mixed effect unified.

Concrete steps of the present invention are as follows:

Step one, get the mixer of mixed effect to be measured, on the same xsect of exit tube wall, offer m the small sircle hole be uniformly distributed along the circumference at mixer, m=10 ~ 16;

Pass into pure water by constant initial flow rate in step 2, mixer, by peristaltic pump, the anhydrous alcohol in dosing tank is added mixer by constant initial flow rate simultaneously, form alcohol water blend;

Step 3, the xsect offering small sircle hole is divided into m fan ring sampling area, the center of each small sircle hole is arranged on the center axis of symmetry of a corresponding fan ring sampling area; Each fan ring sampling area is radially divided into again k fan ring sampling block, k=3 ~ 5; The center of each fan ring sampling block is set to a sampling spot of alcohol water blend sample;

Step 4, the sampling spot of employing densitometer to mixer sample successively, obtain the alcohol relative density at each sampling spot place; When sampling a fan ring sampling area, the small sircle hole bolt at all the other fan ring sampling area places is blocked;

Step 5, according to the alcohol relative density of alcohol water blend and the alcohol concentration table of comparisons, the anti-alcohol concentration pushing away each sampling spot;

Step 6, employing Pitot tube measure flow velocity at each sampling spot;

Step 7, calculating anhydrous alcohol and the mixture homogeneity M of pure water at outlet place, thus measure the mixed effect of mixer to be measured; wherein, σ is the standard deviation of sample relative density, for the average of sample alcohol concentration.

Standard deviation, average concrete calculating formula as follows:

$\mathrm{\σ}=\sqrt{\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\left[v_i{s}_i(c_i-\stackrel{\‾}{c})\right]}$

$\stackrel{\‾}{c}=\frac{1}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{v}_i{s}_i}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{c}_i{v}_i{s}_i$

Wherein, ν _irepresent the flow velocity of i-th sampling spot, c _irepresent the alcohol concentration of i-th sampling spot, s _irepresent the area of i-th sampling spot place fan ring sampling block, 1≤i≤n, n represents sampling spot number, n=km.

The beneficial effect that the present invention has:

The present invention utilizes water and alcohol infinitely to dissolve each other, and there is the corresponding relation of approximately linear in the alcohol concentration of alcohol and aqueous mixtures and alcohol relative density, adopt high-precision densitometer to the sampling of difference position on same xsect, measure the alcohol relative density of alcohol water blend sample, its alcohol concentration of anti-release, calculate each mixing apparatus outlet mixture homogeneity, make the balancing method of different mixing apparatus mixed effect unified.

Accompanying drawing explanation

Fig. 1 is the sampling spot distribution schematic diagram of alcohol water blend sample in the present invention.

Embodiment

Below in conjunction with drawings and Examples, the invention will be further described.

Surveyed the method for mixing apparatus mixed effect by measuring and calculating alcoholic solution mixture homogeneity, concrete steps are as follows:

Step one, get the mixer of mixed effect to be measured, on the same xsect of exit (that segment pipe between vortex generator and outlet) tube wall, offer m the small sircle hole be uniformly distributed along the circumference, m=12 at mixer;

Pass into pure water by constant initial flow rate in step 2, mixer, by peristaltic pump, the anhydrous alcohol in dosing tank is added mixer by constant initial flow rate simultaneously, form alcohol water blend;

Step 3, the xsect offering small sircle hole is divided into m fan ring sampling area, the center of each small sircle hole is arranged on the center axis of symmetry of a corresponding fan ring sampling area; Each fan ring sampling area is radially divided into again k fan ring sampling block, k=3; The center of each fan ring sampling block is set to a sampling spot A of alcohol water blend sample, as shown in Figure 1;

Step 4, the sampling spot of employing densitometer to mixer sample successively, obtain the alcohol relative density at each sampling spot place; When sampling a fan ring sampling area, the small sircle hole bolt at all the other fan ring sampling area places is blocked;

Step 5, according to the alcohol relative density of the alcohol water blend shown in table 1 and alcohol concentration (ethanol content) table of comparisons (20 DEG C), the anti-alcohol concentration pushing away each sampling spot;

Step 6, employing Pitot tube measure flow velocity at each sampling spot;

Step 7, calculating anhydrous alcohol and the mixture homogeneity M of pure water at outlet place, thus measure the mixed effect of mixer to be measured; wherein, σ is the standard deviation of sample relative density, for the average of sample alcohol concentration;

Standard deviation, average concrete calculating formula as follows:

$\mathrm{\σ}=\sqrt{\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\left[v_i{s}_i(c_i-\stackrel{\‾}{c})\right]}$

$\stackrel{\‾}{c}=\frac{1}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{v}_i{s}_i}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{c}_i{v}_i{s}_i$

Wherein, ν _irepresent the flow velocity of i-th sampling spot, c _irepresent the alcohol concentration of i-th sampling spot, s _irepresent the area of i-th sampling spot place fan ring sampling block, 1≤i≤n, n represents sampling spot number, n=km.

If do not have condition to use distilled water to test, can tap water be adopted, but need first to demarcate the alcohol concentration of local tap water and alcohol blend and alcohol relative density relation.

The alcohol relative density of table 1 alcohol water blend and alcohol concentration (ethanol content) table of comparisons (20 DEG C)

Claims (3)

1. surveyed the method for mixing apparatus mixed effect by measuring and calculating alcoholic solution mixture homogeneity, it is characterized in that: the method concrete steps are as follows:

Step one, get the mixer of mixed effect to be measured, on the same xsect of exit tube wall, offer m the small sircle hole be uniformly distributed along the circumference at mixer, m=10 ~ 16;

Pass into pure water by constant initial flow rate in step 2, mixer, by peristaltic pump, the anhydrous alcohol in dosing tank is added mixer by constant initial flow rate simultaneously, form alcohol water blend;

Step 3, the xsect offering small sircle hole is divided into m fan ring sampling area; Each fan ring sampling area is radially divided into again k fan ring sampling block, k=3 ~ 5; The center of each fan ring sampling block is set to a sampling spot of alcohol water blend sample;

Step 4, the sampling spot of employing densitometer to mixer sample successively, obtain the alcohol relative density at each sampling spot place; When sampling a fan ring sampling area, the small sircle hole bolt at all the other fan ring sampling area places is blocked;

Step 5, according to the alcohol relative density of alcohol water blend and the alcohol concentration table of comparisons, the anti-alcohol concentration pushing away each sampling spot;

Step 6, employing Pitot tube measure flow velocity at each sampling spot;

Step 7, calculating anhydrous alcohol and the mixture homogeneity M of pure water at outlet place, thus measure the mixed effect of mixer to be measured; wherein, σ is the standard deviation of sample relative density, for the average of sample alcohol concentration.

2. the method being surveyed mixing apparatus mixed effect by measuring and calculating alcoholic solution mixture homogeneity according to claim 1, be is characterized in that: the center of each small sircle hole is arranged on the center axis of symmetry of a corresponding fan ring sampling area.

3. the method being surveyed mixing apparatus mixed effect by measuring and calculating alcoholic solution mixture homogeneity according to claim 1, be is characterized in that: described standard deviation, average concrete calculating formula as follows:

$\mathrm{\σ}=\sqrt{\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\left[v_i{s}_i(c_i-\stackrel{\‾}{c})\right]}$

$\stackrel{\‾}{c}=\frac{1}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{v}_i{s}_i}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{c}_i{v}_i{s}_i$

Wherein, ν _irepresent the flow velocity of i-th sampling spot, c _irepresent the alcohol concentration of i-th sampling spot, s _irepresent the area of i-th sampling spot place fan ring sampling block, 1≤i≤n, n represents sampling spot number, n=km.