CN101949814A - Method for measuring methane permeability of marsh gas storage membrane - Google Patents

Abstract

The invention relates to a method for measuring the methane permeation amount and coefficient of a marsh gas storage membrane. The method comprises the following specific steps of: firstly, pre-treating a test sample and measuring the thickness of the test sample; secondly, separating a low-pressure chamber from a high-pressure chamber by using the test sample, filling about 0.1MPa of CH4 into the high-pressure chamber, pumping air from the low-pressure chamber until the pressure approaches zero, controlling the temperature to be between 20 and 70 DEG C and controlling the humidity to be between 0 and 100 percent RH according to actual needs; thirdly carrying out an air permeability test and measuring a pressure increment delta p of the low-pressure chamber so as to determine the amount of the CH4 flowing to the low-pressure chamber from the high-pressure chamber through the test sample taking time as a function; and finally, computing the CH4 permeation amount and coefficient according to correlated formulas when the CH4 stably permeates. The method for measuring the methane permeation amount and coefficient of the invention is suitable for testing the CH4 gas permeation characteristic of multiple gas storage materials, such as plastic thin films, composite thin films and the like, and the conditions of the products in actual environment can be simulated through temperature and humidity control so as to meet various requirements on material CH4 permeability test in different environmental conditions.

Description

The infiltrative assay method of a kind of biogas air storage film methane

Technical field

The present invention relates to the assay method of a kind of biogas air storage film methane gas transit dose and gas transmission coefficient.

Background technology

The biogas production technology is a kind of comparatively ripe biomass energy utilization technologies.At present, built the domestic methane tank of a large amount of biogas engineerings and dispersion in world many countries.As the balance means, the air storage link is important unusually in biogas engineering, so the biogas gas storage device occupies very important effect in whole biogas engineering.In early days, often adopt wet type floating cover gas-holder or the air storage of steel high pressure tank.Now air storage film cabinets that adopt are stored biogas more.

Because of its applied special place of biogas air storage film material, it need have good air-tightness with respect to common building film material, thereby the permeance property index of film material is particularly important performance index.Because the principal ingredient of biogas is CH ₄, should mainly investigate the permeance property of film material for this gas.

At present, all formulate special properties of product standard and testing standard both at home and abroad at biogas air storage film material.The film material manufacturer that some are famous such as the mehler company of Germany, agriKomp company etc. all are the company standards that adopt, and do not have unified method of testing and standard.Because advantages such as simple are installed in the economy of biogas air storage film and production, its application in China more and more comes into one's own, and therefore presses at biogas air storage film and formulates unified assay method.

Summary of the invention

The technical problem to be solved in the present invention: in order to set up unified air storage film section product permeance property and testing standard, thereby standard also promotes the sound development of biogas air storage film material industry, the invention provides and a kind ofly regulate and control and test out in uniform temperature, humidity, the pressure limit, methane transit dose and transmission coefficient in the tested film material certain hour, thereby the infiltrative assay method of biogas air storage film methane that the permeance property of film material is made an appraisal.

The technical solution adopted in the present invention: the infiltrative assay method of a kind of biogas air storage film methane specifically may further comprise the steps:

1. the sample of film or thin slice is tested its thickness through after the pre-service, and dry, standby down in room temperature condition;

2. testing table O-ring seal place is coated with one deck vacuum grease;

3. described sample is placed on the described testing table, low-pressure chamber and hyperbaric chamber are separated;

4. low-pressure chamber is vacuumized, described sample should be close to testing table under vacuum, build loam cake and fastening;

5. the hyperbaric chamber is evacuated down to below the 27kPa, and continues the degassing, to get rid of adsorbed gas and the water vapor of sample;

6. temperature is controlled at 20 ℃～70 ℃, and humidity is controlled to be 0～100%RH;

7. fill CH to the hyperbaric chamber ₄, the gaseous tension in hyperbaric chamber is controlled at 1.0 * 10 ⁵Pa～1.1 * 10 ⁵Pa;

8. the experiment of breathing freely: measuring the pressure increment Δ p of low-pressure chamber, is the gas flow of function but confirmed test gas sees through sample by the hyperbaric chamber with time to low-pressure chamber;

9. the variation when low-pressure chamber pressure reduction in the identical time interval keeps constant, then reaches the steady seepage of gas, calculates according to following formula and can obtain methane gas transit dose and transmission coefficient:

$Q_g=\frac{\mathrm{\Δp}}{\mathrm{\Δt}}\×\frac{V}{S}\×\frac{T_0}{p_{0}T}\×\frac{24}{(p_1-p_2)}---\left(1\right)$

In the formula: Q _g-CH ₄The gas permeation amount, cm ³/ m ²DPa;

-when stable seeing through, the arithmetic mean of low-pressure chamber gas pressure change in the unit interval, Pa/h;

V-low-pressure chamber volume, cm ³

The test area of S-sample, m ²

The T-test temperature, K;

p ₁-p ₂The pressure reduction of-sample both sides, Pa;

T ₀, p ₀Temperature under the-standard state (273.15K) and pressure (1.0133X10 ⁵Pa).

$p_g=\frac{\mathrm{\Δp}}{\mathrm{\Δt}}\×\frac{V}{S}\×\frac{T_0}{p_{0}T}\×\frac{D}{(p_1-p_2)}=1.1574\×{10}^{-9}{Q}_g\×D---\left(2\right)$

In the formula: p _g-CH ₄Gas transmission coefficient, cm ³Cm/cm ²SPa;

-when stable seeing through, the arithmetic mean of low-pressure chamber gas pressure change in the unit interval, Pa/s;

The T-test temperature, K;

The D-sample thickness, cm.

Test findings is with the arithmetic mean value representation of every group of sample.

Beneficial effect of the present invention: assay method of the present invention is applicable to multiple air storage material C H such as plastic sheeting, laminated film ₄The test of gas permeation property.Can the situation of analog equipment in actual environment by the control of temperature, humidity, can satisfy the multiple requirement of the material methane gas penetration potential test under the varying environment condition.

Description of drawings

Fig. 1 is the FB(flow block) of a kind of biogas air storage of the present invention film methane perviousness assay method.

Embodiment

Below in conjunction with embodiment technical scheme of the present invention is described further.

Embodiment one:

1. choose 3 on the sample of smooth no visual defects, under the environmental baseline of (20 ± 2) ℃, place exsiccator to place more than the 48h.

2. be coated with one deck vacuum grease at testing table O-ring seal place,, should carefully clean if grease is coated on the disk in the hole.

3. sample is placed on the testing table, applying light makes sample well contact with vacuum grease on the sample bench, and it is smooth that sample should keep, and gauffer must not be arranged.

4. low-pressure chamber is vacuumized, sample should be close to testing table under vacuum, builds loam cake and fastening.

5. the hyperbaric chamber is evacuated down to below the 27kPa, and continues the degassing, to get rid of adsorbed gas and the water vapor of sample.

6. temperature is controlled at 20 ℃, to the requirement of humidity, the humidification instrument is transferred to 0%RH in the consideration test environment.

7. fill CH to the hyperbaric chamber ₄, the gaseous tension in hyperbaric chamber should be 1.0 * 10 ⁵Pa～1.1 * 10 ⁵In the Pa scope.

8. begin air permeability test.Nonlinear phase when beginning to test for rejecting should carry out the pre-air permeability test of 10min.Begin formal air permeability test subsequently, the change value of pressure Δ p and the test period t of record low-pressure chamber.

9. continue test and keep constant, reach stable and see through up to the variation of pressure reduction in the identical time interval.At least get the pressure difference of 3 continuous time intervals, ask its arithmetic mean, calculate CH respectively by formula (1), (2) ₄Transit dose Q _gWith CH ₄Transmission coefficient p _g, and provide evaluation result.

Embodiment two:

1. choose 3 on the sample of smooth no visual defects, under the environmental baseline of (20 ± 2) ℃, place exsiccator to place more than the 48h.

2. be coated with one deck vacuum grease at testing table O-ring seal place,, should carefully clean if grease is coated on the disk in the hole.

3. sample is placed on the testing table, applying light makes sample well contact with vacuum grease on the sample bench, and it is smooth that sample should keep, and gauffer must not be arranged.

4. low-pressure chamber is vacuumized, sample should be close to testing table under vacuum, builds loam cake and fastening.

5. the hyperbaric chamber is vacuumized below 27kPa, and continue the degassing, to get rid of adsorbed gas and the water vapor of sample.

6. according to actual needs, temperature is controlled at 40 ℃, considers in the test environment requirement, and the humidification instrument is transferred to 50%RH humidity.

7. fill CH to the hyperbaric chamber ₄, the gaseous tension in hyperbaric chamber should be 1.0 * 10 ⁵Pa～1.1 * 10 ⁵In the Pa scope.8. begin air permeability test.Nonlinear phase when beginning to test for rejecting should carry out the pre-air permeability test of 10min.Begin formal air permeability test subsequently, the change value of pressure Δ p and the test period t of record low-pressure chamber.

9. continue test and keep constant, reach stable and see through up to the variation of pressure reduction in the identical time interval.At least get the pressure difference of 3 continuous time intervals, ask its arithmetic mean, calculate CH respectively by formula (1), (2) ₄Transit dose Q _gWith CH ₄Transmission coefficient p _g, and provide evaluation result.

Embodiment three:

1. choose 3 on the sample of smooth no visual defects, under the environmental baseline of (20 ± 2) ℃, place exsiccator to place more than the 48h;

2. be coated with one deck vacuum grease at testing table O-ring seal place,, should carefully clean if grease is coated on the disk in the hole;

3. sample is placed on the testing table, applying light makes sample well contact with vacuum grease on the sample bench, and it is smooth that sample should keep, and gauffer must not be arranged;

4. low-pressure chamber is vacuumized, sample should be close to testing table under vacuum, builds loam cake and fastening;

5. the hyperbaric chamber is vacuumized below 27kPa, and continue the degassing, to get rid of adsorbed gas and the water vapor of sample;

6. according to actual needs, temperature is controlled at 70 ℃, considers in the test environment requirement, and the humidification instrument is transferred to 100%RH humidity;

7. fill CH to the hyperbaric chamber ₄, the gaseous tension in hyperbaric chamber should be 1.0 * 10 ⁵Pa～1.1 * 10 ⁵Pa;

8. begin air permeability test.Nonlinear phase when beginning to test for rejecting should carry out the pre-air permeability test of 10min.Begin formal air permeability test subsequently, the change value of pressure Δ p and the test period t of record low-pressure chamber.

9. continue test and keep constant, reach stable and see through up to the variation of pressure reduction in the identical time interval.At least get the pressure difference of 3 continuous time intervals, ask its arithmetic mean, calculate CH respectively by formula (1), (2) ₄Transit dose Q _gWith CH ₄Transmission coefficient p _g, and provide evaluation result.

Claims (1)

1. the infiltrative assay method of biogas air storage film methane is characterized in that, specifically may further comprise the steps:

1. after the sample process pre-service with film or thin slice, test its thickness, and dry, standby down in room temperature condition;

2. testing table O-ring seal place is coated with one deck vacuum grease;

3. described sample is placed on the described testing table, low-pressure chamber and hyperbaric chamber are separated;

4. low-pressure chamber is vacuumized, described sample should be close to testing table under vacuum, build loam cake and fastening;

5. the hyperbaric chamber is evacuated down to below the 27kPa, and continues the degassing, to get rid of adsorbed gas and the water vapor of sample;

6. temperature is controlled at 20 ℃～70 ℃, and humidity is controlled to be 0～100%RH;

7. fill CH to the hyperbaric chamber ₄, the gaseous tension in hyperbaric chamber is controlled at 1.0 * 10 ⁵Pa～1.1 * 10 ⁵Pa;

8. the experiment of breathing freely: measuring the pressure increment Δ p of low-pressure chamber, is the gas flow of function but confirmed test gas sees through sample by the hyperbaric chamber with time to low-pressure chamber;

9. the variation when low-pressure chamber pressure reduction in the identical time interval keeps constant, then reaches the steady seepage of gas, can calculate gas permeation amount and gas transmission coefficient according to formula.

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