CN110646251A - Atmospheric VOCs gas sampling device and preparation method thereof - Google Patents

Abstract

The invention relates to an atmospheric VOCs gas sampling device and a preparation method thereof, wherein the atmospheric VOCs gas sampling device comprises a ceramic bottle body (1) and liquid tetrafluoro (2) as a bottle mouth sealing material. The preparation method comprises the steps of firing a porcelain body, internal glazing, external glazing and bottle mouth glazing. According to the invention, the expensive stainless steel material of the Suma tank and the internal silanization treatment are replaced by the argil and the glazing with extremely low cost, and the device can still keep a better sealing state in a high vacuum state by changing the sealing material, so that the problem that the metal valve and the ceramic material are difficult to be tightly and reliably connected is solved, and the device has a good application prospect.

Description

Atmospheric VOCs gas sampling device and preparation method thereof

Technical Field

The invention belongs to the technical field of gas sampling, and particularly relates to an atmospheric VOCs gas sampling device and a preparation method thereof.

Background

With the development of economy, the problem of air pollution is a more serious problem in China, and the haze caused by particulate matters and suspended matters (namely PM2.5 and PM10) is effectively relieved along with the first wave treatment of the nation and the government. However, the treatment of ozone and VOC (volatile organic compound) gas is a new problem, and China also ranks it as the main target of the second major stage of environmental protection and hardship, and also mentions it in the blue sky action of China.

In the process of treatment, the sampling process is indispensable. Since both the VOC gas and ozone are easily decomposed, storage after sampling becomes a big problem. The measurement accuracy of the VOC gas sensor which is commonly adopted at present is low, and much data has no reference value. And EPA (environmental agency) certified sumai pots (summa cylinders) became the favored sampling device for various institutes and environmental monitoring stations. The inner surface of the suma pot is passivated to ensure the components to be kept stable in storage, the valve is usually high-quality, metal-to-metal sealed, stainless steel film 2/3-rotary valve, the valve and the transmission pipeline have heating function, and the sample residence is ensured to be eliminated. The collected sample is usually subjected to a pre-concentration treatment and then subjected to a composition analysis. However, when the VOC gas with too high concentration is stored, the large amount of residue and the difficulty in cleaning become a big disadvantage of the suma tank, and the devices with tens of thousands of yuan and short service life are not a little burden for various research institutes and environment monitoring stations, and bring difficulty for sampling.

Disclosure of Invention

The invention aims to solve the technical problem of providing an atmospheric VOCs gas sampling device and a preparation method thereof, wherein the expensive stainless steel material of a Suma tank is replaced by argil and glazing with extremely low cost and internal silanization treatment, and the device can still keep a better sealing state in a high vacuum state by changing a sealing material, so that the problem that a metal valve and a ceramic material are difficult to be tightly and reliably connected is solved.

The invention provides an atmospheric VOCs gas sampling device which comprises a ceramic bottle body and a metal valve, wherein liquid PTFE is used as a bottle mouth sealing material and is hereinafter referred to as a 'porcelain blue bottle'.

The porcelain blue bottle is made of ceramic materials, and the effect similar to silanization of a suma jar is achieved through a glazing mode. After gas sampling is carried out, the internal components of the gas are guaranteed to be unchanged, and the gas sampling bottle is based on analysis of the internal components of the gas, and is high in precision and low in cost. Aiming at the problem that a metal valve and a ceramic bottle body are difficult to connect, various sealing materials are researched, the most suitable sealing material is determined to be used as a gasket for connecting the metal and the ceramic, and the components of VOCs gas in the sealing material are not influenced.

On the other hand, the combination of the ceramic bottle body and the metal valve is easy to cause the following problems: has the advantages of light transmission, easy wall hanging, poor pressure bearing property and brittleness and frangibility. Therefore, the following design is made:

the thickness of the ceramic bottle body is 1-2 cm. The thickness is ensured to ensure the pressure bearing performance (1Kg/cm) of the ceramic bottle body.

The outer surface of the ceramic bottle body is coated with black glaze. The black glaze can isolate light, and the problem of light transmission of the ceramic bottle body is solved.

The inner surface of the ceramic bottle body is coated with glaze. The problem of the internal surface of pottery body is coarse and lead to gaseous easy wall built-up is solved.

And a buffer layer is arranged outside the ceramic bottle body. The problem that the ceramic bottle body is fragile and fragile is solved.

The ceramic bottle body is provided with a bottle opening with threads.

Because the material of the bottle body is different from the prior art, the invention has the following problems in the firing process:

1. when firing the porcelain blue bottle, in order to guarantee the smooth installation of later stage valve, breakable pottery is hardly turned into the screw thread on finished product bottle.

2. It is difficult to completely and uniformly glaze the inside of the bottle body.

3. After firing, the worker is driven to form threads, so that black glaze on the bottle mouth is cut off, the interior of the bottle is transparent, and sampling accuracy of VOC gas is affected.

4. Even if the threads are perfectly perfect, there is still the problem of untight joints at the metal to ceramic joint.

Therefore, the invention also provides a preparation method of the atmospheric VOCs gas sampling device, which comprises the following steps:

firing a porcelain blank: ensuring the shape, providing a substrate;

preparing porcelain blanks from kaolin rich in quartz and sericite, and firing after completely air-drying;

when the porcelain blank is fired: in the dehydration period, the temperature is raised to 20-40 ℃ per hour until the temperature is raised to 500 ℃; in the oxidation period, heating to 50-70 ℃ per hour until the temperature is increased to 900 ℃; and firing for 48 hours.

Internal glazing: the interior is ensured to be as smooth as possible; after internal glazing, the temperature is raised to 50-70 ℃ per hour until the temperature is raised to 1250 ℃, and the sintering is carried out for 48 hours.

External glazing: isolating external light; and after external glazing, heating to 50-70 ℃ per hour until the temperature is raised to 1250 ℃, and co-firing for 48 hours.

And (3) glazing again after turning threads on the bottle mouth: further guarantee that the outside is light-tight, prevent to produce the error: and (3) after the bottle mouth is turned with threads and glazed again, heating to 50-70 ℃ per hour until the temperature is 1250 ℃, and co-firing for 36 hours.

Advantageous effects

(1) According to the invention, the expensive stainless steel material of the Suma tank and the internal silanization treatment are replaced by the argil and the glazing with extremely low cost, and the device can still keep a better sealing state in a high vacuum state by changing the sealing material, so that the problem that the metal valve and the ceramic material are difficult to be tightly and reliably connected is solved.

(2) The invention improves the processing mode that the traditional ceramic processing is difficult to combine lathing and ceramic glazing, provides a four-step sintering method, is successfully implemented and has good application prospect.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a manufacturing process of the present invention;

FIG. 3 is sample data of the present invention and a Tedlor gas sampling bag in a print shop;

fig. 4 shows the environment sampling data of the present invention and the suma tank.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

As shown in fig. 1, the present embodiment provides an atmospheric VOCs gas sampling device, that is, a porcelain blue bottle, which includes a ceramic bottle body 1 and a metal valve 2, and uses liquid tetrafluoro 3 as a bottle mouth sealing material. The ceramic bottle body 1 is 5cm thick, and the surface scribbles black glaze, and the internal surface scribbles the glaze, and the outside is equipped with buffer layer 4 with the dacron as the material, and the bottleneck is equipped with screw thread 5.

The firing method comprises the steps of firing greenware, glazing inside, glazing outside, glazing again after screw threads are turned on the bottle mouth, and the firing method comprises the following specific steps:

(1) preparing porcelain blanks from kaolin rich in quartz and sericite, and firing after completely air-drying;

when the porcelain blank is fired: in the dehydration period, the temperature is raised to 20-40 ℃ per hour until the temperature is raised to 500 ℃; in the oxidation period, heating to 50-70 ℃ per hour until the temperature is increased to 900 ℃; firing for 48 hours;

(2) after internal glazing and external glazing, heating to 50-70 ℃ per hour until the temperature is 1250 ℃, and co-firing for 48 hours;

(3) and (3) after the bottle mouth is turned with threads and glazed again, heating to 50-70 ℃ per hour until the temperature is 1250 ℃, and co-firing for 36 hours.

The obtained porcelain blue bottle was subjected to the following tests:

after the internal vacuum degree of the porcelain blue bottle is pumped to be 100pa, the observation is carried out for nine days, and the vacuum degree test result is shown in table 1:

TABLE 1

If ordinary tetrafluoro is used as the bottle mouth sealing material, the results of the same test conditions are shown in table 2:

TABLE 2

As can be seen from tables 1 and 2, when the common tetrafluoro is used as the bottleneck sealing material and the storage time is 1-5 days, the vacuum degree keeps stable fluctuation in a small range; when the storage time is 6-9 days, the vacuum degree is gradually increased along with the increase of the time and deviates from 100 pa. And when the liquid tetrafluoro 3 is used as the bottleneck sealing material, the vacuum degree is kept stable, which shows that the sealing property is better.

② a comparison test is carried out by using a porcelain blue bottle and a Tedlor gas sampling bag, and gas sampling is carried out in a printing workshop of a certain factory, and the results are shown in Table 3 and figure 3.

TABLE 3

	Ethane (III)	Propane	Isobutane	N-butane	Cyclopentane	Isopentane	N-pentane	Ethylene	Propylene (PA)
										No. 7 air bag	1.740	0.761	0.752	0.818	0.769	1.028	0.405	26.611	7.745
No. 8 air bag	2.412	0.810	0.704	0.930	0.514	1.316	0.541	18.820	4.130
										No. 9 air bag	1.922	0.726	0.627	0.668	0.122	0.705	0.393	0.985	0.278
										Minimum value (ppm)	1.740	0.726	0.627	0.668	0.122	0.705	0.393	0.985	0.278
Maximum value (ppm)	2.412	0.810	0.752	0.930	0.769	1.316	0.541	26.611	7.745
										Mean value (ppm)	2.025	0.766	0.694	0.805	0.468	1.016	0.446	15.472	4.051
Ratio (%)	2.10％	0.79％	0.72％	0.84％	0.49％	1.05％	0.46％	16.05％	4.20％
										Porcelain blue bottle (ppm)	1.943	0.735	0.697	0.808	0.573	1.125	0.502	17.384	3.014

According to the data, the performance of the porcelain blue bottle in the aspect of VOC gas collection is excellent, and even the performance of the porcelain blue bottle is more excellent than that of a Tedlor gas sampling bag in partial data.

And thirdly, carrying out a comparison experiment by using a porcelain blue bottle and a suma tank, vacuumizing again after flushing by using nitrogen, and sampling on the grasslands near a home chemical plant (only one group of sampling can be carried out as a comparison group due to overhigh use cost of the suma tank), wherein the results are shown in table 4 and fig. 4.

TABLE 4

	Ethane (III)	Propane	Isobutane	N-butane	Isopentane	N-pentane	Ethylene	Propylene (PA)	Benzene and its derivatives
										Suma pot (Unit: PPB)	12.80	5.34	3.03	3.18	2.67	1.20	14.96	2.99	5.55
Porcelain blue bottle (PPB)	11.35	6.13	3.12	4.02	2.56	1.43	13.39	3.07	6.12
										Unused porcelain blue bottle (PPB)	12.58	5.73	3.05	3.46	2.46	1.17	14.09	2.78	5.43

According to the data, the porcelain blue bottle is flushed by nitrogen after sampling of high-concentration gas, and high accuracy can be still guaranteed. And the performance is basically the same as that of the Suma tank when trace gas is collected, and the gas collecting tank can be used as a low-cost Suma tank substitute.

Claims (9)

1. The utility model provides a gaseous sampling device of atmosphere VOCs which characterized in that: comprises a ceramic bottle body (1) and liquid tetrafluoro (2) as a bottle mouth sealing material.

2. An atmospheric VOCs gas sampling apparatus as defined in claim 1, wherein: the thickness of the ceramic bottle body (1) is 1-2 cm.

3. An atmospheric VOCs gas sampling apparatus as defined in claim 1, wherein: the outer surface of the ceramic bottle body (1) is coated with black glaze.

4. An atmospheric VOCs gas sampling apparatus as defined in claim 1, wherein: the inner surface of the ceramic bottle body (1) is coated with glaze.

5. An atmospheric VOCs gas sampling apparatus as defined in claim 1, wherein: the ceramic bottle body (1) is externally provided with a buffer layer (3).

6. An atmospheric VOCs gas sampling apparatus as defined in claim 1, wherein: the ceramic bottle body (1) is provided with a screw thread (4) at the bottle mouth.

7. A preparation method of an atmospheric VOCs gas sampling device comprises the following steps:

firing the porcelain body, glazing the inside, glazing the outside and glazing the bottle mouth again after turning threads.

8. The method of claim 7, wherein: the method comprises the following specific steps:

(1) preparing porcelain blanks from kaolin, and firing after completely air-drying;

when the porcelain blank is fired: in the dehydration period, the temperature is raised to 20-40 ℃ per hour until the temperature is raised to 500 ℃; in the oxidation period, heating to 50-70 ℃ per hour until the temperature is increased to 900 ℃; firing for 48 hours;

(2) after internal glazing and external glazing, heating to 50-70 ℃ per hour until the temperature is 1250 ℃, and co-firing for 48 hours;

(3) and (3) after the bottle mouth is turned with threads and glazed again, heating to 50-70 ℃ per hour until the temperature is 1250 ℃, and co-firing for 36 hours.

9. The method of claim 8, wherein: the kaolin in the step (1) is rich in quartz and sericite.

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