CN105891406A - Joint detection method for high-purity SO3 gas and impurity SO2 gas therein - Google Patents

Abstract

The invention relates to a joint detection method for high-purity SO3 gas and impurity SO2 gas therein. The joint detection method comprises the following steps of: using an absorbing device for sampling at constant volume, and then using an aqueous alkali for absorbing, thereby acquiring a total volume percentage concentration of the high-purity SO3 gas and impurity SO2 gas therein; treating the absorption liquid; adopting a direct iodometry for measuring the volume percentage concentration of SO2 gas; subtracting the volume percentage concentration of SO2 gas from the total volume percentage concentration of the high-purity SO3 gas and impurity SO2 gas therein, thereby acquiring the concentration of high-purity gas. According to the method provided by the invention, the measuring precision of high-purity SO3 gas is high and the measuring standard deviation is not more than 0.1%. The method provided by the invention can be used for detecting the high-purity SO3 gas and is especially fit for the detection for the high-purity SO3 gas containing few SO2 gas and inert gas.

Description

High-purity SO3Gas and wherein impurity SO2The associated detecting method of gas

Technical field

The present invention relates to high-purity SO₃Gas and wherein impurity SO₂The detection method of gas.The method belongs to a kind of collection sampling, constant volume and absorption Trinitarian detection high-purity SO₃Gas and wherein impurity SO₂The associated detecting method of gas.

Background technology

In a kind of patent process using high-purity sulfur trioxide synthesis chlorosulfonic acid, breach the traditional view that originally can only prepare chlorosulfonic acid with low concentration sulfur trioxide.And use high-concentration sulfur trioxide gas and high concentration hydrogen chloride gas directly to carry out synthetic reaction, and the method has minimizing consumption of raw materials, pollutes the advantages such as little, good product quality, in practice it has proved that, the advantage of this process is approved by people.Therefore high-purity SO₃The detection of gas concentration is particularly significant, can be consuming and settling accounts the scientific basis providing strong of material.But, due to high-purity SO₃Gas has highly acid strong oxidizing property, be to high-purity SO₃Gas carries out detecting and there is the biggest difficulty, it has been reported that SO₃The method of gas detecting has multiple, but is not particularly suited for high-purity SO₃The detection of gas.

As illustrated by Japan Patent JP55032758A2, by with 320W500 DEG C of carbonaceous material contact gas efficient selective by SO₃Change into SO₂(analyzer not being caused corrosion) is used for measuring SO_x、SO₃、SO₂Ratio, but be only applicable to the SO in waste gas, automobile exhaust gas that burns₃、SO₂Detection, belong to the detection of low strength range.

The and for example analysis method of Japan Patent JP55135743A2 sulfur trioxide, describes in the gas containing sulfur trioxide interpolation ammonium, collects and analyze ammonium salt that sulphuric acid is bonded on cooling pipe such that it is able to grasp SO accurately₃The method of concentration.The method very complicated, and can not be simultaneously by SO₃And SO₂Gas joint-detection.

For another example Japan Patent JP203014633A2SO₃Photodensitometer, can be by monitoring the pressure of gas cell, it is provided that one accurately measures SO under high temperature₃The photodensitometer of content, but the method is only applicable to SO in flue gas₃The measurement of content, is not particularly suited for high concentration SO₃Gas content and wherein SO₂The simultaneous determination of foreign gas content.

Summary of the invention

Due to high-purity SO₃Gas has under strong oxidizing property and room temperature the character of easily liquefy (boiling point is 46.8 DEG C), for overcoming prior art to there is high-purity SO₃Gas and wherein SO₂Blank on gas concentration detection method and defect, the present invention provides a kind of high-purity SO₃And wherein impurity SO₂The associated detecting method of gas.

For solving above-mentioned technical problem, the technical solution used in the present invention is as follows:

A kind of high-purity SO₃Gas and wherein impurity SO₂The method of gas concentration joint-detection, including with absorption plant to high-purity SO₁Gas and wherein impurity SO₂Gas carries out constant volume of sampling, and then absorbs with aqueous slkali, obtains high-purity SO₃Gas and wherein impurity SO₂The cumulative volume percentage concentration of gas, then after absorbing liquid is processed, use direct iodimetry to record SO₂The concentration expressed in percentage by volume of gas, by high-purity SO₃Gas and wherein impurity SO₂The cumulative volume percentage concentration of gas deducts SO₂The concentration expressed in percentage by volume of gas is high-purity SO₃Gas concentration, it is characterised in that when absorption plant carries out constant-volume sampling, is to carry out in the thermal environment more than at least 60 DEG C.

When described absorption plant carries out sampling constant volume, carry out under 60 DEG C～80 DEG C of environment.

In the method for the invention, the absorption plant used is the absorption plant of a band insulation jacket, is filled with 60 DEG C～the water of 80 DEG C in insulation jacket.

Described absorption plant includes a sampling constant volume inner tube, and the volume of described sampling constant volume inner tube is 100 ± 0.1ml, is carved with the graduation mark of 95.0-100.0ml at thin head and neck, and scale division value is 0.01ml.

In the method for the invention, the aqueous slkali used is NaOH or KOH solution.

The inventive method is to high-purity SO₃Gas and wherein impurity SO₂During gas concentration joint-detection, during sampling, absorption plant is maintained at poly-sample under 60 DEG C～80 DEG C of environment, it is to avoid SO₃The liquefaction of gas.Material price involved by the method for the present invention is low and easy and simple to handle, detects high-purity SO₃The precision of measurement of gas is good, and measurement standard deviation is not more than 0.1%.The inventive method can be used for high-purity SO₃Gas detecting, is particularly well-suited to containing a small amount of SO₂Gas and high-purity SO of noble gas₃The detection of gas.

Detailed description of the invention

For the technological means making the present invention realize, creation characteristic, reach purpose and be easy to understand with effect, the present invention is further elucidated below.

High-purity SO₃And wherein impurity SO₃The detection method of gas concentration, the glass device of sampling, constant volume and absorption that absorption plant is a band insulation jacket that the method uses.This device includes a sampling constant volume inner tube, and the volume of sampling constant volume inner tube is 100 ± 0.1ml, is carved with the graduation mark of 95.0-100.0ml at thin head and neck, and scale division value is 0.01ml.

When high-purity SO₃Gas and wherein impurity SO₂When gas is by this device, the temperature controlled in external insulation chuck is 60 DEG C～80 DEG C；As being filled with 60 DEG C～the water of 80 DEG C in insulation jacket.And make high-purity SO under positive pressure₃Gas and wherein impurity SO₂After gas is sufficiently displaced from sampling constant volume inner tube, closes the import and export tap of sampling constant volume inner tube, and rapidly rotating gas outlet tap, make overpressure and atmospheric equilibrium in sampling constant volume.Then sampling constant volume inner tube is connected the leveling bottle filling 200ml0.5mol/LNaOH solution, slowly opens tap after driving the bubble of residual out of, make the NaOH solution in leveling bottle and the SO in absorption tube₃Gas and SO₃Gas reacts, and reaction mechanism is as follows:

SO₃+ 2NaOH=Ns₂SO₄+H₂O (1)

SO₂+ 2NaOH=Na₂SO₄+H₂O (2)

Constantly shake absorption bottle, make to fully absorb, after leveling bottle is chosen same level with liquid level in absorption tube, read the scale V of absorbing liquid liquid level₀.Due to SO₃、SO₂Can react completely with NaOH, therefore this volume V₀It is SO₃With SO₂The cumulative volume percentage concentration of mixed gas.

NaOH absorbing liquid in absorption bottle and the NaOH solution in leveling bottle are transferred in the volumetric flask of 250ml together, after fully cleaning the absorbent solution remaining in wall, are settled in 250ml volumetric flask mixing, standby to detect SO₂The volumetric concentration of gas.

Drawing the absorbent solution of 25ml in 250ml volumetric flask in conical flask, dropping 2-3 drips phenolphthalein indicator, with the H of 0.5mol/L₂SO₄Standard titration solution, drops to be become colorless by redness.Its reaction mechanism is；

2NaOH+H₂SO₄=Na₂SO₄+2H₂O (3)

By solution complete for above-mentioned drop reaction again with the I of 0.01mol/L₂Standard titration solution titrates, and the sulfamic acid of addition 1ml40% is as screening agent, to avoid the interference to titration end-point of the nitrogen oxides (NOx) in gas.Dropping 1ml starch indicator makes sample solution be titrated to light blue by colourless, writes down the I of consumption₂The consumption of standard solution, does blank assay.Its reaction mechanism is:

Na₂SO₃+I₂+H₂O=Na₂SO₄+2HI (4)

Calculate SO₂Volumetric concentration, according to formula:

SO₃(V/V) %=V₀-SO₂(V/V) %

Above-mentioned detection method is a kind of high-purity SO₃The detection method of gas, simultaneously can a small amount of impurity SO of carrying secretly of joint-detection₂Gas.Wherein, alkali liquor used removes NaOH, it is also possible to be KOH.

In above-mentioned detection method, the preferable temperature of absorption plant insulation jacket part is 60 DEG C～80 DEG C.

Wherein, CI₂Standard iodine solution substance withdrawl syndrome, mol/L；

V₁₂The consumption of standard iodine solution, ml；

V_BlankThe standard iodine liquid measure that sample blank consumes, mL；

Under 10.945 standard state, with I₂Suitable SO₂The volume shared by amount of material, L；

The sampling quantity of V gas, mL；

Atmospheric pressure during P operation, Pa；

P₀Atmospheric pressure under standard state, Pa；

T₀Absolute temperature, constant 273 DEG C；

The temperature of t gaseous sample, DEG C.

Below by carrying impurity SO secretly₂Gas and high-purity SO of noble gas₃The test experience of gas illustrates beneficial effects of the present invention.

Embodiment 1

Test is at 35 DEG C Celsius, and under the weather conditions of 1 atmospheric pressure, the temperature controlled in insulation jacket is 70 DEG C, and gas temperature is 70 DEG C.Detection result of the test is as follows:

Embodiment 2

Test is at 5 DEG C Celsius, and under the weather conditions of 1 atmospheric pressure, the temperature controlled in insulation jacket is 70 DEG C, and gas temperature is 70 DEG C.Detection result of the test is as follows:

According to data obtained as above and standard deviation value, show in the case of gas flow is stable, high-purity SO in the method₃Gas and wherein impurity SO₂The precision of measurement of gas volume percentage concentration is good, and measurement standard deviation is not more than 0.1%.

Claims (3)

1. high-purity SO₃Gas and wherein impurity SO₂The method of gas concentration joint-detection, including with inhaling Receiving apparatus is to high-purity SO₃₃Gas and wherein impurity SO₂Gas carries out constant volume of sampling, and then inhales by NaOH solution Receive, obtain high-purity SO₃Gas and wherein impurity SO₂The cumulative volume percentage concentration of gas, then to obtained NaOH absorbing liquid is settled to 250ml, take 25mlNaOH absorbing liquid and wherein dropping 2-3 drip phenolphthalein indicator, Use 0.5mol/L H₂SO₄Standard titration solution, drops to be become colorless by redness, uses direct iodimetry the most again Record SO₂The concentration expressed in percentage by volume of gas, by high-purity SO₃Gas and wherein impurity SO₂The cumulative volume hundred of gas Point concentration deducts SO₂The concentration expressed in percentage by volume of gas is high-purity SO₃Gas concentration, its spy is being, institute State absorption plant carry out sample constant volume time, carry out under 60 DEG C of-80 DEG C of environment.

Method the most according to claim 1, it is characterised in that the absorption plant used is a band insulation The absorption plant of chuck, is filled with the water of 60 DEG C-80 DEG C in insulation jacket.

Method the most according to claim 1, it is characterised in that it is fixed that described absorption plant includes a sampling Holding inner tube, the volume of described sampling constant volume inner tube is 100 ± 0.1ml, is carved with 95.0-100.0ml at thin head and neck Graduation mark, scale division value is 0.01ml.