CN1141568C - Burning tube for element analyzer - Google Patents
Burning tube for element analyzer Download PDFInfo
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- CN1141568C CN1141568C CNB011022388A CN01102238A CN1141568C CN 1141568 C CN1141568 C CN 1141568C CN B011022388 A CNB011022388 A CN B011022388A CN 01102238 A CN01102238 A CN 01102238A CN 1141568 C CN1141568 C CN 1141568C
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Abstract
The present invention relates to a combustion tube for an element analyzer. The present invention comprises an inner tube (1), a middle sheathed tube (2) and an outer tube (3), wherein the inner tube (1), the middle sheathed tube (2) and the outer tube (3) are sheathed together, one end of the outer tube (3) is provided with a gas outlet (10), an outlet (9) of the inner tube and the gas outlet (10) of the outer tube are in the same direction, the middle sheathed tube (2) is arranged between the inner tube and the outer tube, an outlet (8) of the middle sheathed tube and the outlet (9) of the inner tube are in the opposite directions, the other end of the outer tube (3) is hermetically connected with the inner tube (1), a gasification tube (4) is arranged in the inner tube (1) which extends out of the outer tube (3), a carrier gas inlet tube (6) and a sample inlet tube (5) which are perpendicular to each other are arranged at a port of the gasification tube, which extends out of the inner tube (1), and an oxygen inlet tube (7) which is perpendicular to the inner tube is arranged at one end of the inner tube (1), which is adjacent to the gasification tube (4). The combustion tube is applicable to instruments using oxidation reactions for measuring the content of organic elements of a trace quantity in samples and is especially applicable to instruments using a microcoulomb method for measuring the content of sulfur and chlorine of a trace quantity in samples.
Description
The invention relates to a combustion tube for an element analyzer, in particular to a combustion tube for an analyzer for determining the content of trace elements in a light organic sample by means of high-temperature oxidative cracking reaction.
The method for measuring the total sulfur content in the sample by using the microcoulometer comprises the following steps: injecting the sample into a quartz combustion tube, fully combusting the sample at high temperature in the presence of oxygen, and quantitatively converting sulfur in the sample into SO2Gas (small portion converted to SO)3A gas); when SO is formed by the reaction2When gas is brought into the titration cell by carrier gas, the gas will react with I in electrolyte in the cell3 -The ions undergo the following chemical reactions: rendering I3 -Reduction of ion concentration, consumption of I3 -The ions are electrically supplemented by the electrolytic anode. The electric quantity consumed in the whole reaction process is measured, and the total sulfur content in the sample can be calculated according to the Faraday's law of electrolysis.
The method for measuring the total chlorine content in the sample by using the microcoulometer is similar to the principle of the total sulfur measuring method, and is different from the method in that chlorine in the sample is converted into HCl gas after high-temperature combustion, and the used titration reaction is Cl-And Ag+The reaction of (1).
In addition to the microcoulomb instrument, the sulfur content in the sample can also be measured by an oxidative cracking/ultraviolet fluorescence instrument, and the measurement principle is that SO generated after the sample is combusted2Introducing gas into the ultraviolet fluorescence chamber, and introducing SO into the fluorescence chamber2The molecules are irradiated by ultraviolet rays to react as follows: sulfur dioxide molecules SO in the excited state2 *Unstable, and will transit to the ground state in a fluorescent manner within a short time: and measuring the intensity of the fluorescence signal generated in the process can indirectly measure the total sulfur content in the sample.
In addition, the chemiluminescence nitrogen content measuring instrument also uses a combustion tube, and the measuring principle of the instrument is as follows: injecting the sample into a quartz combustion tube, fully combusting the sample at high temperature in the presence of oxygen, and quantitatively converting nitrogen in the sample into NO gas (converting a small part into NO)2Gas) generated by the reaction of the gas and the O in the chemical luminescence reaction chamber after the NO gas is brought into the chemical luminescence reaction chamber by the carrier gas3The following reactions occur: generated excited nitrogen dioxide molecule NO2 *Unstable, and will transit to the ground state in the form of an emitted photon in a short time: and measuring the intensity of the chemiluminescence signal generated in the process can indirectly measure the total nitrogen content in the sample.
In the above-mentioned apparatus for measuring the content of trace elements, the structure of the combustion tube directly affects the sample amount in the maximum unit time allowed by the apparatus and the conversion rate of the element to be measured, and thus also affects the indexes of the measuring method, such as precision, accuracy, lower limit of detection and analysis speed. The combustion tubes used by the existing instrument for measuring the content of the trace elements are single-layer glass tubes, and due to the limitation of the tube structure, the resistance of gas passing through is small, so that the sample injection amount in unit time is limited. The small sample amount can cause that the instrument is difficult to achieve satisfactory accuracy and precision when measuring a sample with the element content to be measured being less than 500ppb, even cannot detect,thereby being difficult to meet the requirements of modern petrochemical technology and products.
The invention aims to provide a combustion tube for an analyzer, which can increase the sample volume per unit time, so that a sample can be more sufficiently and effectively oxidized, and the content of trace elements in the sample can be accurately measured.
The combustion tube for the trace element analyzer comprises an inner tube, a middle sleeve and an outer tube which are sleeved together. One end of the outer pipe is provided with a gas outlet, the direction of the outlet of the inner pipe is the same as that of the outlet of the outer pipe, the middle sleeve is arranged between the inner pipe and the outer pipe, and the direction of the outlet of the middle sleeve is opposite to that of the outlet of the inner pipe; the other end of the outer pipe is hermetically connected with the inner pipe, the inner pipe extends out of the outer pipe, a gasification pipe is arranged in the inner pipe, a carrier gas inlet pipe and a sample inlet pipe which are perpendicular to each other are arranged at the port of the gasification pipe, which extends out of the inner pipe, and an oxygen inlet pipe which is perpendicular to the inner pipe is arranged at one end, close to the gasification pipe, of the inner pipe.
The outlet of the inner pipe can be in a round hole shape, the preferred opening shape is in a straight line shape, a cross shape or a meter shape, and the more preferred opening shape is a cross slit. The slit opening can increase gas resistance, so that a sample can be more fully subjected to oxidation reaction in the inner tube, and meanwhile, the gas injected into the middle sleeve can be more uniform, so that the sample can be combusted more stably and more uniformly.
The outlet of the middle sleeve of the combustion tube is open, so that the resistance of the combustion tube is not excessively increased.
The gasification pipe arranged in the inner pipe of the combustion pipe is a capillary pipe, and the inner diameter of the gasification pipe is 0.5-2.0 mm. The capillary tube with smaller inner diameter is used as the guide tube of the gasification section, thereby not only accelerating the analysis speed, but also avoiding the carbon deposit of the sample caused by the thermal cracking due to oxygen deficiency in the gasification tube.
The shape of the gas outlet of the outer tube is determined according to the type of analyzer used. When the combustion tube is used for a microcoulomb meter, the gas outlet of the outer tube is a hemispherical outer ground and is matched with the ground in the gas inlet of the microcoulomb titration cell.
When the invention is used for an ultraviolet fluorescence sulfur content tester and a chemiluminescence nitrogen content tester, the gas outlet of the outer tube can be a straight tube so as to be connected with a dehydration device.
A baffle is arranged in the sample injection pipe of the combustion pipe, a sample injection hole is formed in the center of the baffle and is sealed by a sealing gasket, and the sealing gasket can be made of silicon rubber and the like. The arrangement of the baffle plate can ensure that the plug is not pushed into the combustion tube when sample introduction.
The carrier gas inlet pipe and the sampling pipe are communicated with the gasification pipe, and the oxygen inlet pipe is communicated with the inner pipe. The gasifying tube is set to gasify the liquid sample inside the tube and to enter the inner tube of the burning tube for chemical reaction with the oxygen introduced into the inner tube. The length of the gasification tube is dependent on the temperature setting of the combustion zone of the burner tube to ensure that the outlet of the gasification tube is in the proper temperature zone.
And fixing knots are arranged between the inner pipe and the middle sleeve pipe and between the middle sleeve pipe and the outer pipe, and the material of the fixing knots is the same as that of the combustion pipe. The fixing knots can be arranged at any position in the tube to ensure that the three tubes of the combustion tube are connected into a whole, and the number of the fixing knots on the same section of the tube is at least two, preferably three.
The material of the combustion tube can be selected from high-temperature-resistant and corrosion-resistant materials, such as temperature-resistant glass, preferably quartz glass. The substance to be detected and the instrument for measuring the content of the substance. The instrument matched with the combustion tube can be a microcoulometer, an ultraviolet fluorescence tester, a chemiluminescence tester and the like, and is particularly suitable for testing samples with the content of elements to be tested lower than 1ppm, and the elements to be tested comprise sulfur, chlorine, nitrogen and the like. The carrier gas used in the measurement is a gas that does not participate in the reaction, preferably argon, and helium or nitrogen may be used.
Compared with the common single-layer structure, the structure of the combustion tube is designed into a three-layer sleeve structure, and the airflow resistance is increased, so that the channeling phenomenon is avoided, the retention time of a sample in the combustion tube can be prolonged, the sample can be more fully reacted with oxygen, the oxidation reaction is closer to a chemical equilibrium state, and the conversion rate of the sample is further improved. Under the conditions of the same outer pipe diameter and the same oxygen and carrier gas flow, the allowable sample injection amount in unit time is larger, so that the detection lower limit level of the method can be improved, and the sensitivity, the accuracy and the precision of the instrument can be improved; under the condition of the same outer tube diameter and the same sample feeding amount per unit time, the total gas amount required for ensuring the sufficient combustion and conversion of the sample is smaller than that of a single-layer tube, so that the detection sensitivity of the instrument can be improved. In conclusion, for the same instrument, the use of the burner tube of the invention results in higher accuracy, better precision, and faster and easier measurement of low sample content than the use of the conventional single layer burner tube.
FIG. 1 is a schematic view of the structure of the burner tube of the present invention.
FIG. 2 is a schematic view showing the shape of the opening of the inner tube of the burner tube according to the present invention.
The invention is described in detail below with reference to the accompanying drawings: as can be seen from fig. 1, the combustion tube provided by the invention comprises an inner tube 1, a middle sleeve 2 and an outer tube 3 which are sleeved together, wherein one end of the outer tube 3 is provided with a gas outlet 10, the direction of an outlet 9 of the inner tube is the same as that of the gas outlet 10 of the outer tube, and an outlet 8 of the middle sleeve is open and opposite to that of the outlet 9 of the inner tube. The middle sleeve 2 is disposed between the inner tube 1 and the outer tube 3 with a certain space therebetween to allow gas to flow. The inner tube 1 and the middle sleeve 2, and the middle sleeve 2 and the outer tube 3 are provided with fixed knots 13. The other end of outer tube and inner tube sealing connection, inner tube 1 stretch out outer tube 3, are equipped with vaporizer 4 in it, vaporizer 4 is the capillary of internal diameter 1.0 millimeter, and its port that stretches out the inner tube is equipped with mutually perpendicular's carrier gas intake pipe 6 and advances appearance pipe 5, and the one end that inner tube 1 is close to vaporizer 4 is equipped with inner tube vertically oxygen intake pipe 7.
In fig. 1, the outer tube gas outlet 10 is shaped as a hemispherical ground and just inserts into the inlet of the microcoulometric titration cell. The diameter of the hemispherical outer grinding opening is equal to that of the grinding opening in the air inlet of the titration cell.
The oxygen inlet pipe 7 is directly communicated with the inner pipe 1, and the carrier gas inlet pipe 6 and the sample inlet 5 are directly communicated with the gasification pipe 4. The sample inlet pipe 5 is provided with a baffle 11, and a small hole 12 is arranged at the center of the baffle and is sealed by a silicone rubber pad as can be clearly seen from the sectional schematic diagram.
The outlet 9 of the inner tube of the combustion tube can be in the shape of a slit with various shapes, such as a linear slit, a cross slit or a meter-shaped slit shown in fig. 2, or a round small hole which is not shown in the figure. The inner tube opening shown in fig. 1 is shaped as a cross slit.
The use method of the combustion tube used for the microcoulomb meter comprises the following steps: firstly, the combustion tube is heated to the required temperatureAt the reaction temperature, a sample to be detected is sucked by a micro-injector, the needle head of the injector penetrates through a sealing rubber pad at the sample inlet pipe 5 and is inserted into the gasification pipe 4, and the sample is pushed into the injector at a constant speed; after the sample is gasified in the gasification tube, the sample is carried into the inner tube 1 by the carrier gas entering the gasification tube 4 from the carrier gas inlet tube 6, and the oxygen enters the inner tube 1 from the oxygen inlet tube 7. The oxygen entering the inner tube reacts with the sample, and the reaction gas passes through the inner tube 1, enters the middle sleeve 2 and then enters the outer tube 3 from the outlet of the middle sleeve 2. After the sample is reacted in the high temperature region shown in FIG. 1, the element to be detected therein is converted into a substance capable of being detected, for example, SO in the case of sulfur detection2Gas, when chlorine is detected, is converted into HCl gas. The reacted gas mixture is discharged from an outer tube gas outlet 10 and enters a titration cell, a titrant is selected according to the element to be measured, and I is used for measuring sulfur3 -Titrating the solution; for chlorine measurement, Ag is used+The solution was titrated. The total sulfur content or the total chlorine content in the sample can be calculated by measuring the power consumption of the whole titration process.
The results of the application of the present invention will be described in detail below by way of examples, but the present invention is not limited thereto.
Example 1
The combustion tube of the invention is matched with a microcoulometer to be used for measuring the total sulfur content in a sample.
The temperature of the gasification pipe 4 is raised to 800 ℃, the temperature of the high-temperature area of the combustion pipe is raised to 1000 ℃, argon with the flow rate of 100 ml/min is introduced into the carrier gas inlet pipe 6, and oxygen with the flow rate of 300 ml/min is introduced into theoxygen inlet pipe 7. A50 microliter gasoline fraction oil sample is injected into the gasification tube from the sample inlet hole 12 by an injector, and the sample is gasified in the gasification tube 4, enters a high-temperature combustion area and is discharged into a titration cell from a gas outlet 10. The total sulfur content in the sample is measured by a conventional microcoulomb sulfur content measuring instrument, and the lower detection limit of the method can reach 20 ppb.
Example 2
The combustion tube of the invention is matched with a microcoulometer to be used for measuring the total chlorine content in a sample:
the total chlorine content in gasoline distillate oil samples was determined by the conventional microcoulomb chlorine content determination method under the conditions of example 1, and the lower detection limit of the method was up to 50 ppb.
Claims (6)
1. A combustion tube for an analyzer for measuring the content of trace elements in a sample is characterized in that the combustion tube comprises an inner tube (1), a middle sleeve (2) and an outer tube (3) which are sleeved together, a gas outlet (10) is formed in one end of the outer tube (3), the direction of the gas outlet (10) of the inner tube is the same as that of the gas outlet (10) of the outer tube, the middle sleeve (2) is arranged between the inner tube and the outer tube, and the direction of the outlet (8) of the middle sleeve is opposite to that of the outlet (9) of the inner tube; the other end and the inner tube (1) sealing connection of outer tube (3), outer tube (3) are stretched out in inner tube (1), are equipped with gasification pipe (4) in it, and the port that gasification pipe stretched out inner tube (1) is equipped with mutually perpendicular's carrier gas intake pipe (6)and advances appearance pipe (5), and the one end that inner tube (1) is close to gasification pipe (4) is equipped with inner tube vertically oxygen intake pipe (7).
2. Burner tube according to claim 1, characterized in that the inner tube outlet (9) is circular, straight, cross-shaped or m-shaped.
3. The burner tube according to claim 1, wherein the vaporizing tube (4) is a capillary tube having an inner diameter of 0.5 to 2.0 mm.
4. Burner tube according to claim 1, characterized in that the middle sleeve outlet (8) is open-mouthed.
5. The burner tube according to claim 1, characterized in that the inner tube (1) and the middle sleeve (2), and the middle sleeve (2) and the outer tube (3) are provided with fixing knots (13) therebetween.
6. Burner tube according to claim 1, characterized in that the sampling tube (5) has a baffle (11) inside, the baffle (11) having a sampling hole (12) in the center, which hole is sealed by a rubber gasket.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011022388A CN1141568C (en) | 2001-01-18 | 2001-01-18 | Burning tube for element analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011022388A CN1141568C (en) | 2001-01-18 | 2001-01-18 | Burning tube for element analyzer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1365002A CN1365002A (en) | 2002-08-21 |
| CN1141568C true CN1141568C (en) | 2004-03-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB011022388A Expired - Fee Related CN1141568C (en) | 2001-01-18 | 2001-01-18 | Burning tube for element analyzer |
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| Country | Link |
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| CN (1) | CN1141568C (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100552435C (en) * | 2008-03-14 | 2009-10-21 | 朱明俊 | Special quartz tube for measuring sulfur by pulse type ultraviolet fluorescence method |
| CN102564815A (en) * | 2010-12-17 | 2012-07-11 | 江苏江分电分析仪器有限公司 | Quartz pyrolysis tube for micro component analysis |
| CN102410951A (en) * | 2011-11-03 | 2012-04-11 | 泰州市中环分析仪器有限公司 | Sulfur nitrogen chlorine blind sleeve type quartz cracking tube |
| CN102798697A (en) * | 2012-08-23 | 2012-11-28 | 苏州金宏气体股份有限公司 | Method for on-line detection of content of trace amount of sulfur in high purity ammonia or ultrapure ammonia |
| CN103399074B (en) * | 2013-07-29 | 2015-05-13 | 中国石油化工股份有限公司 | Quartz tube device for determining trace total sulfur and trace total chlorine |
| CN103592331B (en) * | 2013-11-13 | 2016-05-25 | 陕西科技大学 | The detection method of adsorbable organic chloride in a kind of Wastewater from Bleaching in Paper Making |
| CN108169405A (en) * | 2017-12-01 | 2018-06-15 | 宁波出入境检验检疫局检验检疫技术中心 | Oil and the big sample size combustion tube of petroleum chemicals analysis |
| CN109580327A (en) * | 2018-12-17 | 2019-04-05 | 北矿检测技术有限公司 | Pyrohydrolysis combustion tube |
| CN112964751A (en) * | 2021-02-05 | 2021-06-15 | 上海元析仪器有限公司 | Double-layer combustion tube for total organic carbon analyzer |
| CN114460057A (en) * | 2022-02-23 | 2022-05-10 | 宋东芹 | Portable sulfur, chlorine and nitrogen element integrated tester |
-
2001
- 2001-01-18 CN CNB011022388A patent/CN1141568C/en not_active Expired - Fee Related
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| Publication number | Publication date |
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| CN1365002A (en) | 2002-08-21 |
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Granted publication date: 20040310 Termination date: 20180118 |