Reaction tube for vertical furnace UV fluorescence total sulfur analyzer

Abstract

The present invention provides a reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer, comprising an inner quartz tube, an intermediate quartz tube, and an outer quartz tube of different diameters and spaced radially apart. The inner quartz tube has an upper end connected to a sample inlet and an argon gas inlet via a sample inlet pipe; the lower end of the inner quartz tube has an opening; the upper end of the outer quartz tube is welded and sealed to a top surface with the upper end of the inner quartz tube; an oxygen inlet is connected to a position on the top surface that is not connected to the inner quartz tube; and a gas outlet is connected to the lower end of the outer quartz tube; the upper end of the intermediate quartz tube is welded to the outer wall of the inner quartz tube and formed with 1-8 notches; the lower end of the intermediate quartz tube is sealed and located below the lower end of the inner quartz tube. The present invention can achieve more complete gasification and combustion, thereby reducing the formation of carbon deposits.

Description

Technical Field

[0001] The invention relates to a reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer, and belongs to the field of total sulfur detection of petroleum products such as light liquid hydrocarbons such as gasoline, diesel, benzene, natural gas and liquefied petroleum gas. Background Art

[0002] Sulfur content is an important detection indicator in light liquid hydrocarbons and their products. With the improvement of environmental protection requirements, the sulfur content in the exhaust gas after the combustion of liquid hydrocarbon samples must be controlled to reduce the emission and concentration of pollutants. Online monitoring of sulfur content is of great significance to improving the oil processing process and improving the quality of oil products.

[0003] Ultraviolet fluorescence total sulfur analyzers are mainly used in refineries and related petrochemical product manufacturers. They are generally installed in laboratories or mobile testing vehicles to detect the sulfur content in collected samples.

[0004] The UV fluorescence total sulfur analyzer mainly analyzes samples including: blending gasoline, diesel, naphtha, kerosene, benzene, alkanes, gas oil, natural gas and liquefied petroleum gas, etc.

[0005] The analyzer measures compliance with the following standards:

[0006] ①American Society for Testing and Materials standard: ASTM D5453 "Determination of Total Sulphur in Light Hydrocarbons, Motor Fuels and Oils by Ultraviolet Fluorescence" uses ultraviolet fluorescence to determine the total sulfur content in light hydrocarbons, motor diesel and various oils.

[0007] ②Petrochemical Industry Standard - Arbitrate Analysis Method: SH / T 0689 Determination of Total Sulfur Content in Light Hydrocarbons, Motor Fuels, and Other Oils (Ultraviolet Fluorescence Method, Designated the UV as the Arbitrate Method for Sulfur Measurement).

[0008] ③National Standard: GB / T 17040-2008 Determination of sulfur content in petroleum and petroleum products.

[0009] Currently, ultraviolet fluorescence total sulfur analyzers are divided into vertical furnace type and horizontal furnace type according to the placement of the reaction tube. The present invention is directed to an ultraviolet fluorescence total sulfur analyzer of the vertical furnace type.

[0010] The reaction tube of the vertical furnace type ultraviolet fluorescence total sulfur analyzer usually adopts a two-layer tube design. The inner quartz tube and the outer quartz tube are welded together. The oxygen connecting tube is welded at the welding position. The welding position should be sealed. One end of the inner quartz tube extends out of the outer tube, and the argon connecting tube is welded at the extending position. This end is the sample injection end, and the other end is not sealed. Some manufacturers have a section at this end designed as an opaque quartz tube type; this end of the inner quartz tube is located at 1 / 3 to 1 / 2 of the overall length of the outer quartz tube; the gas outlet connecting tube is welded to the end of the outer quartz tube that is not welded to the inner quartz tube.

[0011] Ultraviolet fluorescence total sulfur analyzers usually use electric heating furnaces to heat and maintain the reaction tube at a certain temperature. The characteristics of electric heating furnaces determine that the high-temperature area of the heating furnace is located in the center of the heating furnace. The farther away from the center, the lower the temperature, and the temperature of the entire heating area is not evenly distributed.

[0012] Ultraviolet fluorescence total sulfur analyzers are usually placed on the laboratory table, and the sample inlets of vertical furnace-type ultraviolet fluorescence total sulfur analyzers are all at the top. In order to facilitate sample injection, the height of the analyzer cannot be increased indefinitely, which limits the heating area of the heating furnace. When the heating area is certain, a double-layer quartz reaction tube is used. In order to ensure sufficient vaporization of the liquid sample, the size of the inner quartz tube inside the outer quartz tube should be increased as much as possible. However, as the length of the inner quartz tube increases, the combustion area of the sample after vaporization will be reduced accordingly. This will cause the sample to not burn completely when it is completely vaporized, or the gasification and combustion are not complete, resulting in carbon deposition. Over time, carbon black produced by incomplete combustion will accumulate at the outlet of the reaction tube, and even accumulate in the membrane dryer. When the carbon deposition is serious, it will not only damage the reaction tube and membrane dryer, but also may result in erroneous measurement results. Summary of the Invention

[0013] In order to solve the problems of existing quartz reaction tubes, the present invention provides a reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer.

[0014] To achieve the above object, the technical solution adopted by the present invention is:

[0015] A reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer, characterized by comprising an inner quartz tube, a middle quartz tube, and an outer quartz tube of different diameters and spaced apart from each other in the radial direction, wherein:

[0016] The upper end of the inner quartz tube is connected with a sampling port and an argon gas inlet through a sampling pipe; the lower end of the inner quartz tube has an opening;

[0017] The upper end of the outer quartz tube and the upper end of the inner quartz tube are welded and sealed on a top surface, an oxygen inlet is connected to a position on the top surface that is not connected to the inner quartz tube, and the lower end of the outer quartz tube is connected to a gas outlet;

[0018] The upper end of the middle quartz tube is welded to the outer wall of the inner quartz tube and is formed with 1-8 notches. The lower end of the middle quartz tube is closed and located below the lower end of the inner quartz tube.

[0019] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: the inner diameter of the inner quartz tube is 5mm to 8mm, the wall thickness is 1mm to 5mm, and the length is 200mm to 300mm.

[0020] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: the inner diameter of the sampling pipe is different from the inner diameter of the inner quartz tube.

[0021] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: the opening at the lower end of the inner quartz tube is an integral opening, a straight opening, a cross opening or a multi-hole opening.

[0022] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: the sampling port is a threaded sampling port, the length of the threaded part is 5mm to 10mm, and the argon gas inlet is connected to the sampling pipe 3mm to 8mm away from the lower end of the thread.

[0023] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer comprises an outer quartz tube with an inner diameter of 27 mm to 40 mm, a wall thickness of 1.5 mm to 3 mm, and a length of 280 mm to 400 mm.

[0024] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: the sample inlet extends out of the top surface by 15mm to 20mm.

[0025] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: the inner diameter of the middle layer quartz tube is 9mm to 32mm, the wall thickness is 1mm to 3mm, its upper end is 30mm to 80mm away from the top surface, and the lower end is located 2mm to 20mm below the lower end of the inner layer quartz tube.

[0026] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: each of the notches is 3mm to 5mm long and 2mm to 4mm wide.

[0027] The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer, wherein: there are no less than 4 contact points between the outer wall of the middle quartz tube and the inner wall of the outer quartz tube, and the contact points will not cause a seal to be formed between the middle quartz tube and the outer quartz tube.

[0028] The three-layer quartz tube design of the present invention is adopted, in which the inner quartz tube and the middle quartz tube are both the sample gasification parts. Compared with the two-layer quartz tube, as the sizes of the inner quartz tube and the middle quartz tube increase, the size of the gasification part increases exponentially, and the size of the combustion part can always remain unchanged, and is increased by nearly one-fold compared with the double-layer tube, which better ensures that the gasification and combustion of the sample are more complete, thereby reducing the formation of carbon deposits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention provides a schematic structural diagram of a reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer.

[0030] Explanation of reference numerals: inner quartz tube 1; sampling pipe 11; opening 12; middle quartz tube 2; notch 21; outer quartz tube 3; top surface 31; sampling port 4; argon ball-type joint 5; oxygen ball-type joint 6; gas outlet ball head 7. DETAILED DESCRIPTION

[0031] like Figure 1 As shown, the present invention provides a reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer, comprising an inner quartz tube 1, an intermediate quartz tube 2, and an outer quartz tube 3 having different diameters and spaced apart from each other in the radial direction, wherein:

[0032] The inner quartz tube 1 has an inner diameter of 5 mm to 8 mm, a wall thickness of 1 mm to 5 mm, and a length of 200 mm to 300 mm. The upper end of the inner quartz tube 1 is sealed and welded to an inlet port 4 having an inlet pipe 11, and the inlet port 4 allows the sample to enter. The inner diameter of the inlet pipe 11 may be different from the inner diameter of the inner quartz tube 1. The lower end of the inner quartz tube 1 has an opening 12, which may be a whole opening, a straight opening, a cross opening, or a multi-hole opening.

[0033] The sampling port 4 can be a threaded sampling port, the length of the threaded portion is 5mm to 10mm, and the end surface is flat to facilitate sealing with a rubber gasket; an argon ball-type connector 5 (serving as an argon gas inlet) is welded in a branched form on the sampling pipe 11 at a position 3mm to 8mm from the lower end of the thread, and the argon ball-type connector 5 is approximately 20mm to 30mm away from the sampling pipe 11;

[0034] The outer quartz tube 3 has an inner diameter of 27 mm to 40 mm, a wall thickness of 1.5 mm to 3 mm, and a length of 280 mm to 400 mm. The upper end of the outer quartz tube 3 is welded and sealed to a top surface 31 with the upper end of the inner quartz tube 1, and the injection port 4 extends approximately 15 mm to 20 mm from the top surface 31. An oxygen ball joint 6 (serving as an oxygen inlet) is welded to a position on the top surface 31 that is not connected to the inner quartz tube 1. The oxygen ball joint 6 is approximately 20 mm to 60 mm from the top surface 31. A gas outlet ball joint 7 is welded to the lower end of the outer quartz tube 3. The gas outlet ball joint 7 is 20 mm to 60 mm from the lower end of the outer quartz tube 3.

[0035] The middle quartz tube 2 has an inner diameter of 9 mm to 32 mm, a wall thickness of 1 mm to 3 mm, and a length related to the inner quartz tube 1. The upper end of the middle quartz tube 2 is welded to the outer wall of the inner quartz tube 1 at a position approximately 30 mm to 80 mm from the top surface 31. One to eight notches 21 are formed at the upper end of the middle quartz tube 2. The notches 21 are 3 mm to 5 mm long and 2 mm to 4 mm wide. The lower end of the middle quartz tube 2 is closed and located 2 mm to 20 mm below the lower end of the inner quartz tube 1.

[0036] There are no less than 4 contact points between the outer wall of the intermediate quartz tube 2 and the inner wall of the outer quartz tube 3 (the contact points do not lead to a seal between the intermediate quartz tube 2 and the outer quartz tube 3, which is not shown in the figure) to prevent the inner quartz tube 1 and the intermediate quartz tube 2 from falling off during transportation and use.

[0037] When the present invention is used, the sample enters the inner quartz tube 1 through the sampling port 4, and argon enters the inner quartz tube 1 through the argon ball-type joint 5. Under the action of external heating, the sample is vaporized and then flows out from the lower end of the inner quartz tube 1 together with the argon, enters the middle quartz tube 2 and continues to vaporize until it flows out from the notch 21 at the upper end of the middle quartz tube 2 and reaches the upper end position of the outer quartz tube 3; then it undergoes a combustion reaction with the oxygen fed by the oxygen ball-type joint 6 at the upper end of the outer quartz tube 3. After complete combustion, the sample is discharged from the gas outlet ball head 7 at the lower end of the outer quartz tube 3.

[0038] It can be seen that the inner quartz tube 1 and the middle quartz tube 2 of the present invention are both the sample gasification parts. Compared with the two-layer quartz tube, as the sizes of the inner quartz tube 1 and the middle quartz tube 2 increase, the size of the gasification part increases exponentially; and the size of the combustion part remains unchanged and is nearly doubled compared with the double-layer tube; therefore, the present invention can ensure that the gasification and combustion of the sample are more complete, thereby reducing the formation of carbon deposits.

[0039] The present invention has also been tested:

[0040] Experimental conditions:

[0041] Argon and oxygen pressures are approximately 200 kPa

[0042] Argon flow rate: 130 mL / min

[0043] Oxygen flow rate is 450mL / min

[0044] Heating furnace temperature is 1050℃

[0045] The test results of the standard samples are shown in Table 1. It can be seen that the linearity of the standard curve meets the national standard requirements.

[0046] Table 1 Standard sample test results

[0047]

[0048]

[0049] The test results of light hydrocarbon samples are shown in Table 2. It can be seen that the test results of various samples also meet the requirements.

[0050] Table 2 Test results of light hydrocarbon samples

[0051]

[0052]

[0053] The above description is only illustrative of the present invention and not restrictive. Those skilled in the art will understand that many modifications, changes or equivalents may be made without departing from the spirit and scope defined by the claims, and all of them will fall within the scope of protection of the present invention.

Claims

1. A reaction tube for a vertical furnace ultraviolet fluorescence total sulfur analyzer, characterized in that: The invention comprises an inner quartz tube, an intermediate quartz tube and an outer quartz tube having different diameters and spaced apart from each other in the radial direction, wherein: The upper end of the inner quartz tube is connected to the sampling port and the argon gas inlet through the sampling pipe; the lower end of the inner quartz tube has an opening; the inner quartz tube has an inner diameter of 5mm to 8mm, a wall thickness of 1mm to 5mm, and a length of 200mm to 300mm; The upper end of the outer quartz tube is welded and sealed to a top surface with the upper end of the inner quartz tube. An oxygen inlet is connected to a position on the top surface that is not connected to the inner quartz tube, and a gas outlet is connected to the lower end of the outer quartz tube. The outer quartz tube has an inner diameter of 27 mm to 40 mm, a wall thickness of 1.5 mm to 3 mm, and a length of 280 mm to 400 mm. The upper end of the intermediate quartz tube is welded to the outer wall of the inner quartz tube and is formed with 1-8 notches, each of which is 3mm to 5mm long and 2mm to 4mm wide. The lower end of the intermediate quartz tube is closed and located below the lower end of the inner quartz tube. The inner diameter of the intermediate quartz tube is 9mm to 32mm, the wall thickness is 1mm to 3mm, the upper end is 30mm to 80mm away from the top surface, and the lower end is located 2mm to 20mm below the lower end of the inner quartz tube.

2. The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer according to claim 1, characterized in that: The inner diameter of the sampling pipe is different from the inner diameter of the inner quartz tube.

3. The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer according to claim 1, characterized in that: The opening at the lower end of the inner quartz tube is an integral opening, a straight opening, a cross opening or a multi-hole opening.

4. The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer according to claim 1, characterized in that: The injection port is a threaded injection port, the length of the threaded portion is 5mm to 10mm, and the argon gas inlet is connected to the injection pipe at a position 3mm to 8mm away from the lower end of the thread.

5. The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer according to claim 4, characterized in that: The injection port extends out of the top surface by 15 mm to 20 mm.

6. The reaction tube for the vertical furnace ultraviolet fluorescence total sulfur analyzer according to claim 1, characterized in that: There are no less than four contact points between the outer wall of the middle quartz tube and the inner wall of the outer quartz tube, and the contact points will not cause a seal to be formed between the middle quartz tube and the outer quartz tube.

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