Continuous monitoring method and system for total sulfur of oil product

Abstract

The invention belongs to oil product monitoring, and particularly relates to a continuous monitoring method and system for total sulfur of an oil product, and the continuous monitoring method comprises a sample introduction stage and a detection stage; the sample injection stage is as follows: the first liquid pump gradually feeds the extracted oil product into the detection device, meanwhile, the second liquid pump extracts the oil product, and the detection device outputs a measurement signal St of the total sulfur content in the oil product; switching a flow path, pumping the oil product by using the first liquid pump, gradually feeding the pumped oil product into the detection device by using the second liquid pump, and outputting a measurement signal Sc of the total sulfur content in the oil product during switching by using the detection device; the switching time is adjusted using the measurement signals St, Sc. The invention has the advantages of stable constant current and the like.

Description

Technical Field

[0001] The invention relates to fluorescence spectroscopy technology, and in particular to a continuous monitoring method and system for total sulfur in oil products. Background Art

[0002] The sulfur content in petrochemical products is an important indicator. There are strict upper sulfur content limits for crude oil, intermediate products and downstream finished products. The total sulfur analysis of oil products is mainly used in the oil hydrogenation, catalytic reforming, oil blending and other stages of oil refineries, as well as related petrochemical products such as gasoline, diesel, naphtha, kerosene, etc. By online monitoring of sulfur content, production can be guided and product quality can be improved.

[0003] There are three main methods for testing total sulfur in oil products used for online analysis: 1. Lead acetate paper tape method. After the sample sulfur is reduced to H2S, it is contacted with a white paper tape with lead acetate. The reaction generates black lead sulfide attached to the paper tape. The sulfur content of the oil is obtained by accurately measuring the color change. Envent and Galvanic products use this method.

[0004] The lead acetate paper tape method requires the use of a large amount of hydrogen to reduce sulfur, and the paper tape needs to be replaced frequently, so it is not very safe and convenient.

[0005] 2. Ultraviolet fluorescence method. All sulfur in the sample is oxidized to SO2 at a high temperature above 1000℃. SO2 is stimulated to emit light by ultraviolet fluorescence. The intensity of the light emission is proportional to the sulfur content. The sulfur content is obtained by measuring the intensity of the excitation light. This method is also the arbitration method used in the standard. Products from PAC, Thermo Fisher, Teledyne and other companies use this method. The shortcomings of the ultraviolet fluorescence method are: Injection requires the use of a rotary valve, intermittent injection, non-continuous detection, and a fixed injection volume. Samples of different concentrations require replacement of devices (generally divided into high and low range versions).

[0006] The pipeline at the rear end of the rotary valve relies on gas to push the oil, which is prone to residue when the viscosity is high, causing measurement errors. Thermoelectric uses a gasifier to gasify the oil in advance and then mix it with the carrier gas. The system of this solution is relatively complex and it is still a non-continuous detection.

[0007] 3. X-ray fluorescence method. X-ray fluorescence method is a non-contact, non-destructive measurement method that uses X-rays to directly excite sulfur atoms in the sample to emit light, and measures the fluorescence intensity to obtain the sulfur content. XOS's products use this method. The shortcomings of X-ray fluorescence method are: The detection limit is not as good as the ultraviolet fluorescence method; it has very high performance requirements for the film that can transmit X-rays on the irradiation window, and oil stains, wrinkles, thickness, etc. have a great influence on the measurement results. Summary of the invention

[0008] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a method for continuous monitoring of total sulfur in oil products, which solves the problem that the current total sulfur meter can only measure intermittently, and can automatically change the sample amount according to the feedback of the measured concentration to detect a wider sulfur concentration range, thereby realizing true real-time monitoring.

[0009] The objective of the present invention is achieved through the following technical solutions: A method for continuous monitoring of total sulfur in oil products includes a sampling phase and a detection phase; the sampling phase is: The first liquid pump gradually delivers the extracted oil to the detection device, while the second liquid pump extracts the oil, and the detection device outputs a measurement signal St of the total sulfur content in the oil; The flow path is switched, the first liquid pump extracts the oil product, and at the same time, the second liquid pump gradually delivers the extracted oil product to the detection device, and the detection device outputs a measurement signal Sc of the total sulfur content in the oil product during the switching; The switching time is adjusted using the measurement signals St, Sc.

[0010] The purpose of the present invention is also to provide a continuous monitoring system for total sulfur in oil products that implements the above-mentioned monitoring method. The purpose of the invention is achieved through the following technical solutions.

[0011] A continuous monitoring system for total sulfur in oil products, comprising a sampling device and a detection device; the sampling device comprises: a first liquid pump and a first switching valve, wherein the first liquid pump is used to extract and push out the oil product, and the first switching valve is used to enable the first liquid pump to selectively connect the oil chamber and the detection device; a second liquid pump and a second switching valve, wherein the second liquid pump is used to extract and push out the oil product, and the second switching valve is used to make the second liquid pump selectively connect the oil chamber and the detection device; A control device is used to adjust the operation of the liquid pump according to the measurement signal output by the detection device.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. It truly realizes continuous real-time sampling detection and achieves "zero delay"; Automatic constant current calibration, based on the feedback of the measurement signal, adjusts the coordination time of the two pumps inside the injection system to form a stable continuous flow; Dynamic flow regulation, based on the measurement signal feedback, enables wide range sulfur concentration sample detection without high and low range switching; 2. Simple structure; The atomization combustion system is designed to allow the oil to enter the combustion furnace in the form of liquid mist, fully mixed with the combustion-supporting gas, burn evenly, and stably deliver gas to the analysis room without the need for a gasification furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings: Figure 1 It is a structural schematic diagram of the continuous monitoring system for total sulfur in oil products of the present invention.

[0014] In the accompanying drawings, 11-a first liquid pump, 12-a second liquid pump, 21-a first switching valve, 22-a second switching valve, 31-an oil chamber, 41 a debubbler, 51-a pressure reducing valve, 52-a flow limiting valve, 53-a back pressure valve, 61-an oil product inlet, 62-a carrier gas inlet, 63-a dilution gas inlet, 64-atomizing nozzle, 65-a throat, 71-a combustion chamber, 72-an insulation layer, and 81-a control device. DETAILED DESCRIPTION

[0015] Figure 1 The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents.

[0016] Example 1.

[0017] A continuous monitoring system for total sulfur in oil products according to this embodiment is as follows: Figure 1 As shown, including: The sampling device includes a liquid pump and a switching valve. The first liquid pump 11 is used to extract and push out the oil product. The first switching valve 21 is used to make the first liquid pump 11 selectively connect the oil chamber 31 and the detection device. The second liquid pump 12 is used to extract and push out the oil product. The second switching valve 22 is used to make the second liquid pump 12 selectively connect the oil chamber 31 and the detection device.

[0018] The control device 81 is used to adjust the operation of the first liquid pump 11 and the second liquid pump 12 according to the measurement signal output by the detection device.

[0019] The detection device adopts an ultraviolet fluorescence analyzer.

[0020] In order to achieve a stable constant current, further, the control device 81 includes: A judging unit, the judging unit being used to judge whether the measurement signal Sc is within a first set range related to St; If the result is negative, the control unit adjusts the working time Ts of the first liquid pump 11 and the second liquid pump 12 to T ˊ s=Ts-(1-Sc / St), Ts =V / Q, V is the volume of oil extracted by the first liquid pump 11 or the second liquid pump 12 in a single time, Q is the flow rate of oil discharged by the first liquid pump 11 or the second liquid pump 12. The maximum value within the first setting range is St+k1A, the minimum value is St-k2A, A is the standard deviation of the measurement signal St, and k1 and k2 are coefficients respectively.

[0021] A continuous monitoring method for total sulfur in oil products in this embodiment includes a sampling phase and a detection phase; the sampling phase is: The first liquid pump 11 gradually delivers the extracted oil to the detection device, while the second liquid pump 12 extracts the oil, and the detection device outputs a measurement signal St of the total sulfur content in the oil; The flow path is switched, the first liquid pump 11 extracts the oil product, and at the same time, the second liquid pump 12 gradually sends the extracted oil product into the detection device, and the detection device outputs a measurement signal Sc of the total sulfur content in the oil product during the switching; The switching time is adjusted using the measurement signals St, Sc.

[0022] In order to achieve a stable constant current, further, the switching adjustment method is: Determining whether the measurement signal Sc is within a first set range related to St; If the answer is no, adjust the working time Ts of the liquid pump (the first liquid pump 11 and the second liquid pump 12) to T ˊ s=Ts-(1-Sc / St), Ts =V / Q, V is the volume of oil extracted by the first liquid pump 11 or the second liquid pump 12 in a single time, Q is the flow rate of oil discharged by the first liquid pump 11 or the second liquid pump 12. The maximum value within the first setting range is St+k1A, the minimum value is St-k2A, A is the standard deviation of the measurement signal St, and k1 and k2 are coefficients respectively.

[0023] In order to achieve the goal of not requiring range switching, further, the measurement signal St and the light source reference fluorescence intensity S are obtained. R and determining whether the ratio is within a second set range; If the measured signal is less than the minimum value of the second setting range, the flow rate of the oil discharged by the liquid pump is increased; If the measured signal is greater than the maximum value of the second setting range, the flow rate of the oil discharged by the liquid pump is reduced.

[0024] In order to improve the quantitative accuracy of oil products, further, the first liquid pump 11 and the second liquid pump 12 are respectively injection pumps, the first switching valve 21 is used to make the first liquid pump 11 selectively connect the oil chamber 31 and the detection device, and the second switching valve 22 is used to make the second liquid pump 12 selectively connect the oil chamber 31 and the detection device, and the detection device uses an ultraviolet fluorescence analyzer.

[0025] In order to improve the detection accuracy, the oil discharged from the first liquid pump 11 or the second liquid pump 12 is further sent to the combustion chamber 71 after being atomized and diluted.

[0026] In order to improve the quantitative accuracy of the oil, the oil enters the oil chamber 31 after decompression, and the two liquid outlets on the lower side of the debubbler 41 are respectively connected to the first liquid pump 11 and the second liquid pump 12, and the oil mixed with bubbles is discharged.

[0027] Example 2.

[0028] An application example of the method and system for continuous monitoring of total sulfur in oil products in Example 1 of the present invention.

[0029] In this application example, Figure 1 As shown, the oil passes through the pressure reducing valve 51 and enters the oil chamber 31. The oil that passes through the debubbler 41 (after removing the bubbles) is connected to the first switching valve 21 and the second switching valve 22 through the liquid outlet at the lower side of the oil chamber 31, and the oil mixed with bubbles is discharged from the oil chamber 31 and passes through the limiting valve 52 and the back pressure valve 53 in sequence.

[0030] In the sample injection device, the first switching valve 21 and the second switching valve 22 are three-way electromagnetic valves. The first liquid pump 11 and the second liquid pump 12 are the same injection pump. The input end of the control device 81 is connected to the detection device, and the output end is connected to the first liquid pump 11 and the second liquid pump 12.

[0031] The atomization and dilution device adopts a Venturi structure, with an oil product inlet 61, a carrier gas port 62, a dilution gas inlet 63 and an atomizing nozzle 64, and the end of the atomizing nozzle 64 is located in the throat 65. The carrier gas entering the carrier gas pipe from the carrier gas port 62 surrounds the oil product pipe and is then compressed (the radius of the interlayer between the oil product pipe and the carrier gas pipe becomes smaller). The dilution gas enters the dilution gas pipe from the inlet 63, is transmitted around the carrier gas pipe, and is then compressed (the radius of the interlayer between the dilution gas pipe and the carrier gas pipe becomes smaller). The carrier gas and the dilution gas expand in the throat 65, so that the oil product is atomized and diluted, and then enters the combustion chamber 71. The outer side of the combustion chamber 71 is wrapped with an insulation layer 72.

[0032] The gas discharged from the combustion chamber 71 is sent to a detection device, which uses an ultraviolet fluorescence analyzer, which is a prior art in this field.

[0033] A continuous monitoring method for total sulfur in oil products in this embodiment includes a sampling phase and a detection phase; the sampling phase is: The oil passes through the pressure reducing valve 51 and enters the oil chamber 31. The oil that passes through the debubbler 41 (after removing the bubbles) is connected to the first switching valve 21 and the second switching valve 22 through the liquid outlet at the lower side of the oil chamber 31. The oil mixed with bubbles is discharged from the oil chamber 31 and passes through the limiting valve 52 and the back pressure valve 53 in sequence.

[0034] The first liquid pump 11 gradually delivers the extracted oil to the atomization and dilution device and the detection device in sequence. At the same time, the second liquid pump 12 extracts the oil, and the detection device outputs a measurement signal (fluorescence signal) St of the total sulfur content in the oil.

[0035] The flow path is switched, the first liquid pump 11 extracts the oil, and at the same time, the second liquid pump 12 gradually sends the extracted oil into the detection device, and the detection device outputs a measurement signal (fluorescence signal) Sc of the total sulfur content in the oil at the time of switching.

[0036] The switching time is adjusted by using the measurement signals St and Sc, specifically: The judging unit judges whether the measurement signal Sc is within a first setting range related to St. The maximum value in the first setting range is St+2A, the minimum value is St-2A, and A is the standard deviation of the measurement signal St.

[0037] If the answer is no, adjust the working time Ts of the liquid pump (the first liquid pump 11 and the second liquid pump 12) to T ˊ s=Ts-(1-Sc / St), Ts =V / Q, V is the volume of oil extracted by the first liquid pump 11 in a single time, and Q is the flow rate of oil discharged by the first liquid pump 11.

[0038] That is, if Sc is too small, then (1-Sc / St)>0, and the pump switching time needs to be advanced to eliminate the interruption of flow.

[0039] If Sc is too large, then (1-Sc / St)<0, and the pump switching time needs to be delayed to eliminate overshoot.

[0040] Obtain the measurement signal St and the light source reference fluorescence intensity S R , determining whether the ratio is within a second setting range (0.2-0.8); If the measured signal is less than the minimum value of the second setting range, the flow rate of the oil discharged by the first liquid pump 11 or the second liquid pump 12 is increased, Q ˊ =2.5Q; If the measured signal is greater than the maximum value of the second setting range, the flow rate of the oil discharged by the first liquid pump 11 or the second liquid pump 12 is reduced, Q ˊ =Q / 1.6.

Claims

1. A method for continuous monitoring of total sulfur in oil products, comprising a sampling stage and a detection stage; characterized in that: The injection stage is: The first liquid pump gradually delivers the extracted oil to the detection device, while the second liquid pump extracts the oil, and the detection device outputs a measurement signal St of the total sulfur content in the oil; The flow path is switched, the first liquid pump extracts the oil product, and at the same time, the second liquid pump gradually delivers the extracted oil product to the detection device, and the detection device outputs a measurement signal Sc of the total sulfur content in the oil product during the switching; The switching time is adjusted using the measurement signals St, Sc.

2. The method for continuous monitoring of total sulfur in oil products according to claim 1, characterized in that: The switching adjustment method is as follows: Determining whether the measurement signal Sc is within a first set range related to St; If the answer is no, adjust the working time Ts of the liquid pump to T ˊ s=Ts-(1-Sc / St), Ts =V / Q, V is the volume of oil extracted by the liquid pump in a single time, and Q is the flow rate of oil discharged by the liquid pump.

3. The method for continuous monitoring of total sulfur in oil products according to claim 2, characterized in that: The maximum value within the first setting range is St+k1A, and the minimum value is St-k2A, where A is the standard deviation of the measurement signal St, and k1 and k2 are coefficients respectively.

4. The method for continuous monitoring of total sulfur in oil products according to claim 1, characterized in that: Obtain the measurement signal St and the light source reference fluorescence intensity S R and determining whether the ratio is within a second set range; If the measured signal is less than the minimum value of the second setting range, the flow rate of the oil discharged by the liquid pump is increased; If the measured signal is greater than the maximum value of the second setting range, the flow rate of the oil discharged by the liquid pump is reduced.

5. The method for continuous monitoring of total sulfur in oil products according to claim 1, characterized in that: The first liquid pump and the second liquid pump are injection pumps respectively. The first switching valve is used to make the first liquid pump selectively connect the oil chamber and the detection device. The second switching valve is used to make the second liquid pump selectively connect the oil chamber and the detection device. The detection device uses an ultraviolet fluorescence analyzer.

6. The method for continuous monitoring of total sulfur in oil products according to claim 1, characterized in that: The oil discharged from the liquid pump is atomized and diluted and then sent to the combustion chamber.

7. The method for continuous monitoring of total sulfur in oil products according to claim 6, characterized in that: The Venturi structure is used to achieve oil atomization and dilution.

8. The method for continuous monitoring of total sulfur in oil products according to claim 1, characterized in that: The oil product enters the oil chamber after being decompressed, and two liquid outlets on the lower side of the debubbler are respectively connected to the first liquid pump and the second liquid pump, and the oil product mixed with bubbles passing through the debubbler is discharged.

9. A continuous monitoring system for total sulfur in oil products, comprising a sampling device and a detection device; characterized in that: The sample injection device comprises: a first liquid pump and a first switching valve, wherein the first liquid pump is used to extract and push out the oil product, and the first switching valve is used to enable the first liquid pump to selectively connect the oil chamber and the detection device; a second liquid pump and a second switching valve, wherein the second liquid pump is used to extract and push out the oil product, and the second switching valve is used to make the second liquid pump selectively connect the oil chamber and the detection device; A control device is used to adjust the operation of the liquid pump according to the measurement signal output by the detection device.

10. The continuous monitoring system for total sulfur in oil products according to claim 9, characterized in that: The control device comprises A judging unit, the judging unit being used to judge whether the measurement signal Sc is within a first set range related to St; If the result is no, the control unit adjusts the working time Ts of the liquid pump to T ˊ s=Ts-(1-Sc / St), Ts =V / Q, V is the volume of oil extracted by the liquid pump in a single time, and Q is the flow rate of oil discharged by the liquid pump.

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