Method and system for flame luminosity on-line detection of sulfur-containing compound content in natural gas

Abstract

The present invention provides a flame photometric online detection method and system for the content of sulfur-containing compounds in natural gas, which includes a sampling device, a pressure reduction system, a chromatography column system and a flame photometric detector, the chromatography column system is provided with a carrier gas input line and a chromatography column including a boiling point column and a sulfur column therein, the output port of the sampling device is connected to the input port of the pressure reduction system through a first transport line, the output port of the pressure reduction system is connected to the input port of the boiling point column through a connecting line that can be controlled on and off, the input port of the boiling point column and the input port of the sulfur column are each connected to the carrier gas input line through a connecting line that can be controlled on and off, the output port of the boiling point column is connected to the input port of the sulfur column through a connecting line that can be controlled on and off, the output port of the boiling point column is connected to the input port of the boiling point column through a connecting line that can be controlled on and off, the output port of the sulfur column is connected to the input port of the boiling point column through a connecting line that can be controlled on and off, and the output port of the boiling point column and the output port of the sulfur column are each connected to the input port of the flame photometric detector through a connecting line that can be controlled on and off.

Description

[Technical field]

[0001] The present invention belongs to the technical field of natural gas detection, and particularly relates to a flame luminosity online detection method and system for the content of sulfur-containing compounds in natural gas. [Background technology]

[0002] With the increasing demand for energy, increasing the proportion of natural gas in the energy mix will optimize the energy mix, effectively resolve the issues of energy supply security and ecological environmental protection, and play an important role in realizing the sustainable development of economy and society. In order to improve the quality of natural gas products, the key technical indicators in the GB 17820-2018 "Natural Gas" standard, which is the core standard for the natural gas industry, have been further improved and more detailed and stricter requirements have been set, especially the technical indicator of the total sulfur content in natural gas is 200mg / m 3 to 20 mg / m 3 and a request for instantaneous values ​​has also been submitted.

[0003] At present, the total sulfur content of the purified gas from each purification plant is approximately 10 mg / m 3 to 100 mg / m 3 Most have an H2S content of 6 mg / m 3 The key to reducing the sulfur content is to reduce the contents of carbonyl sulfide, thiol, etc. in the purified gas. This places new requirements on the natural gas purification process and requires a corresponding rapid and accurate detection method.

[0004] At present, the general detection method for total sulfur in purified gas and natural gas transported by pipeline is still to sample on-site and detect it in the laboratory using oxidization microcoulometry and ultraviolet fluorescence method, but this method cannot meet the current needs of new production process control. With the gradual application of natural gas total sulfur online detection technology, ultraviolet absorption spectroscopy and hydrogen decomposition-rate meter colorimetric method are applied in the field of online detection of total sulfur in natural gas. However, due to the particularities of the equipment configuration, technical parameters and application principles, there are still many problems in online application, and it is not easy to comprehensively apply them to the online detection of total sulfur and sulfur-containing compounds in natural gas. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, which can quickly and effectively realize the online analysis and measurement of the content of at least six kinds of sulfur-containing compounds in natural gas. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, the system including a sampling device, a pressure reduction system, a chromatography column system and a flame luminosity detector; The sampling device is for obtaining natural gas to be analyzed online in a natural gas pipeline; The flame photometric detector is used to combust each component sent to the flame photometric detector, detect the light transmittance, and convert it into an electrical signal to detect the content of sulfur-containing compounds in the natural gas to be analyzed; The chromatography column system is provided with a carrier gas input line, and the chromatography column system includes a chromatography column including a boiling point column and a sulfur column (e.g., the column is composed of a boiling point column and a sulfur column); The output port of the sampling device is connected to the input port of the pressure reduction system via a first transport pipeline, the output port of the pressure reduction system is connected to the input port of the boiling point column via an on / off controllable connecting pipeline, the input port of the boiling point column and the input port of the sulfur column are each connected to the carrier gas input pipeline via an on / off controllable connecting pipeline, the output port of the boiling point column is connected to the input port of the sulfur column via an on / off controllable connecting pipeline, the output port of the sulfur column is connected to the input port of the boiling point column via an on / off controllable connecting pipeline, and the output port of the boiling point column and the output port of the sulfur column are each connected to the input port of a flame photometric detector via an on / off controllable connecting pipeline.

[0007] The flame luminosity online detection system for the content of sulfur-containing compounds in natural gas provided by the present invention can be suitably applied to the online analysis of the content of sulfur-containing compounds in natural gas in a natural gas pipeline, and can realize the content measurement of at least six kinds of sulfur-containing compounds.The flame luminosity online detection system for the content of sulfur-containing compounds in natural gas provided by the present invention has the following beneficial effects:

[0008] (1) The installed sampling device can sample the natural gas in the natural gas pipeline in real time, and send it to the pressure reducing system to reduce the pressure of the natural gas through the pressure reducing system, so that the flow rate of the natural gas can be adjusted so that the flow rate of the natural gas entering the chromatography column system is appropriate, and the carrier gas is used to drive it and separate it in the chromatography column. The installed sulfur column and boiling point column can more effectively separate the sulfur-containing compounds in the natural gas. In addition, a flame photometric detector is used to burn each component, detect the light transmittance, and convert it into an electrical signal, so that the content of the sulfur-containing compounds in the natural gas can be easily detected.

[0009] (2) The unique connection manner of each component in the chromatography column system of the present invention can realize the separation of at least six different sulfur-containing compounds in natural gas more quickly and accurately, thereby improving the efficiency and accuracy of the detection of sulfur-containing compounds in natural gas. Specifically, the unique connection manner of each component in the chromatography column system of the present invention can realize the following, based on the chromatographic separation characteristics of different components in natural gas: separating some components in natural gas using one boiling point column and one sulfur column in sequence; separating some components using two boiling point columns and one sulfur column, specifically, separating some components using a boiling point column, a sulfur column and a boiling point column in sequence; and separating some components using only one boiling point column.

[0010] (3) This system eliminates the previously cumbersome process of obtaining natural gas and then detecting it in a laboratory, making the detection of sulfur-containing compounds in natural gas more efficient and applicable to the current high demands of natural gas extraction.

[0011] (4) This system can reduce the detection costs of enterprises, and allows enterprises to independently detect sulfur-containing compounds in natural gas, which is very convenient and efficient.

[0012] In the above-mentioned flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, preferably, the sampling device includes a mounting base and a sampling probe fixedly connected to the mounting base, the sampling probe is connected to the first transport pipeline, and the mounting base is attached to the natural gas pipeline to fix the sampling device to the natural gas pipeline, and the sampling probe disposed in the natural gas pipeline enables online sampling of the natural gas in the natural gas pipeline. More preferably, the sampling probe is provided with a self-tracing pressure reducer. This preferred embodiment is more useful for sampling the natural gas in the natural gas pipeline, and has a good sampling effect.

[0013] In the above-mentioned flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, preferably, the first transport pipeline is provided with a first valve, and the first transport pipeline is opened and closed by the first valve.

[0014] In the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, a filtering net is preferably provided in the first transport pipeline.

[0015] In the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, preferably, the pressure reduction system includes a primary pressure reduction means and a secondary pressure reduction means connected in series, the input port of the secondary pressure reduction means being connected to the output port of the primary pressure reduction means via a second transport pipeline, the input port of the primary pressure reduction means being connected to the output port of the sampling device via the first transport pipeline as the input port of the pressure reduction system, and the output port of the secondary pressure reduction means being connected to the input port of the boiling point column via a connecting pipeline that can be turned on and off as the output port of the pressure reduction system.

[0016] The above-mentioned preferred embodiment is more suitable for online analysis of sulfur-containing compounds in natural gas in a natural gas pipeline by providing a primary pressure reducing means and a secondary pressure reducing means to reduce the pressure of the natural gas to be analyzed, and can precisely control the pressure drop of the natural gas obtained from the natural gas pipeline and better realize the adjustment of the natural gas flow rate.

[0017] More preferably, the primary pressure reducing means includes a primary pressure reducing tank, a first heated film type pressure reducer, a second heated film type pressure reducer, a first pressure gauge and a second pressure gauge, the first heated film type pressure reducer, the second heated film type pressure reducer, the first pressure gauge and the second pressure gauge are all provided in the primary pressure reducing tank, a first communicating pipe is provided between the first heated film type pressure reducer and the second heated film type pressure reducer, one end of the first communicating pipe is connected to an output port of the first heated film type pressure reducer and the other end of the first communicating pipe is connected to an output port of the second heated film type pressure reducer. the other end of the first transport pipeline is inserted into the primary pressure reduction tank and communicates with the input port of the first heated film type pressure reducer, the first pressure gauge is attached to the first connecting pipe and is connected to the first connecting pipe, the other end of the first transport pipeline is inserted into the primary pressure reduction tank and communicates with the input port of the first heated film type pressure reducer, one end of the second transport pipeline is inserted into the primary pressure reduction tank and is connected to the output port of the second heated film type pressure reducer, the second pressure gauge is attached to the second transport pipeline and is connected to the second transport pipeline. More preferably, the primary pressure reduction means further includes a primary heat insulation layer laid on the inner wall of the primary pressure reduction tank.

[0018] In the above-mentioned preferred embodiment, by providing the first heated membrane pressure reducer and the second heated membrane pressure reducer, it can perform dual functions, and the pressure reduction effect is significantly more efficient, which is more advantageous for the operation of reducing the pressure of natural gas in the process of online analysis of sulfur-containing compounds in natural gas in a natural gas pipeline.

[0019] More preferably, the secondary pressure reducing means includes a secondary pressure reducing tank, a knob type pressure reducer, a second connecting pipe, and a third pressure gauge, the knob type pressure reducer, the second connecting pipe, and the third pressure gauge are all provided in the secondary pressure reducing tank, one end of the second transport pipeline is inserted into the secondary pressure reducing tank and connected to an input port of the knob type pressure reducer, one end of the second connecting pipe is connected to an output port of the knob type pressure reducer, the other end of the second connecting pipe is connected to one end of the third pressure gauge, and the other end of the third pressure gauge is connected to an input port of the boiling point column via a connecting pipeline that can be turned on and off as an output port of the secondary pressure reducing means. Still more preferably, the secondary pressure reducing means further includes a secondary heat insulation layer laid on an inner wall of the secondary pressure reducing tank.

[0020] In the above preferred embodiment, a knob-type pressure reducer is used to perform a secondary pressure reduction, which further reduces the pressure of the natural gas to be analyzed, and is more advantageous for controlling the flow rate of the natural gas during the online analysis of sulfur-containing compounds in the natural gas in the natural gas pipeline.

[0021] In the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas preferably further comprises a circulating tracing tube, the depressurization system further comprises a tracing module, and the circulating tracing tube and the tracing module are communicated to heat the natural gas to be analyzed in the depressurization system. This preferred embodiment can prevent condensation of sulfur-containing compounds in natural gas during the online analysis of the sulfur-containing compounds in the natural gas in the natural gas pipeline when the natural gas is depressurized.

[0022] More preferably, a primary heating pipe and a primary exhaust pipe are provided between the circulation tracing tube and the primary pressure reducing means, one end of the primary heating pipe is connected to the circulation tracing tube and the other end is connected to one end of the primary pressure reducing means, one end of the primary exhaust pipe is connected to the other end of the primary pressure reducing means and the other end of the primary exhaust pipe is connected to the circulation tracing tube, and a secondary heating pipe and a secondary exhaust pipe are provided between the circulation tracing tube and the secondary pressure reducing means, one end of the secondary heating pipe is connected to the circulation tracing tube and the other end is connected to one end of the secondary pressure reducing means, one end of the secondary exhaust pipe is connected to the other end of the secondary pressure reducing means and the other end of the secondary exhaust pipe is connected to the circulation tracing tube.

[0023] In one embodiment, one end of the primary heating tube is connected to the circulating tracing tube, and the other end of the primary heating tube is connected to the tracing section inlet of the first heated film pressure reducer and the tracing section inlet of the second heated film pressure reducer, respectively, to heat the first heated film pressure reducer and the second heated film pressure reducer, thereby preventing condensation of the natural gas to be analyzed during pressure reduction. One end of the primary discharge tube is connected to the circulating tracing tube, and the other end of the primary discharge tube is connected to the tracing section outlet of the first heated film pressure reducer and the tracing section outlet of the second heated film pressure reducer, respectively.

[0024] In one embodiment, one end of the secondary heating tube is connected to the circulating tracing tube, and the other end of the secondary heating tube is connected to the inlet of the tracing section of the knob-type pressure reducer to heat the knob-type pressure reducer, thereby preventing condensation of the natural gas to be analyzed during pressure reduction. One end of the secondary discharge tube is connected to the circulating tracing tube, and the other end of the secondary discharge tube is connected to the outlet of the tracing section of the knob-type pressure reducer.

[0025] In the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, the chromatography column system is preferably provided with a quantification tube for temporarily storing the natural gas to be analyzed that has entered the chromatography column system, and the chromatography column system is used to realize quantification of the natural gas to be analyzed by separating the sulfur-containing compounds.

[0026] In the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, a ten-way valve is preferably provided in the chromatography column system, and the ten-way valve controls the on / off of the controllable communication relationship between each means in the chromatography column.

[0027] More preferably, the ten-way valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port and a tenth valve port, arranged in a clockwise direction, and the ten-way valve is an adjustable valve, and by controlling the shift position of the ten-way valve, the first valve port can be communicated with the second valve port, the third valve port can be communicated with the fourth valve port, the fifth valve port can be communicated with the sixth valve port, the seventh valve port can be communicated with the eighth valve port, and the ninth valve port can be communicated with the tenth valve port, in one gear, while the tenth valve port is communicated with the first valve port, the second valve port is communicated with the third valve port, the fourth valve port is communicated with the fifth valve port, the sixth valve port is communicated with the seventh valve port, and the eighth valve port is communicated with the ninth valve port. One of the tenth valve port and the ninth valve port of the ten-way valve is connected to the output port of the pressure reducing system through a third transport pipeline, the natural gas to be analyzed enters through the tenth or ninth valve port of the ten-way valve, and the other of the tenth valve port and the ninth valve port of the ten-way valve discharges excess gas. A metering pipe is provided between the first valve port of the ten-way valve and the eighth valve port of the ten-way valve to temporarily store the natural gas to be analyzed and realize the quantification of the natural gas to be analyzed, the first valve port of the ten-way valve is connected to the eighth valve port of the ten-way valve through the metering pipe, and the carrier gas input pipeline is connected to the second valve port of the ten-way valve. The boiling point column is provided between the fourth valve port of the ten-way valve and the seventh valve port of the ten-way valve, such that the fourth valve port of the ten-way valve is communicated with the seventh valve port of the ten-way valve through the boiling point column, the sulfur column is provided between the third valve port of the ten-way valve and the sixth valve port of the ten-way valve, such that the third valve port of the ten-way valve is communicated with the sixth valve port of the ten-way valve through the sulfur column, and the fifth valve port of the ten-way valve is communicated with the flame photometric detector.

[0028] In one embodiment, the ten-way valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port and a tenth valve port in a clockwise direction, the ten-way valve is an adjustable valve, and through the shift position control of the ten-way valve, the first valve port can communicate with the second valve port, the third valve port can communicate with the fourth valve port, the fifth valve port can communicate with the sixth valve port, the seventh valve port can communicate with the eighth valve port, and the ninth valve port can communicate with the tenth valve port in one gear, while the tenth valve port communicates with the first valve port, the second valve port communicates with the third valve port, the fourth valve port communicates with the fifth valve port, the sixth valve port communicates with the seventh valve port, and the eighth valve port communicates with the ninth valve port in the other gear. The output port of the pressure reducing system is connected to the tenth valve port of the ten-way valve through the third transport pipeline, the natural gas to be analyzed enters through the tenth valve port of the ten-way valve, and the ninth valve port of the ten-way valve discharges excess gas. Between the first valve port of the ten-way valve and the eighth valve port of the ten-way valve, a metering tube is provided to temporarily store the natural gas to be analyzed and realize the quantification of the natural gas to be analyzed, the first valve port of the ten-way valve is connected to the eighth valve port of the ten-way valve through the metering tube, and the carrier gas input pipeline is connected to the second valve port of the ten-way valve. A boiling point column is provided between the fourth valve port of the ten-way valve and the seventh valve port of the ten-way valve, such that the fourth valve port of the ten-way valve is connected to the seventh valve port of the ten-way valve through the boiling point column, and a sulfur column is provided between the third valve port of the ten-way valve and the sixth valve port of the ten-way valve, such that the third valve port of the ten-way valve is connected to the sixth valve port of the ten-way valve through the sulfur column. The fifth valve port of the ten-way valve is in communication with a flame intensity detector.

[0029] In one embodiment, the ten-way valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port and a tenth valve port in a clockwise direction, the ten-way valve is an adjustable valve, and through the shift position control of the ten-way valve, the first valve port can communicate with the second valve port, the third valve port can communicate with the fourth valve port, the fifth valve port can communicate with the sixth valve port, the seventh valve port can communicate with the eighth valve port, and the ninth valve port can communicate with the tenth valve port in one gear, while the tenth valve port communicates with the first valve port, the second valve port communicates with the third valve port, the fourth valve port communicates with the fifth valve port, the sixth valve port communicates with the seventh valve port, and the eighth valve port communicates with the ninth valve port in the other gear. The output port of the pressure reducing system is connected to the ninth valve port of the ten-way valve through the third transport pipeline, the natural gas to be analyzed enters through the ninth valve port of the ten-way valve, and the tenth valve port of the ten-way valve discharges excess gas. Between the first valve port of the ten-way valve and the eighth valve port of the ten-way valve, a metering pipe is provided to temporarily store the natural gas to be analyzed and realize the quantification of the natural gas to be analyzed, the first valve port of the ten-way valve is connected to the eighth valve port of the ten-way valve through the metering pipe, and the carrier gas input pipe is connected to the second valve port of the ten-way valve. A boiling point column is provided between the fourth valve port of the ten-way valve and the seventh valve port of the ten-way valve, such that the fourth valve port of the ten-way valve is connected to the seventh valve port of the ten-way valve through the boiling point column, and a sulfur column is provided between the third valve port of the ten-way valve and the sixth valve port of the ten-way valve, such that the third valve port of the ten-way valve is connected to the sixth valve port of the ten-way valve through the sulfur column. The fifth valve port of the ten-way valve is in communication with a flame intensity detector.

[0030] In the above-mentioned flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, the boiling point column is preferably a squalane column. More preferably, the length of the boiling point column is 0.8 m or more, and even more preferably 0.6 m. This preferred embodiment is advantageous for separating sulfur-containing compounds in natural gas.

[0031] In the above-mentioned flame photometric online detection system for the content of sulfur-containing compounds in natural gas, the sulfur column is preferably an oxydipropionitrile column. More preferably, the length of the sulfur column is 1.7 m or more. This preferred embodiment is advantageous for separating sulfur-containing compounds in natural gas.

[0032] In the above-mentioned flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, preferably, the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas further includes a display fixedly connected to the flame luminosity detector, the display being electrically connected to the flame luminosity detector, and the display displaying the detection result of the flame luminosity detector.

[0033] In the above-mentioned online flame luminosity detection system for the content of sulfur-containing compounds in natural gas, preferably, the online flame luminosity detection system for the content of sulfur-containing compounds in natural gas further comprises an alarm interlocking device and a combustible gas detection alarm, the alarm interlocking device and the combustible gas detection alarm are both electrically connected to the flame luminosity detector, and the combustible gas detection alarm is used to detect whether a combustible gas leak occurs near the flame luminosity detector, so as to avoid safety hazards. The alarm interlocking device is a controller, and when the combustible gas detection alarm detects a combustible gas leak, it closes the first transport pipeline in a timely manner to stop the transport and detection of the gas to be detected, so as to avoid further safety accidents.

[0034] By adopting the above-mentioned preferred embodiment, there is a beneficial effect of avoiding the leakage of flammable gas and avoiding safety accidents.

[0035] In the above-mentioned flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, preferably, the flame luminosity online detection system for the content of sulfur-containing compounds in natural gas further includes a standard gas substance storage bottle, and a standard gas substance transport pipeline is provided between the standard gas substance storage bottle and the chromatography column system, one end of the standard gas substance transport pipeline is connected to the input port of the chromatography column system and the other end is connected to the output port of the standard gas substance storage bottle, and a second valve is provided in the standard gas substance transport pipeline, and the second valve opens and closes the standard gas substance transport pipeline.

[0036] This preferred embodiment allows for easy calibration with standard gas substances on a batch-by-batch or daily basis, further improving the accuracy of detection of sulfur-containing compounds in the natural gas being analyzed.

[0037] The present invention provides a flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, in which the method includes:

[0038] S1: Collect a sulfur-containing compound standard gas substance, detect the sulfur-containing compound content in the sulfur-containing compound standard gas substance, and obtain a sulfur-containing compound content standard curve. S2: Using a sampling device, obtain natural gas transported in the natural gas pipeline, send it to a pressure reduction system, and reduce the pressure to obtain reduced pressure natural gas. S3: The reduced pressure natural gas obtained in step S2 is sent to a chromatography column system, and the reduced pressure natural gas is separated by sequentially using a boiling point column and a sulfur column under the driving of a carrier gas, and the separated components are sent to a flame photometric detector, which combusts and detects them, and obtains a detection spectrum. S4: Until the carbonyl sulfur (i.e., carbonyl sulfide) components in the natural gas are separated from the sulfur column in step S2, the carrier gas is transferred to the input port of the sulfur column, the output port of the sulfur column is connected to the input port of the boiling point column, and the output port of the boiling point column is connected to the input port of the flame photometric detector. Under the drive of the carrier gas, the remaining components are continuously separated by the chromatography column system, and the separated components are sent from the output port of the boiling point column to the flame photometric detector, where they are combusted and detected by the flame photometric detector to obtain a detection spectrum. S5: Obtain response peak area value data based on the detection spectrum obtained in steps S3 and S4, and obtain the sulfur-containing compound content in the natural gas based on the sulfur-containing compound content standard curve obtained in step S1.

[0039] The flame luminosity online detection method for the content of sulfur-containing compounds in natural gas provided by the present invention can carry out online detection of sulfur-containing compounds in natural gas, the detection operation is simple, and the content of sulfur-containing compounds in natural gas can be obtained with just a simple calculation, which can be operated by enterprises themselves and does not require detection in a professional laboratory, thereby reducing the production costs of enterprises, and at the same time, speeding up the detection efficiency of sulfur-containing compounds in natural gas and improving the detection accuracy of sulfur-containing compounds in natural gas.

[0040] In the above-mentioned flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, in step S3, the reduced pressure natural gas is separated using a boiling point column and a sulfur column in sequence under the driving of a carrier gas, and hydrogen sulfide, carbonyl sulfur, methyl mercaptan, and ethyl mercaptan in the sulfur-containing compounds are discharged in sequence from the boiling point column (the time difference between hydrogen sulfide and carbonyl sulfur components is extremely small), enter the sulfur column for separation, and further increase the separation time difference between each component, and hydrogen sulfide and carbonyl sulfur are discharged in sequence from the sulfur column, and then enter the flame luminosity detector for combustion and detection by the flame luminosity detector. In step S4, the carrier gas is transferred to the input port of the sulfur column until the carbonyl sulfur components in the natural gas are discharged from the sulfur column (at this time, the ethyl thioether components are soon discharged from the boiling point column), the output port of the sulfur column is connected to the input port of the boiling point column, and the output port of the boiling point column is connected to the input port of the flame photometric detector, and the remaining components are continuously separated using the chromatography column system under the driving of the carrier gas, and the ethyl thioether, n-butyl mercaptan, methyl mercaptan, and ethyl mercaptan components are sequentially discharged from the boiling point column, and then enter the flame photometric detector and are combusted and detected by the flame photometric detector. In the entire separation process, some components in natural gas, such as hydrogen sulfide and carbonyl sulfur components, are separated using one boiling point column and one sulfur column in sequence, some components in natural gas, such as methyl mercaptan and ethyl mercaptan components, are separated using two boiling point columns and one sulfur column, specifically, they are separated using a boiling point column, a sulfur column and a boiling point column in sequence, and some components in natural gas, such as ethyl thioether and n-butyl mercaptan components, are separated using only one boiling point column.

[0041] In the above-mentioned flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, the pressure of the reduced pressure natural gas obtained in step S2 is preferably 0.18 to 0.25 MPa (e.g., 0.2 MPa). In one embodiment, the acquired natural gas to be transported into the natural gas pipeline is transported to a primary pressure reducing means via the first transport pipeline, the pressure of the natural gas is reduced to 1.8 to 2.5 MPa (e.g., 2 MPa) via the primary pressure reducing means, and further transported to a secondary pressure reducing means via the second transport pipeline, the pressure of the natural gas is reduced to 0.18 to 0.25 MPa (e.g., 0.2 MPa) via the secondary pressure reducing means, to obtain reduced pressure natural gas.

[0042] In the above-mentioned flame photometric online detection method for the content of sulfur-containing compounds in natural gas, when a sulfur column is used for separation, the operating temperature of the sulfur column is preferably 55 to 65°C (for example, 62°C).

[0043] In the above-mentioned flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, when separation is performed using a boiling point column, the operating temperature of the boiling point column is preferably 65 to 75°C (eg, 70°C).

[0044] In the above-mentioned flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, it is preferred to use nitrogen gas as the carrier gas.

[0045] In the above-mentioned flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, the flow rate of the carrier gas is preferably 22 ml / min.

[0046] In the above-mentioned method for online flame luminosity detection of the content of sulfur-containing compounds in natural gas, it is preferable to transport the separated components to a flame luminosity detector and realize combustion and detection by the flame luminosity detector as follows.

[0047] The separated components are transported to a flame photometer, and hydrogen at a pressure of 0.24 MPa and a flow rate of 40 ml / min and air at a pressure of 0.24 MPa and a flow rate of 80 ml / min are added, and combustion and detection are performed using the flame photometer at 150°C.

[0048] In the above-mentioned flame photometric online detection method for the content of sulfur-containing compounds in natural gas, the above-mentioned "sample a sulfur-containing compound standard gas material, detect the content of sulfur-containing compounds in the sulfur-containing compound standard gas material, and obtain a standard curve for the content of sulfur-containing compounds" is as follows: Step S11: preparing standard gas substances using methane, hydrogen sulfide, carbonyl sulfur, methyl mercaptan, ethyl mercaptan, ethyl thioether, and n-butyl mercaptan, and collecting at least four sets of standard gas substances with different concentrations of sulfur-containing compounds; and step S12 of detecting each standard gas substance obtained in step S11, obtaining corresponding response peak area value data, and plotting a content standard curve of each sulfur-containing compound with the concentration of each sulfur-containing compound on the vertical axis and the corresponding response peak area value of each sulfur-containing compound on the horizontal axis.

[0049] The sulfur-containing compounds used in the standard gas substances may be determined based on the types of sulfur-containing compounds in the natural gas to be detected.

[0050] Standard gas substances generally contain a large amount of one component as the base gas, and the sulfur-containing compound standard gas substances in natural gas are prepared based on the actual components in natural gas. Since the most abundant component in natural gas is methane, methane is used as the base gas or supplementary gas to obtain a specific content of sulfur-containing compound standard gas substances.

[0051] By adopting this preferred embodiment, it is more advantageous to calculate the content of sulfur-containing compounds in natural gas.

[0052] In order to more clearly describe the technical solutions of the embodiments of the present invention, the following will briefly describe the drawings necessary for describing the embodiments. In the following description, the drawings are only some embodiments of the present invention, and it is obvious to those skilled in the art that they can obtain other drawings based on these drawings without creative efforts. [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a schematic diagram of a flame luminosity online detection system for determining the content of sulfur-containing compounds in natural gas provided by an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a primary pressure reducing means in one embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram showing the configuration of a secondary pressure reducing means in one embodiment of the present invention. [Figure 4A] FIG. 2 is a schematic diagram of a connection configuration of a ten-way valve in one embodiment of the present invention. [Figure 4B] FIG. 2 is a schematic diagram of a connection configuration of a ten-way valve in one embodiment of the present invention. [Figure 4C] FIG. 2 is a schematic diagram of a connection configuration of a ten-way valve in one embodiment of the present invention. [Figure 4D] FIG. 2 is a schematic diagram of a connection configuration of a ten-way valve in one embodiment of the present invention. [Figure 5A] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5B] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5C] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5D] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5E]FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5F] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5G] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5H] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5I] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 5J] FIG. 1 is a schematic diagram of the workflow of a flame luminosity online detection system for sulfur-containing compound content in natural gas in one embodiment of the present invention. [Figure 6A] FIG. 2 is a standard curve diagram of hydrogen sulfide in one embodiment of the present invention. [Figure 6B] FIG. 2 is a standard curve diagram of carbonyl sulfide in one embodiment of the present invention. [Figure 6C] FIG. 2 is a standard curve diagram of methyl mercaptan in one embodiment of the present invention. [Figure 6D] FIG. 2 is a standard curve diagram of ethyl mercaptan in one embodiment of the present invention. [Figure 6E] FIG. 2 is a standard curve diagram of ethyl thioether in one embodiment of the present invention. [Figure 6F] FIG. 2 is a standard curve diagram for n-butyl mercaptan in one embodiment of the present invention. [Explanation of symbols]

[0054] 1 natural gas pipeline, 2 detection port, 3 mounting base, 4 sampling probe, 5 first transport pipeline, 6 first valve, 7 circulation tracing tube, 8 primary pressure reducing means, 9 second transport pipeline, 10 secondary pressure reducing means, 11 primary heating tube, 12 secondary heating tube, 13 third transport pipeline, 14 flame photometric detector, 15 standard gas substance storage bottle, 16 standard gas substance transport pipe, 17 exhaust pipe, 18 flammable gas detection alarm, 19 alarm interlocking device, 20 power supply box, 21 primary pressure reducing tank, 22 primary insulation layer, 23 first heated membrane type pressure reducer, 24 first hot air tube, 25 second hot air tube, 26 first pressure gauge, 27 first connecting tube, 28 second heated membrane type pressure reducer, 29 second pressure gauge, 30 secondary pressure reducing tank, 31 secondary insulation layer, 32 3rd hot air tube, 33 alarm, 34 knob-type pressure reducer, 35 2nd connecting tube, 36 3rd pressure gauge, 38 chromatography column system, 39 display, 40 boiling point column, 41 sulfur column, 42 1st valve port, 43 2nd valve port, 44 3rd valve port, 45 4th valve port, 46 5th valve port, 47 6th valve port, 48 7th valve port, 49 8th valve port, 50 9th valve port, 51 10th valve port, 52 1st exhaust pipe, 53 2nd exhaust pipe, 54 metering pipe DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention are described below clearly and completely with reference to the drawings of the embodiments of the present invention. Of course, the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be obtained by those skilled in the art based on the embodiments of the present invention without any creative efforts belong to the protection scope of the present invention.

[0056] The principles and ideas of the present invention will be described in detail below with reference to several representative embodiments of the present invention.

[0057] Working Example As shown in Figures 1 to 4D, this embodiment provides a flame luminosity online detection system for the content of sulfur-containing compounds in natural gas, which includes a sampling device, a pressure reduction system, a chromatography column system 38, and a flame luminosity detector (FPD) 14. Among them, the chromatography column system 38 is provided with a carrier gas input line, and the chromatography column system 38 is provided with a chromatography column including a boiling point column 40 and a sulfur column 41 (for example, the chromatography column is composed of the boiling point column 40 and the sulfur column 41).

[0058] The sampling end of the sampling device is disposed in the natural gas pipeline 1, and obtains the natural gas transported in the natural gas pipeline 1 online, and the natural gas in the natural gas pipeline 1 enters the sampling device together with the natural gas transport power part.

[0059] Between the sampling device and the decompression system, a first transport pipeline 5 is provided, one end of which is fixedly connected to and communicates with an output port of the sampling device, and the other end of which is fixedly connected to and communicates with an input port of the decompression system. As a result, the natural gas sampled by the sampling device enters the decompression system via the first transport pipeline 5 and is decompressed.

[0060] Between the chromatography column system 38 and the decompression system, a third transport pipe 13 is provided, one end of which is fixedly connected to the output port of the decompression system and the other end of which is fixedly connected to the input port of the chromatography column system 38, and the input port of the chromatography column system 38 and the input port of the boiling point column 40 are connected via an on / off controllable connecting pipe, the input port of the boiling point column 40 and the input port of the sulfur column 41 are each connected to a carrier gas input pipe via an on / off controllable connecting pipe, the output port of the boiling point column 40 and the input port of the sulfur column 41 are each connected to an on / off controllable connecting pipe, the output port of the sulfur column 41 and the input port of the boiling point column 40 are each connected to an input port of the flame photometric detector 14 via an on / off controllable connecting pipe. The decompressed natural gas enters the chromatography column system 38, where it is separated under the action of the carrier gas.

[0061] The flame photometric detector 14 is used to burn each component, detect the light transmittance, convert it into an electrical signal, and detect the content of sulfur-containing compounds in the natural gas to be analyzed. Compounds separated from natural gas are burned and detected by the flame photometric detector 14. The flame photometric detector 14 is a known device, and is a highly sensitive and selective detector that generates a detection signal only for sulfur- and phosphorus-containing organic matter. The principle of sulfur detection is that after sulfur-containing organic matter is burned in a hydrogen-rich flame, it emits characteristic blue-violet light with a wavelength of 350 nm to 430 nm and a maximum intensity of 394 nm. The characteristic light passes through a filter, and the intensity change of the characteristic light is detected by a photomultiplier tube and converted into an electrical signal, allowing the sulfur content to be detected.

[0062] Preferably, in this embodiment, the sampling device includes a mounting base 3 and a sampling probe 4 fixedly connected to the mounting base 3, the sampling probe 4 is provided with a self-tracing pressure reducer, the sampling probe 4 is connected to a first transport pipeline 5, and the mounting base 3 is attached to a natural gas pipeline 1. Here, the natural gas pipeline 1 is provided with a detection port 2, and the mounting base 3 and the detection port 2 are provided with a connection flange, which can be easily connected via the connection flange. The sampling probe 4 is disposed in the natural gas pipeline 1, the sampling probe 4 is connected to the first transport pipeline 5, and the natural gas in the natural gas pipeline 1 enters the sampling probe 4 by itself, and further enters the first transport pipeline 5.

[0063] Preferably, in this embodiment, the first transport pipeline 5 is equipped with a first valve 6 and a filter net. The first valve 6 is installed in the first transport pipeline 5, and the first transport pipeline 5 is opened and closed through the first valve 6. Here, the first valve 6 is an electromagnetic valve that can be controlled by an electric signal, so that the operation is more convenient, and the filter net has a mesh size of 120 to 160, which can filter out particulate impurities contained in the natural gas.

[0064] Preferably, in this embodiment, the pressure reduction system includes a primary pressure reduction means 8 and a secondary pressure reduction means 10. Between the primary pressure reduction means 8 and the sampling device, a first transport pipeline 5 is provided, one end of which is fixedly connected to and communicates with an output port of the sampling device and the other end of which is fixedly connected to and communicates with an input port of the primary pressure reduction means 8, which is an input port of the pressure reduction system, and the natural gas acquired by the sampling device enters the primary pressure reduction means 8 through the first transport pipeline 5 and is subjected to pressure reduction treatment. Between the secondary pressure reduction means 10 and the primary pressure reduction means 8, a second transport pipeline 9 is provided, one end of which is fixedly connected to and communicates with the output port of the primary pressure reduction means 8 and the other end of which is fixedly connected to and communicates with the input port of the secondary pressure reduction means 10, and the natural gas is depressurized through the primary pressure reduction means 8 and then enters the secondary pressure reduction means 10 for a second pressure reduction.

[0065] Preferably, in this embodiment, as shown in FIG. 2, the primary pressure reducing means 8 includes a primary pressure reducing tank 21, a primary heat retaining layer 22, a first heated film type pressure reducer 23, a second heated film type pressure reducer 28, a first pressure gauge 26, and a second pressure gauge 29. The primary heat retaining layer 22 is laid on the inner wall of the primary pressure reducing tank 21. The first heated film type pressure reducer 23, the second heated film type pressure reducer 28, the first pressure gauge 26, and the second pressure gauge 29 are all provided in the primary pressure reducing tank 21. A first communication pipe 27 is provided between the first heated film type pressure reducer 23 and the second heated film type pressure reducer 28. One end of the first communication pipe 27 is connected to the output port of the first heated film type pressure reducer 23, and the other end is connected to the input port of the second heated film type pressure reducer 28. The first pressure gauge 26 is attached to the first communication pipe 27 and is connected to the first communication pipe 27. The other end of the first transport pipeline 5 is inserted into the primary pressure reduction tank 21 and communicated with the input port of the first heated membrane pressure reducer 23. One end of the second transport pipeline 9 is inserted into the primary pressure reduction tank 21 and communicated with the output port of the second heated membrane pressure reducer 28. The second pressure gauge 29 is attached to the second transport pipeline 9 and communicated with the second transport pipeline 9. The pressure reduction effect of the natural gas by the first heated membrane pressure reducer 23 is observed by the first pressure gauge 26, and the pressure of the natural gas is obtained in real time. The pressure reduction effect of the natural gas by the second heated membrane pressure reducer 28 is observed by the second pressure gauge 29, and the pressure of the natural gas is obtained in real time, and the pressure reduction effect is adjusted, thereby improving the detection accuracy of the natural gas. Here, the first heated membrane pressure reducer 23, the second heated membrane pressure reducer 28, the first pressure gauge 26, and the second pressure gauge 29 are all existing equipment. The primary heat insulation layer 22 is made of a polymer heat insulation material.

[0066] Preferably, in this embodiment, as shown in Fig. 3, the secondary pressure reducing means 10 includes a secondary pressure reducing tank 30, a secondary heat insulating layer 31, a knob type pressure reducer 34, a second connecting pipe 35, and a third pressure gauge 36. The secondary heat insulating layer 31 is laid on the inner wall of the secondary pressure reducing tank 30, and the knob type pressure reducer 34, the second connecting pipe 35, and the third pressure gauge 36 are all installed in the secondary pressure reducing tank 30. The other end of the second transport pipeline 9 is inserted into the secondary pressure reducing tank 30 and communicates with the input port of the knob type pressure reducer 34. One end of the second connecting pipe 35 is communicated with the output port of the knob type pressure reducer 34, and the other end is communicated with one end of the third pressure gauge 36. One end of the third transport pipeline 13 is communicated with the other end of the third pressure gauge 36. Here, the pressure of the natural gas reduced by the knob-type pressure reducer 34 is detected by the third pressure gauge 36 to control the flow rate of the natural gas, thereby making it possible to more accurately detect the content of sulfur-containing compounds in the natural gas. Here, the secondary insulation layer 31 is made of a polymer material, and the third pressure gauge 36 and the knob-type pressure reducer 34 are conventional technologies.

[0067] Preferably, in this embodiment, an alarm 33 is further provided in the secondary pressure reducing tank 30. The alarm 33 can detect the presence or absence of a natural gas leak and can issue an alarm in a timely manner.

[0068] Preferably, in this embodiment, the circulation tracing pipe 7 for supplying high-temperature gas is further included, and a primary heating pipe 11 and a primary exhaust pipe 52 are provided between the circulation tracing pipe 7 and the primary pressure reducing means 8. One end of the primary heating pipe 11 is connected to the circulation tracing pipe 7, and the other end is connected to the inlet of the tracing module of the primary pressure reducing means 8. One end of the primary exhaust pipe 52 is connected to the outlet of the tracing module of the primary pressure reducing means 8, and the other end of the primary exhaust pipe 52 is connected to the circulation tracing pipe 7. Here, the first hot air pipe 24 and the second hot air pipe 25 are respectively connected to one end of the primary heating pipe 11, and the first hot air pipe 24 is connected to the inlet of the tracing part of the first heated film pressure reducer 23, and the second hot air pipe 25 is connected to the inlet of the tracing part of the second heated film pressure reducer 28, thereby heating the first heated film pressure reducer 23 and the second heated film pressure reducer 28 to prevent condensation from occurring during the natural gas pressure reduction process. The primary discharge pipe 52 is connected to the outlet of the tracing part of the first heated film pressure reducer 23 and the outlet of the tracing part of the second heated film pressure reducer 28. Between the circulation tracing pipe 7 and the secondary pressure reducer 10, the secondary heating pipe 12 and the secondary discharge pipe 53 are provided. One end of the secondary heating pipe 12 is connected to the circulation tracing pipe 7, and the other end is connected to the inlet of the tracing module of the secondary pressure reducer 10. One end of the secondary discharge pipe 53 is connected to the outlet of the tracing module of the secondary pressure reducer 10, and the other end of the secondary discharge pipe 53 is connected to the circulation tracing pipe 7. Here, the third hot air pipe 32 is provided in the secondary pressure reducer tank 30, one end of which is connected to and communicated with the secondary heating pipe 12 and the other end of which is connected to the inlet of the tracing part of the knob type pressure reducer 34, to prevent condensation from occurring during the natural gas pressure reduction process. The secondary discharge pipe 53 is connected to the outlet of the tracing part of the knob type pressure reducer 34.

[0069] Since sulfur-containing compounds are highly susceptible to adsorption or chemical reaction with various materials, the sampling probe, mounting base 3, first valve 6, first transport pipeline 5, second transport pipeline 9, third transport pipeline 13, etc. are all made of suitable sulfur-inactive or passivated materials, and the materials selected must be adapted to the gas and sampling method, and the internal and external conditions of the sampling device must ensure that the composition of the sampled gas is not decomposed and the composition of the gas is not changed. Here, the position of the sampling probe in the natural gas pipeline 1 is not at a corner or at a middle part of the horizontally installed natural gas pipeline 1, but at a place other than the corner or middle part of the horizontally installed natural gas pipeline 1. In this way, the detection accuracy of the sulfur-containing compound content of natural gas can be improved.

[0070] Preferably, in this embodiment, the boiling point column 40 is a squalane column having a length of 0.8 m, and the sulfur column 41 is an oxydipropionitrile column having a length of 1.7 m. In one embodiment, the basic parameters of the chromatography column system 38 are as shown in Table 1 below.

[0071] [Table 1]

[0072] A ten-way valve and a metering tube 54 are provided in the chromatography column system, and the ten-way valve controls on / off between each communication means in the chromatography column.

[0073] As shown in Figures 4A, 4B, 4C, and 4D, the ten-way valve is provided with, in a clockwise direction, a first valve port 42, a second valve port 43, a third valve port 44, a fourth valve port 45, a fifth valve port 46, a sixth valve port 47, a seventh valve port 48, an eighth valve port 49, a ninth valve port 50, and a tenth valve port 51. The ten-way valve is an adjustable valve, and by controlling the shift position of the ten-way valve, in the A stage (as shown in Figures 4A and 4C), the first valve port 42 communicates with the second valve port 43, the third valve port 44 communicates with the fourth valve port 45, the fifth valve port 46 communicates with the sixth valve port 47, the seventh valve port 48 communicates with the eighth valve port 49, and the ninth valve port 50 communicates with the tenth valve port 51. In the B stage (as shown in Figures 4B and 4D), the tenth valve port 51 communicates with the first valve port 42, the second valve port 43 communicates with the third valve port 44, the fourth valve port 45 communicates with the fifth valve port 46, the sixth valve port 47 communicates with the seventh valve port 48, and the eighth valve port 48 communicates with the ninth valve port 49.

[0074] One of the tenth valve port 51 and the ninth valve port 50 of the ten-way valve is connected to the third transport pipeline 13, the natural gas to be analyzed enters through the tenth valve port 51 or the ninth valve port 50 of the ten-way valve, and the other of the tenth valve port 51 and the ninth valve port 50 of the ten-way valve is used to discharge excess gas. Here, as shown in Figures 4A and 4B, the tenth valve port 51 of the ten-way valve is connected to the third transport pipeline 13, the natural gas to be analyzed enters through the tenth valve port 51 of the ten-way valve, and the ninth valve port 50 of the ten-way valve is used to discharge excess gas. Here, as shown in Figures 4C and 4D, the ninth valve port 50 of the ten-way valve is connected to the third transport pipeline 13, the natural gas to be analyzed enters through the ninth valve port 50 of the ten-way valve, and the tenth valve port 51 of the ten-way valve is used to discharge excess gas.

[0075] Between the first valve port 42 of the ten-way valve and the eighth valve port 49 of the ten-way valve, a metering pipe 54 is provided for temporarily storing the natural gas to be analyzed and quantifying the natural gas to be analyzed. The first valve port 42 of the ten-way valve is connected to the eighth valve port 49 of the ten-way valve via the metering pipe 54. The carrier gas input line is connected to the second valve port 43 of the ten-way valve. The boiling point column 40 is provided between the fourth valve port 45 of the ten-way valve and the seventh valve port 48 of the ten-way valve such that the fourth valve port 45 of the ten-way valve is connected to the seventh valve port 48 via the boiling point column 40. The sulfur column is provided between the third valve port 44 of the ten-way valve and the sixth valve port 47 of the ten-way valve such that the third valve port 44 of the ten-way valve is connected to the sixth valve port 47 of the ten-way valve via the sulfur column. The fifth valve port 46 of the ten-way valve is connected to the flame photometric detector 14.

[0076] Preferably, in this embodiment, the gas supply system further includes a standard gas substance storage bottle 15. Between the standard gas substance storage bottle 15 and the chromatography column system 38, a standard gas substance transport pipe 16 is provided, one end of which is connected to the input port of the chromatography column system 38 and the other end of which is connected to the output port of the standard gas substance storage bottle 15. The standard gas substance transport pipe 16 is provided with a second valve, and the standard gas substance transport pipe 16 can be opened or closed by the second valve to transport the standard gas substance by the standard gas substance storage bottle 15, thereby facilitating calibration using the standard gas substance every batch or every day and further improving the detection accuracy of sulfur-containing compounds in natural gas. Here, the standard gas substance storage bottle 15 may be a container having a sulfur-inert inner coating.

[0077] Preferably, this embodiment further includes a display 39 fixedly connected to the flame intensity detector 14. The display 39 is electrically connected to the flame intensity detector 14, and the display 39 displays the detection result of the flame intensity detector 14.

[0078] Preferably, this embodiment further includes an alarm interlocking device 19 and a combustible gas detection alarm 18. The alarm interlocking device 19 and the combustible gas detection alarm 18 are both electrically connected to the flame intensity detector 14, and the alarm interlocking device 19 is electrically connected to the first valve 6. Here, the combustible gas detection alarm 18 is used to detect whether a combustible gas leak occurs near the flame intensity detector 14 and avoid safety risks. The alarm interlocking device 19 is a controller. When the combustible gas detection alarm 18 detects that a combustible gas leak occurs, it closes the first valve 6 in a timely manner to stop the transportation and detection of natural gas and avoid further safety accidents.

[0079] Preferably, in this embodiment, an exhaust pipe 17 is further provided on the side wall of the flame photometer 14, so that the smoke after combustion can be exhausted far away through the exhaust pipe 17 to avoid safety hazards.

[0080] Preferably, this embodiment further includes a power supply box 20 electrically connected to and for supplying power to the first valve 6, the flame photometric detector 14, the chromatography column system 38 and the display 39.

[0081] The present embodiment also provides a flame luminosity online detection method for the content of sulfur-containing compounds in natural gas, including:

[0082] Step S1: Obtain a calibration curve spectrum.

[0083] Step S101: Prepare standard gas substances from six known sulfur-containing compounds stored in a standard gas substance storage bottle, specifically hydrogen sulfide, carbonyl sulfur, methyl mercaptan, ethyl mercaptan, ethyl thioether and n-butyl mercaptan, together with methane, to prepare a total of five sets of standard gas substances with different concentrations of sulfur-containing compounds, 1#, 2#, 3#, 4# and 5#. The concentrations of sulfur-containing compounds in each set of standard gas substances are referred to in Tables 2 to 7.

[0084] Step S102: The standard gas substance obtained in step S101 is introduced into the chromatography column system 38 and the flame photometric detector 14, and detection is performed on the standard gas substance obtained in step S101 to detect the sulfur-containing compound content in the standard gas substance (i.e., the natural gas standard sample), and a spectrum of the natural gas standard sample is obtained (which can be performed in the same manner as in step 3 below).

[0085] Step S103: Obtain the spectrum of the natural gas standard sample through the display 39, obtain the response value of the FPD according to the spectrum, obtain the corresponding response peak area value data, and plot the standard curve of each sulfur-containing compound content with the concentration of each standard as the vertical axis and the corresponding response peak area value of each standard as the horizontal axis. See Figures 6A to 6F for the results.

[0086] The concentration of each standard substance and the corresponding response peak area data are specifically shown in Tables 2 to 7 below.

[0087] [Table 2]

[0088] [Table 3]

[0089] [Table 4]

[0090] [Table 5]

[0091] [Table 6]

[0092] [Table 7]

[0093] Step S2: Use a sampling probe to sample the natural gas transported in the natural gas pipeline 1, and filter out particulate impurities through a filter net. Then, send the natural gas to the primary pressure reducing means 8 through the first transport pipeline 5. Under the double pressure reducing action of the first heated membrane pressure reducer 23 and the second heated membrane pressure reducer 28 in the primary pressure reducing means 8, the pressure of the natural gas is reduced to 2 MPa. Then, send the natural gas to the secondary pressure reducing means 10 through the second transport pipeline 9. The pressure of the natural gas is reduced to 0.2 MPa through the knob type pressure reducer 34 in the secondary pressure reducing means 10 to obtain reduced pressure natural gas.

[0094] Step S3: The reduced pressure natural gas obtained in step S2 is sent to the chromatography column system 38 via the third transport pipeline 13 (the temperature of the reduced pressure natural gas when it enters the chromatography column system 38 is controlled to 45°C), and the reduced pressure natural gas is separated in the chromatography column system 38 under the driving force of nitrogen at a pressure of 0.24 MPa and a flow rate of 22 ml / min, and the separated product is sent to the flame photometric detector 14 for combustion and detection, and a detection spectrum is obtained (see Figures 5A to 5J for the flow).

[0095] Step S301: The reduced pressure natural gas obtained in step S2 is sent to the chromatography column system 38 via the third transport pipeline 13. At this time, the ten-way valve is at the B stage (shown in Figures 4B and 4D). At this time, the tenth valve port 51 is connected to the first valve port 42, the second valve port 43 is connected to the third valve port 44, the fourth valve port 45 is connected to the fifth valve port 46, the sixth valve port 47 is connected to the seventh valve port 48, and the eighth valve port 48 is connected to the ninth valve port 49.

[0096] As shown in Fig. 4B, the reduced pressure natural gas enters through the tenth valve port 51, then flows to the first valve port 42, and then enters the metering pipe where it is temporarily stored, and the excess reduced pressure natural gas is discharged through the ninth valve port 50. Alternatively, as shown in Fig. 4D, the reduced pressure natural gas enters through the ninth valve port 50, then flows to the eighth valve port 48, and then enters the metering pipe where it is temporarily stored, and the excess reduced pressure natural gas is discharged through the tenth valve port 51.

[0097] Step S302: The ten-way valve is adjusted to the A stage (as shown in FIGS. 4A and 4C), in which the first valve port 42 communicates with the second valve port 43, the third valve port 44 communicates with the fourth valve port 45, the fifth valve port 46 communicates with the sixth valve port 47, the seventh valve port 48 communicates with the eighth valve port 49, and the ninth valve port 50 communicates with the tenth valve port 51.

[0098] Nitrogen gas with a pressure of 0.24 MPa and a flow rate of 22 ml / min is injected into the second valve port 3, enters the metering tube through the first valve port 42, drives the decompressed natural gas temporarily stored in the metering tube, passes through the eighth valve port 49 and the seventh valve port 48 in sequence, and then enters the boiling point column 40, where it is separated at a temperature of 70°C. Since the boiling points of each sulfur-containing compound are different, different flow rates are provided, and different sulfur-containing compounds enter the fourth valve port 45 in sequence under the action of the carrier gas nitrogen gas, enter the sulfur column 41 through the third valve port 44, and are separated again in the sulfur column 41 at a temperature of 68°C. The hydrogen sulfide and carbonyl sulfur components in the sulfur-containing compounds leave the sulfur column in sequence, pass through the sixth valve port 47 and the fifth valve port 46 in sequence, and enter the flame photometric detector 14 to obtain a spectrum by combustion and detection. Here, the temperature of the natural gas when it enters the chromatography column system 38 is controlled to 45°C.

[0099] Step S303: After the carbonyl sulfur components in the natural gas leave the sulfur column, adjust the ten-way valve so that the ten-way valve is at stage B (as shown in Figures 4B and 4D), and at this time, the tenth valve port 51 communicates with the first valve port 42, the second valve port 43 communicates with the third valve port 44, the fourth valve port 45 communicates with the fifth valve port 46, the sixth valve port 47 communicates with the seventh valve port 48, and the eighth valve port 48 communicates with the ninth valve port 49.

[0100] Nitrogen gas with a pressure of 0.24 MPa and a flow rate of 22 ml / min is injected into the second valve port 3, and enters the sulfur column 41 through the third valve port 43. The remaining components of natural gas in the sulfur column 41 are driven to continue separation, while the remaining components ethyl thioether and n-butyl mercaptan in the boiling point column 40 are continuously separated and sequentially leave the boiling point column 40. The methyl mercaptan and ethyl mercaptan components in the sulfur-containing compounds sequentially leave the sulfur column 41 and enter the boiling point column 40 again for separation, and finally leave the boiling point column 40 in the order of ethyl thioether, n-butyl mercaptan, methyl mercaptan, and ethyl mercaptan. The components that leave the boiling point column 40 pass through the fourth valve port 45 and the fifth valve port 46 in order and enter the flame photometric detector 14, where they are combusted and detected to obtain a spectrum.

[0101] Here, combustion and detection using the flame luminosity detector 14 is realized by the following method. Hydrogen gas at a pressure of 0.24 MPa and a flow rate of 40 ml / min and air at a pressure of 0.24 MPa and a flow rate of 80 ml / min are fed to the flame luminosity detector 14, and combustion and detection are performed by the flame luminosity detector 14 at 150°C to obtain a detection spectrum. Here, hydrogen gas is the combustion gas and air is the supporting gas.

[0102] Step S4: Response peak data is obtained based on the detection spectrum obtained in step S3, and the response peak data is input into the standard curve of each sulfur-containing compound content obtained in step S1, and the content of the sulfur-containing compound in the natural gas is read from the graph.

[0103] This gives the content of sulfur-containing compounds in the natural gas, where the total sulfur content in the natural gas is the sum of the content concentrations of the different sulfur-containing compounds.

[0104] The error value of this online detection method is ≦5%, which is within the error range, which shows that this flame luminosity online detection system for the content of sulfur-containing compounds in natural gas can effectively detect the content of sulfur-containing compounds in natural gas online, and has high detection accuracy.

[0105] In the present invention, the principles and embodiments of the present invention have been described using specific examples. However, the explanation of the above examples is merely intended to aid in understanding the method of the present invention and its core ideas. At the same time, those skilled in the art may find changes in the specific embodiments and application scope based on the ideas of the present invention. As such, the contents of this specification should not be construed as limiting the present invention.

Claims

1. 1. A flame luminosity online detection system for sulfur-containing compound content in natural gas, comprising: A sampling device, a pressure reduction system, a chromatography column system and a flame photometric detector are included. The chromatography column system is provided with a carrier gas input line, and the chromatography column system is provided with a chromatography column including a boiling point column and a sulfur column, the boiling point column is a squalane column, and the sulfur column is an oxydipropionitrile column; The output port of the sampling device is connected to the input port of the pressure reduction system via a first transport pipeline, the output port of the pressure reduction system is connected to the input port of the boiling point column via an on / off controllable connecting pipeline, the input port of the boiling point column and the input port of the sulfur column are each connected to the carrier gas input pipeline via an on / off controllable connecting pipeline, the output port of the boiling point column is connected to the input port of the sulfur column via an on / off controllable connecting pipeline, the output port of the sulfur column is connected to the input port of the boiling point column via an on / off controllable connecting pipeline, and the output port of the boiling point column and the output port of the sulfur column are each connected to the input port of a flame photometric detector via an on / off controllable connecting pipeline.

2. the sampling device includes a mounting base and a sampling probe fixedly connected to the mounting base; the sampling probe is in communication with the first transport pipeline; the mounting base is attached to the natural gas pipeline so as to secure the sampling device to the natural gas pipeline and to enable online sampling of natural gas in the natural gas pipeline by a sampling probe disposed in the natural gas pipeline; The system of claim 1 .

3. The first transport pipeline is provided with a first valve for opening and closing the first transport pipeline. The system of claim 1 .

4. The pressure reducing system includes a primary pressure reducing means and a secondary pressure reducing means connected in series, an input port of the secondary pressure reducing means communicates with an output port of the primary pressure reducing means via a second transport pipeline, an input port of the primary pressure reducing means communicates with an output port of the sampling device via the first transport pipeline as an input port of the pressure reducing system, and an output port of the secondary pressure reducing means communicates with an input port of the boiling point column via a connection pipeline that can be on / off controlled as an output port of the pressure reducing system. The system of claim 1 .

5. the primary pressure reducing means includes a primary pressure reducing tank, a first heated membrane type pressure reducer, a second heated membrane type pressure reducer, a first pressure gauge and a second pressure gauge; the first heated membrane type pressure reducer, the second heated membrane type pressure reducer, the first pressure gauge, and the second pressure gauge are all provided in the primary pressure reducer tank, a first communication pipe is provided between the first heated film type pressure reducer and the second heated film type pressure reducer, the first communication pipe having one end communicating with an output port of the first heated film type pressure reducer and the other end communicating with an input port of the second heated film type pressure reducer; the first pressure gauge is attached to the first communicating pipe so as to be in communication with the first communicating pipe; the other end of the first transport pipeline is inserted into the primary pressure reducing tank and communicates with an input port of the first heated membrane pressure reducing device; the second transport pipeline has one end inserted into the primary pressure reducing tank and communicates with an output port of the second heated membrane pressure reducing device; The second pressure gauge is attached to the second transport pipeline so as to be in communication with the second transport pipeline. The system of claim 4.

6. the secondary pressure reducing means includes a secondary pressure reducing tank, a knob type pressure reducer, a second communicating pipe, and a third pressure gauge, the knob type pressure reducer, the second communicating pipe, and the third pressure gauge being all provided in the secondary pressure reducing tank; the second transport line has one end inserted into the secondary pressure reducing tank and communicates with the input port of the knob-type pressure reducer; the second communication pipe has one end communicating with the output port of the knob-type pressure reducer and the other end communicating with one end of the third pressure gauge; the other end of the third pressure gauge is connected to the input port of the boiling point column via a connecting pipe that can be turned on and off as an output port of the secondary pressure reducing means; The system of claim 4.

7. The flame photometric online detection system for detecting sulfur-containing compound content in natural gas further comprises a circulating tracing tube; The reduced pressure system further includes a trace module; The circulating tracing tube is in communication with the tracing module so as to heat the natural gas to be analyzed in the reduced pressure system. The system of claim 1 .

8. The chromatography column system is provided with a quantification tube for temporarily storing the natural gas to be analyzed that has entered the chromatography column system, so as to realize quantification of the natural gas to be analyzed by separating sulfur-containing compounds using the chromatography column system; The system of claim 1 .

9. 9. The system of claim 8, wherein a ten-way valve is provided within the chromatography column system for controlling on / off of the controllable communication between each of the means in the chromatography column.

10. the ten-way valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction; the ten-way valve is a valve that can be adjusted by shift position control so that, in one of the shift positions, the first valve port communicates with the second valve port, the third valve port communicates with the fourth valve port, the fifth valve port communicates with the sixth valve port, the seventh valve port communicates with the eighth valve port, and the ninth valve port communicates with the tenth valve port, and, in another of the shift positions, the tenth valve port communicates with the first valve port, the second valve port communicates with the third valve port, the fourth valve port communicates with the fifth valve port, the sixth valve port communicates with the seventh valve port, and the eighth valve port communicates with the ninth valve port, one of the tenth valve port and the ninth valve port of the ten-way valve is connected to an output port of a pressure reducing system via a third transport line, and the other of the tenth valve port and the ninth valve port of the ten-way valve is used to discharge excess gas; A metering pipe is provided between the first valve port of the ten-way valve and the eighth valve port of the ten-way valve to temporarily store the natural gas to be analyzed and quantify the natural gas to be analyzed, and the first valve port of the ten-way valve is connected to the eighth valve port of the ten-way valve via the metering pipe; a carrier gas input line communicating with a second valve port of the ten-way valve; a boiling point column is provided between the fourth valve port of the ten-way valve and the seventh valve port of the ten-way valve so as to communicate the fourth valve port of the ten-way valve with the seventh valve port of the ten-way valve; a sulfur column is provided between the third valve port of the ten-way valve and the sixth valve port of the ten-way valve so as to communicate the third valve port of the ten-way valve with the sixth valve port of the ten-way valve; a fifth valve port of the ten-way valve communicating with a flame intensity detector; The system of claim 9.

11. 2. The system of claim 1, wherein the length of the boiling point column is 0.8 m or more.

12. 2. The system of claim 1, wherein the length of the sulfur column is 1.7 m or more.

13. The flame luminosity online detection system for the content of sulfur-containing compounds in natural gas further includes an alarm interlock device and a combustible gas detection alarm electrically connected to the flame luminosity detector for detecting whether a combustible gas leak occurs near the flame luminosity detector; The alarm interlocking device is a controller that immediately closes the first transport pipeline when the flammable gas detection alarm detects a flammable gas leak, thereby stopping the transport and detection of the gas to be detected. The system of claim 1 .

14. The flame photometric online detection system for sulfur-containing compound content in natural gas further includes a standard gas substance storage bottle; a standard gas substance transport pipeline is provided between the standard gas substance storage bottle and the chromatography column system, the one end of the pipeline being connected to an input port of the chromatography column system and the other end being connected to an output port of the standard gas substance storage bottle, and the standard gas substance transport pipeline is provided with a second valve for opening and closing the standard gas substance transport pipeline; The system of claim 1 .

15. A method for online detection of flame luminosity of a sulfur-containing compound content in natural gas using a system for online detection of flame luminosity of a sulfur-containing compound content in natural gas according to any one of claims 1 to 14, comprising: Step S1 of collecting a sulfur-containing compound standard gas material, detecting the sulfur-containing compound content in the sulfur-containing compound standard gas material, and obtaining a sulfur-containing compound content standard curve; Step S2: obtaining natural gas transported in a natural gas pipeline using a sampling device, sending the natural gas to a pressure reduction system and reducing the pressure to obtain reduced pressure natural gas; Step S3: sending the reduced pressure natural gas obtained in step S2 to a chromatography column system, and separating the reduced pressure natural gas by sequentially using a boiling point column and a sulfur column under the driving of a carrier gas, and sending the separated components to a flame photometric detector, which combusts and detects the components to obtain a detection spectrum; In step S2, after the carbonyl sulfur components in the natural gas are separated from the sulfur column, the carrier gas is transferred to the input port of the sulfur column, the output port of the sulfur column is connected to the input port of the boiling point column, and the output port of the boiling point column is connected to the input port of the flame photometric detector. Under the driving of the carrier gas, the remaining components are continuously separated by the chromatography column system, and the separated components are sent from the output port of the boiling point column to the flame photometric detector, and are combusted and detected by the flame photometric detector to obtain a detection spectrum. Step S4. Step S5: obtaining response peak area value data based on the detection spectrum obtained in steps S3 and S4, and obtaining the content of sulfur-containing compounds in the natural gas based on the standard curve of the content of sulfur-containing compounds obtained in step S1; A method comprising:

16. The method according to claim 15, wherein when the separation is carried out using a sulfur column, the operating temperature of the sulfur column is 55 to 65°C.

17. The method according to claim 15, wherein when separation is carried out using a boiling point column, the operating temperature of the boiling point column is 65 to 75°C.

18. The above "collecting a sulfur-containing compound standard gas substance, detecting the sulfur-containing compound content in the sulfur-containing compound standard gas substance, and obtaining a sulfur-containing compound content standard curve" means Step S11 of preparing at least four sets of standard gas substances having different concentrations of sulfur-containing compounds using methane, hydrogen sulfide, carbonyl sulfur, methyl mercaptan, ethyl mercaptan, ethyl thioether, and n-butyl mercaptan; Step S12: performing detection for each standard gas substance obtained in step S11, obtaining corresponding response peak area value data, and plotting a content standard curve of each sulfur-containing compound with the concentration of each sulfur-containing compound on the vertical axis and the corresponding response peak area value of each sulfur-containing compound on the horizontal axis; 16. The method of claim 15, comprising:

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