Steam cracking product on-line near infrared spectrum analysis device and analysis method

Abstract

The present application provides a kind of steam cracking product online near infrared spectrum analysis device, comprising: self-cleaning system includes inert gas pipeline, steam pipeline, water pipeline, one-stage heater and two-stage heater;Analysis system and cooling separation system, inert gas pipeline, steam pipeline and water pipeline are connected in parallel and are gathered into self-cleaning medium main pipe after entering one-stage heater, after one-stage heater, it is divided into two ways, one way enters two-stage heater after being merged with a cracking product pipeline, then enters analysis system after two-stage heating, the other way is connected with cooling separation system;Analysis system includes flow cell and flow cell insulation heating jacket, flow cell insulation heating jacket wraps part structure of flow cell, the upper end of flow cell is connected with two-stage heater, and the lower end of flow cell is connected with cooling separation system.The analysis device can be used for high temperature, trace coke containing steam cracking product analysis, simple structure, easy operation, convenient disassembly and maintenance, high analysis precision.

Description

Technical Field

[0001] This invention relates to the field of steam cracking technology in petrochemicals, and particularly to an online near-infrared spectroscopy analysis device and method for steam cracking products. Background Technology

[0002] Low-carbon olefins, represented by ethylene, are important chemical raw materials and occupy an important position in the national economy. Currently, more than 95% of the world's ethylene production processes use tubular furnace steam cracking technology. This process utilizes hydrocarbon feedstocks such as ethane, C3 and C4 hydrocarbons, light hydrocarbons, naphtha, and hydrotreated tail oil to carry out cracking reactions with dilution steam in the radiant section coils of the cracking furnace under high temperature, short residence, and low hydrocarbon partial pressure conditions to obtain ethylene, propylene, and butadiene products, and co-produce basic chemical raw materials such as benzene, toluene, xylene, C5, and C9. It plays a pivotal role in the petrochemical industry.

[0003] The process of producing low-carbon olefins through steam cracking is significantly affected by feedstock. Due to the continuous expansion of steam cracking unit capacity and the insufficient supply of high-quality ethylene cracking feedstock, ethylene cracking feedstock is gradually moving towards heavier and more diversified feedstocks. In addition, the increasing complexity of the composition of cracking feedstock in the storage tanks of steam cracking plants and the frequent changes in its sources, coupled with the lack of timely and effective process solutions, seriously affect the low-carbon olefin yield, operating status, and economic benefits of the cracking unit.

[0004] To optimize the process parameters of steam cracking furnaces, timely and effective analysis results of cracking products are required. Currently, research on the cracking process of organic hydrocarbons mainly relies on offline or online analytical methods. The compositional analysis of related cracking products is only performed after the cracking reaction is complete. Conventional methods for analyzing cracking products employ gas chromatography, but due to limitations such as column properties, instrument hardware conditions, and applicable environments, gas chromatography cannot handle samples containing water or at high temperatures, and the sample processing and analysis time is long, failing to meet the demand for rapid measurement of high-temperature water-containing products from steam cracking. Existing methods for calibrating steam cracking products are also time-consuming and involve complex calibration steps. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention provides an online near-infrared spectroscopy analysis device and method for steam cracking products. This near-infrared spectroscopy analysis device can be used for the analysis of steam cracking products containing trace amounts of coke at high temperatures. It features simple structure, easy operation, convenient disassembly and maintenance, and high analytical accuracy.

[0006] To achieve the above objectives, the present invention provides an online near-infrared spectroscopy analysis device for steam cracking products, the near-infrared spectroscopy analysis device comprising:

[0007] The self-cleaning system includes an inert gas pipeline, a steam pipeline, a water pipeline, a first-stage heater, and a second-stage heater.

[0008] The analysis system and the cooling separation system are described above. The inert gas pipeline, steam pipeline and water pipeline are connected in parallel and converge into a self-cleaning medium main pipe before entering a first-stage heater. After passing through the first-stage heater, the pipeline splits into two paths. One path merges with a pyrolysis product pipeline and enters a second-stage heater. After being heated in two stages, the pipeline enters the analysis system. The other path is connected to the cooling separation system.

[0009] The analysis system includes a flow cell and a flow cell insulation and heating jacket. The flow cell insulation and heating jacket covers part of the flow cell structure. The upper end of the flow cell is connected to the two-stage heater of the self-cleaning system, and the lower end of the flow cell is connected to the cooling and separation system.

[0010] In some embodiments, the flow cell is composed of a vertically intersecting flow tube and a horizontally intersecting observation tube. The observation tube is sealed by an internal sealing lens, and the outside of the sealing lens is fixed by an observation port connector connected to the outside of the observation tube. The other end of the observation port connector is connected to a light path adjustment tube with a cooling function, and the end of the light path adjustment tube is sealed by a light source signal fixing end cap.

[0011] The upper end of the flow tube is connected to the self-cleaning system via a connecting reducer, and the lower end is connected to the cooling separation system via a connecting reducer.

[0012] In some embodiments, the optical path adjustment tube body has an optical path adjustment lens inside, and the optical path adjustment lens is fixed by the optical path adjustment tube body and its internal fixed support sleeve;

[0013] The outer wall of the optical path adjustment tube has a shell structure of cooling tube, and the cooling medium enters or exits through the cooling medium flow interface on both sides of the cooling tube, and completes the heat extraction of the inside of the optical path adjustment tube in the cooling cavity.

[0014] In some embodiments, the internal structure of the observation tube, the observation port connector, the optical path adjustment tube, and the light source signal fixing end cap are symmetrically distributed along the flow tube.

[0015] One end of the light source signal fixing cap has a light source transmitting signal connector fixed at the center, and the other end of the light source signal fixing cap has a light source receiving signal connector fixed at the center.

[0016] In some embodiments, the top end of the flow tube is connected to the material inlet via a connecting reducer, and the bottom end of the flow tube is connected to the material outlet via a connecting reducer. A filter is provided in the upper section of the flow tube, and the filter is installed between the connecting reducer and the observation tube.

[0017] In some embodiments, the inert gas pipeline has an inert gas pipeline control valve, an inert gas flow meter, and an inert gas check valve arranged in sequence.

[0018] The steam pipeline has a steam pipeline control valve, a steam flow meter, and a steam check valve arranged in sequence.

[0019] The water pipeline is connected in sequence to a water storage tank, a water pipeline control valve, a metering pump, and a water pipeline check valve. The mass of the water storage tank is measured by a metering scale.

[0020] In some embodiments, a pyrolysis product pipeline control valve is provided on the pyrolysis product pipeline; a steam cleaning control valve is provided on the connecting pipeline between the first-stage heater and the second-stage heater, the steam cleaning control valve being located before the pyrolysis product pipelines merge; and a steam discharge control valve is provided on the connecting pipeline between the first-stage heater and the cooling separation system, the steam discharge control valve being located at the front end where it merges with the analysis system pipeline.

[0021] In some embodiments, the cooling separation system includes two series coolers, a cooling collection tank, a gas flow meter, and connecting pipelines;

[0022] One stage cooler is connected in series with the second stage cooler. One end of the first stage cooler is connected to the first stage heater in the self-cleaning system, and the other end is connected to the flow cell in the analysis system. The end of the second stage cooler is connected to the cooling collection tank. After gas-liquid separation in the cooling collection tank, the liquid product is discharged from the drain line connected to the bottom of the cooling collection tank. A drain line control valve is installed on the drain line.

[0023] In some embodiments, the gaseous product is discharged from a corresponding pipeline at the top of the cooling collection tank. This pipeline is divided into two paths: one path is connected to a direct exhaust pipeline to discharge the gas directly, and the other path is connected to a metering exhaust pipeline to discharge the gas. The metering exhaust pipeline is equipped with a gas flow meter.

[0024] A direct exhaust line control valve is provided on the direct exhaust line, and a metering exhaust line control valve is provided on the metering exhaust line. The metering exhaust line control valve is located at the inlet front end of the gas flow meter.

[0025] This invention also provides an online near-infrared spectroscopy analysis method for steam cracking products, using the online near-infrared spectroscopy analysis device for steam cracking products as described above. The analysis method includes the following steps:

[0026] S1, Equipment Start-up

[0027] The cooling tube of the optical path regulating tube on the flow cell of the start-up analysis system and the first-stage cooler, second-stage cooler and cooling collection tank of the cooling separation system are circulated for cooling.

[0028] Close the steam discharge control valve, open the steam cleaning control valve, and open the metering exhaust pipeline control valve or the direct exhaust pipeline control valve; start the first-stage heater, the second-stage heater in the self-cleaning system, and the flow cell insulation heating jacket in the analysis system;

[0029] Meanwhile, monitor the temperature rise of the first-stage heater, the second-stage heater, and the insulation and heating jacket of the flow pool. When any of the first-stage heater, the second-stage heater, or the insulation and heating jacket of the flow pool reaches 300℃±5℃, start the steam pipeline or water pipeline in the self-cleaning system. That is, open the steam pipeline control valve and adjust the steam feed rate of the steam flow meter, or open the water pipeline control valve and start the metering pump to adjust the water feed rate.

[0030] S2, Background Test

[0031] After all parameters of the device reach the set values ​​and the device runs stably, the water or steam feed rate of the device is adjusted according to the water content of the feed of the pyrolysis products at the upper end. The water or steam feed rate is adjusted to be close to or equal to the water content in the pyrolysis products. After the device runs stably again, near-infrared spectroscopy is collected to obtain the background test results.

[0032] S3, Analysis and Testing

[0033] Close the steam cleaning control valve, open the steam discharge control valve, open the pyrolysis product pipeline control valve, and perform pyrolysis product analysis and testing. The analysis and testing results can be subtracted from the background test results.

[0034] S4, System Cleaning

[0035] Close the steam discharge control valve, open the steam cleaning control valve, close the cracking product pipeline control valve, adjust the steam or water pipeline feed rate in the self-cleaning system, and clean the pipeline and analysis system.

[0036] If the pyrolysis product analysis is performed again, repeat steps S2, S3, and S4.

[0037] S5, Device Shutdown

[0038] Shut down the first-stage heater, the second-stage heater in the self-cleaning system, and the heating jacket of the flow cell in the analysis system. At the same time, monitor the cooling of the first-stage heater, the second-stage heater, and the heating jacket of the flow cell. When the temperature of any one of the first-stage heater, the second-stage heater, or the heating jacket of the flow cell drops to 300℃±5℃, start the inert gas pipeline in the self-cleaning system, that is, open the inert gas pipeline control valve and set the inert gas flow meter to adjust the inert gas feed rate.

[0039] Close the steam and water pipelines, i.e., close the steam pipeline control valve, zero the steam flow meter, close the water pipeline control valve, and shut down the metering pump. When the temperature of the first-stage heater, the second-stage heater in the self-cleaning system, and the insulation heating jacket of the flow cell in the analysis system drops to 80℃±5℃, close the inert gas pipeline, i.e., close the inert gas pipeline control valve, zero the inert gas flow meter, close the metering exhaust pipeline control valve and the direct exhaust pipeline control valve, and shut down the cooling pipe of the optical path regulating pipe in the analysis system and the first-stage cooler, the second-stage cooler, and the cooling collection tank in the cooling separation system.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] The online near-infrared spectroscopy analysis device for steam pyrolysis products provided by this invention has a self-cleaning system that can clean the pipelines and lenses, extending the device maintenance cycle. Furthermore, the self-cleaning system of this invention has multiple media interfaces, which are flexible in selection and highly practical.

[0042] The online near-infrared spectroscopy analysis device for steam pyrolysis products provided by this invention uses a flow cell with cooling function, which can be used for high-temperature pyrolysis product analysis. At the same time, the flow cell of this invention is composed of a vertical flow tube and a horizontal observation tube perpendicularly intersecting each other. This structure design has a small fluid dead zone, and the flow tube has a filter, which can reduce the contamination of the lens and pipeline by carbon powder in the pyrolysis products, thereby improving the accuracy of spectral analysis.

[0043] The online near-infrared spectroscopy analysis device for steam cracking products provided by this invention can eliminate or reduce the interference of water in the cracking products on the spectral analysis results through background testing, thereby improving the accuracy and precision of spectral analysis. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the online near-infrared spectroscopy analysis device for steam cracking products shown in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the flow cell structure in the online near-infrared spectroscopy analysis device for steam cracking products shown in an embodiment of the present invention;

[0047] Figure 3 The spectrum is obtained by experimental analysis of pyrolysis products using the online near-infrared spectroscopy analysis device for steam pyrolysis products as shown in the embodiment of the invention.

[0048] in:

[0049] 1-Self-cleaning system; 101-Inert gas pipeline; 102-Steam pipeline; 103-Water pipeline; 104-First stage heater; 105-Second stage heater; 106-Self-cleaning medium main pipe; 107-Pyrolysis product pipeline; 1011-Inert gas pipeline control valve; 1012-Inert gas flow meter; 1013-Inert gas check valve; 1021-Steam pipeline control valve; 1022-Steam flow meter; 1023-Steam check valve; 1031-Water storage tank; 1032-Water pipeline control valve; 1033-Metering pump; 1034-Water pipeline check valve; 1035-Metering scale; 1041-Steam cleaning control valve; 1042-Steam discharge control valve; 1071-Pyrolysis product pipeline control valve;

[0050] 2-Analysis system; 21-Flow cell; 22-Flow cell insulation and heating jacket;

[0051] 201-Material inlet; 202-Connecting reducer; 203-Filter plate; 204-Flow tube; 205-Flow chamber; 206-Sealing lens; 207-Optical path adjustment tube; 208-Cooling chamber; 209-Light source transmitting signal connector; 210-Light source signal fixing end cap; 211-Fixed support sleeve; 212-Optical path adjustment lens; 213-Cooling medium flow interface; 214-Observation port connector; 215-Sealing gasket; 216-Observation tube; 217-Cooling tube; 218-Light source receiving signal connector; 219-Material outlet;

[0052] 3-Cooling separation system; 301-First stage cooler; 302-Second stage cooler; 303-Cooling collection tank; 304-Drainage line; 3041-Drainage line control valve; 305-Direct exhaust line; 3051-Direct exhaust line control valve; 306-Metering exhaust line; 3061-Gas flow meter; 3062-Metering exhaust line control valve. Detailed Implementation

[0053] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments to further understand the purpose, solution and effect of the present invention, but it is not intended to limit the scope of protection of the appended claims.

[0054] Certain terms are used in this specification and the following claims to refer to specific components or parts. Those skilled in the art will understand that users or manufacturers may use different names or terms to refer to the same component or part. This specification and the following claims do not distinguish components or parts by differences in name, but rather by differences in function. The terms "comprising" and "including" used throughout this specification and the following claims are open-ended and should be interpreted as "including but not limited to". Furthermore, the term "connection" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connections made through other means.

[0055] It should be noted that in the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and "about", or "approximately", "substantially", "left and right", etc., indicating the orientation or positional relationship or parameters, are all based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, a specific size, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0056] Near-infrared spectroscopy is favored by many because its absorption regions coincide with the combination frequencies and overtones of the vibrations of hydrogen-containing groups (OH, NH, CH) in organic molecules. Characterization scanning using near-infrared spectroscopy can obtain characteristic information of hydrogen-containing groups in organic molecules in samples. It has advantages such as convenience, speed, efficiency, accuracy, low cost, and non-destructiveness to samples. Furthermore, near-infrared spectroscopy can be used for in-situ characterization in harsh reaction environments such as high pressure.

[0057] To address the technical problems of time-consuming and complex calibration procedures in existing steam cracking product calibration methods, this invention provides an online near-infrared spectroscopy analysis device for steam cracking products. The device includes a self-cleaning system, an analysis system, and a cooling and separation system. The high-temperature cracking product pipeline merges with the corresponding pipeline of the self-cleaning system and enters the analysis system after reheating. After spectral analysis by the analysis system, the cracking products are cooled and separated by the cooling and separation system before being discharged from the device. The self-cleaning system has a pipeline directly connected to the cooling and separation system, facilitating material switching and enabling background moisture measurement to eliminate or reduce the interference of water in the cracking products on the analytical results, thus improving analytical accuracy. The analysis system features a vertically cross-structured flow cell with cooling and filtration functions, suitable for analyzing high-temperature steam cracking products containing trace amounts of coke. It features a simple structure, easy disassembly and maintenance, fast analysis speed, and high analytical accuracy.

[0058] Specifically, participation such as Figure 1-2 As shown, an embodiment of the present invention provides an online near-infrared spectroscopy analysis device for steam cracking products, the near-infrared spectroscopy analysis device comprising:

[0059] The self-cleaning system 1 includes an inert gas pipeline 101, a steam pipeline 102, a water pipeline 103, a first-stage heater 104, and a second-stage heater 105, for providing a high-temperature cleaning medium.

[0060] The analysis system 2 and the cooling separation system 3 are connected in parallel by the inert gas pipeline 101, steam pipeline 102 and water pipeline 103, which are then connected to form a self-cleaning medium main pipe 106 and enter a first-stage heater 104. After passing through the first-stage heater 104, the pipeline splits into two paths. One path merges with a pyrolysis product pipeline 107 and enters a second-stage heater 105. After being heated in two stages, the pipeline enters the analysis system 2. The other path is connected to the cooling separation system 3.

[0061] The analysis system 2 includes a flow cell 21 and a flow cell insulation and heating jacket 22. The flow cell insulation and heating jacket 22 encloses part of the structure of the flow cell 21. The upper end of the flow cell 21 is connected to the second-stage heater 105 of the self-cleaning system 1, and the lower end of the flow cell 21 is connected to the cooling and separation system 3.

[0062] In this embodiment, the temperature of the first stage heater 104 is controlled at 600℃-850℃, the temperature of the second stage heater 105 is controlled at 700℃-850℃, and the temperature of the flow pool insulation and heating jacket 22 is controlled at 700℃-850℃.

[0063] In this embodiment, the flow cell 21 is composed of a vertically intersecting flow tube 204 and a horizontally intersecting observation tube 216. The observation tube 216 is sealed by a high-temperature resistant sealing lens 206 inside. The outer side of the sealing lens 206 is fixed by an observation port connector 214 connected to the outer side of the observation tube 216. The other end of the observation port connector 214 is connected to a light path adjustment tube 207 with a cooling function. The end of the light path adjustment tube 207 is sealed by a light source signal fixing cap 210. The upper end of the flow tube 204 is connected to the self-cleaning system 1 through a connecting reducer 202, and the lower end is connected to the cooling separation system 3 through a connecting reducer 202. The sealing lens 206 in the observation tube 216 is clamped and fixed by the internal support groove of the observation tube 216 and the observation port connector 214. The sealing lens 206 is made of high-transmittance, high-temperature resistant sapphire glass or quartz glass. Furthermore, in this embodiment, the distance between the inner surface (the mirror surface that contacts the pyrolysis products in the flow tube) of the sealing lens 206 is no more than 3 times the diameter of the flow tube 204, so as to reduce the dead angle of the pyrolysis products flow.

[0064] In this embodiment, the optical path adjustment tube 207 has an optical path adjustment lens 212 inside, and the optical path adjustment lens 212 is fixed by the optical path adjustment tube 207 and its internal fixed support sleeve 211;

[0065] The outer wall of the optical path adjustment tube 207 has a shell structure of a cooling tube 217, and a cooling cavity 208 is formed inside the cooling tube 217. The cooling medium enters or exits through the cooling medium flow interface 213 on both sides of the cooling tube 217 to reduce the internal temperature of the optical path adjustment tube 207 (heat extraction from the inside of the optical path adjustment tube 207 is completed in the cooling cavity 208).

[0066] Specifically, in this embodiment, the inner diameter of the observation port connector 214 is approximately the same as the inner diameter of the optical path adjustment tube 207, ensuring that the optical path passes through in parallel. Furthermore, the optical path adjustment tube 207 contains an optical path adjustment lens 212, which is fixed by a support groove and a stainless steel fixed support sleeve 211 within the optical path adjustment tube 207. The optical path adjustment lens 212 is made of high-transmittance, high-temperature resistant sapphire glass or quartz glass. Furthermore, the outer side of the optical path adjustment tube 207 has a cooling tube 217 with a shell structure, which cools the optical path adjustment tube 207 and protects the light source signal connector. The cooling medium inside the cooling tube is water or a mixture of water and ethylene glycol, controlling the temperature of the optical path adjustment tube near the light source signal fixing end cap to not exceed 55°C.

[0067] In this embodiment, the internal structure of the observation tube 216, the observation port connector 214, the optical path adjustment tube 207, and the light source signal fixing end cap 210 are symmetrically distributed along the flow tube 204; wherein, the light source transmitting signal connector 209 is fixed at the center of the light source signal fixing end cap 210 at one end, and the light source receiving signal connector 218 is fixed at the center of the light source signal fixing end cap 210 at the other end.

[0068] In this embodiment, the top end of the flow tube 204 is connected to the material inlet 201 via a connecting reducer 202, and the bottom end of the flow tube 204 is connected to the material outlet 219 via a connecting reducer 202. A filter 203 is provided in the upper section of the flow tube 204. The filter 203 is installed between the connecting reducer 202 and the observation tube 216. Material from upstream enters the flow cavity 205 of the flow tube 204 from the material inlet 201 and exits from the material outlet 219 below the flow tube 204. Specifically, a filter 203 is installed on the flow cavity of the flow tube 204 of the flow pool 21. The filter 203 is installed higher than the observation tube and is used to filter and disperse pyrolysis products. In this embodiment, the heat insulation and heating jacket of the flow pool mainly wraps or covers the connecting reducer, the flow tube, and part of the observation tube of the flow pool. The temperature of the heat insulation and heating jacket of the flow pool is controlled at 700℃-850℃.

[0069] In this embodiment, the connections of the sealing lens 206, the optical path adjustment lens 212, the two sides of the fixed support sleeve 211, as well as the connecting variable diameter 202, the flow tube 204, the observation tube 216, the observation port connector 214, the optical path adjustment tube 207, and the light source signal fixing end cap 210 are sealed with sealing gaskets 215. The sealing gaskets 215 are graphite gaskets or asbestos gaskets.

[0070] In this embodiment, the inert gas pipeline 101 has an inert gas pipeline control valve 1011, an inert gas flow meter 1012, and an inert gas check valve 1013 arranged in sequence; the transport medium is nitrogen, carbon dioxide, argon, etc., either from the outside or contained in a steel cylinder, preferably nitrogen from a steel cylinder.

[0071] The steam pipeline 102 has a steam pipeline control valve 1021, a steam flow meter 1022 and a steam check valve 1023 arranged in sequence, and the medium it conveys is external high-temperature steam.

[0072] The water pipeline 103 is sequentially connected to a water storage tank 1031, a water pipeline control valve 1032, a metering pump 1033, and a water pipeline check valve 1034. The mass of the water storage tank 1031 is measured by a metering scale 1035. The medium it conveys is deionized water, and the feed mass of the deionized water can be measured by a metering scale below the water storage tank.

[0073] In this embodiment, a pyrolysis product pipeline control valve 1071 is provided on the pyrolysis product pipeline 107; a steam cleaning control valve 1041 is provided on the connecting pipeline between the first stage heater 104 and the second stage heater 105, and the steam cleaning control valve 1041 is located before the pyrolysis product pipeline 107 merges; a steam discharge control valve 1042 is provided on the connecting pipeline between the first stage heater 104 and the cooling separation system 3, and the steam discharge control valve 1042 is located at the front end where it merges with the analysis system 2 pipeline.

[0074] The cooling separation system 3 described in this embodiment includes two series coolers, a cooling collection tank 303, a gas flow meter 3061, and connecting pipelines, and is used for gas-liquid cooling separation of high-temperature pyrolysis products.

[0075] One stage cooler 301 and the second stage cooler 302 are connected in series. One end of the first stage cooler 301 is connected to the first stage heater 104 in the self-cleaning system 1, and the other end is connected to the flow cell 21 in the analysis system 2. The end of the second stage cooler 302 is connected to the cooling collection tank 303. After gas-liquid separation in the cooling collection tank 303, the liquid product is discharged through the drain line 304 connected to the bottom of the cooling collection tank 303. A drain line control valve 3041 is installed on the drain line 304. In this embodiment, the first stage cooler 301 and the second stage cooler 302 can reduce the material temperature to 20℃-40℃; the controlled temperature inside the cooling collection tank 303 is 0-5℃.

[0076] In this embodiment, the gaseous product is discharged from the corresponding pipeline at the top of the cooling collection tank 303. The pipeline is divided into two paths: one path is connected to the direct exhaust pipeline 305 to directly discharge the gas, and the other path is connected to the metering exhaust pipeline 306 to discharge the gas. The metering exhaust pipeline 306 is equipped with a gas flow meter 3061.

[0077] A direct exhaust line control valve 3051 is provided on the direct exhaust line 305, and a metering exhaust line control valve 3062 is provided on the metering exhaust line 306. The metering exhaust line control valve 3062 is located at the inlet front end of the gas flow meter 3061.

[0078] In the cooling separation system 3 described in this embodiment, both the cooler and the cooling collection tank are shell-type cooling structures, and their cooling medium is water or a mixture of water and ethylene glycol. The front end of the cooler is connected to a heater in the analysis system and the self-cleaning system, which can rapidly reduce the high temperature of the upstream material to 20℃-40℃. The front end of the cooling collection tank is connected to the cooler, and the rear end of the cooling collection tank is divided into two paths: one path is connected to a direct exhaust pipeline to directly discharge gas, and the other path is connected to a metering exhaust pipeline for gas discharge. The metering exhaust pipeline is equipped with a gas flow meter, and the controlled temperature inside the cooling collection tank is 0-5℃. The bottom of the cooling collection tank is equipped with a drain pipeline, and in this embodiment, the gas flow meter is preferably a wet flow meter.

[0079] Another embodiment of the present invention provides an online near-infrared spectroscopy analysis method for steam cracking products, using the online near-infrared spectroscopy analysis device for steam cracking products as described above, characterized in that: the analysis method includes the following steps:

[0080] S1, Equipment Start-up

[0081] The cooling tube 217 of the optical path regulating tube 207 on the flow cell 21 of the analysis system and the first-stage cooler 301, the second-stage cooler 302 and the cooling collection tank 303 in the cooling separation system are circulated for cooling, so that the temperature of the optical path regulating tube 207 near the light source signal fixing head 210 does not exceed 55°C, the internal control temperature of the first-stage cooler and the second-stage cooler is maintained at 20°C-40°C, and the control temperature in the cooling collection tank is maintained at 0-5°C.

[0082] Close the steam discharge control valve 1042, open the steam cleaning control valve 1041, and open the metering exhaust pipeline control valve 3062 or the direct exhaust pipeline control valve 3051; start the first stage heater 104 and the second stage heater 105 in the self-cleaning system and the flow cell insulation heating jacket 22 in the analysis system, and set the control temperature of the first stage heater 104 to 600℃-850℃, the control temperature of the second stage heater 105 to 700℃-850℃, and the control temperature of the flow cell insulation heating jacket to 700℃-850℃;

[0083] Meanwhile, monitor the temperature rise of the first-stage heater 104, the second-stage heater 105, and the heat insulation and heating jacket 22 of the flow pool. When any one of the first-stage heater 104, the second-stage heater 105, or the heat insulation and heating jacket 22 of the flow pool reaches 300℃±5℃, start the steam pipeline or water pipeline in the self-cleaning system. That is, open the steam pipeline control valve 1021 and adjust the steam feed rate of the steam flow meter 1022, or open the water pipeline control valve 1032 and start the metering pump 1033 to adjust the water feed rate.

[0084] S2, Background Test

[0085] After all parameters of the device reach the set values ​​and the device runs stably, adjust the water or steam feed rate of the device according to the water content of the upper pyrolysis product feed (the water content of the upper pyrolysis product feed can be calculated by pyrolysis product calibration or flow estimation method). Adjust the water or steam feed rate to be close to or equal to the water content in the pyrolysis product. After the device runs stably again, perform near-infrared spectroscopy to obtain background test results.

[0086] S3, Analysis and Testing

[0087] Close the steam cleaning control valve 1041, open the steam discharge control valve 1042, open the pyrolysis product pipeline control valve 1071, and perform pyrolysis product analysis and testing. The analysis and testing results can be subtracted from the background test results.

[0088] S4, System Cleaning

[0089] Close the steam discharge control valve 1042, open the steam cleaning control valve 1041, close the cracking product pipeline control valve 1071, adjust the steam or water pipeline feed rate in the self-cleaning system, and clean the pipeline and analysis system.

[0090] If the pyrolysis product analysis is performed again, repeat steps S2, S3, and S4.

[0091] S5, Device Shutdown

[0092] Shut down the heating of the first stage heater 104 and the second stage heater 105 in the self-cleaning system and the heat insulation and heating jacket 22 of the flow cell in the analysis system. At the same time, monitor the cooling of the first stage heater 104, the second stage heater 105 and the heat insulation and heating jacket 22 of the flow cell. When the temperature of any one of the first stage heater 104, the second stage heater 105 or the heat insulation and heating jacket 22 of the flow cell drops to 300℃±5℃, start the inert gas pipeline 101 in the self-cleaning system, that is, open the inert gas pipeline control valve 1011 and set the inert gas flow meter 1012 to adjust the inert gas feed rate.

[0093] Close the steam pipeline 102 and water pipeline 103, i.e., close the steam pipeline control valve 1021, zero the steam flow meter 1022, close the water pipeline control valve 1032, and close the metering pump 1033. When the temperature of the first-stage heater 104 and the second-stage heater 105 in the self-cleaning system and the heat insulation and heating jacket 22 of the flow pool in the analysis system drops to 80℃±5℃, close the inert gas pipeline 101, i.e., close the inert gas pipeline control valve 1011, zero the inert gas flow meter 1012, close the metering exhaust pipeline control valve 3062 and the direct exhaust pipeline control valve 3051, and close the cooling pipe 217 of the optical path regulating pipe 207 in the analysis system and the first-stage cooler 301, the second-stage cooler 302 and the cooling collection tank 303 in the cooling separation system. During the operation of the device, the drain pipeline control valve on the drain pipeline at the bottom of the cooling collection tank 303 can be switched on and off as needed to drain the cooling collection tank in the cooling separation system.

[0094] The pyrolysis products were analyzed using the online near-infrared spectroscopy analysis device for steam pyrolysis products described in the above embodiments of the present invention, and the results were obtained. Figure 3 The analytical spectra of the pyrolysis products after background subtraction were obtained from the test. Figure 3 As can be seen, the peaks in the analytical spectrum are distinct and easy to identify.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An online near-infrared spectroscopy analysis device for steam cracking products, characterized in that: The near-infrared spectroscopy analysis device includes: The self-cleaning system includes an inert gas pipeline, a steam pipeline, a water pipeline, a first-stage heater, and a second-stage heater. The analysis system and the cooling separation system are described above. The inert gas pipeline, steam pipeline and water pipeline are connected in parallel and converge into a self-cleaning medium main pipe before entering a first-stage heater. After passing through the first-stage heater, the pipeline splits into two paths. One path merges with a pyrolysis product pipeline and enters a second-stage heater. After being heated in two stages, the pipeline enters the analysis system. The other path is connected to the cooling separation system. The analysis system includes a flow cell and a flow cell insulation and heating jacket. The flow cell insulation and heating jacket covers part of the flow cell structure. The upper end of the flow cell is connected to the two-stage heater of the self-cleaning system, and the lower end of the flow cell is connected to the cooling and separation system. The flow cell is composed of a vertically intersecting flow tube and a horizontally intersecting observation tube. The observation tube is sealed by an internal sealing lens. The outer side of the sealing lens is fixed by an observation port connector connected to the outer side of the observation tube. The other end of the observation port connector is connected to a light path adjustment tube with a cooling function. The end of the light path adjustment tube is sealed by a light source signal fixing cap. The upper end of the flow tube is connected to the self-cleaning system via a connecting variable diameter, and the lower end is connected to the cooling separation system via a connecting variable diameter. The cooling separation system includes two series-connected coolers, a cooling collection tank, a gas flow meter, and connecting pipelines; One stage cooler is connected in series with the second stage cooler. One end of the first stage cooler is connected to the first stage heater in the self-cleaning system, and the other end is connected to the flow cell in the analysis system. The end of the second stage cooler is connected to the cooling collection tank. After gas-liquid separation in the cooling collection tank, the liquid product is discharged from the drain line connected to the bottom of the cooling collection tank. A drain line control valve is installed on the drain line. The gaseous product is discharged from the corresponding pipeline at the top of the cooling collection tank. This pipeline is divided into two lines: one line is connected to the direct exhaust pipeline to discharge the gas directly, and the other line is connected to the metering exhaust pipeline for gas discharge. The metering exhaust pipeline is equipped with a gas flow meter. A direct exhaust line control valve is provided on the direct exhaust line, and a metering exhaust line control valve is provided on the metering exhaust line. The metering exhaust line control valve is located at the inlet front end of the gas flow meter.

2. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The optical path adjustment tube body has an optical path adjustment lens inside, and the optical path adjustment lens is fixed by the optical path adjustment tube body and its internal fixed support sleeve; The outer wall of the optical path adjustment tube has a shell structure of cooling tube, and the cooling medium enters or exits through the cooling medium flow interface on both sides of the cooling tube, and completes the heat extraction of the inside of the optical path adjustment tube in the cooling cavity.

3. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The internal structure of the observation tube, the observation port connector, the optical path adjustment tube, and the light source signal fixing end cap are symmetrically distributed along the flow tube. One end of the light source signal fixing cap has a light source transmitting signal connector fixed at the center, and the other end of the light source signal fixing cap has a light source receiving signal connector fixed at the center.

4. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The top end of the flow tube is connected to the material inlet via a connecting reducer, and the bottom end of the flow tube is connected to the material outlet via a connecting reducer. A filter is provided in the upper section of the flow tube, and the filter is installed between the connecting reducer and the observation tube.

5. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The inert gas pipeline has an inert gas pipeline control valve, an inert gas flow meter, and an inert gas check valve arranged in sequence. The steam pipeline has a steam pipeline control valve, a steam flow meter, and a steam check valve arranged in sequence. The water pipeline is connected in sequence to a water storage tank, a water pipeline control valve, a metering pump, and a water pipeline check valve. The mass of the water storage tank is measured by a metering scale.

6. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: A pyrolysis product pipeline control valve is provided on the pyrolysis product pipeline; a steam cleaning control valve is provided on the connecting pipeline between the first-stage heater and the second-stage heater, and the steam cleaning control valve is located before the pyrolysis product pipelines merge; a steam discharge control valve is provided on the connecting pipeline between the first-stage heater and the cooling separation system, and the steam discharge control valve is located at the front end where it merges with the analysis system pipeline.

7. A method for online near-infrared spectroscopy analysis of steam cracking products, using the online near-infrared spectroscopy analysis device for steam cracking products as described in any one of claims 1-6, characterized in that: The analytical method includes the following steps: S1, Equipment Start-up The cooling tube of the optical path regulating tube on the flow cell of the start-up analysis system and the first-stage cooler, second-stage cooler and cooling collection tank of the cooling separation system are circulated for cooling. Close the steam discharge control valve, open the steam cleaning control valve, and open the metering exhaust pipeline control valve or the direct exhaust pipeline control valve; start the first-stage heater, the second-stage heater in the self-cleaning system, and the flow cell insulation heating jacket in the analysis system; Meanwhile, monitor the temperature rise of the first-stage heater, the second-stage heater, and the insulation and heating jacket of the flow pool. When any of the first-stage heater, the second-stage heater, or the insulation and heating jacket of the flow pool reaches 300℃±5℃, start the steam pipeline or water pipeline in the self-cleaning system. That is, open the steam pipeline control valve and adjust the steam feed rate of the steam flow meter, or open the water pipeline control valve and start the metering pump to adjust the water feed rate. S2, Background Test After all parameters of the device reach the set values ​​and the device runs stably, the water or steam feed rate of the device is adjusted according to the water content of the feed of the pyrolysis products at the upper end. The water or steam feed rate is adjusted to be close to or equal to the water content in the pyrolysis products. After the device runs stably again, near-infrared spectroscopy is collected to obtain the background test results. S3, Analysis and Testing Close the steam cleaning control valve, open the steam discharge control valve, open the pyrolysis product pipeline control valve, and perform pyrolysis product analysis and testing. The analysis and testing results can be subtracted from the background test results. S4, System Cleaning Close the steam discharge control valve, open the steam cleaning control valve, close the pyrolysis product pipeline control valve, adjust the steam or water feed rate in the self-cleaning system, and clean the pipelines and analysis system; If the pyrolysis product analysis is performed again, steps S2, S3, and S4 should be repeated. S5, Device Shutdown Shut down the first-stage heater, the second-stage heater in the self-cleaning system, and the heating jacket of the flow cell in the analysis system. At the same time, monitor the cooling of the first-stage heater, the second-stage heater, and the heating jacket of the flow cell. When the temperature of any one of the first-stage heater, the second-stage heater, or the heating jacket of the flow cell drops to 300℃±5℃, start the inert gas pipeline in the self-cleaning system, that is, open the inert gas pipeline control valve and set the inert gas flow meter to adjust the inert gas feed rate. Close the steam and water pipelines, i.e., close the steam pipeline control valve, zero the steam flow meter, close the water pipeline control valve, and shut down the metering pump. When the temperature of the first-stage heater, the second-stage heater in the self-cleaning system, and the insulation heating jacket of the flow cell in the analysis system drops to 80℃±5℃, close the inert gas pipeline, i.e., close the inert gas pipeline control valve, zero the inert gas flow meter, close the metering exhaust pipeline control valve and the direct exhaust pipeline control valve, and shut down the cooling pipe of the optical path regulating pipe in the analysis system and the first-stage cooler, the second-stage cooler, and the cooling collection tank in the cooling separation system.

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