On-line near infrared spectrum analysis device and analysis method for steam cracking products

Abstract

The invention provides an on-line near infrared spectrum analysis device for steam cracking products. The on-line near infrared spectrum analysis device comprises a self-cleaning system, wherein the self-cleaning system comprises an inert gas pipeline, a steam pipeline, a water pipeline, a first-section heater and a second-section heater; the analysis system, the cooling separation system, the inert gas pipeline, the steam pipeline and the water pipeline are connected in parallel and are gathered into a self-cleaning medium header pipe, the self-cleaning medium header pipe enters a first-section heater and is divided into two paths after passing through the first-section heater, one path is converged with a cracking product pipeline, enters a second-section heater, is subjected to second-section heating and then enters the analysis system, and the other path enters the second-section heater after passing through the second-section heater; the other path is connected with the cooling separation system; the analysis system comprises a flow cell and a flow cell heat preservation heating jacket, the flow cell heat preservation heating jacket wraps part of the structure of the flow cell, the upper end of the flow cell is connected with the two-section heater, and the lower end of the flow cell is connected with the cooling separation system. The analysis device can be used for analyzing high-temperature steam cracking products containing trace coke, and is simple in structure, easy to operate, convenient to disassemble and maintain and high in analysis precision.

Description

Technical Field

[0001] The invention relates to the technical field of steam cracking in petrochemical industry, and in particular to an online near-infrared spectrum analysis device and analysis method for steam cracking products. Background Art

[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 uses hydrocarbon raw materials such as ethane, C3 and C4, light hydrocarbons, naphtha, and hydrogenation tail oil and dilution steam to undergo high temperature, short residence, and low hydrocarbon partial pressure conditions in the coil of the radiation section of the cracking furnace for cracking reactions to obtain ethylene, propylene, and butadiene products, and co-produce basic chemical raw materials such as benzene, toluene, xylene, C5, C9, etc., which plays a vital role in petrochemicals.

[0003] The process of steam cracking to produce low-carbon olefins is significantly affected by raw materials. Due to the continuous expansion of the capacity of steam cracking units and the shortage of high-quality ethylene cracking raw materials, the raw materials for ethylene cracking are gradually moving towards heavy and diversified directions. In addition, the complexity of the cracking raw material composition in the storage tanks of steam cracking enterprises and the frequent changes in their sources, as well as the lack of timely and effective process solutions, have seriously affected the low-carbon olefin yield, operating status and economic benefits of the cracking unit.

[0004] In order to optimize the process parameters of the steam cracking furnace, timely and effective cracking product analysis results are needed as support. At present, the research on the cracking process of organic hydrocarbons is mainly carried out through offline or online analysis methods. The composition analysis of the relevant cracking products is carried out only after the cracking process reaction is completed. The conventional cracking product analysis method uses gas chromatography, but due to the limitations of the chromatographic column properties, instrument hardware conditions, applicable environment, etc., gas chromatography cannot handle water-containing and high-temperature samples, and the sample processing and analysis time is relatively long, which cannot meet the rapid measurement requirements of high-temperature water-containing products of steam cracking; the existing steam cracking product calibration method is time-consuming and the calibration steps are complicated. Summary of the invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention provides an online near-infrared spectral analysis device and analysis method for steam cracking products. The near-infrared spectral analysis device can be used for analyzing steam cracking products obtained at high temperature and containing trace amounts of coke, and has the characteristics of simple structure, easy operation, convenient disassembly and maintenance, and high analysis accuracy.

[0006] In order to achieve the above object, the present invention provides an online near-infrared spectral analysis device for steam cracking products, the near-infrared spectral analysis device comprising:

[0007] A self-cleaning system, the self-cleaning system comprising 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, the inert gas pipeline, the steam pipeline and the water pipeline are connected in parallel and aggregated into a self-cleaning medium main pipe and then enter a first stage heater, and then are divided into two paths after passing through the first stage heater, one of which is merged with a cracking product pipeline and then enters the second stage heater, and then enters the analysis system after two stages of heating, and the other is connected to the cooling separation system;

[0009] Among them, the analysis system includes a circulation pool and a circulation pool insulation and heating jacket, the circulation pool insulation and heating jacket wraps part of the circulation pool structure, the upper end of the circulation pool is connected to the second stage heater of the self-cleaning system, and the lower end of the circulation pool is connected to the cooling and separation system.

[0010] In some embodiments, the circulation pool is composed of a vertical circulation tube body and a horizontal observation tube body that are perpendicularly crossed, the observation tube body is sealed by a sealing lens inside it, the outside of the sealing lens is fixed by an observation port joint connected to the outside of the observation tube body, the other end of the observation port joint is connected to an optical path adjustment tube body with a cooling function, and the end of the optical path adjustment tube body is sealed by a light source signal fixing head;

[0011] The upper end of the circulation pipe body is connected to the self-cleaning system through a connecting reducer, and the lower end is connected to the cooling separation system through a connecting reducer.

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

[0013] The outer wall of the optical path regulating tube body has a cooling tube body with a shell structure, and the cooling medium enters or is discharged through the cooling medium circulation interfaces on both sides of the cooling tube body, so as to remove heat from the inside of the optical path regulating tube body in the cooling cavity.

[0014] In some embodiments, the observation tube body, the observation port joint, the internal structure of the optical path adjustment tube body, and the light source signal fixing head are symmetrically distributed along the circulation tube body;

[0015] Among them, a light source sending signal connector is fixed at the center of the light source signal fixing head at one end, and a light source receiving signal connector is fixed at the center of the light source signal fixing head at the other end.

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

[0017] In some of the embodiments, the inert gas pipeline has an inert gas pipeline control valve, an inert gas flow meter and an inert gas one-way valve arranged in sequence;

[0018] The steam pipeline is provided with 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 one-way valve, and the mass of the water storage tank is measured by a metering scale.

[0020] In some of the embodiments, a cracking product pipeline control valve is provided on the cracking 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 cracking product pipeline merges; a steam emission control valve is provided on the connecting pipeline between the first stage heater and the cooling separation system, and the steam emission control valve is located at the front end of the merge with the analysis system pipeline.

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

[0022] One of the first-stage coolers is connected in series with the second-stage cooler. The front end of the first-stage cooler is connected to a first-stage heater in the self-cleaning system on one path, and is connected to a circulation pool in the analysis system on the other path. The end of the second-stage cooler is connected to a cooling collection tank. After gas-liquid separation in the cooling collection tank, the liquid product is discharged from a drain pipeline connected to the bottom of the cooling collection tank. A drain pipeline control valve is provided on the drain pipeline.

[0023] In some embodiments, the gas phase product is discharged from the corresponding pipeline at the top of the cooling collection tank, and the pipeline is divided into two paths, one of which is connected to the direct exhaust pipeline to directly discharge the gas, and the other is connected to the metering exhaust pipeline for gas discharge, and the metering exhaust pipeline is provided with a gas flow meter;

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

[0025] The present invention also provides an online near-infrared spectral analysis method for steam cracking products, using the above-mentioned online near-infrared spectral analysis device for steam cracking products, and the analysis method comprises the following steps:

[0026] S1. Start the device

[0027] Start the circulating refrigeration of the cooling tube of the optical path regulating tube on the circulation pool in the analysis system and the first stage cooler, the second stage cooler and the cooling collection tank in the cooling separation system;

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

[0029] At the same time, pay attention to the temperature rise of the first stage heater, the second stage heater and the heat preservation and heating jacket of the circulation pool. When the temperature of any of the first stage heater, the second stage heater or the heat preservation and heating jacket of the circulation 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 amount of the steam flowmeter, or open the water pipeline control valve and start the metering pump to adjust the water feed amount;

[0030] S2. Background test

[0031] After all parameters of the device reach the set values ​​and run smoothly, adjust the water or steam feed amount of the device according to the water content of the upper end cracking product feed, adjust the water or steam feed amount to be close to or equal to the water content in the cracking product, and after the device runs smoothly again, perform near-infrared spectrum acquisition to obtain background test results;

[0032] S3. Analysis and testing

[0033] Close the steam cleaning control valve, open the steam discharge control valve, open the cracking product pipeline control valve, and conduct cracking product analysis test. The analysis test results can be deducted 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 pipeline or water pipeline feed rate in the self-cleaning system, and clean the pipeline and analysis system;

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

[0037] S5. Device shutdown

[0038] Turn off the heating of the first stage heater, the second stage heater in the self-cleaning system and the heat preservation heating jacket of the circulation pool in the analysis system. At the same time, pay attention to the cooling of the first stage heater, the second stage heater and the heat preservation heating jacket of the circulation pool. When the temperature of any of the first stage heater, the second stage heater or the heat preservation heating jacket of the circulation pool 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 flowmeter to adjust the inert gas feed amount;

[0039] Close the steam pipeline and water pipeline, that is, close the steam pipeline control valve, adjust the steam flowmeter to zero, close the water pipeline control valve, turn off the metering pump, and when the temperature of the first stage heater, second stage heater in the self-cleaning system and the circulation pool insulation heating jacket in the analysis system drops to 80℃±5℃, close the inert gas pipeline, that is, close the inert gas pipeline control valve, adjust the inert gas flowmeter to zero, close the metering exhaust pipeline control valve and the direct exhaust pipeline control valve, and turn off the cooling pipe body of the optical path adjustment tube body in the analysis system and the first stage cooler, second stage cooler and cooling collection tank refrigeration in the cooling separation system.

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

[0041] The steam cracking product online near-infrared spectroscopy analysis device provided by the present invention has a self-cleaning system, which can realize the cleaning of pipelines and lenses and extend the maintenance cycle of the device. The self-cleaning system of the device of the present invention has a variety of medium interfaces, which are flexible to select and highly practical.

[0042] The online near-infrared spectral analysis device for steam cracking products provided by the present invention adopts a circulation pool with a cooling function, which can be used for high-temperature cracking product analysis. At the same time, the circulation pool of the present invention is composed of a vertical circulation tube body and a horizontal observation tube body that are vertically crossed. The fluid dead angle of this structural design is small, and the circulation tube body has a filter sheet, which can reduce the pollution of carbon powder in the cracking product to the lens and the pipeline, thereby improving the accuracy of the spectral analysis.

[0043] The online near-infrared spectral analysis device for steam cracking products provided by the present 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 the spectral analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

[0047] Figure 3 This is a spectrum of experimental analysis of cracking products using the online near-infrared spectroscopy analysis device for steam cracking products 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-cracking product pipeline; 1011-inert gas pipeline control valve, 1012-inert gas flowmeter; 1013-inert gas one-way valve; 1021-steam pipeline control valve; 1022-steam flowmeter; 1023-steam one-way valve; 1031-water storage tank; 1032-water pipeline control valve; 1033-metering pump; 1034-water pipeline one-way valve; 1035-metering scale; 1041-steam cleaning control valve; 1042-steam discharge control valve; 1071-cracking product pipeline control valve;

[0050] 2-analysis system; 21-circulation cell; 22-circulation cell insulation and heating jacket;

[0051] 201-Material inlet; 202-Connection reducer; 203-Filter; 204-Circulation tube; 205-Circulation cavity; 206-Sealing lens; 207-Optical path adjustment tube; 208-Cooling cavity; 209-Light source signal sending connector; 210-Light source signal fixed head; 211-Fixed support sleeve; 212-Optical path adjustment lens; 213-Cooling medium circulation 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 pipeline; 3041-Drainage pipeline control valve; 305-Direct exhaust pipeline; 3051-Direct exhaust pipeline control valve; 306-Metered exhaust pipeline; 3061-Gas flow meter; 3062-Metered exhaust pipeline control valve. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is described in detail below in conjunction with 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 claims attached to the present invention.

[0054] Certain words are used in the specification and subsequent claims to refer to specific components or parts. It should be understood by those of ordinary skill in the art that technical users or manufacturers may refer to the same component or part by different nouns or terms. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but use differences in the functions of components or parts as the criteria for distinction. "Including" and "comprising" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connect" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0055] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and "about", or "approximately", "substantially", "left and right" and the like indicating directions or positional relationships or parameters are all based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description content, and do not indicate or imply that the referred device or element must have a specific direction, specific size, or be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0056] Since near-infrared spectroscopy is consistent with the absorption region of the combined frequency and each harmonic frequency of the vibration of hydrogen-containing groups (OH, NH, CH) in organic molecules, the characteristic information of hydrogen-containing groups in organic molecules in the sample can be obtained through near-infrared spectroscopy characterization scanning. It has the advantages of convenience, rapidity, high efficiency, accuracy, low cost, and no damage to samples. In addition, near-infrared spectroscopy can be used for in-situ characterization in harsh reaction environments such as high pressure. Therefore, this technology is favored by more and more people.

[0057] In view of the technical problems such as the time-consuming and complicated calibration steps of the existing steam cracking product calibration method, the present invention provides an online near-infrared spectral analysis device for steam cracking products, which includes a self-cleaning system, an analysis system and a cooling and separation system. After the high-temperature cracking product pipeline merges with the corresponding pipeline of the self-cleaning system and enters the analysis system after being heated again, the cracking product is spectrally analyzed by the analysis system and then cooled and separated by the cooling and separation system before being discharged from the device, wherein the self-cleaning system has a pipeline directly connected to the cooling and separation system, which is convenient for material switching, can perform water-containing background measurement, eliminate or reduce the interference of water in the cracking product on the analysis result, and improve the analysis accuracy. The vertical cross-structured flow cell with cooling and filtering functions in the analysis system can be used for the analysis of high-temperature steam cracking products containing trace coke, and has the characteristics of simple structure, easy disassembly and maintenance, fast analysis speed, high analysis accuracy, etc.

[0058] Specifically, participation in Figure 1-2 As shown, an embodiment of the present invention provides an online near-infrared spectral analysis device for steam cracking products, and the near-infrared spectral analysis device comprises:

[0059] A self-cleaning system 1, wherein the self-cleaning system 1 comprises 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, the inert gas pipeline 101, the steam pipeline 102 and the water pipeline 103 are connected in parallel and aggregated into a self-cleaning medium main pipe 106 and then enter a first stage heater 104, and are divided into two paths after passing through the first stage heater 104, one of which merges with a cracking product pipeline 107 and then enters a second stage heater 105, and then enters the analysis system 2 after two-stage heating, and the other is connected to the cooling separation system 3;

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

[0062] In this embodiment, the control temperature of the first stage heater 104 is 600°C-850°C, the control temperature of the second stage heater 105 is 700°C-850°C, and the control temperature of the circulation pool insulation heating jacket 22 is 700°C-850°C.

[0063] In this embodiment, the circulation pool 21 is composed of a vertical circulation tube body 204 and a horizontal observation tube body 216 that cross each other vertically. The observation tube body 216 is blocked by a high temperature resistant sealing lens 206 inside it. The outside of the sealing lens 206 is fixed by an observation port joint 214 connected to the outside of the observation tube body 216. The other end of the observation port joint 214 is connected to an optical path adjustment tube body 207 with a cooling function. The end of the optical path adjustment tube body 207 is sealed by a light source signal fixing head 210. The upper end of the circulation tube body 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 body 216 is clamped and fixed by the internal support groove of the observation tube body 216 and the observation port joint 214. The sealing lens 206 is a sapphire glass or quartz glass with high light transmittance and high temperature resistance. Furthermore, in this embodiment, the spacing between the inner surfaces of the sealing lens 206 (the mirror surface contacting the cracking product in the flow tube body) is not greater than 3 times the diameter of the flow tube body 204 to reduce the dead angle of the cracking product flow.

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

[0065] The outer wall of the optical path adjustment tube body 207 has a cooling tube body 217 with a shell structure, and a cooling cavity 208 is formed inside the cooling tube body 217; its cooling medium enters or is discharged through the cooling medium circulation interface 213 on both sides of the cooling tube body 217, thereby reducing the internal temperature of the optical path adjustment tube body 207 (heat is extracted from the inside of the optical path adjustment tube body 207 in the cooling cavity 208).

[0066] Specifically, the inner diameter of the observation port joint 214 in this embodiment is similar to the inner diameter of the optical path adjustment tube body 207, which can ensure that the light path passes in parallel; further, the optical path adjustment tube body 207 is provided with an optical path adjustment lens 212, and the optical path adjustment lens 212 is fixed by a support groove in the optical path adjustment tube body 207 and a stainless steel fixed support sleeve 211, and the optical path adjustment lens 212 is a sapphire glass or quartz glass with high light transmittance and high temperature resistance; further, the outer side of the optical path adjustment tube body 207 is provided with a cooling tube body 217 with a shell structure, so as to realize cooling of the optical path adjustment tube body 207 and protect the light source signal connector, and the cooling medium in the cooling tube body is water or a mixture of water and ethylene glycol, and the temperature of the optical path adjustment tube body near the fixed head end of the light source signal is controlled not to exceed 55°C.

[0067] The observation tube body 216, the observation port connector 214, the internal structure of the optical path adjustment tube body 207, and the light source signal fixed head 210 described in this embodiment are axially symmetrically distributed along the flow tube body 204; wherein, a light source sending signal connector 209 is fixed at the center of the light source signal fixed head 210 at one end, and a light source receiving signal connector 218 is fixed at the center of the light source signal fixed head 210 at the other end.

[0068] In the present embodiment, the top end of the circulation tube body 204 is connected to the material inlet 201 through the connecting reducer 202, and the bottom end of the circulation tube body 204 is connected to the material outlet 219 through the connecting reducer 202. A filter plate 203 is provided on the upper section of the circulation tube body 204, and the installation position of the filter plate 203 is between the connecting reducer 202 and the observation tube body 216. The material from the upstream enters the circulation cavity 205 of the circulation tube body 204 from the material inlet 201 and is discharged from the material outlet 219 below the circulation tube body 204. Specifically, a filter plate 203 is installed on the circulation cavity in the circulation tube body 204 of the circulation pool 21, and the installation position of the filter plate 203 is higher than the observation tube body, which is used to filter and disperse the cracking products. The circulation pool insulation and heating jacket described in the present embodiment mainly wraps or covers the connecting reducer, the circulation tube body and part of the observation tube body of the circulation pool, and the circulation pool insulation and heating jacket controls the temperature of 700℃-850℃.

[0069] In this embodiment, the sealing lens 206, the optical path adjustment lens 212, the two sides of the fixed support sleeve 211, and the connection parts of the reducer 202, the flow tube body 204, the observation tube body 216, the observation port joint 214, the optical path adjustment tube body 207, the light source signal fixed head 210 and other components are sealed with sealing gaskets 215, and the sealing gaskets 215 are graphite gaskets or asbestos gaskets.

[0070] The inert gas pipeline 101 described in this embodiment has an inert gas pipeline control valve 1011, an inert gas flow meter 1012 and an inert gas one-way valve 1013 arranged in sequence; its conveying medium is nitrogen, carbon dioxide, argon, etc. from the outside or in a cylinder, preferably nitrogen in a 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 its conveying medium is external high-temperature steam;

[0072] The water pipeline 103 is connected in sequence 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 conveying medium is deionized water. The feed mass of the deionized water can be measured by a metering scale under the water storage tank.

[0073] In this embodiment, a cracking product pipeline control valve 1071 is provided on the cracking 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 merging of the cracking product pipeline 107; a steam discharge control valve 1042 is provided on the connecting pipeline between the first stage heater 104 and the cooling and separation system 3, and the steam discharge control valve 1042 is located at the front end of the merging with the analysis system 2 pipeline.

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

[0075] The first stage cooler 301 and the second stage cooler 302 are connected in series. The front end of the first stage cooler 301 is connected to the first stage heater 104 in the self-cleaning system 1 through one path, and is connected to the circulation pool 21 in the analysis system 2 through the other path. 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 phase product is discharged from the drainage pipeline 304 connected to the bottom of the cooling collection tank 303. The drainage pipeline control valve 3041 is provided on the drainage pipeline 304. In this embodiment, the first stage cooler 301 and the second stage cooler 302 can reduce the material temperature to 20℃-40℃; the control temperature in the cooling collection tank 303 is 0-5℃.

[0076] In this embodiment, the gas phase product is discharged from the corresponding pipeline on the top of the cooling collection tank 303. The pipeline is divided into two routes, one of which is connected to the direct exhaust pipeline 305 to directly discharge the gas, and the other is connected to the metering exhaust pipeline 306 to discharge the gas. The metering exhaust pipeline 306 is provided with a gas flow meter 3061.

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

[0078] In the cooling separation system 3 described in this embodiment, the cooler and the cooling collection tank are both shell cooling structures, and the cooling medium is water or a mixture of water and ethylene glycol; the front end of the cooler is connected to the analysis system and a section of the heater in the self-cleaning system, which can quickly reduce the upstream high-temperature material to 20°C-40°C; 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 of which is connected to the direct exhaust pipeline to directly discharge the gas, and the other is connected to the metering exhaust pipeline for gas discharge. The metering exhaust pipeline is provided with a gas flowmeter, and the control temperature in the cooling collection tank is 0-5°C; the bottom of the cooling collection tank is provided with a drainage pipeline, and the gas flowmeter described in this embodiment is preferably a wet flowmeter.

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

[0080] S1. Start the device

[0081] Start the cooling tube 217 of the optical path adjustment tube 207 on the circulation pool 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 to circulate refrigeration, keep the temperature of the optical path adjustment tube 207 close to the light source signal fixed head 210 not exceeding 55°C, keep the internal control temperature of the first stage cooler and the second stage cooler at 20°C-40°C, and keep the control temperature in the cooling collection tank at 0-5°C;

[0082] Close the steam emission control valve 1042, open the steam cleaning control valve 1041, 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 circulation pool insulation heating jacket 22 in the analysis system, set the control temperature of the first stage heater 104 to 600°C-850°C, the control temperature of the second stage heater 105 to 700°C-850°C, and the control temperature of the circulation pool insulation heating jacket to 700°C-850°C;

[0083] At the same time, pay attention to the temperature rise of the first stage heater 104, the second stage heater 105 and the heat preservation and heating jacket 22 of the circulation pool. When the temperature of any one of the first stage heater 104, the second stage heater 105 or the heat preservation and heating jacket 22 of the circulation pool reaches 300°C ± 5°C, start the steam pipeline or water pipeline in the self-cleaning system, that is, open the steam pipeline control valve 1021, adjust the steam feed amount of the steam flow meter 1022, or open the water pipeline control valve 1032, start the metering pump 1033 to adjust the water feed amount;

[0084] S2. Background test

[0085] After all parameters of the device reach the set values ​​and run smoothly, adjust the water or steam feed amount of the device according to the water content of the upper end cracking product feed (the water content of the upper end cracking product feed can be calculated by cracking product calibration or flow estimation method), adjust the water or steam feed amount to be close to or equal to the water content in the cracking product, and after the device runs smoothly again, perform near-infrared spectrum acquisition 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 cracking product pipeline control valve 1071, and perform cracking product analysis test, and the analysis test result can be deducted from the background test result;

[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 pipeline or water pipeline feed rate in the self-cleaning system, and clean the pipeline and analysis system;

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

[0091] S5. Device shutdown

[0092] Turn off the heating of the first stage heater 104, the second stage heater 105 in the self-cleaning system and the heat preservation and heating jacket 22 of the circulation pool in the analysis system. At the same time, pay attention to the cooling of the first stage heater 104, the second stage heater 105 and the heat preservation and heating jacket 22 of the circulation pool. When the temperature of any one of the first stage heater 104, the second stage heater 105 or the heat preservation and heating jacket 22 of the circulation pool drops to 300°C ± 5°C, 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 flowmeter 1012 to adjust the inert gas feed amount;

[0093] The steam pipeline 102 and the water pipeline 103 are closed, that is, the steam pipeline control valve 1021 is closed, the steam flow meter 1022 is zeroed, the water pipeline control valve 1032 is closed, and the metering pump 1033 is closed. When the temperature of the first stage heater 104, the second stage heater 105 in the self-cleaning system and the heat preservation heating jacket 22 of the circulation pool in the analysis system drops to 80°C±5°C, the inert gas pipeline 101 is closed, that is, the inert gas pipeline control valve 1011 is closed, the inert gas flow meter 1012 is zeroed, the metering exhaust pipeline control valve 3062 and the direct exhaust pipeline control valve 3051 are closed, and the cooling pipe body 217 of the optical path adjustment pipe body 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 are closed for refrigeration; wherein, 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 opened and closed as needed to drain the cooling collection tank in the cooling separation system.

[0094] The online near-infrared spectroscopy analysis device for steam cracking products described in the above embodiment of the present invention was used to analyze the cracking products. Figure 3 The analytical spectrum of the pyrolysis product after background subtraction test, from Figure 3 It can be seen that the peaks in the analytical spectrum are distinct and easy to identify.

[0095] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution 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 comprises: A self-cleaning system, the self-cleaning system comprising 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, the inert gas pipeline, the steam pipeline and the water pipeline are connected in parallel and aggregated into a self-cleaning medium main pipe and then enter a first stage heater, and then are divided into two paths after passing through the first stage heater, one of which is merged with a cracking product pipeline and then enters the second stage heater, and then enters the analysis system after two stages of heating, and the other is connected to the cooling separation system; Among them, the analysis system includes a circulation pool and a circulation pool insulation and heating jacket, the circulation pool insulation and heating jacket wraps part of the circulation pool structure, the upper end of the circulation pool is connected to the second stage heater of the self-cleaning system, and the lower end of the circulation pool is connected to the cooling and separation system.

2. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The circulation pool is composed of a vertical circulation tube body and a horizontal observation tube body that are perpendicularly crossed, the observation tube body is blocked by a sealing lens inside it, the outside of the sealing lens is fixed by an observation port joint connected to the outside of the observation tube body, the other end of the observation port joint is connected to an optical path adjustment tube body with a cooling function, and the end of the optical path adjustment tube body is sealed by a light source signal fixing head; The upper end of the circulation pipe body is connected to the self-cleaning system through a connecting reducer, and the lower end is connected to the cooling separation system through a connecting reducer.

3. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 2, characterized in that: The optical path adjusting tube body has an optical path adjusting lens inside, and the optical path adjusting lens is fixed by the optical path adjusting tube body and the fixed support sleeve inside the optical path adjusting tube body; The outer wall of the optical path regulating tube body has a cooling tube body with a shell structure, and the cooling medium enters or is discharged through the cooling medium circulation interfaces on both sides of the cooling tube body, so as to remove heat from the inside of the optical path regulating tube body in the cooling cavity.

4. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 2, characterized in that: The observation tube body, the observation port joint, the internal structure of the optical path adjustment tube body, and the light source signal fixing head are symmetrically distributed along the flow tube body; Among them, a light source sending signal connector is fixed at the center of the light source signal fixing head at one end, and a light source receiving signal connector is fixed at the center of the light source signal fixing head at the other end.

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

6. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The inert gas pipeline is provided with an inert gas pipeline control valve, an inert gas flow meter and an inert gas one-way valve which are arranged in sequence; The steam pipeline is provided with 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 one-way valve, and the mass of the water storage tank is measured by a metering scale.

7. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: A cracking product pipeline control valve is provided on the cracking 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 cracking product pipeline merges; 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 of the merge with the analysis system pipeline.

8. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The cooling and separation system comprises two sections of series coolers, a cooling collection tank, a gas flow meter and connecting pipelines; One of the first-stage coolers is connected in series with the second-stage cooler. The front end of the first-stage cooler is connected to a first-stage heater in the self-cleaning system on one path, and is connected to a circulation pool in the analysis system on the other path. The end of the second-stage cooler is connected to a cooling collection tank. After gas-liquid separation in the cooling collection tank, the liquid product is discharged from a drain pipeline connected to the bottom of the cooling collection tank. A drain pipeline control valve is provided on the drain pipeline.

9. The online near-infrared spectroscopy analysis device for steam cracking products according to claim 1, characterized in that: The gas phase product is discharged from the corresponding pipeline on the top of the cooling collection tank. The pipeline is divided into two routes, one of which is connected to the direct exhaust pipeline to directly discharge the gas, and the other is connected to the metering exhaust pipeline for gas discharge. The metering exhaust pipeline is equipped with a gas flow meter. A direct exhaust pipeline control valve is provided on the direct exhaust pipeline, and a metered exhaust pipeline control valve is provided on the metered exhaust pipeline. The metered exhaust pipeline control valve is located at the air inlet front end of the gas flow meter.

10. An online near-infrared spectral analysis method for steam cracking products, using the online near-infrared spectral analysis device for steam cracking products according to any one of claims 1 to 9, characterized in that: The analytical method comprises the following steps: S1. Start the device Start the circulating refrigeration of the cooling tube of the optical path regulating tube on the circulation pool in the analysis system and the first stage cooler, the second stage cooler and the cooling collection tank in the cooling separation system; Close the steam emission control valve, open the steam cleaning control valve, open the metering exhaust pipeline control valve or the direct exhaust pipeline control valve; start the first stage heater and second stage heater in the self-cleaning system and the flow cell insulation heating jacket in the analysis system; At the same time, pay attention to the temperature rise of the first stage heater, the second stage heater and the heat preservation and heating jacket of the circulation pool. When the temperature of any of the first stage heater, the second stage heater or the heat preservation and heating jacket of the circulation 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 amount of the steam flowmeter, or open the water pipeline control valve and start the metering pump to adjust the water feed amount; S2. Background test After all parameters of the device reach the set values ​​and run smoothly, adjust the water or steam feed amount of the device according to the water content of the upper end cracking product feed, adjust the water or steam feed amount to be close to or equal to the water content in the cracking product, and after the device runs smoothly again, perform near-infrared spectrum acquisition to obtain background test results; S3. Analysis and testing Close the steam cleaning control valve, open the steam discharge control valve, open the cracking product pipeline control valve, and conduct cracking product analysis test. The analysis test results can be deducted from the background test results; S4. System cleaning Close the steam discharge control valve, open the steam cleaning control valve, close the cracking product pipeline control valve, adjust the steam pipeline or water pipeline feed rate in the self-cleaning system, and clean the pipeline and analysis system; If the cleavage product analysis is performed again, repeat steps S2, S3, and S4; S5. Device shutdown Turn off the heating of the first stage heater, the second stage heater in the self-cleaning system and the heat preservation heating jacket of the circulation pool in the analysis system. At the same time, pay attention to the cooling of the first stage heater, the second stage heater and the heat preservation heating jacket of the circulation pool. When the temperature of any of the first stage heater, the second stage heater or the heat preservation heating jacket of the circulation pool 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 flowmeter to adjust the inert gas feed amount; Close the steam pipeline and water pipeline, that is, close the steam pipeline control valve, adjust the steam flowmeter to zero, close the water pipeline control valve, turn off the metering pump, and when the temperature of the first stage heater, second stage heater in the self-cleaning system and the circulation pool insulation heating jacket in the analysis system drops to 80℃±5℃, close the inert gas pipeline, that is, close the inert gas pipeline control valve, adjust the inert gas flowmeter to zero, close the metering exhaust pipeline control valve and the direct exhaust pipeline control valve, and turn off the cooling pipe body of the optical path adjustment tube body in the analysis system and the first stage cooler, second stage cooler and cooling collection tank refrigeration in the cooling separation system.

Images