Online measurement system and method for carbon deposit content of methanol to olefins catalyst

Abstract

The present invention discloses an online measurement system and method for the carbon deposit content of a methanol to olefins catalyst, which belongs to the field of measurement technology and can solve the problem in the prior art that the carbon deposit content of the catalyst in an MTO industrial device cannot be quickly and accurately measured. The system comprises: a reactor module; a measuring tube located inside the reactor module or connected to the reactor module, for accommodating the catalyst to be detected; a signal acquisition module for acquiring a scattered light signal of the catalyst to be detected in a catalyst particle accumulation state or a dense phase flow state; a processing module for converting the scattered light signal into a voltage signal or a color image, and acquiring the catalyst carbon deposit content corresponding to the image characteristic value of the voltage signal or the color image according to a correlation function; the correlation function characterizes the correspondence between the catalyst carbon deposit content calibrated by the signal acquisition module in the catalyst accumulation state and the image characteristic value of the voltage signal or the color image. The present invention is used for online measurement of catalyst carbon deposit content.

Description

Technical Field

[0001] The invention relates to an online measurement system and method for carbon deposit content of a methanol to olefins catalyst, belonging to the technical field of measurement. Background Art

[0002] Methanol to olefins (MTO) is an important new process for producing basic chemical raw materials such as ethylene and propylene via a non-petroleum route. Similar to other acid-catalyzed hydrocarbon reactions, the MTO reaction produces products accompanied by catalyst carbon deposition. Studies have shown that maintaining a certain amount of carbon deposition on the catalyst during the MTO reaction is conducive to the production of light olefins (ethylene + propylene). When the carbon deposition content reaches approximately 8%, the selectivity of light olefins reaches its highest, corresponding to the optimal operating window. Therefore, in industrial production, quickly obtaining the carbon deposition content of the catalyst in the reactor and regenerator, and guiding the timely and precise regulation of the catalyst carbon deposition amount, are of great significance for further improving the efficiency of MTO industrial equipment.

[0003] Currently, there are three main methods for quantitatively analyzing carbon deposits on MTO catalysts: offline measurement, model prediction, and online measurement. Offline measurement methods vary widely, provide accurate results, and are the most widely used. However, they require sampling from the industrial plant and bringing the sample to the laboratory for analysis, resulting in long analysis cycles and significant lag in results. This makes it difficult to guide timely control of the carbon deposit content of catalysts in industrial plants, and is labor-intensive and cumbersome. Model prediction uses mathematical models to predict the carbon deposit content of regenerated or regenerated catalysts in industrial plants based on operating parameters such as reactor temperature, pressure, and catalyst residence time. While these mathematical models can provide timely predictions of the carbon deposit content of catalysts in industrial reactors, due to the complex reaction systems and operating conditions of industrial plants, these indirect model predictions are not very reliable and have not been adopted by the industry. Online measurement refers to methods that can quickly and accurately determine the carbon deposit content of catalysts in industrial plants. To meet the needs of rapid testing in industrial production, researchers are actively exploring methods for rapid online measurement of catalyst carbon deposit content in industrial plants. However, to date, no online measurement technology has been developed that can quickly and accurately determine the carbon deposit content of catalysts in MTO industrial plants. Summary of the Invention

[0004] The present invention provides an online measurement system and method for the carbon deposit content of a methanol to olefins catalyst, which can solve the problem in the prior art that the carbon deposit content of the catalyst in an MTO industrial device cannot be measured quickly and accurately.

[0005] In one aspect, the present invention provides an online measurement system for carbon deposit content in a methanol to olefins catalyst, characterized by comprising:

[0006] A reactor module, wherein a reaction catalyst is placed in the reactor module;

[0007] a measuring tube, the measuring tube being located inside the reactor module or connected to the reactor module and being used to accommodate the catalyst to be detected; the catalyst to be detected being a part of the reaction catalyst;

[0008] a signal acquisition module connected to the measuring tube and configured to acquire a scattered light signal of the catalyst to be detected in a catalyst particle accumulation state or a dense phase flow state;

[0009] A processing module, which is connected to the signal acquisition module, is used to convert the scattered light signal into a voltage signal or a color image, and obtain the catalyst carbon deposit content corresponding to the image characteristic value of the voltage signal or the color image according to a correlation function; the correlation function represents the correspondence between the catalyst carbon deposit content calibrated by the signal acquisition module under the accumulation state of the catalyst to be detected and the image characteristic value of the voltage signal or the color image.

[0010] Optionally, the system further includes a cleaning module, which is used to deliver backflush gas into the measuring tube to clean the measuring tube.

[0011] Optionally, the reactor module includes a reactor and / or a catalyst delivery pipeline; the measuring tube is located outside the reactor or the catalyst delivery pipeline;

[0012] The system further comprises an outlet pipe, a cooling stripping pipe and a collecting tank; one end of the outlet pipe is connected to the wall of the reactor or the catalyst delivery pipeline, and the other end is connected to the port of the cooling stripping pipe; the other end of the cooling stripping pipe is connected to the port of the measuring pipe; and the other end of the measuring pipe is connected to the collecting tank;

[0013] The outlet pipe is used to transport a portion of the reaction catalyst as the catalyst to be tested into the cooling stripping pipe; the cooling stripping pipe is used to cool and strip the catalyst to be tested, and then transport the catalyst to be tested to the measuring pipe;

[0014] The collecting tank is used to collect the catalyst output from the measuring tube;

[0015] The outlet pipe, the cooling stripping pipe and the measuring pipe are all provided with an air inlet; the cooling stripping pipe and the collecting tank are provided with an air outlet; the cleaning module is used to transport backflush gas to each pipe body through the air inlet.

[0016] Optionally, the system further includes a control module, and a first valve provided at the air inlet of the outlet pipe, a second valve provided on the pipeline connecting the outlet pipe and the cooling stripping pipe, a third valve provided on the pipeline connecting the cooling stripping pipe and the measuring pipe, a fourth valve provided at the air inlet of the cooling stripping pipe, a fifth valve provided at the air inlet of the inclined section of the measuring pipe, a sixth valve provided at the air inlet of the vertical section, and a seventh valve provided on the pipeline connecting the measuring pipe and the collecting tank;

[0017] The control module is used to control the opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve and the seventh valve.

[0018] Optionally, the reactor module includes a reactor and / or a catalyst delivery pipeline; the measuring tube is located outside the reactor or the catalyst delivery pipeline;

[0019] The system further includes an outlet pipe and a return pipe; one end of the outlet pipe is connected to the wall of the reactor or catalyst delivery pipeline, and the other end is connected to the port of the measuring pipe; the other port of the measuring pipe is connected to the port of the return pipe, and the other port of the return pipe is connected to the wall of the reactor or catalyst delivery pipeline;

[0020] The outlet pipe is used to transport a portion of the reaction catalyst as a catalyst to be detected into the measuring pipe;

[0021] The return pipe is used to return the catalyst output from the measuring pipe to the reactor or the catalyst delivery pipeline;

[0022] The measuring tube and the return tube are both provided with an air inlet; the cleaning module is used to deliver backflush gas to each tube body through the air inlet.

[0023] Optionally, the system further includes a control module, and an eighth valve provided on the connecting pipeline between the outlet pipe and the measuring pipe, a ninth valve provided at the air inlet of the measuring pipe, and a tenth valve provided at the air inlet of the return pipe;

[0024] The control module is used to control the opening or closing of the eighth valve, the ninth valve and the tenth valve.

[0025] Optionally, the reactor module includes a reactor and / or a catalyst delivery pipeline; the measuring tube is located inside the reactor or catalyst delivery pipeline; the signal acquisition module passes through the wall of the reactor or catalyst delivery pipeline and the wall of the measuring tube, and is inserted into the catalyst to be detected accumulated in the measuring tube to collect the scattered light signal of the catalyst to be detected;

[0026] The measuring tube is provided with an air inlet; the cleaning module is used to deliver backflush gas to the measuring tube through the air inlet.

[0027] Optionally, the system further comprises a control module, and an eleventh valve provided at the air inlet of the measuring tube;

[0028] The control module is used to control the opening or closing of the eleventh valve.

[0029] Optionally, the measuring tube is any one of a regular cylindrical shape, an inverted cylindrical shape, a regular conical shape, an inverted conical shape and a variable diameter shape.

[0030] Optionally, the measuring tube is an opaque tube.

[0031] Optionally, the signal acquisition module passes through the wall of the measuring tube and is inserted into the catalyst to be detected accumulated in the measuring tube to collect the scattered light signal of the catalyst to be detected;

[0032] or,

[0033] A transparent window is provided on the wall of the measuring tube, and the signal acquisition module collects the scattered light signal of the catalyst to be detected through the transparent window.

[0034] Optionally, the cleaning module is further configured to deliver backflush gas to the transparent window to clean the transparent window.

[0035] Optionally, the signal acquisition module includes a light shielding box and an optical fiber probe arranged in the light shielding box;

[0036] The optical fiber probe is used to transmit a light signal to the catalyst to be detected and receive a scattered light signal of the catalyst to be detected.

[0037] Optionally, the cleaning module is further configured to deliver backflush gas to the optical fiber probe to clean the optical fiber probe.

[0038] Optionally, the fiber optic probe has a probe diameter of 5 mm to 20 mm.

[0039] Optionally, the optical fiber probe consists of multiple detection heads.

[0040] Optionally, the light source of the optical fiber probe is any one of natural light, ultraviolet light, infrared light and fluorescence.

[0041] Optionally, the fluorescence wavelength is 300nm-700nm.

[0042] In another aspect, the present invention provides a method for measuring carbon deposit content in an online measurement system for a methanol to olefins catalyst as described above, the method comprising:

[0043] A series of MTO standard catalyst samples with different carbon deposit contents were prepared in a laboratory small fluidized bed reactor.

[0044] The carbon deposit content of each standard catalyst sample is measured using a thermogravimetric analyzer or an infrared carbon-sulfur analyzer as the standard carbon deposit content;

[0045] The standard catalyst samples are respectively loaded into measuring tubes, and the standard catalyst samples are allowed to be in a free stacking state. The scattered light signals of the standard catalyst samples are collected using an optical fiber probe, and the scattered light signals are converted into corresponding voltage signals or color images.

[0046] calibrating a correlation function between the catalyst carbon deposit content and the image characteristic value of the voltage signal or the color image according to the standard carbon deposit content and the converted voltage signal or color image;

[0047] The signal acquisition module is used to collect the scattered light signal of the catalyst to be detected online, the processing module is used to convert the scattered light signal into a voltage signal or a color image, and the catalyst carbon deposit content corresponding to the image characteristic value of the voltage signal or the color image is obtained according to the correlation function.

[0048] The beneficial effects that the present invention can produce include:

[0049] The online measurement system for the carbon deposit content of a methanol to olefins catalyst provided by the present invention is based on the principle of measuring the highly sensitive characteristics of MTO catalysts with different carbon deposit contents to light signals. The higher the carbon deposit content of the catalyst, the darker the color, the stronger the absorption of the light signal, and the weaker the corresponding scattered light. Using an optical fiber probe with both the function of transmitting and receiving light signals, the light emitted by the light source is introduced into the measurement area, and the scattered light signal of the carbon deposited catalyst is received at the same time. The received scattered light signal is converted into a corresponding voltage signal or color image through a photoelectric conversion device or a CCD imaging device. By preparing a standard catalyst sample to calibrate the correlation function between the carbon deposit content of the catalyst and the characteristic value of the voltage signal or image, the measurement signal of the optical fiber probe is converted into the corresponding carbon deposit content based on the correlation function, thereby realizing rapid measurement of the carbon deposit amount of the MTO catalyst. Furthermore, the calibrated optical fiber probe measurement module is coupled with different forms of catalyst online sampling systems to realize rapid online measurement of the carbon deposit content of the catalyst in the industrial device, greatly shortening the detection cycle, and being able to timely guide the precise control of the carbon deposit amount of the catalyst in the industrial device, thereby improving the economic benefits of the MTO industrial device. At the same time, it eliminates the tedious steps of manual sampling on the industrial device and then sending it to the analysis room for measurement using instruments such as thermogravimetric analysis, thus saving the manpower consumption caused by frequent sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The correlation function between the catalyst carbon deposit content and the voltage signal provided in the embodiment of the present invention;

[0051] Figure 2 Schematic diagram of an intermittent online measurement system for carbon deposit content of catalysts in an industrial device provided by an embodiment of the present invention;

[0052] Figure 3 The correlation function between the catalyst carbon deposit content and the image characteristic value B value provided by the embodiment of the present invention;

[0053] Figure 4 A schematic diagram of a continuous online measurement system for carbon deposit content of catalysts in an industrial device provided by an embodiment of the present invention;

[0054] Figure 5 Schematic diagram of a direct insertion online measurement system for carbon deposit content of catalysts in industrial devices provided by an embodiment of the present invention;

[0055] Figure 6 Schematic diagram of different types of measuring tube structures provided by embodiments of the present invention.

[0056] List of parts and reference numerals:

[0057] 11. Reactor module; 12. Measuring tube; 13. Outlet pipe; 14. Cooling stripping pipe; 15. Collecting tank; 16. First valve; 17. Second valve; 18. Third valve; 19. Fourth valve; 20. Fifth valve; 21. Sixth valve; 22. Seventh valve; 23. Return pipe; 24. Eighth valve; 25. Ninth valve; 26. Tenth valve; 27. Eleventh valve; 28. Transparent window; 29. Light-shielding box; 30. Fiber optic probe; 31. Light source transmitter; 32. Control module; 33. Gas outlet; 34. Processing unit. DETAILED DESCRIPTION

[0058] The present invention is described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0059] An embodiment of the present invention provides an online measurement system for the carbon deposit content of a methanol to olefins catalyst, comprising: a reactor module 11, wherein the reactor module 11 contains a reaction catalyst; a measuring tube 12, wherein the measuring tube 12 is located inside the reactor module 11 or connected to the reactor module 11, and is used to accommodate the catalyst to be detected; the catalyst to be detected is a part of the reaction catalyst; a signal acquisition module, wherein the signal acquisition module is connected to the measuring tube 12, and is used to obtain a scattered light signal of the catalyst to be detected in a catalyst particle accumulation state or a dense phase flow state; a processing module, wherein the processing module is connected to the signal acquisition module, and is used to convert the scattered light signal into a voltage signal or a color image, and obtain the catalyst carbon deposit content corresponding to the image characteristic value of the voltage signal or the color image according to a correlation function; the correlation function represents the correspondence between the catalyst carbon deposit content calibrated by the signal acquisition module in the catalyst accumulation state and the image characteristic value of the voltage signal or the color image.

[0060] The measuring tube 12 is an opaque tube.

[0061] In actual applications, the signal acquisition module can pass through the wall of the measuring tube 12 and be inserted into the catalyst to be detected accumulated in the measuring tube 12 to collect the scattered light signal of the catalyst to be detected; alternatively, a transparent window 28 can be provided on the wall of the measuring tube 12, and the signal acquisition module collects the scattered light signal of the catalyst to be detected through the transparent window 28; this embodiment of the present invention is not limited to this.

[0062] In an embodiment of the present invention, the system further includes a cleaning module, which is configured to deliver backflush gas into the measuring tube 12 to clean the measuring tube 12 .

[0063] refer to Figure 2 、 Figure 4 and Figure 5As shown, the signal acquisition module includes a light shielding box 29 and a fiber optic probe disposed within the light shielding box 29; the fiber optic probe is used to transmit light signals to the catalyst to be detected and receive scattered light signals from the catalyst to be detected; the fiber optic probe includes a fiber optic probe 30 and a light source transmitter 31. The processing module may include a CCD imager or a photoelectric converter, and a processing unit 34; the photoelectric converter or CCD imaging device may convert the received scattered light signal into a corresponding voltage signal or color image; the processing unit 34 may obtain the catalyst carbon deposit content corresponding to the image feature value of the voltage signal or color image based on the correlation function. The fiber optic probe has the function of both transmitting and receiving scattered light, has a diameter of 5-20 mm, and can be composed of 1-5 probe heads.

[0064] The light source of the fiber optic probe can be natural light, ultraviolet light, infrared light, or fluorescence with a fluorescence wavelength of 300nm-700nm. The fiber optic probe can be directly inserted into the catalyst accumulated in the measuring tube 12 for measurement or can be measured non-contact through the transparent window 28 installed on the tube wall.

[0065] The optical fiber probe assembly is fixed in an opaque light shielding box 29 so that it is not affected by external light. The optical fiber probe, measuring tube 12 and light shielding box 29 are assembled into an integral module and connected to the online measurement system for measurement.

[0066] The cleaning module is also used to deliver backflush gas to the transparent window 28 to clean the transparent window 28. Furthermore, the cleaning module is also used to deliver backflush gas to the fiber optic probe to clean the fiber optic probe. Specifically, high-pressure inert gas can be used to purge the fiber optic probe or the transparent window 28.

[0067] The steps for calibrating the correlation function between catalyst carbon deposit content and voltage signals in the above system are as follows: Standard catalyst samples are placed into the measuring tube 12. The fiber optic probe is inserted into the catalyst sample with the highest carbon deposit content and calibrated to the minimum voltage value. The fiber optic probe is then inserted into the catalyst sample with the lowest carbon deposit content and calibrated to the maximum voltage value. The fiber optic probe is then inserted into the remaining catalyst samples and the corresponding voltage is measured for each sample. Finally, the correlation function between catalyst carbon deposit content and voltage signals is calibrated using data fitting or machine learning algorithms.

[0068] The steps for calibrating the correlation function between catalyst carbon deposit content and image eigenvalues in the above-mentioned system are as follows: Standard catalyst samples are individually loaded into measuring tube 12. An optical fiber probe is inserted directly into each catalyst sample or captured through a transparent window 28 mounted on measuring tube 12 to obtain an image of the catalyst. Next, image processing techniques are used to extract the image's eigenvalues (grayscale, R, G, B, H, S, and V values), selecting those that are closely correlated with carbon deposit content. Finally, data fitting or machine learning algorithms are used to calibrate the correlation function between catalyst carbon deposit content and image eigenvalues.

[0069] The optical fiber probe in the present invention can be calibrated using the above two methods, but is not limited to these two methods.

[0070] The online measurement system for carbon deposit content of methanol to olefins catalyst provided by the present invention includes three measurement structures: intermittent, continuous, and direct insertion.

[0071] The first structure is an intermittent measurement structure; Figure 2 As shown, specifically: the reactor module 11 includes a reactor and / or a catalyst delivery pipeline; the measuring tube 12 is located outside the reactor or the catalyst delivery pipeline; the system also includes an outlet pipe 13, a cooling stripping pipe 14 and a collecting tank 15; one end of the outlet pipe 13 is connected to the pipe wall of the reactor or the catalyst delivery pipeline, and the other end is connected to the port of the cooling stripping pipe 14; the other port of the cooling stripping pipe 14 is connected to the port of the measuring tube 12; the other port of the measuring tube 12 is connected to the collecting tank 15; the outlet pipe 13 is used to transport a portion of the reaction catalyst as the catalyst to be tested into the cooling stripping pipe 14; the cooling stripping pipe 14 is used to transport the catalyst to be tested to the measuring tube 12 after cooling and stripping operations on the catalyst to be tested; the collecting tank 15 is used to collect the catalyst output from the measuring tube 12; the outlet pipe 13, the cooling stripping pipe 14 and the measuring tube 12 are all provided with an air inlet; the cooling stripping pipe 14 and the collecting tank 15 are provided with an air outlet 33; the cleaning module is used to transport backflush gas to each tube body through the air inlet.

[0072] Preferably, the system also includes a control module 32, as well as a first valve 16 arranged at the air inlet of the outlet pipe 13, a second valve 17 arranged on the connecting pipeline between the outlet pipe 13 and the cooling stripping pipe 14, a third valve 18 arranged on the connecting pipeline between the cooling stripping pipe 14 and the measuring pipe 12, a fourth valve 19 arranged at the air inlet of the cooling stripping pipe 14, a fifth valve 20 arranged at the air inlet of the inclined section of the measuring pipe 12 and a sixth valve 21 at the air inlet of the vertical section, and a seventh valve 22 arranged on the connecting pipeline between the measuring pipe 12 and the collecting tank 15; the control module 32 is used to control the opening or closing of the first valve 16, the second valve 17, the third valve 18, the fourth valve 19, the fifth valve 20, the sixth valve 21 and the seventh valve 22.

[0073] The catalyst online sampling system used in this intermittent measurement consists of a cooling stripping tube 14, a collection tank 15, a control module 32, a gas backflush module, a computer and control software. The calibrated fiber optic probe measurement module is connected to the lower part of the cooling stripping tube 14 for measurement. The catalyst is controlled to flow out of the sampling tube by the control module 32. After cooling and steam stripping by the cooling stripping tube 14, it falls into the measuring tube 12 and the carbon deposit amount is measured using the fiber optic probe measurement module. The measurement results are directly fed back to the control center for the optimization of the device operation. The measured catalyst falls directly into the collection tank 15 and is regularly returned to the reactor. Finally, the fiber optic probe and pipeline are cleaned by the gas backflush module to prevent contamination of the next measurement. This online measurement system can be installed on the reactor wall or on the catalyst circulation pipeline. It is suitable for both high-temperature resistant fiber optic probes and low-temperature fiber optic probes.

[0074] The second structure is a continuous measurement structure; refer to Figure 4 As shown, specifically: the reactor module 11 includes a reactor and / or a catalyst delivery pipeline; the measuring tube 12 is located outside the reactor or the catalyst delivery pipeline; the system also includes an outlet pipe 13 and a return pipe 23; one end of the outlet pipe 13 is connected to the pipe wall of the reactor or the catalyst delivery pipeline, and the other end is connected to the port of the measuring tube 12; the other port of the measuring tube 12 is connected to the port of the return pipe 23, and the other port of the return pipe 23 is connected to the pipe wall of the reactor or the catalyst delivery pipeline; the outlet pipe 13 is used to transport a part of the reaction catalyst as a catalyst to be detected into the measuring tube 12; the return pipe 23 is used to return the catalyst output from the measuring tube 12 to the reactor or the catalyst delivery pipeline; both the measuring tube 12 and the return pipe 23 are provided with an air inlet; the cleaning module is used to transport backflush gas to each tube body through the air inlet.

[0075] Preferably, the system also includes a control module 32, as well as an eighth valve 24 arranged on the connecting pipeline between the outlet pipe 13 and the measuring pipe 12, a ninth valve 25 arranged at the air inlet of the measuring pipe 12, and a tenth valve 26 arranged at the air inlet of the return pipe 23; the control module 32 is used to control the opening or closing of the eighth valve 24, the ninth valve 25 and the tenth valve 26.

[0076] The catalyst online sampling system used in this continuous measurement consists of an outlet pipe 13, a return pipe 23, a control module 32, a gas backflush module, a computer and control software. The calibrated fiber optic probe measurement module is connected to the lower part of the outlet pipe 13 for measurement. The catalyst flows out of the outlet pipe 13, passes through the measuring tube 12 in the fiber optic probe measurement module, and is returned to the reactor through the return pipe 23. The catalyst is controlled by the valve control module 32 to maintain continuous flow of the dense phase, and the fiber optic probe is used to continuously measure the carbon deposit amount of the catalyst in the dense phase flow. The measurement results are directly fed back to the control center for optimized operation of the device. Before each measurement begins, the fiber optic probe or the transparent window 28 needs to be cleaned by backflush gas to prevent adherent particles from affecting the measurement results. This online measurement system can be installed on the reactor wall or on the catalyst circulation pipeline. It is suitable for both high-temperature fiber optic probes and low-temperature fiber optic probes.

[0077] The third structure is a direct insertion measurement structure; Figure 5 As shown, specifically: the reactor module 11 includes a reactor and / or a catalyst delivery pipeline; the measuring tube 12 is located inside the reactor or the catalyst delivery pipeline; the signal acquisition module passes through the pipe wall of the reactor or the catalyst delivery pipeline, and passes through the pipe wall of the measuring tube 12, and is inserted into the catalyst to be detected accumulated in the measuring tube 12 to collect the scattered light signal of the catalyst to be detected; an air inlet is provided on the measuring tube 12; and the cleaning module is used to deliver backflush gas to the measuring tube 12 through the air inlet.

[0078] Preferably, the system further includes a control module 32 and an eleventh valve 27 provided at the air inlet of the measuring tube 12 ; the control module 32 is used to control the opening or closing of the eleventh valve 27 .

[0079] The catalyst online sampling system used in this direct insertion measurement consists of different types of measuring tubes 12, a gas backflush module, a computer, and control software. The fiber optic probe is combined with different types of measuring tubes 12 and then installed directly inside the reactor. The specially structured measuring tube 12 blocks the flow of particles in the bed, creating a particle accumulation state inside the measuring tube 12 at the end of the fiber optic probe to measure the carbon deposit content, eliminating the need for external sampling. Figure 6 As shown, the shapes of the measuring tube 12 include, but are not limited to, upright / inverted cylinders, upright / inverted cones, and tapered shapes. Before each measurement, backflush gas is introduced to refresh the catalyst particles accumulated within the measuring tube 12 and to clean and cool the fiber optic probe. This online sampling method is only applicable to high-temperature fiber optic probes.

[0080] Another embodiment of the present invention provides a method for measuring carbon deposit content in an online measurement system for a methanol-to-olefins catalyst as described above, the method comprising:

[0081] Step 1: Prepare a series of MTO standard catalyst samples with different carbon deposit contents in a laboratory small fluidized bed reactor.

[0082] In practical applications, samples need to be prepared under operating conditions close to those in industrial production.

[0083] Step 2: Use a thermogravimetric analyzer or an infrared carbon-sulfur analyzer to measure the carbon deposit content of each standard catalyst sample as the standard carbon deposit content.

[0084] Step 3: Load the standard catalyst samples into the measuring tubes 12 respectively, let the standard catalyst samples be in a free stacking state, use the optical fiber probe to collect the scattered light signals of the standard catalyst samples, and convert the scattered light signals into corresponding voltage signals or color images.

[0085] Specifically, the scattered light signal of the catalyst can be received by directly inserting the optical fiber probe into the accumulated catalyst or through the high-transparency window 28 installed on the pipe wall.

[0086] Step 4: Calibrate the correlation function between the catalyst carbon deposit content and the image feature value of the voltage signal or color image based on the standard carbon deposit content and the converted voltage signal or color image.

[0087] Step 5: Use the signal acquisition module to collect the scattered light signal of the catalyst to be tested online, use the processing module to convert the scattered light signal into a voltage signal or a color image, and obtain the catalyst carbon deposit content corresponding to the image feature value of the voltage signal or color image based on the correlation function.

[0088] By integrating the calibrated fiber optic probe measurement module with different online sampling systems, the carbon deposit content of catalysts in industrial reactors can be quickly measured online and the results can be directly fed back to the central control room.

[0089] The present invention further provides three specific embodiments to illustrate the technical solution of the present invention in detail, as follows:

[0090] Example 1

[0091] First, under operating conditions similar to those used in industrial production, 10 MTO standard catalyst samples with varying carbon deposit contents were prepared in a laboratory-scale fluidized bed reactor using fresh catalyst from the same batch as used in industrial production. This covers the carbon deposit range of catalysts used in MTO industrial production. Second, the carbon deposit contents of all catalyst samples were accurately measured using a thermogravimetric analyzer (TGA). The results are shown in Table 1. Furthermore, all catalyst samples were placed in opaque measuring tubes 12 and measured using a PV6M fiber optic probe developed by the Institute of Process Engineering, Chinese Academy of Sciences, under dense-phase conditions. Specifically, the fiber optic probe was inserted into the sample with the highest carbon deposit content and calibrated to a minimum voltage of 0.5 V. The fiber optic probe was then inserted into the sample with the lowest carbon deposit content and calibrated to a maximum voltage of 4.5 V. The fiber optic probe was then inserted into the remaining catalyst samples, and the corresponding voltage was measured for each catalyst sample. Table 1 shows the voltage values obtained from four replicate measurements of the 10 catalyst samples using the TGA, along with the TGA-derived carbon deposit contents. It can be seen that the voltage values measured four times for the same catalyst sample are very close, indicating that the measurement method has excellent repeatability. Furthermore, as the carbon deposit content increases, the voltage values measured by the fiber optic probe show a regular decrease, demonstrating the fiber optic probe's excellent sensitivity to catalysts with different carbon deposit contents. Figure 1 Based on the above experimental data, the correlation function between the catalyst carbon deposit content and the measured voltage value is established by linear fitting, that is, y = 13.05113-1.72925x, and the correlation coefficient R 2 Table 2 compares the measurement results of an unknown carbon deposit content of an MTO industrial catalyst using thermogravimetric and optical fiber methods. If the thermogravimetric result is taken as the accurate value, the optical fiber method's measurement error is approximately 1.5%. This fully demonstrates the promising application of optical fiber probes for measuring carbon deposit content in densely packed MTO catalysts.

[0092] like Figure 2As shown, by connecting a calibrated fiber optic probe measurement module to a catalyst online sampling system, rapid online measurement of catalyst carbon deposits in industrial plants can be achieved. The online sampling system consists of a cooling stripping pipe 14, a collection tank 15, a valve control module 32, a gas backflush module, a computer, and control software. The specific measurement steps are: (1) Before testing, all valves are closed; (2) the first valve 16 is opened and backflush gas is introduced for 5-10 seconds to backflush the catalyst deposited in the pipeline back into the reactor, thereby refreshing the catalyst to be tested. (3) Close the first valve 16, open the second valve 17, let a small amount of catalyst in the reactor enter the cooling stripping pipe 14, and then quickly close the second valve 17; (4) Open the fourth valve 19, pass the backflush gas to cool the catalyst for 2-5 minutes, and at the same time replace the gas carried in the catalyst to prevent the gas from liquefying after cooling and causing catalyst agglomeration and poor fluidity; (5) After the catalyst is cooled to 50-150℃, open the third valve 18 to let all the catalyst fall into the measuring tube 12, and the optical fiber probe is immersed in the accumulated catalyst particles. (6) Open the sixth valve 21 to clean and purge the end of the optical fiber probe for 2-3 seconds, and then measure the carbon deposit content of the catalyst. To improve the measurement accuracy, this process is repeated more than 4 times, and the average value of multiple measurements is taken as the final measurement result; (7) After the measurement is completed, open the seventh valve 22 to allow the catalyst to fall into the collection tank 15 at the bottom; (8) Open the fifth valve 20 and pass back-blowing gas to purge the catalyst particles adhering to the pipeline to prevent residual catalyst fines from contaminating the next measurement; (9) Close all valves to complete the measurement. After multiple debugging and optimization, the above 9 steps can be automatically executed. During actual measurement, just click the "Start Measurement" command in the control software, and the measurement results will be transmitted to the central control room in real time.

[0093] Table 1 Voltage values and carbon deposit contents measured by thermogravimetric method using PV6M fiber optic probe for 4 repeated measurements of 11 MTO catalyst samples with different carbon deposit contents

[0094]

[0095] Table 2 Comparison of the measurement results of a certain MTO industrial carbon deposition catalyst using thermogravimetric and optical fiber methods

[0096]

[0097] Example 2

[0098] First, a standard catalyst sample identical to that in Example 1 is used to calibrate the correlation function between the catalyst carbon deposit content and the image characteristic value. The specific steps are: the catalyst samples are respectively placed in a measuring tube 12 equipped with a transparent window 28, and each catalyst sample in a stacked state is imaged four times using an optical fiber probe with an imaging function. Table 3 shows the B value of the images taken four times by the optical fiber probe for 10 catalyst samples and the catalyst carbon deposit content measured by thermogravimetric measurement. It can be seen that the B value deviation of the four repeated images of the same catalyst sample is very small, which shows that the imaging optical fiber probe has very good repeatability when measuring the catalyst carbon deposit content. In addition, as the carbon deposit content increases, the B value of the image taken by the optical fiber probe also shows a regular decline, which shows that the carbon deposit content of the MTO catalyst is highly correlated with the characteristic value B value of the image. Figure 3 Based on the above experimental data, the correlation function between the catalyst carbon deposit content and the image B value is established by polynomial fitting, that is:

[0099] y=-2219.425+1486.31x 0.5 -404.61x+57.562x 1.5 -4.516593x 2 +0.18544x 2.5 -0.0031155x 3 , correlation coefficient R 2 Table 4 compares the measurement results of an MTO industrial catalyst with unknown carbon deposit content using thermogravimetric and fiber optic imaging. If the thermogravimetric measurement result is taken as the accurate value, the deviation of the fiber optic imaging measurement result is approximately 1.5%.

[0100] like Figure 4As shown, by connecting the calibrated imaging fiber probe measurement module to the catalyst online sampling system, the rapid online measurement of the carbon deposit content of the catalyst in the industrial device can be achieved. The online sampling system consists of an outlet pipe 13, a return pipe 23, a valve control system, a gas backflush system, a computer and control software. The specific test steps are: (1) Open the eighth valve 24 to allow the catalyst to flow out of the outlet pipe 13; (2) Open the tenth valve 26 to introduce backflush gas; (3) By adjusting the opening of the eighth valve 24 and the tenth valve 26, the dense phase of the catalyst formed in the pipeline is allowed to flow slowly; (4) Open the ninth valve 25 to purge and clean the transparent window 28 for 2-3 seconds, and then use the fiber optic probe to measure the carbon deposit content of the dense phase flowing catalyst through the transparent window 28. In order to improve the measurement accuracy, this process is repeated more than 4 times, and the average value of multiple measurements is taken as the final measurement result. The measurement result will be directly fed back to the control center for the optimization operation of the device. The above steps can be automatically executed. When actually measuring, just click the "Start Measurement" command in the control software. Compared with Example 1, the measurement steps of this online sampling device are simpler and can achieve continuous measurement.

[0101] Table 3 B values of 10 catalyst samples taken four times by optical fiber probe and the carbon deposit content of catalysts measured by thermogravimetric method

[0102]

[0103]

[0104] Table 4 Comparison of the measurement results of a certain MTO industrial carbon deposit catalyst using thermogravimetric method and fiber optic imaging method

[0105]

[0106] Example 3

[0107] First, the correlation function between the catalyst carbon deposit content and the voltage signal was calibrated using the same method as in Example 1.

[0108] like Figure 5As shown, the high-temperature resistant fiber optic probe assembly with the measuring tube 12 is directly installed in the industrial reactor for measurement without the need for external sampling. The specific test steps are: (1) When measurement is not required, the eleventh valve 27 is kept in the open state, and the back-blowing gas will surround the fiber optic probe to prevent the probe from being worn and keep the probe clean. (2) When measurement is required, the eleventh valve 27 is closed, the back-blowing gas is cut off, and catalyst particles in a piled state will be formed in the specially structured measuring tube 12. (3) The fiber optic probe measuring instrument can be turned on to measure the catalyst carbon deposit content. (4) The back-blowing gas is turned on for 5-10 seconds (i.e., the eleventh valve 27 is opened), and the catalyst particles accumulated at the end of the probe are updated before the next measurement can be performed. In order to improve the measurement accuracy, 4 repetitions are performed, and the average value of multiple measurements is taken as the final measurement result. The measurement result will be directly fed back to the control center for the optimization operation of the device. The above operation steps can be automatically executed. When actually measuring, just click the "Start Measurement" command in the control software. Compared with Examples 1 and 2, the measurement steps are simpler, but the fiber optic probe needs to be resistant to high temperatures.

[0109] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A methanol to olefins catalyst carbon deposit content online measurement system, characterized in that: include: A reactor module, wherein a reaction catalyst is placed in the reactor module; a measuring tube, the measuring tube being located inside the reactor module or connected to the reactor module and being used to accommodate the catalyst to be detected; the catalyst to be detected being a part of the reaction catalyst; a signal acquisition module connected to the measuring tube and configured to acquire a scattered light signal of the catalyst to be detected in a catalyst particle accumulation state or a dense phase flow state; a processing module, connected to the signal acquisition module, configured to convert the scattered light signal into a voltage signal or a color image, and obtain, based on a correlation function, a catalyst carbon deposit content corresponding to an image characteristic value of the voltage signal or the color image; the correlation function representing a correspondence between the catalyst carbon deposit content calibrated by the signal acquisition module under the accumulation state of the catalyst to be detected and the image characteristic value of the voltage signal or the color image; The system further comprises a cleaning module, wherein the cleaning module is used to deliver backflush gas into the measuring tube to clean the measuring tube; The reactor module includes a reactor and / or a catalyst delivery pipeline; the measuring tube is located outside the reactor or the catalyst delivery pipeline; The system further comprises an outlet pipe, a cooling stripping pipe and a collecting tank; one end of the outlet pipe is connected to the wall of the reactor or the catalyst delivery pipeline, and the other end is connected to the port of the cooling stripping pipe; the other end of the cooling stripping pipe is connected to the port of the measuring pipe; and the other end of the measuring pipe is connected to the collecting tank; The outlet pipe is used to transport a portion of the reaction catalyst as the catalyst to be tested into the cooling stripping pipe; the cooling stripping pipe is used to cool and strip the catalyst to be tested, and then transport the catalyst to be tested to the measuring pipe; The collecting tank is used to collect the catalyst output from the measuring tube; The outlet pipe, the cooling stripping pipe and the measuring pipe are all provided with an air inlet; the cooling stripping pipe and the collecting tank are provided with an air outlet; the cleaning module is used to transport backflush gas to each pipe body through the air inlet.

2. The system according to claim 1, wherein: The system further includes a control module, and a first valve provided at the air inlet of the outlet pipe, a second valve provided on the pipeline connecting the outlet pipe and the cooling stripping pipe, a third valve provided on the pipeline connecting the cooling stripping pipe and the measuring pipe, a fourth valve provided at the air inlet of the cooling stripping pipe, a fifth valve provided at the air inlet of the inclined section of the measuring pipe, a sixth valve provided at the air inlet of the vertical section, and a seventh valve provided on the pipeline connecting the measuring pipe and the collecting tank; The control module is used to control the opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve and the seventh valve.

3. The system according to claim 1, wherein: The reactor module includes a reactor and / or a catalyst delivery pipeline; the measuring tube is located outside the reactor or the catalyst delivery pipeline; The system further includes an outlet pipe and a return pipe; one end of the outlet pipe is connected to the wall of the reactor or catalyst delivery pipeline, and the other end is connected to the port of the measuring pipe; the other port of the measuring pipe is connected to the port of the return pipe, and the other port of the return pipe is connected to the wall of the reactor or catalyst delivery pipeline; The outlet pipe is used to transport a portion of the reaction catalyst as a catalyst to be detected into the measuring pipe; The return pipe is used to return the catalyst output from the measuring pipe to the reactor or the catalyst delivery pipeline; The measuring tube and the return tube are both provided with an air inlet; the cleaning module is used to deliver backflush gas to each tube body through the air inlet.

4. The system according to claim 3, characterized in that The system further includes a control module, an eighth valve provided on the connecting pipe between the outlet pipe and the measuring pipe, a ninth valve provided at the air inlet of the measuring pipe, and a tenth valve provided at the air inlet of the return pipe; The control module is used to control the opening or closing of the eighth valve, the ninth valve and the tenth valve.

5. The system according to claim 1, wherein: The reactor module includes a reactor and / or a catalyst delivery pipeline; the measuring tube is located inside the reactor or catalyst delivery pipeline; the signal acquisition module passes through the wall of the reactor or catalyst delivery pipeline and the wall of the measuring tube, and is inserted into the catalyst to be tested accumulated in the measuring tube to collect the scattered light signal of the catalyst to be tested; The measuring tube is provided with an air inlet; the cleaning module is used to deliver backflush gas to the measuring tube through the air inlet.

6. The system according to claim 5, characterized in that The system further includes a control module, and an eleventh valve disposed at the air inlet of the measuring tube; The control module is used to control the opening or closing of the eleventh valve.

7. The system according to claim 1, wherein: The measuring tube is in any one of a regular cylindrical shape, an inverted cylindrical shape, a regular conical shape, an inverted conical shape and a variable diameter shape.

8. The system according to claim 1, wherein: The measuring tube is an opaque tube.

9. The system according to claim 1, wherein: The signal acquisition module passes through the wall of the measuring tube and is inserted into the catalyst to be detected accumulated in the measuring tube to collect the scattered light signal of the catalyst to be detected; or, A transparent window is provided on the wall of the measuring tube, and the signal acquisition module collects the scattered light signal of the catalyst to be detected through the transparent window.

10. The system according to claim 9, characterized in that The cleaning module is further used to deliver backflush gas to the transparent window to clean the transparent window.

11. The system according to claim 1, wherein: The signal acquisition module includes a light shielding box and an optical fiber probe arranged in the light shielding box; The optical fiber probe is used to transmit a light signal to the catalyst to be detected and receive a scattered light signal of the catalyst to be detected.

12. The system according to claim 11, wherein: The cleaning module is further used to deliver backflush gas to the optical fiber probe to clean the optical fiber probe.

13. The system according to claim 11, wherein: The diameter of the optical fiber probe is 5 mm to 20 mm.

14. The system according to claim 11, wherein: The optical fiber probe is composed of a plurality of detection heads.

15. The system according to claim 11, wherein: The light source of the optical fiber probe is any one of natural light, ultraviolet light, infrared light and fluorescence.

16. The system according to claim 15, wherein: The fluorescence wavelength is 300nm-700nm.

17. A method for measuring carbon deposit content in an online measurement system for a methanol to olefins catalyst according to any one of claims 1 to 16, characterized in that: The method comprises: A series of MTO standard catalyst samples with different carbon deposit contents were prepared in a laboratory small fluidized bed reactor. The carbon deposit content of each standard catalyst sample is measured using a thermogravimetric analyzer or an infrared carbon-sulfur analyzer as the standard carbon deposit content; The standard catalyst samples are respectively loaded into measuring tubes, and the standard catalyst samples are allowed to be in a free stacking state. The scattered light signals of the standard catalyst samples are collected using an optical fiber probe, and the scattered light signals are converted into corresponding voltage signals or color images. calibrating a correlation function between the catalyst carbon deposit content and the image characteristic value of the voltage signal or the color image according to the standard carbon deposit content and the converted voltage signal or color image; The signal acquisition module is used to collect the scattered light signal of the catalyst to be detected online, the processing module is used to convert the scattered light signal into a voltage signal or a color image, and the catalyst carbon deposit content corresponding to the image characteristic value of the voltage signal or the color image is obtained according to the correlation function.

Images