Online analysis method and device for hydrogen chloride in catalytic reforming hydrogen

Abstract

The present invention discloses an online analysis method and device for hydrogen chloride in catalytic reformed hydrogen. The method comprises the following steps: A. configuring multiple groups of reformed hydrogen samples with different hydrogen chloride contents using reformed hydrogen collected on-site, and respectively filling the multiple groups of reformed hydrogen samples into pressure-resistant, light-transmitting containers; B. measuring light intensity data at receiving ends of the multiple groups of reformed hydrogen samples using a laser emitting unit and a laser receiving unit of a hydrogen chloride online analyzer, establishing a correspondence between the light intensity data and hydrogen chloride content data, and forming a basic database; C. constructing a prediction analysis model with the light intensity data as an independent variable and the hydrogen chloride content data as a dependent variable based on the correspondence; D. symmetrically drilling holes along radial sides of a reformed hydrogen dechlorination tank outlet pipeline to construct a laser path, and sealingly installing a pressure-resistant, light-transmitting unit at the drilled holes; measuring light intensity data at the on-site reformed hydrogen receiving end using a laser emitting unit and a laser receiving unit respectively provided at both ends of the laser path; and E. calculating on-site hydrogen chloride content data using the prediction analysis model and the measured light intensity data at the on-site reformed hydrogen receiving end.

Description

Technical Field

[0001] The present invention relates to the technical field of oil refining, and in particular to an online analysis method and device for hydrogen chloride in catalytic reforming hydrogen. Background Art

[0002] Catalytic reforming uses C6-C11 naphtha fraction as a feedstock. Under certain operating conditions and with the help of a catalyst, the hydrocarbon molecules undergo structural restructuring, converting cycloalkanes and alkanes into aromatics or isoalkanes while simultaneously producing hydrogen. Reforming catalysts contain chlorine, but chlorine is unstable on the catalyst and easily lost during the reforming reaction. Consequently, the reformed hydrogen contains a certain amount of chlorine. Before being delivered to the reactor, the reformed hydrogen is dechlorinated in a dechlorination tank. These tanks are typically operated in series, with one tank in operation and the other in standby mode.

[0003] Operators monitor the chlorine content of reformed hydrogen and guide dechlorination unit operations based on daily reformed hydrogen analysis and test data or on-site testing data. Conventional daily reformed hydrogen composition analysis in existing technologies suffers from time-consuming and delayed results, while on-site testing is labor-intensive and requires single-point monitoring. Consequently, hydrogen chloride breakthrough in reformed hydrogen often occurs, leading to significant delays in operational adjustments. Chlorine in reformed hydrogen can cause serious production accidents. Chlorine can corrode pipelines, leading to hydrogen leaks and subsequent safety incidents. It can also easily mix with ammonia-containing substances to form ammonium salt crystals, which can clog pipelines.

[0004] Chinese patent application CN108548699A discloses an online hydrogen chloride monitoring and analysis system that addresses the issues of short optical path, insufficient instrument measurement accuracy, and high maintenance requirements. The system includes a sampling head connected to the gas chamber inlet via a filter, a high-temperature electric valve, and a switching three-way valve. The gas chamber outlet is connected to a jet pump. One path of the jet pump passes through electric valve A, an air compressor, and electric valve B to the inlet of the high-temperature electric valve, while the other path of the jet pump is directly discharged. A standard gas storage bottle with a flow meter is connected to the other inlet of the switching three-way valve. All components are connected by a heat-tracing pipeline. The gas chamber includes a gas pipeline, a transmitting and receiving optical path component bracket, a reflecting optical path component bracket, a laser transmitter, a transmitting and receiving total reflection prism, a laser receiver, and a reflecting total reflection prism. Laser light emitted by the laser transmitter passes through the reflecting total reflection prism, the transmitting and receiving total reflection prism, the reflecting total reflection prism, and the laser receiver, forming a multi-return optical path. This prior art uses a sampling device to transport gas to the analyzer for testing. The results are not real-time data, making it unsuitable for real-time control systems.

[0005] Therefore, there is an urgent need for a method and device that can ensure the monitoring accuracy of the hydrogen chloride content in catalytic reforming hydrogen and can also perform real-time online analysis of the hydrogen chloride content.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] The object of the present invention is to provide a method and device for online analysis of hydrogen chloride in catalytic reforming hydrogen, which can not only ensure the monitoring accuracy of the hydrogen chloride content in catalytic reforming hydrogen, but also can analyze the hydrogen chloride content online in real time, thereby providing data reference for the optimized operation of the dechlorination tank in a timely manner, preventing the reforming hydrogen from carrying chlorine, and promoting the safe and stable operation of downstream devices.

[0008] To achieve the above objectives, according to a first aspect of the present invention, a method for online analysis of hydrogen chloride in catalytic reformed hydrogen is provided, comprising the following steps: A. preparing multiple groups of reformed hydrogen samples having different hydrogen chloride contents using reformed hydrogen collected on-site, and respectively filling the multiple groups of reformed hydrogen samples into pressure-resistant, light-transmitting containers; B. measuring light intensity data at receiving ends of the multiple groups of reformed hydrogen samples using a laser emitting unit and a laser receiving unit of an online hydrogen chloride analyzer, establishing a correspondence between the light intensity data and hydrogen chloride content data, and forming a basic database; C. constructing a prediction and analysis model based on the correspondence, with the light intensity data as the independent variable and the hydrogen chloride content data as the dependent variable; D. symmetrically drilling holes along radial sides of the outlet pipeline of a reformed hydrogen dechlorination tank to form a laser path through the pipeline, and sealingly installing pressure-resistant, light-transmitting units at the drilled holes; measuring light intensity data at the on-site reformed hydrogen receiving end using a laser emitting unit and a laser receiving unit respectively provided at both ends of the laser path; and E. calculating on-site hydrogen chloride content data using the prediction and analysis model and the measured light intensity data at the on-site reformed hydrogen receiving end.

[0009] Furthermore, in the above technical solution, the prediction analysis model can be obtained through data fitting, neural network model or genetic algorithm.

[0010] Furthermore, in the above technical solution, when the prediction and analysis model is obtained by data fitting, a piecewise function can be used to construct a corresponding relationship between the light intensity data and the hydrogen chloride content data.

[0011] Furthermore, in the above technical solution, the data fitting format can be: y = Ax 3 +Bx 2 +Cx+D; where x is the light intensity data, y is the hydrogen chloride content data, and A, B, C, and D are fitting coefficients.

[0012] Furthermore, in the above technical solution, a step of correcting the fitting coefficients may be included before step E.

[0013] Furthermore, in the above technical solution, the correction of the fitting coefficient can be specifically performed as follows: calculating the model calculated value of the hydrogen chloride content data according to the initial value of the fitting coefficient; comparing the actual measured value of the hydrogen chloride content at a certain moment with the model calculated value at that moment; when the relative deviation between the actual measured value and the model calculated value at that moment exceeds a threshold, importing the actual measured value of the hydrogen chloride content and the light intensity at that moment into the basic database; and refitting the data within the range of the piecewise function corresponding to the actual measured light intensity value to obtain a corrected fitting coefficient.

[0014] Furthermore, in the above technical solution, step E may also include: according to the calculated hydrogen chloride content data, when it is determined that the hydrogen chloride content exceeds the control threshold and lasts for a certain period of time, issuing an alarm or adjusting the dechlorination tank operation.

[0015] Furthermore, in the above technical solution, the control thresholds may include 0.5ppm and 1ppm; when the calculated hydrogen chloride content in the reformed hydrogen is greater than 0.5ppm and lasts for 5 minutes or more, an alarm is issued; when the calculated hydrogen chloride content in the reformed hydrogen is greater than 1ppm and lasts for 5 minutes or more, the reformed hydrogen is switched to another spare dechlorination tank or the order of the two dechlorination tanks is changed.

[0016] Furthermore, in the above technical solution, the pressure-resistant and light-transmitting unit in step D can be made of glass material, and the glass material is specifically: soda-lime glass, borosilicate glass, high-purity SiO2 glass or alkali-free aluminosilicate glass, with a maximum pressure resistance of 35-40 kg; the sealing material can be synthetic fiber, polytetrafluoroethylene or polyetheretherketone resin.

[0017] To achieve the above-mentioned object, according to a second aspect of the present invention, the present invention further provides an online analysis device for hydrogen chloride in catalytic reformed hydrogen, comprising: a sampling unit, which configures a plurality of groups of reformed hydrogen samples with different hydrogen chloride contents using reformed hydrogen collected on-site, and respectively fills the plurality of groups of reformed hydrogen samples into pressure-resistant, light-transmitting containers; a hydrogen chloride online analyzer, which respectively measures light intensity data at a receiving end of the plurality of groups of reformed hydrogen samples using a laser emitting unit and a laser receiving unit; and measures light intensity data at an on-site reformed hydrogen receiving end; a prediction model construction unit, which constructs a prediction analysis model with light intensity data as an independent variable and hydrogen chloride content data as a dependent variable based on a correspondence between light intensity data and hydrogen chloride content data; and a hydrogen chloride content calculation unit, which calculates on-site hydrogen chloride content data using the prediction model and the light intensity data measured at the on-site reformed hydrogen receiving end.

[0018] Furthermore, in the above technical solution, the pressure-resistant light-transmitting container may be a pressure-resistant glass container.

[0019] Furthermore, in the above technical solution, the laser emitting unit may include: an infrared laser light source, which is used to provide continuous infrared laser; and a chopper, which modulates the continuous infrared laser into pulsed light.

[0020] Furthermore, in the above technical solution, the laser receiving unit may include: a filter, which receives and filters the infrared light whose intensity is weakened after being absorbed by hydrogen chloride in the reformed hydrogen; a convex lens, which focuses the filtered infrared light; and a detector, whose photosensitive surface receives the focused infrared light and converts the optical signal carrying the change in hydrogen chloride concentration into an electrical signal.

[0021] Furthermore, in the above technical solution, a light-transmitting wafer for sealing may be provided between the laser emitting unit, the laser receiving unit and the laser path.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The present invention measures light intensity data at a sample receiving end of different groups of reformed hydrogen samples containing different hydrogen chloride contents in a sampling container using a hydrogen chloride online analyzer, constructs a piecewise function based on the correspondence between the hydrogen chloride content and the light intensity data, determines the coefficients of each piecewise function by fitting, and finally calculates the hydrogen chloride content in the reformed hydrogen at the outlet pipeline of the on-site dechlorination tank based on the constructed piecewise function, thereby enabling real-time analysis and detection of the hydrogen chloride content in the reformed hydrogen;

[0024] 2) The present invention adopts a basic database to replace the standard gas analysis chamber used in the prior art, avoiding the shortcomings of standard gas leakage and gas pool damage, thereby achieving the purpose of saving investment and promoting long-term operation of the system;

[0025] 3) By using the measured data of hydrogen chloride content regularly tested on site, the measured data can be imported into the basic database and the corresponding piecewise function coefficients can be recalibrated to obtain more accurate hydrogen chloride simulation calculation values;

[0026] 4) The real-time simulation calculation of the present invention can analyze the hydrogen chloride content in reformed hydrogen in real time, overcoming the shortcomings of the current low frequency of hydrogen chloride analysis and detection in reformed hydrogen and delayed problem detection. It can promptly detect conditions such as chlorine breakthrough in reformed hydrogen, guide the dechlorination tank to make operational adjustments, and avoid the impact of chlorine-containing hydrogen on downstream equipment;

[0027] 5) The present invention does not need to reduce the pressure of the reformed hydrogen to normal pressure, and does not need to draw out a separate stream of reformed hydrogen. It has the characteristics of simple process and wide adaptability to pressure range.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the on-line analysis device of hydrogen chloride in catalytic reforming hydrogen of the present invention.

[0030] Figure 2 The figure is a schematic flow chart of the on-line analysis method of hydrogen chloride in catalytic reforming hydrogen of the present invention.

[0031] Figure 3 It is a flow chart of an implementation method of constructing a predictive analysis model in the on-line analysis method of hydrogen chloride in catalytic reforming hydrogen of the present invention.

[0032] Figure 4 It is a schematic diagram of the corresponding relationship between the hydrogen chloride content of the catalytic reforming hydrogen sample of the present invention and the light intensity data at the receiving end of the sample container.

[0033] Figure 5 This invention Figure 4 Schematic diagram of the first piecewise function after data fitting.

[0034] Figure 6 This invention Figure 4 Schematic diagram of the second piecewise function after data fitting.

[0035] Figure 7 It is a connection diagram of the hydrogen chloride online control system of the present invention.

[0036] Description of main reference numerals:

[0037] 1-Reforming hydrogen pipeline, 11-Laser path, 12-Flange, 2-Laser emitting unit, 20-First light-transmitting chip, 21-Infrared laser light source, 22-Chopper, 3-Laser receiving unit, 30-Second light-transmitting chip, 31-Filter, 32-Convex lens, 33-Detector, 4-Pressure-resistant light-transmitting unit, 5-Control unit, 51-Control module, 52-Basic database;

[0038] 100-first dechlorination tank, 200-second dechlorination tank, 300-hydrogen chloride online control unit. DETAILED DESCRIPTION

[0039] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0040] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0041] In this document, for ease of description, spatially relative terms such as "below," "beneath," "down," "above," "above," etc. may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0042] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0043] Example 1

[0044] The online analysis device for hydrogen chloride in catalytic reformed hydrogen of the present invention comprises a sampling unit and an online hydrogen chloride analyzer. The sampling unit prepares multiple groups of reformed hydrogen samples with different hydrogen chloride contents using reformed hydrogen collected on-site, and then separately fills each of the reformed hydrogen samples into a pressure-resistant, light-transmitting container. Preferably, but not limiting, the pressure-resistant, light-transmitting container can be a glass sample container with good light transmittance. Specifically, the glass material can be soda-lime glass, borosilicate glass, high-purity SiO2 glass, or alkali-free aluminosilicate glass, with a maximum pressure resistance of 35-40 kg. Specifically, 3-20 groups of reformed hydrogen samples can be collected from the device site, and the content of each component can be measured using laboratory analysis methods such as chromatography, colorimetric tube analysis, acid-base titration, etc., preferably chromatography. For each group of reformed hydrogen samples, hydrogen chloride gas with different contents is prepared. The prepared reformed hydrogen samples with a certain amount of hydrogen chloride gas are then filled into the light-transmitting, pressure-resistant glass sample containers. The container is maintained at room temperature, and the reformed hydrogen pressure ranges from 10 to 25 kg.

[0045] like Figure 1As shown, the hydrogen chloride online analyzer of the present invention includes a laser emitting unit 2 and a laser receiving unit 3, and may also include a control unit 5. In the sampling stage, the light intensity data of the aforementioned multiple groups of reformed hydrogen sample receiving ends can be measured respectively by the laser emitting unit 2 and the laser receiving unit 3; in the field measurement stage, the light intensity data of the field reformed hydrogen receiving end can be measured by the laser emitting unit 2 and the laser receiving unit 3. Specifically, in the field measurement stage, first, at the outlet pipeline of the reformed hydrogen dechlorination tank, the number, position and size of the openings are determined, and pressure-resistant glass is installed, and the connection between the pressure-resistant glass and the pipeline is sealed. Then, the aforementioned units of the hydrogen chloride online analyzer of the present invention are installed and connected. The number of openings can be an even number such as 2, 4, 6, 8, etc., preferably 2 openings. The opening position is to drill holes on both sides of the radial direction of the outlet pipeline of the reformed hydrogen dechlorination tank, and the center connecting line of the opening is parallel to the horizontal ground. The opening size (diameter) is 10-200mm, preferably 40-100mm. Pipes 11 are symmetrically installed at the openings on both sides. Pipes 11 are connected to the reformed hydrogen pipeline 1 via flanges 12. Pipes 11 serve as the laser path of the present invention. Considering that the reformed hydrogen pipeline is a pressure pipeline and the openings need to be transparent, pressure-resistant and transparent units 4 are installed at the openings on both sides. Pressure-resistant and transparent units 4 can be composed of pressure-resistant and transparent glass and sealing materials. The pressure-resistant and transparent glass can be made of the material used for the sample container, namely soda-lime glass, borosilicate glass, high-purity SiO2 glass, or alkali-free aluminosilicate glass, with a maximum pressure resistance of 35-40 kg. The sealing material can be made of synthetic fiber, polytetrafluoroethylene, polyetheretherketone resin, etc., preferably reinforced modified polytetrafluoroethylene. The laser emitting unit 2 and the laser receiving unit 3 are respectively connected to the outer ends of the pipeline 11. The connection between the laser emitting unit 2 and the pipeline 11 is sealed and a first transparent chip 20 is provided at the seal. The connection between the laser receiving unit 3 and the pipeline 11 is sealed and a second transparent chip 30 is provided at the seal. The laser emitting unit 2 is used to emit infrared laser light and includes an infrared laser light source 21 and a chopper 22. The infrared laser light source 21 is used to provide continuous infrared laser light, preferably using a quantum cascade laser; the chopper can modulate the continuous infrared laser light into pulsed light, and existing mature products can be used. The laser receiving unit 3 is used to receive infrared laser signals and includes a filter 31, a convex lens 32, and a detector 33. The filter 31 receives and filters the infrared light whose intensity is weakened after being absorbed by hydrogen chloride in the reformed hydrogen; the convex lens 32 focuses the filtered infrared light; the photosensitive surface of the detector 33 receives the focused infrared light and can convert the optical signal carrying the change in hydrogen chloride concentration into an electrical signal. The electrical signal can be used to obtain the light intensity data measured on site (represented by voltage V). Furthermore, the materials of the filter 31, convex lens 32, and detector 33 can all be made of single crystal calcium fluoride material with good light transmittance in the mid-infrared band. During the sampling phase, the laser emitting unit 2 and the laser receiving unit 3 are connected to both end surfaces of the transparent sample container to test the light intensity signals at the receiving end of different samples.

[0046] Furthermore, the present invention uses a sampling unit to sample reformed hydrogen and determine its hydrogen chloride content. A hydrogen chloride online analyzer then measures light intensity data at the receiving end of the sample container, establishes a correspondence between the light intensity data and the hydrogen chloride content, and finally calculates the hydrogen chloride content in the reformed hydrogen in real time based on the measured light intensity data. This allows for real-time calculation of the hydrogen chloride content in the reformed hydrogen, avoiding the lag associated with sample collection and laboratory analysis. Based on this, the apparatus of the present invention also includes a prediction model construction unit and a hydrogen chloride content calculation unit. The prediction model construction unit constructs a prediction analysis model based on the correspondence between the light intensity data and the hydrogen chloride content data, using the light intensity data as the independent variable and the hydrogen chloride content data as the dependent variable. The sample data required to construct the prediction model comes from a basic database 52 in the control unit 5. The control module 51 in the control unit 5 is used for frequency analysis of the hydrogen chloride online analyzer and regulation and control of the dechlorination process based on the calculated hydrogen chloride content. The hydrogen chloride content calculation unit calculates the on-site hydrogen chloride content data based on the prediction model and the measured light intensity data at the receiving end of the reformed hydrogen. Furthermore, the present invention can interconnect the hydrogen chloride online analyzer with the hydrogen chloride online control system. After the hydrogen chloride online control system receives the abnormal hydrogen chloride content data signal from the control module 51, that is, when it determines that the hydrogen chloride content exceeds the control threshold and lasts for a certain period of time, it will issue an alarm or adjust the dechlorination tank operation. Figure 7 In the manner shown, the first dechlorination tank 100 and the second dechlorination tank 200 are connected in parallel, and the second dechlorination tank 200 is used as a backup dechlorination tank. When abnormal data occurs, the hydrogen chloride online control system will alarm and can further switch to use the backup dechlorination tank.

[0047] Example 2

[0048] Further Figure 2 As shown, the present invention also provides an online analysis method for hydrogen chloride in catalytic reforming hydrogen, comprising the following steps:

[0049] Step S101: multiple groups of reformed hydrogen samples with different hydrogen chloride contents are prepared using reformed hydrogen collected on site, and the multiple groups of reformed hydrogen samples are respectively filled into pressure-resistant and light-transmitting containers. The following is an example to illustrate:

[0050] Taking a refinery's 800,000 t / a continuous reforming unit as an example, the production of dechlorinated reformed hydrogen is 23,000 Nm 3 / h, pressure 2.2MPa, the composition of reformed hydrogen under typical working conditions is as follows: 1-H2; 2-CH4; 3-C2H6; 4-C3H8; 5-iC4H 10 ;6-nC4H 10 ;7-C5H 12The pipeline is DN300 and the wall thickness is 10.0mm. The dechlorination tank adopts a 1-on, 1-off operation mode.

[0051] Five groups of reformed hydrogen samples were collected from the plant site, and the content of each component was measured using laboratory chromatography. Hydrogen chloride gas with different contents was prepared for each group of reformed hydrogen samples. Each group of reformed hydrogen samples was filled into alkali-free aluminosilicate glass sample containers, measuring 50 mm × 300 mm, at room temperature and maintained at a pressure of 2.1 MPa. Tables 1-5 show these.

[0052] Table 1

[0053]

[0054]

[0055] Table 2

[0056]

[0057] Table 3

[0058]

[0059] Table 4

[0060]

[0061]

[0062] Table 5

[0063]

[0064] In step S102, the laser emitting unit and laser receiving unit of the hydrogen chloride online analyzer measure light intensity data at the receiving end of multiple sets of reformed hydrogen samples, establish a correspondence between the light intensity data and hydrogen chloride content data, and form a basic database. Specifically, the laser emitting unit and laser receiving unit of the hydrogen chloride online analyzer are connected to the two end surfaces of the sample container. The light intensity signal at the receiving end of different samples is measured and represented by a voltage V. The correspondence between the measured light intensity data and hydrogen chloride content data is shown in Tables 1 to 5.

[0065] In step S103, a predictive analysis model is constructed based on the corresponding relationship in step S102, using the light intensity data as the independent variable and the hydrogen chloride content data as the dependent variable. The predictive analysis model in this step can be obtained through methods such as data fitting, neural network models, and genetic algorithms. Preferably, a piecewise function mathematical model structure is used to describe the mathematical relationship between light intensity and hydrogen chloride content in reformed hydrogen. Specifically, the data in Tables 1 to 5 are summarized and summarized in Table 6.

[0066] Table 6: Summary of Hydrogen Chloride Content-Light Intensity Data

[0067] HCl, ppm 0 0.2 0.4 0.6 0.8 1.0 1.5 2.0 4.0 8.0 16.0 Table 1 - Light intensity, V 4.75 4.73 4.72 4.71 4.68 4.65 4.58 4.54 4.48 4.31 4.21 Table 2 - Light intensity, V 4.76 4.74 4.72 4.71 4.69 4.66 4.59 4.55 4.47 4.32 4.2 Table 3 - Light intensity, V 4.77 4.73 4.73 4.71 4.68 4.67 4.6 4.56 4.48 4.31 4.21 Table 4 - Light intensity, V 4.75 4.73 4.72 4.7 4.69 4.67 4.59 4.56 4.48 4.32 4.2 Table 5 - Light intensity, V 4.76 4.74 4.72 4.71 4.68 4.69 4.58 4.55 4.47 4.31 4.19 Average light intensity, V 4.76 4.73 4.72 4.71 4.68 4.67 4.59 4.55 4.48 4.31 4.20

[0068] According to the data in Table 6, with the hydrogen chloride content as the ordinate and the light intensity data as the abscissa, a curve is drawn on the coordinate axis using the light intensity and hydrogen chloride content data in Tables 1 to 5, as shown in FIG. Figure 4 As shown, from Figure 4 It can be seen that the relationship between hydrogen chloride content and light intensity presents a piecewise function relationship distribution. When the piecewise function is used to construct the corresponding relationship between light intensity data and hydrogen chloride content data, the data fitting format can be expressed as: y = Ax 3 +Bx 2 +Cx+D; where x is the light intensity data, y is the hydrogen chloride content data, and A, B, C, and D are fitting coefficients. Specifically, using the light intensity (4.52→4.75) as the boundary, the average light intensity data in Table 6 and the hydrogen chloride data are used for data fitting to obtain a piecewise function relationship, as shown in formula (1):

[0069]

[0070] In the above formula (1), y is the hydrogen chloride content in the reformed hydrogen, ppm; x is the infrared laser intensity detected by the receiving end, V.

[0071] The corresponding relationship between each piecewise function is as follows Figures 5 and 6 As shown, the hydrogen chloride content in the on-site reformed hydrogen can be calculated based on the on-site measured light intensity data using formula (1).

[0072] Step S104: symmetrically drill holes along the radial sides of the reformed hydrogen dechlorination tank outlet pipeline to construct a pipeline 11 to form a laser path. A pressure-resistant and light-transmitting unit (see the device section in Example 1) is sealed and installed at the drilled holes; and light intensity data at the on-site reformed hydrogen receiving end is measured by the laser emitting unit 2 and the laser receiving unit 3 respectively provided at both ends of the laser path.

[0073] Step S105: To make the calculation result of the on-site hydrogen chloride content more accurate, the present invention preferably but not restrictively adds a step of correcting the fitting coefficient (see Figure 3). Specifically, first, the model calculation value of the hydrogen chloride content data is calculated according to the initial value of the fitting coefficient (i.e., the coefficients A, B, C, and D in Formula 1); since the actual production measured values ​​are collected regularly on site (using laboratory methods), the actual measured value of the hydrogen chloride content at a certain moment can be compared with the model calculation value at that moment. When the relative deviation between the actual measured value and the model calculation value at that moment exceeds the threshold, this step is executed and the actual measured value of the hydrogen chloride content and the light intensity at that moment is imported into the basic database; according to the piecewise function range corresponding to the actual measured value of the light intensity, the data within the range is refitted to obtain the corrected fitting coefficient (i.e. Figure 3 ). Refitting only the data within the range of the piecewise function can effectively reduce the amount of calculation while ensuring accuracy. If the relative deviation does not exceed the threshold, step S106 is still performed using the initial fitting coefficients.

[0074] Step S106 , calculating the on-site hydrogen chloride content data using the prediction analysis model and the measured light intensity data at the on-site reformed hydrogen receiving end.

[0075] Step S107, based on the calculated hydrogen chloride content data, when it is determined that the hydrogen chloride content exceeds the control threshold and lasts for a certain period of time, an alarm is issued or the dechlorination tank operation is adjusted. Specifically, the present invention sets the control threshold to two levels, that is, the first threshold is 0.5ppm and the second threshold is 1ppm. When the calculated hydrogen chloride content in the reformed hydrogen is greater than 0.5ppm and lasts for 5 minutes or more, an alarm is issued to remind the operator to strengthen the dechlorination supervision of the device and take samples for analysis in time; when the calculated hydrogen chloride content in the reformed hydrogen is greater than 1ppm and lasts for 5 minutes or more, the reformed hydrogen is switched to another spare dechlorination tank or the order of the two dechlorination tanks is changed. Figure 7 In the process, the first dechlorination tank 100 is switched to the second dechlorination tank 200, that is, the inlet and outlet valves of the second dechlorination tank 200 are opened, and the inlet and outlet valves of the first dechlorination tank 100 are closed, and the test is re-performed after stable operation.

[0076] The online analysis device for hydrogen chloride in catalytic reformed hydrogen of Example 1 and the online analysis method for hydrogen chloride in catalytic reformed hydrogen of Example 2 of the present invention are used. Different groups of reformed hydrogen samples containing different hydrogen chloride contents are arranged in a sampling container. The light intensity data at the sample receiving end is measured using a hydrogen chloride online analyzer. A piecewise function is constructed based on the correspondence between the hydrogen chloride content and the light intensity data. The coefficients of each piecewise function are determined by fitting. Finally, the hydrogen chloride content in the reformed hydrogen at the outlet pipeline of the on-site dechlorination tank is calculated based on the constructed piecewise function. The hydrogen chloride content in the reformed hydrogen can be analyzed and detected in real time. The present invention uses a basic database to replace the standard gas analysis chamber used in the prior art, avoiding the problems of easy leakage of standard gas and easy damage of the gas pool. The invention can eliminate the deficiency of hydrogen chloride content, thereby achieving the purpose of saving investment and promoting long-term operation of the system; by using the measured data of hydrogen chloride content regularly detected on site, the measured data can be imported into the basic database and the corresponding piecewise function coefficients can be recalibrated to obtain more accurate hydrogen chloride simulation calculation values; through the real-time simulation calculation of the present invention, the hydrogen chloride content in the reformed hydrogen can be analyzed and detected in real time, which makes up for the shortcomings of the current low frequency of hydrogen chloride analysis and detection in reformed hydrogen and delayed problem discovery, and can timely discover working conditions such as chlorine breakthrough in reformed hydrogen, guide the dechlorination tank to make operational adjustments, and avoid the impact of chlorine-containing hydrogen on downstream equipment; the present invention does not need to reduce the pressure of reformed hydrogen to normal pressure, and does not separately draw out a reformed hydrogen flow, and has the characteristics of simple process and wide pressure range.

[0077] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is apparent that many changes and variations are possible in light of the foregoing teachings. The exemplary embodiments are selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and variations. Any simple modifications, equivalent variations, and modifications made to the exemplary embodiments described above are intended to fall within the scope of protection of the present invention.

Claims

1. A method for online analysis of hydrogen chloride in catalytic reforming hydrogen, characterized in that: The steps include: A. preparing multiple groups of reformed hydrogen samples with different hydrogen chloride contents using reformed hydrogen collected on-site, and filling the multiple groups of reformed hydrogen samples into pressure-resistant, light-transmitting containers; B. measuring light intensity data of the plurality of groups of reformed hydrogen sample receiving ends respectively by a laser emitting unit and a laser receiving unit of a hydrogen chloride online analyzer, establishing a corresponding relationship between the light intensity data and the hydrogen chloride content data, and forming a basic database; C. constructing a prediction analysis model based on the corresponding relationship, with the light intensity data as an independent variable and the hydrogen chloride content data as a dependent variable; the prediction analysis model is obtained by data fitting, and when the data is obtained by data fitting, a piecewise function is used to construct the corresponding relationship between the light intensity data and the hydrogen chloride content data; D. Drill holes symmetrically along the radial sides of the reformed hydrogen dechlorination tank outlet pipeline to construct a pipeline to form a laser path, and seal and install a pressure-resistant light-transmitting unit at the drilled holes; measure the light intensity data of the on-site reformed hydrogen receiving end through the laser emitting unit and laser receiving unit respectively provided at both ends of the laser path; E. Calculating on-site hydrogen chloride content data using the prediction analysis model and the measured light intensity data at the on-site reformed hydrogen receiving end.

2. The online analysis method for hydrogen chloride in catalytic reforming hydrogen according to claim 1, characterized in that: The data fitting format is: y=Ax 3 +Bx 2 +Cx+D; where x is the light intensity data, y is the hydrogen chloride content data, and A, B, C, and D are fitting coefficients.

3. The online analysis method for hydrogen chloride in catalytic reforming hydrogen according to claim 2, characterized in that: Before step E, the method further includes the step of correcting the fitting coefficients.

4. The method for online analysis of hydrogen chloride in catalytic reforming hydrogen according to claim 3, characterized in that: The correction of the fitting coefficient is specifically as follows: Calculate the model calculation value of hydrogen chloride content data according to the initial value of the fitting coefficient; The actual measured value of the hydrogen chloride content at a certain moment is compared with the model calculated value at that moment. When the relative deviation between the actual measured value and the model calculated value at that moment exceeds a threshold, the hydrogen chloride content and the light intensity measured value at that moment are imported into the basic database; and according to the piecewise function range corresponding to the light intensity measured value, the data within the range is refitted to obtain a corrected fitting coefficient.

5. The online analysis method for hydrogen chloride in catalytic reforming hydrogen according to claim 1, characterized in that: After step E, the method further includes: according to the calculated hydrogen chloride content data, when it is determined that the hydrogen chloride content exceeds the control threshold and lasts for a certain period of time, issuing an alarm or adjusting the dechlorination tank operation.

6. The method for online analysis of hydrogen chloride in catalytic reforming hydrogen according to claim 5, characterized in that: The control thresholds include 0.5ppm and 1ppm; When the calculated hydrogen chloride content in the reformed hydrogen is greater than 0.5ppm and lasts for 5 minutes or more, an alarm will be issued; when the calculated hydrogen chloride content in the reformed hydrogen is greater than 1ppm and lasts for 5 minutes or more, the reformed hydrogen will be switched to another spare dechlorination tank or the order of the two dechlorination tanks will be changed.

7. The method for online analysis of hydrogen chloride in catalytic reforming hydrogen according to claim 1, characterized in that: The pressure-resistant light-transmitting unit in step D is made of glass, specifically soda-lime glass, borosilicate glass, high-purity SiO2 glass or alkali-free aluminosilicate glass, with a maximum pressure resistance of 35-40 kg; the sealing material is made of synthetic fiber, polytetrafluoroethylene or polyetheretherketone resin.

8. An online analysis device for hydrogen chloride in catalytic reforming hydrogen, characterized in that: include: A sampling unit, which uses the reformed hydrogen collected on site to prepare multiple groups of reformed hydrogen samples with different hydrogen chloride contents, and respectively fills the multiple groups of reformed hydrogen samples into pressure-resistant and light-transmitting containers; A hydrogen chloride online analyzer, which measures light intensity data of the plurality of groups of reformed hydrogen sample receiving ends respectively through a laser emitting unit and a laser receiving unit; and measures light intensity data of the on-site reformed hydrogen receiving end; A prediction model construction unit constructs a prediction analysis model with the light intensity data as an independent variable and the hydrogen chloride content data as a dependent variable based on the correspondence between the light intensity data and the hydrogen chloride content data; the prediction analysis model is obtained by data fitting, and when obtained by data fitting, a piecewise function is used to construct the correspondence between the light intensity data and the hydrogen chloride content data; A hydrogen chloride content calculation unit calculates on-site hydrogen chloride content data using the prediction model and the measured light intensity data of the on-site reformed hydrogen receiving end.

9. The online analysis device for hydrogen chloride in catalytic reformed hydrogen according to claim 8, characterized in that: The pressure-resistant light-transmitting container is a pressure-resistant glass container.

10. The online analysis device for hydrogen chloride in catalytic reformed hydrogen according to claim 8, characterized in that: The laser emitting unit comprises: An infrared laser light source, which is used to provide continuous infrared laser; A chopper modulates the continuous infrared laser light into pulse light.

11. The online analysis device for hydrogen chloride in catalytic reformed hydrogen according to claim 8, characterized in that: The laser receiving unit comprises: a filter that receives and filters infrared light whose intensity is weakened after being absorbed by hydrogen chloride in reformed hydrogen; a convex lens that focuses the filtered infrared light; The detector, whose photosensitive surface receives the focused infrared light, converts the optical signal carrying the change in hydrogen chloride concentration into an electrical signal.

12. The online analysis device for hydrogen chloride in catalytic reformed hydrogen according to claim 8, characterized in that: A light-transmitting wafer for sealing is respectively provided between the laser emitting unit, the laser receiving unit and the laser path.

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