Level measurement method for horizontal stirred bed reactors and radioactive instrument detector

Abstract

The application provides a level measurement method of a horizontal stirred bed reactor and a radioactive instrument detector, and the method comprises the following steps: acquiring a high-side level and a low-side level detected by the radioactive instrument detector; confirming a range of installation inclination angles of a radioactive source according to the high-side level and the low-side level in the reactor; acquiring a height of an actual level in the reactor, and confirming positions and measurement ranges of a first circular-arc flexible optical fiber detector and a second circular-arc flexible optical fiber detector according to the height of the actual level in the reactor and the range of the installation inclination angles; acquiring a size of a stirring shaft in the reactor, and confirming a range of a blind area of the detector measurement according to the size of the stirring shaft in the reactor; and calculating a height of a non-horizontal distributed material to be measured according to the range of the blind area of the detector measurement, a first measurement length and a second measurement length measured by the first circular-arc flexible optical fiber detector and the second circular-arc flexible optical fiber detector. The level of the horizontal stirred bed reactor can be accurately measured.

Description

Technical Field

[0001] This invention relates to the field of chemical production, and more specifically, to a method for measuring the level of a horizontal stirred bed reactor and a radioactive instrument detector. Background Technology

[0002] Horizontal reactors are an important type of equipment widely used in chemical production, with applications in various processes across chemical and environmental protection fields. Particularly in the polypropylene industry, processes such as the Innovene process, the Horizone process, and the SPG-II / III process all utilize horizontal stirred bed reactors.

[0003] The polypropylene process utilizes a horizontal stirred bed reactor, capable of producing various polypropylene products such as homopolymers, random copolymers, and impact copolymers. The material level in the reactor has a direct and significant impact on the polymerization process performance. If the powder level in the reactor is too low, uneven powder distribution will affect product performance, and it will also lead to reduced reaction load and failure to reach production targets. Conversely, if the material level in the reactor is too high, polymer powder entrainment can cause blockages, affecting long-term operation of the equipment. Therefore, how to accurately measure the material level in a horizontal stirred bed reactor has always been a pressing issue in the production of various polypropylene products. Summary of the Invention

[0004] In view of this, the present invention discloses a method for measuring the level of a horizontal stirred bed reactor and a radioactive instrument detector, which solves the problem of level measurement being affected by changes in material density and non-horizontally distributed materials in a completely non-invasive cylindrical horizontal stirred bed reactor.

[0005] Specifically, the present invention is achieved through the following technical solutions:

[0006] In a first aspect, this application proposes a method for measuring the level in a horizontal stirred bed reactor, the method comprising:

[0007] The method for acquiring the high-side and low-side material levels detected by a radioactive instrument detector includes: a radioactive source, a first arc-shaped flexible fiber optic detector, and a second arc-shaped flexible fiber optic detector. The radioactive source is positioned at a first target location on the sidewall of the horizontal stirred bed reactor. The first and second arc-shaped flexible fiber optic detectors are positioned at a second and a third target location on the sidewall of the horizontal stirred bed reactor. A flexible fiber optic detector group consisting of the first and second arc-shaped flexible fiber optic detectors is located relative to the radioactive source. The first arc-shaped flexible fiber optic detector is used to measure the low-side material level generated by stirring in the horizontal stirred bed reactor, and the second arc-shaped flexible fiber optic detector is used to measure the high-side material level generated by stirring in the horizontal stirred bed reactor.

[0008] Based on the high-side and low-side material levels in the reactor, determine the range of the radiation source installation tilt angle;

[0009] The actual level height in the reactor is obtained, and the position and measurement range of the first and second arc-shaped flexible fiber optic detectors are confirmed based on the actual level height and tilt angle range in the reactor.

[0010] Obtain the dimensions of the stirring shaft in the reactor, and confirm the blind zone range of the detector based on the dimensions of the stirring shaft in the reactor;

[0011] The height of the non-horizontally distributed material to be measured is calculated based on the first measurement length and the second measurement length measured by the first and second arc-shaped flexible fiber optic detectors within the blind zone of the detector measurement blind zone.

[0012] Optionally, based on the high-side and low-side levels in the reactor, the range of the radiation source installation tilt angle is determined, including:

[0013] Based on the reactor inner diameter, the reactor minimum diameter angle of repose, the reactor maximum diameter angle of repose, the high side height at the maximum level, and the average height of the material in the reactor at the maximum level, the low side height and high side height at the maximum level are determined. The high side height at the maximum level is the sum of the heights from the bottom of the circle to the center of the circle and the intersection of the 45° extension line from the center of the circle to the outer circle.

[0014] The length of the material surface is determined based on the low side height and high side height, chord length and chord height at maximum level;

[0015] The tilt angle is determined based on the height difference between the two sides of the material surface and the length of the material surface.

[0016] Optionally, the low-side height and high-side height at maximum level can be calculated using the following formulas:

[0017]

[0018] h=2h avg - H≈0.6464D;

[0019] Among them, h avg =0.75•D, where D is the inner diameter of the reactor, H is the height of the high side at maximum level, and h is the height of the low side at maximum level.

[0020] Alternatively, the tilt angle can be determined using the following formula:

[0021] Sin θ =Δh / c' ≈ 0.2072D / 0.866D ≈0.2393;

[0022] Where θ is the tilt angle, Δh is the height difference between the two sides of the material surface, and c' is the length of the material surface, Δh = H –h, c' = 0.866D.

[0023] Optionally, the blind zone range of the detector can be confirmed by the following steps:

[0024] Obtain the diameter of the detector and the diameter of the stirring shaft, calculate the target central angle, and ensure that the detector and the stirring shaft are coaxial.

[0025] Calculate the blind zone arc length based on the target's central angle and the detector's diameter;

[0026] The measurement blind zone arc length of the first and second arc-shaped flexible fiber optic detectors is determined based on the position of the detectors.

[0027] Alternatively, the target central angle can be calculated using the following formula:

[0028] γ=360°- 4•(∠POQ )=4•(90°- arccos (d / D'))= 4•arcsin (d / D');

[0029] Let the diameter of the stirring shaft (small circle) be d, and the diameter of the detector (large circle arc) be D'.

[0030] ∠POQ is the central angle formed by a ray originating from point P (the radiation source), tangent to the smaller circle at point Q, and the center O of the larger circle (which is concentric with the smaller circle).

[0031] Alternatively, the blind zone arc length can be calculated using the following formula:

[0032] L'= R'•γ=4•R'•arcsin (d / D') =2•D• arcsin (d / D').

[0033] Optionally, the height of the non-horizontally distributed test material can be determined through the following steps:

[0034] Based on the low-side length measured by the first arc-shaped flexible fiber optic detector and the blind zone range of the first arc-shaped flexible fiber optic detector, the first projected central angle of the measurement blind zone of the first arc-shaped flexible fiber optic detector is determined.

[0035] The material height on the lower side is determined based on the first projected central angle and the radius of the reactor.

[0036] Based on the low-side length measured by the second arc-shaped flexible fiber optic detector and the blind zone range of the second arc-shaped flexible fiber optic detector, the second projected central angle of the measurement blind zone of the second arc-shaped flexible fiber optic detector is determined;

[0037] The height of the material on the higher side is determined based on the second projected central angle and the radius of the reactor;

[0038] The material tilt angle is determined based on the height of the material on the lower side and the height of the material on the higher side.

[0039] Alternatively, the material tilt angle can be determined using the following formula:

[0040] ;

[0041] Where H is the height of the material on the high side, h is the height of the material on the low side, and R is the reactor radius.

[0042] Secondly, the present invention discloses a radioactive instrument detector, which includes: a radioactive source, a first arc-shaped flexible fiber optic detector, and a second arc-shaped flexible fiber optic detector.

[0043] The radiation source is positioned at a first target location on the side wall of the horizontal stirred bed reactor. The first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector are positioned at a second target location and a third target location on the side wall of the horizontal stirred bed reactor, respectively. The flexible fiber optic detector group, consisting of the first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector, is located at a relative position to the radiation source. The first arc-shaped flexible fiber optic detector is used to measure the low-side material level generated by stirring in the horizontal stirred bed reactor, and the second arc-shaped flexible fiber optic detector is used to measure the high-side material level generated by stirring in the horizontal stirred bed reactor.

[0044] The method for measuring the level of a horizontal stirred bed reactor and the radioactive instrument detector proposed in this application solve the problem of level measurement being affected by changes in material density and non-horizontally distributed materials in a completely non-invasive cylindrical horizontal stirred bed reactor. Attached Figure Description

[0045] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0046] Figure 1 A schematic flowchart illustrating a method for measuring the level in a horizontal stirred bed reactor, provided as an embodiment of this application;

[0047] Figure 2 Schematic diagram of the radioactive instrument detector provided in this application Figure 1 ;

[0048] Figure 3Schematic diagram of the radioactive instrument detector provided in this application Figure 2 ;

[0049] Figure 4 Schematic diagram of the radioactive instrument detector provided in this application Figure 3 . Detailed Implementation

[0050] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of systems and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0051] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0052] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0053] This application relates to the field of chemical production. Specifically, it relates to a method for measuring the level in a horizontal stirred bed reactor and a radioactive instrument detector.

[0054] Horizontal reactors are an important type of equipment widely used in chemical production, with applications in various processes across chemical and environmental protection fields. Particularly in the polypropylene industry, processes such as the Innovene process, the Horizone process, and the SPG-II / III process all utilize horizontal stirred bed reactors.

[0055] The polypropylene process utilizes a horizontal stirred bed reactor, capable of producing various polypropylene products such as homopolymers, random copolymers, and impact copolymers. The material level in the reactor has a direct and significant impact on the polymerization process performance. If the powder level in the reactor is too low, uneven powder distribution will affect product performance, and it will also lead to reduced reaction load and failure to reach production targets. Conversely, if the material level in the reactor is too high, polymer powder entrainment can cause blockages, affecting long-term operation of the equipment. Therefore, how to accurately measure the material level in a horizontal stirred bed reactor has always been a pressing issue in the production of various polypropylene products.

[0056] Specifically, because the materials inside the reactor (propylene, ethylene, hydrogen, etc.) undergo polymerization reactions, their density changes, and they are flammable, explosive, and toxic. Polymer powder can also cause frequent pipe blockages. Therefore, the reactor should adopt a completely non-invasive equipment structure design. Using radioactive instruments based on the "ray absorption principle," the level inside the equipment can be measured in a completely non-contact manner.

[0057] The principle of level measurement using radioactive instruments: When gamma rays are emitted from the radiation source, they pass through the equipment wall and the material being measured inside to reach the detector. Their intensity decreases exponentially with the thickness of the material they pass through. When the level changes, the thickness of the material through which the rays pass also changes, maintaining a certain functional relationship.

[0058] The detector receives the intensity of rays after they have penetrated a material, and the degree of attenuation is proportional to the material's thickness or density. Beer-Lambert's law describes the relationship between ray intensity and medium thickness: I = I₀e⁻¹ −μH

[0059] Where I0 is the initial radiation intensity, I is the intensity after penetration, μ is the absorption coefficient, and H is the medium thickness.

[0060] After gamma rays penetrate the medium, the intensity change is sensed by the detector and converted into the modulation of optical signal parameters. The modulated optical signal is then converted into an electrical signal, and the medium thickness data is obtained after demodulation.

[0061] When the material level rises and blocks the radiation, the intensity of the radiation detected by the detector decreases; conversely, when the material level falls, the intensity of the radiation detected by the detector increases. Therefore, the level of the material can be determined based on the intensity of the detected radiation.

[0062] There are four common methods for measuring the level using radioactive instruments:

[0063] (1) Rod source / point detector method

[0064] A key feature is that the length of the rod source is determined by the required measurement range. The intensity distribution of the rod source ensures linearity in the measurement, meaning that the detector's measurement is linearly related to changes in the level. Therefore, calibration and operation are straightforward.

[0065] (2) Rod detector / point source method

[0066] The length of the rod detector depends on the required measurement range. If the required measurement range is too large, more than two rod detectors are needed. If the ray range of a single point source is insufficient, two or more point sources are used.

[0067] (3) Rod source / rod detector method

[0068] If the measurement range is too large, and the distance from the detector to the source is too great, or the wall of the equipment is too thick, a rod source / rod detector configuration should be selected. In this case, the lengths of both the source and the detector should be equal to the measurement range.

[0069] (4) Point source / point detector method

[0070] When the measurement range is small, a point source / point detector configuration can be selected. Since the level measurement result is related to the material density, the influence of the gaseous medium on the level should be considered. When the pressure in the reactor increases, the density of the gaseous medium increases, causing the detector to measure a level higher than the actual material level. The nonlinearity of level measurement by radioactive instruments is caused by density changes. One densitometer can be added to measure the gas phase density, and another to measure the solid phase density; then compensation and correction can be performed based on the density measurement results.

[0071] Specifically, the shortcomings of existing technology are as follows:

[0072] (1) Measurement accuracy issues

[0073] For rod source / point detectors and rod source / rod detector measurement methods: Since the horizontal stirred bed reactor is cylindrical, the length of the rod source and the measurement of the detector are nonlinear with the change of the material level, making them difficult to calibrate or confirm.

[0074] For point source / point detector measurement methods: Because level measurement results are related to the density of the material, such as level measurement in a vertical stirred reactor using UNIPOL's patented polypropylene process, it is only applicable to vertical containers. For level measurements in a horizontal stirred bed reactor where the material is not horizontally distributed, even with compensation using gas density measurements, there will still be significant errors.

[0075] For point source / rod detector measurement methods: Due to the presence of agitators in horizontal stirred bed reactors, the material level in the reactor is not horizontally distributed. Therefore, it is necessary to consider the large measurement range of the horizontal stirred bed reactor and the need to avoid the obstruction of the agitator shaft by the X-ray beam. The Innovene, Horizone, and SPGII / III processes share many similarities, with essentially the same reactor design, including similar level measurement methods. Specifically, the Innovene and SPGII / III processes use horizontal reactors with one horizontal shaft agitator, while the Horizone process uses a horizontal reactor with two horizontal shaft agitators. In all these processes, the horizontal stirred bed reactors exhibit a non-horizontally distributed material level, making accurate level measurement difficult. This is especially true for horizontal reactors with one horizontal shaft agitator, where the material distribution is highly inclined due to the fluidization of polymer particles, making the actual level height even more difficult to measure. For example, in the horizontal stirred bed reactor of Innovene's patented polypropylene process, level measurement requires setting up two radiation sources and three rod detectors to measure the level on the low side (using two detectors) or the high side (using one detector), which results in a large actual error compared to the actual level.

[0076] (2) Safety hazards

[0077] When a radiation source is installed outside a horizontal stirred bed reactor, the radiation needs to penetrate the outer wall of the equipment or the shielding of the intermediate stirring shaft. This requires the selection of a radiation source with a larger radiation intensity, which may expose on-site personnel to radiation values ​​far exceeding those permitted by local regulations. Therefore, a greater degree of radiation source protection is required.

[0078] Uncontrolled material levels in a horizontal stirred bed reactor can lead to the following accidents: high material levels can cause excessive load on the agitator, resulting in abnormal stress and breakage of the drive shaft; low material levels can lead to insufficient catalyst residence time and incomplete reaction, which may cause explosive polymerization.

[0079] (3) The instrument is difficult to operate.

[0080] In Innovene's patented polypropylene process, radioactive instruments are indirect measurement instruments. Before normal use, the instruments must be calibrated or verified on the equipment using material simulation (such as measuring the detector count rate when the stirrer is running and stopping). Furthermore, gas phase density correction needs to be performed in actual production in order to establish the input-output relationship and obtain relatively accurate measurement values.

[0081] Based on this, this application proposes a method for measuring the level of a horizontal stirred bed reactor.

[0082] Please see Figure 1This application discloses a schematic flow chart of a method for measuring the level in a horizontal stirred bed reactor. Specifically, the method for measuring the level in a horizontal stirred bed reactor proposed in this application includes:

[0083] S101. Obtain the high-side level and low-side level detected by the radioactive instrument detector.

[0084] The radioactive instrument detector includes a radioactive source, a first arc-shaped flexible fiber optic detector, and a second arc-shaped flexible fiber optic detector. The radioactive source is positioned at a first target location on the sidewall of the horizontal stirred bed reactor. The first and second arc-shaped flexible fiber optic detectors are positioned at a second and a third target location on the sidewall of the horizontal stirred bed reactor. The flexible fiber optic detector group, consisting of the first and second arc-shaped flexible fiber optic detectors, is located relative to the radioactive source. The first arc-shaped flexible fiber optic detector is used to measure the low-side level generated by stirring in the horizontal stirred bed reactor, and the second arc-shaped flexible fiber optic detector is used to measure the high-side level generated by stirring in the horizontal stirred bed reactor.

[0085] For details, please refer to Figures 2-4 The radioactive instrument detector includes: a radioactive source 1; a reactor 2 (cylindrical shell); a stirring shaft 3; a second arc-shaped flexible fiber optic detector 4; and a second arc-shaped flexible fiber optic detector 5.

[0086] This application analyzes the shortcomings of existing technologies. The present invention utilizes a radiometric instrument composed of a single point-source radioactive source and two arc-shaped flexible fiber optic detectors to perform completely non-invasive level measurement in a horizontal stirred bed reactor. Because the horizontal cylindrical stirred bed reactor contains a horizontal stirrer, the reactor level is not horizontally distributed. By confirming the tilt angle of the material surface, the tilt angle of the radioactive source is determined to be perpendicular to the material surface, achieving maximum radiation range from a single radioactive source.

[0087] Please continue reading. Figures 2-4 The horizontal stirred bed reactor is a horizontal cylindrical shape with a radioactive point source on the outer wall, a horizontal stirrer in the middle, and two arc-shaped radiation detectors on the outside. The following geometric model is established based on the cross-section: reactor (large circle), stirrer (small circle), detectors (arcs), with the three circles concentric.

[0088] Then a geometric model can be established, and the level can be measured according to the arc length formula (arc length = radius • central angle) or the central angle formula (central angle = arc length / radius).

[0089] In this way, a single radiation source avoids interference between rays from multiple radiation sources; the flexible fiber optic detector can fit perfectly into the cylindrical horizontal stirred bed reactor; the two arc-shaped detectors can measure the material level on one side of the horizontal stirred bed reactor, which is lower and on the other side, due to stirring; the material level can be accurately determined by constructing a geometric model of a single point ray and two arcs using a radioactive instrument composed of a single point radiation source and two arc-shaped flexible fiber optic detectors.

[0090] S102. Based on the high-side and low-side material levels in the reactor, confirm the range of the tilt angle for installing the radioactive source.

[0091] Specifically, based on the high and low side material levels in the reactor, the range of the radiation source installation tilt angle is determined, including:

[0092] Based on the reactor inner diameter, the reactor minimum diameter angle of repose, the reactor maximum diameter angle of repose, the high side height at the maximum level, and the average height of the material in the reactor at the maximum level, the low side height and high side height at the maximum level are determined. The high side height at the maximum level is the sum of the heights from the bottom of the circle to the center of the circle and the intersection of the 45° extension line from the center of the circle to the outer circle.

[0093] The length of the material surface is determined based on the low side height and high side height, chord length and chord height at maximum level;

[0094] The tilt angle is determined based on the height difference between the two sides of the material surface and the length of the material surface.

[0095] The lower side height and upper side height at maximum level can be calculated using the following formulas:

[0096]

[0097] h=2h avg - H≈0.6464D;

[0098] Among them, h avg =0.75•D, where D is the inner diameter of the reactor, H is the height of the high side at maximum level, and h is the height of the low side at maximum level.

[0099] The tilt angle can be determined using the following formula:

[0100] Sin θ =Δh / c' ≈ 0.2072D / 0.866D ≈0.2393;

[0101] Where θ is the tilt angle, Δh is the height difference between the two sides of the material surface, and c' is the length of the material surface, Δh = H –h, c' = 0.866D.

[0102] Specifically, the material in a horizontal stirred bed reactor is powder. Due to the rotation of the stirring shaft blades, the material rises on one side and lies low on the other side along the direction of rotation. The maximum angle of material accumulation should be considered in terms of the angle of repose. The angle of repose is the angle between the free surface of the accumulated powder and the horizontal plane when the powder is in static equilibrium. It is also called the angle of accumulation or dynamic angle of repose. The angle of repose of powder is generally between 35° and 55°.

[0103] As an example, when the material is at its minimum level, the material surface tilt angle θ formed by material agitation is considered to be an average angle of repose of 45°; when the material is at its maximum level (average height of 75% of the diameter), the material surface tilt angle θ formed by material agitation is determined as follows:

[0104] In the parameter determination step: Let the inner diameter of the reactor be D, and the radius be R = D / 2. With a repose angle of 45°, the height H at maximum material level is the sum of the heights from the bottom of the circle to the center and the intersection of the 45° extension lines from the center to the outer circle. The formula is as follows:

[0105]

[0106] The process requires the average material height h in the horizontal stirred bed reactor at maximum level. avg X% of the diameter is 75%

[0107] h avg =X% • D=0.75• D

[0108] Let the height of the lower side at maximum level be h. The material volume balance must satisfy:

[0109] h avg •D = [(H + h) / 2] • D;

[0110] Simplifying, we get:

[0111] h=2 •h avg - H (absolute value required), substituting the numerical value, we get h≈0.6464D.

[0112] In the step of determining the relationship between the tilt angle and the height, the height difference between the two sides of the material surface Δh = H - h ≈0.8536D - 0.6464D≈ 0.2072D;

[0113] When the height of the maximum material level is h avg When the chord length c = R = 0.5D, according to the relationship that the chord height to the center b = 0.75DR = 0.25D, by applying the Pythagorean theorem, a 2 +b 2 =c 2 ,have to ≈0.433D, the length of the material surface c'=2a=0.866D;

[0114] Substituting the tilt angle Sin θ = Δh / c' ≈ 0.2072D / 0.866D ≈ 0.2393;

[0115] The tilt angle θ is approximately 13.8°.

[0116] When the radiation source is perpendicular to the inclined surface of the material, its radiation range is maximized, which is more conducive to the detector receiving the radiation and detecting the area obstructed by the material. Therefore, considering the minimum and maximum material levels, the material surface inclination angle θ is between 14° and 45°, with an engineering recommendation of θ ≈ 30° (considering a safety margin). This invention sets one radiation source at the intersection of the extended line of the outer circle of the cylindrical horizontal stirred bed reactor, where the angle between the outer circle and the vertical axis of the center is 30°.

[0117] Thus, based on the material's stacking characteristics and the process's requirement for the material's maximum average height, the range of the installation tilt angle of the radiation source at the material level is determined through a geometric model.

[0118] S103. Obtain the actual level height in the reactor, and based on the actual level height and tilt angle range in the reactor, confirm the position and measurement range of the first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector.

[0119] Specifically, the blind zone range of the detector can be confirmed through the following steps:

[0120] Obtain the diameter of the detector and the diameter of the stirring shaft, calculate the target central angle, and ensure that the detector and the stirring shaft are coaxial.

[0121] Calculate the blind zone arc length based on the target's central angle and the detector's diameter;

[0122] The measurement blind zone arc length of the first and second arc-shaped flexible fiber optic detectors is determined based on the position of the detectors.

[0123] The target central angle can be calculated using the following formula:

[0124] γ=360°- 4•(∠POQ )=4•(90°- arccos (d / D'))= 4•arcsin (d / D');

[0125] Let the diameter of the stirring shaft (small circle) be d, and the diameter of the detector (large circle arc) be D'.

[0126] ∠POQ is the central angle formed by the ray originating from point P (the radiation source), tangent to the small circle at point Q, and the center O of the concentric large and small circles.

[0127] The blind zone arc length can be calculated using the following formula:

[0128] L'= R'•γ=4•R'•arcsin (d / D') =2•D• arcsin (d / D').

[0129] Please see Figures 2-4 This application involves installing two flexible detectors below a horizontal stirred bed reactor. These flexible detectors can be installed in a concentric arc outside the cylindrical reactor. The two detectors are divided into two arc segments by the extension of the radiation source to the center (with an angle of 30° between the extension and the perpendicular axis of the center). The measurement range of the detectors includes the length of both detectors.

[0130] The second arc-shaped flexible fiber optic detector is used to measure the height of the highest side of the maximum level. The central angle between the highest point of the arc of the second arc-shaped flexible fiber optic detector and the horizontal center line of the circle should be higher than the 45° angle of repose. Therefore, this invention determines 60° (considering a safety margin).

[0131] Therefore, the measurement range of the second arc-shaped flexible fiber optic detector begins at a central angle of 60° with the horizontal center line of the circle and ends at the intersection of the extended line with an angle of 30° with the vertical axis of the circle. The second arc-shaped flexible fiber optic detector can completely measure the material on the high side of the reactor from the maximum level to the minimum level.

[0132] The length of the first arc-shaped flexible fiber optic detector is the lower side height at which the maximum level is measured. The central angle between the highest point of the arc of the first arc-shaped flexible fiber optic detector and the horizontal center line of the circle should be higher than the central angle β determined by the following formula:

[0133] Since the cylindrical reactor and the arc-shaped detector are concentric circles, the formula for the central angle can be simplified. According to the previous section, the lower side height at maximum level h≈0.6464D; the radius of the circle r=D / 2; the vertical distance to the chord passing through the center of the circle b = h –r = 0.6464D - 0.5D = 0.1464D;

[0134] Sinβ = b / r = 0.1464D / 0.5D = 0.2928;

[0135] β = arcsin (b / (D / 2)) = arcsin (0.2928) ≈ 17.02°.

[0136] The central angle is 17°. Therefore, the present invention determines the central angle between the highest point of the arc of the first arc-shaped flexible fiber optic detector and the horizontal center line of the circle to be 30° (considering a safety margin).

[0137] Therefore, the measurement range of the first arc-shaped flexible fiber optic detector begins at a central angle of 30° with the horizontal center line of the circle and ends at the intersection of the extension line with an angle of 30° with the vertical axis of the circle. The first arc-shaped flexible fiber optic detector can completely measure the material on the lower side of the reactor from the maximum level to the minimum level.

[0138] Thus, based on the material's stacking characteristics and the process's requirement for the material's maximum average height, the measurement range of the two detectors is determined through a geometric model.

[0139] S104. Obtain the dimensions of the stirring shaft in the reactor, and confirm the blind zone range of the detector based on the dimensions of the stirring shaft in the reactor.

[0140] Specifically, the radiation source emits rays from the inner edge of the reactor that are tangential to the stirring shaft at the center of the reactor. Because the rays are blocked by the stirring shaft, a certain measurement blind zone is generated on the detector. This is confirmed as follows:

[0141] The steps for calculating the central angle γ of the blind zone include:

[0142] Let the diameter of the detector (large circle) be D', and the radius be R' = D' / 2; the diameter of the stirring shaft (small circle) be d, and the radius be r = d / 2; and the arc length of the blind zone where the detector's rays are blocked by the stirring shaft be L'.

[0143] According to geometric optics and the geometric relationship of concentric circles, the ray originates from point P (the radiation source) and is tangent to the small circle at point Q. Connecting the point of tangency Q and the center O of the circle forms a right angle (tangent property). In the right triangle OPQ, if Cos (∠POQ) = r / R' = d / D', then the central angle ∠POQ = arccos (d / D').

[0144] Projecting the small circle onto the large circle arc, according to the central angle formula, the central angle γ = 360° - 4•(∠POQ) = 4•(90° - arccos(d / D')) = 4•arcsin(d / D');

[0145] The steps for calculating the blind zone arc length L' are as follows:

[0146] According to the arc length formula, the relationship between the blind zone arc length L' and the projected central angle γ is as follows:

[0147] L'= R'•γ=4•R'•arcsin (d / D') =2•D• arcsin (d / D');

[0148] Based on the setup of the two detectors on the high and low sides in the previous section, the measurement blind zone arc length L” = L’ / 2 = D• arcsin (d / D’) for each detector segment.

[0149] In this way, based on the installation tilt angle of the radiation source, the size of the stirring shaft, and the diameter of the reactor, the range of the detector's measurement blind zone can be determined through a geometric model.

[0150] S105. Calculate the height of the non-horizontally distributed material to be measured based on the first measurement length and the second measurement length measured by the first and second arc-shaped flexible fiber optic detectors within the blind zone of the detector measurement blind zone.

[0151] Specifically, the height of non-horizontally distributed test material can be determined through the following steps:

[0152] Based on the low-side length measured by the first arc-shaped flexible fiber optic detector and the blind zone range of the first arc-shaped flexible fiber optic detector, the first projected central angle of the measurement blind zone of the first arc-shaped flexible fiber optic detector is determined.

[0153] The material height on the lower side is determined based on the first projected central angle and the radius of the reactor.

[0154] Based on the low-side length measured by the second arc-shaped flexible fiber optic detector and the blind zone range of the second arc-shaped flexible fiber optic detector, the second projected central angle of the measurement blind zone of the second arc-shaped flexible fiber optic detector is determined;

[0155] The height of the material on the higher side is determined based on the second projected central angle and the radius of the reactor;

[0156] The material tilt angle is determined based on the height of the material on the lower side and the height of the material on the higher side.

[0157] The material tilt angle can be determined using the following formula:

[0158] ;

[0159] Where H is the height of the material on the high side, h is the height of the material on the low side, and R is the reactor radius.

[0160] As an example, the height of non-horizontally distributed materials can be determined using the following steps:

[0161] To determine the material height by measuring the length with a detector, the following geometric model needs to be established and solved:

[0162] Reactor: cylindrical, with a cross-sectional diameter D and a radius R = D / 2, and the center is the origin O(0,0).

[0163] Stirring shaft: cylindrical, with a cross-sectional diameter d and a radius r = d / 2, and its center is concentric with the reactor.

[0164] Detectors: Two flexible detectors are installed on the outside of the cylindrical reactor in concentric arcs with diameter D' and radius R'=D' / 2. They measure the projected central angle γ of the blind zone and the arc length of the part of the radiation blocked by the material and stirring shaft. The measurement length L of the second arc-shaped flexible fiber optic detector and the measurement length l of the first arc-shaped flexible fiber optic detector are also measured.

[0165] Material surface: material level height (lower side of material) h, material level height (higher side of material) H, material surface inclination angle θ.

[0166] Then, the following geometric relationships can be established based on the above parameters:

[0167] Based on the measured length of the first arc-shaped flexible fiber optic detector, the central angle α is obtained using the arc length formula: α = l / R'

[0168] When α ≥ 120°, the material level height (lower side of the material) h = R • (1 + sin(α - 120°))

[0169] When 30° < α < 120°, the material level height (lower side of the material) h = R • (1 - cos(α - 30°))

[0170] When γ < α < 30°, the material level height (lower side of the material) h = R • (1 - cos(30° - α))

[0171] Based on the measured length of the second arc-shaped flexible fiber optic detector, the central angle β is obtained using the arc length formula: β = L / R

[0172] When β ≥ 60°, the material level height (higher side) H = R • (1 + sin(β - 60°))

[0173] When γ < α < 60°, the material level height (lower side) H = R • (1 - sin(β - 60°))

[0174] Let the relationship between the inclination angle θ of the material surface and the highest point H and the lowest point h be:

[0175] tanθ = L / (Hh) = L / Δh

[0176] Where L is the projected length of the material surface in the horizontal direction.

[0177] The projection of the material surface onto a circular cross-section is a chord. The relationship between the projection length L and the radius R of the circle is as follows:

[0178] ;

[0179] Substituting Δh = L•tan θ, we can solve for the relationship between L and θ.

[0180] If H and h are known, the tilt angle can be obtained directly from the simplified formula:

[0181] ;

[0182] The above can be used to determine the height of the material level, accurately reflecting the height of the material in the reactor and the inclination of the material surface, thus preventing accidents caused by excessively high or low material levels.

[0183] In this way, based on the detector's measured length, the height of the non-horizontally distributed material can be determined using a geometric model.

[0184] This application utilizes a level measurement method employing a radioactive instrument composed of a single point-source radiation source and two arc-shaped flexible X-ray detectors. This method accurately measures the height of non-horizontally distributed materials, providing control targets for the residence time of materials within the reactor and the reactor's conversion rate. This improves product performance and ensures stable process operation. It solves the problem of level measurement in a completely non-invasive cylindrical horizontal stirred bed reactor. The completely non-invasive container structure completely eliminates the possibility of leakage of explosive or toxic media inside the reactor, ensuring process safety.

[0185] This invention relates to a radioactive instrument for measuring material level, consisting of a single point-source radioactive source and two arc-shaped flexible radiation detectors. Compared to combinations of multiple radioactive sources, this reduces the number of sources and lowers the risk of leakage. The extended measurement range of the arc-shaped flexible detectors reduces the measurement error of the rod detectors, enabling accurate measurement of material height and preventing accidents caused by excessively high or low material levels.

[0186] This invention confirms that the blind zone range of the detector measurement is generated by the shielding of the stirring shaft against radiation. When designing radioactive instruments, it is not necessary to consider the shielding of radiation by the stirring shaft. Furthermore, the influence of the blade thickness on the photoelectric pulse can be eliminated in the post-processing of the detector signal based on the blade rotation frequency. Therefore, it is only necessary to select the minimum usable radiation source based on the shell thickness of the container and the material, thereby reducing the radiation safety impact on the surrounding working environment.

[0187] On the other hand, please see Figures 2-4 The radioactive instrument detector includes: a radioactive source, a first arc-shaped flexible fiber optic detector, and a second arc-shaped flexible fiber optic detector.

[0188] The radiation source is positioned at a first target location on the side wall of the horizontal stirred bed reactor. The first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector are positioned at a second target location and a third target location on the side wall of the horizontal stirred bed reactor, respectively. The flexible fiber optic detector group, consisting of the first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector, is located at a relative position to the radiation source. The first arc-shaped flexible fiber optic detector is used to measure the low-side material level generated by stirring in the horizontal stirred bed reactor, and the second arc-shaped flexible fiber optic detector is used to measure the high-side material level generated by stirring in the horizontal stirred bed reactor.

[0189] The level detection equipment and instruments used in this application are products with corresponding functions and models from VEGA Germany, which can meet the level detection requirements.

[0190] For the above system embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this disclosure according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0191] Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices), magnetic disks (e.g., internal disks or removable disks), magneto-optical disks, and CD-ROMs and DVD-ROMs. Processors and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0192] Finally, it should be noted that although this specification contains many specific implementation details, these should not be construed as limiting the scope of any invention or the scope of the claims, but rather are primarily used to describe the features of specific embodiments of a particular invention. Certain features described in the various embodiments of this specification may also be implemented in combination in a single embodiment. On the other hand, various features described in a single embodiment may also be implemented separately in various embodiments or in any suitable sub-combination. Furthermore, while features may function in certain combinations as described above and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and a claimed combination may refer to a sub-combination or a variation of a sub-combination.

[0193] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0194] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result. Furthermore, the processes depicted in the drawings are not necessarily shown in a specific order or sequence to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0195] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method of level measurement of a horizontal stirred bed reactor, characterized in that, The method includes: The high-side and low-side levels detected by a radioactive instrument detector are obtained. The radioactive instrument detector includes a radioactive source, a first arc-shaped flexible fiber optic detector, and a second arc-shaped flexible fiber optic detector. The radioactive source is positioned at a first target location on the sidewall of the horizontal stirred bed reactor. The first and second arc-shaped flexible fiber optic detectors are positioned at second and third target locations on the sidewall of the horizontal stirred bed reactor. The flexible fiber optic detector group, consisting of the first and second arc-shaped flexible fiber optic detectors, is located relative to the radioactive source. The first arc-shaped flexible fiber optic detector measures the low-side level generated by stirring in the horizontal stirred bed reactor, and the second arc-shaped flexible fiber optic detector measures the high-side level generated by stirring in the horizontal stirred bed reactor. Based on the high-side and low-side levels in the reactor, the range of the radioactive source's installation tilt angle is determined. The actual height of the material level in the reactor is determined, and the positions and measurement ranges of the first and second arc-shaped flexible fiber optic detectors are confirmed based on the actual height of the material level and the range of the tilt angle. The dimensions of the stirring shaft in the reactor are obtained, and the measurement blind zone range of the detectors is confirmed based on the dimensions of the stirring shaft. The height of the non-horizontally distributed material to be measured is determined based on the measurement blind zone range of the detectors, the first measurement length and the second measurement length measured by the first and second arc-shaped flexible fiber optic detectors. The measurement blind zone range of the detectors is confirmed through the following steps: the diameter of the detectors and the diameter of the stirring shaft are obtained, and the target central angle is calculated, with the detectors coaxial with the stirring shaft. The blind zone arc length is calculated based on the target central angle and the diameter of the detectors. The measurement blind zone arc lengths of the first and second arc-shaped flexible fiber optic detectors are determined based on the positions of the detectors.

2. The method of claim 1, wherein, Based on the high and low side material levels in the reactor, the range of the radiation source installation tilt angle is determined, including: determining the low and high side heights at the maximum material level based on the reactor inner diameter, the angle of repose of the reactor minimum material diameter, the angle of repose of the reactor maximum material diameter, the high side height at the maximum material level, and the average height of the material in the reactor at the maximum material level; the high side height at the maximum material level is the sum of the heights from the bottom of the circle to the center and the intersection of the 45° extension lines from the center to the outer circle; determining the material surface length based on the low and high side heights at the maximum material level, the chord length, and the chord height; and determining the tilt angle based on the height difference between the two sides of the material surface and the material surface length.

3. The method according to claim 2, characterized in that, The low side height and the high side height at the maximum inventory are calculated by the following equations: h = 2h avg - H = 0.6464D; where h avg = 0.75 • D, D is the internal diameter of the reactor, H is the high side height at the maximum inventory, and h is the low side height at the maximum inventory.

4. The method of claim 2, wherein, The tilt angle is determined by the following formula: Sin θ = Δh / c' ≈ 0.2072D / 0.866D ≈ 0.2393; where θ is the tilt angle, Δh is the height difference between the two sides of the material surface, and c' is the length of the material surface, Δh = H – h, c' = 0.866D.

5. The method of claim 1, wherein, The target central angle is calculated using the following formula: γ = 360° - 4•(∠POQ) = 4•(90° - arccos(d / D')) = 4•arcsin(d / D'); the diameter of the stirring shaft is d, and the diameter of the detector is D'; ∠POQ is the central angle formed by the ray originating from the radiation source P, tangent to the stirring shaft at point Q, and the center O.

6. The method of claim 1, wherein, The blind zone arc length is calculated using the following formula: L' = R•γ = 4•R•arcsin (d / D') = 2•D•arcsin (d / D'); where d is the diameter of the stirring shaft, D' is the diameter of the detector, L' is the blind zone arc length, γ is the target central angle, D is the diameter of the reactor, and R is the radius of the reactor.

7. The method according to claim 1, characterized in that, The height of the non-horizontally distributed test material is determined by the following steps: Based on the first measurement length and the measurement blind zone range of the first arc-shaped flexible fiber optic detector, the first projected central angle of the measurement blind zone of the first arc-shaped flexible fiber optic detector is determined; based on the first projected central angle and the radius of the reactor, the height of the material on the lower side is determined; based on the second measurement length and the measurement blind zone range of the second arc-shaped flexible fiber optic detector, the second projected central angle of the measurement blind zone of the second arc-shaped flexible fiber optic detector is determined; based on the second projected central angle and the radius of the reactor, the height of the material on the higher side is determined; based on the height of the material on the lower side and the height of the material on the higher side, the material tilt angle is determined.

8. The method according to claim 7, characterized in that, The material tilt angle is determined using the following formula: ;in, H represents the height of the material on the higher side, h represents the height of the material on the lower side, and R represents the reactor radius.

9. A radioactive instrument detector for measuring the level in the horizontal stirred bed reactor as described in claim 1, characterized in that, The radioactive instrument detector includes: a radioactive source, a first arc-shaped flexible fiber optic detector, and a second arc-shaped flexible fiber optic detector; the radioactive source is disposed at a first target position on the side wall of the horizontal stirred bed reactor, the first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector are disposed at a second target position and a third target position on the side wall of the horizontal stirred bed reactor, and the flexible fiber optic detector group consisting of the first arc-shaped flexible fiber optic detector and the second arc-shaped flexible fiber optic detector is located at the relative position of the radioactive source; the first arc-shaped flexible fiber optic detector is used to measure the low-side material level generated by stirring in the horizontal stirred bed reactor, and the second arc-shaped flexible fiber optic detector is used to measure the high-side material level generated by stirring in the horizontal stirred bed reactor.

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