A separation device for separating m-cresol

Abstract

This invention relates to the field of m-p-cresol separation technology, and more particularly to a separation device for m-p-cresol separation production, comprising a fixed bed; a data acquisition module for real-time acquisition of p-cresol concentration and liquid flow rate; an interface determination module for determining a first interface and a second interface, including a leveling monitoring unit for determining whether the contact between the m-p-cresol mixture and the adsorbent is qualified based on an interface level index, and adjusting the spray flow rate of the m-p-cresol mixture; and an interface monitoring module for determining whether the adsorption process of p-cresol is qualified based on a spacing stability index between the first and second interfaces, and optimizing the flow rate adjustment coefficient; and an efficiency monitoring module for determining whether the separation efficiency of the m-p-cresol mixture is qualified based on the adsorption utilization rate of the adsorbent, and optimizing a preset level index. This invention improves the adsorption utilization rate of the adsorbent.

Description

Technical Field

[0001] This invention relates to the field of m-p-cresol separation technology, and more particularly to a separation device for the production of m-p-cresol. Background Technology

[0002] m-p-cresol, as an important fine chemical intermediate, is widely used in pharmaceuticals, pesticides, fragrances, and other fields. Its separation and purification is a key step in chemical production. Due to the extremely similar physicochemical properties of m-p-cresol isomers, conventional separation methods such as distillation are difficult to achieve efficient separation. Adsorption methods have become the mainstream technical solution due to their advantages of high separation efficiency and low energy consumption. Currently, fixed-bed adsorption devices are mostly used in industrial production for the separation of m-p-cresol. By filling specific adsorbents, p-cresol is selectively adsorbed to achieve separation from m-cresol. However, existing fixed-bed separation devices generally suffer from problems such as uneven spraying of the liquid distributor and unbalanced drainage of the liquid drainer during actual operation. This can easily lead to uneven radial flow velocity distribution of the liquid in the bed, resulting in reduced adsorbent utilization and unstable separation efficiency. Moreover, existing devices often rely on manual experience for parameter adjustment, which has strong adjustment lag and low precision, making it difficult to meet the stringent requirements of separation stability and product purity for continuous industrial production.

[0003] Chinese Patent Application Publication No. CN119425135A discloses a continuous refining apparatus and method for crude phenol. The apparatus includes a crude phenol storage tank, a dehydration tower, a primary distillation tower, a phenol fractionation tower, an o-cresol fractionation tower, a m- and p-cresol tower, an extractive distillation tower, and a p-cresol fractionation tower connected in sequence, with each tower top individually connected to a cooler. The method specifically includes the following steps: (1) discharging phenol water; (2) discharging heavy fraction; (3) discharging phenol; (4) discharging o-cresol; (5) discharging residual oil at the bottom of the tower; (6) extractive distillation to discharge m-cresol; and (7) discharging p-cresol, with the extractant being recycled. Compared with traditional continuous distillation processes, this invention uses vacuum distillation to separate the various components, resulting in higher product separation, fewer theoretical plates, and lower energy consumption. It achieves the production of high-purity phenolic products with low energy consumption, low cost, and high efficiency, greatly improving economic and environmental benefits.

[0004] The existing technology also has the following problems: when using a fixed bed adsorption device to adsorb and separate m- and p-cresol mixed liquids, there is a lack of real-time monitoring of the adsorption state of the adsorbent during the adsorption process. It is difficult to accurately perceive the uniformity of contact between the adsorbent and the mixed liquid and the synchronicity of the adsorption reaction process. This can easily lead to situations where the adsorbent is locally oversaturated and fails to switch to desorption in time or is not fully adsorbed in some areas, resulting in waste. Ultimately, this leads to a low adsorption utilization rate of the adsorbent. Summary of the Invention

[0005] To address this, the present invention provides a separation device for the production of m-p-cresol, which overcomes the problem in the prior art that lacks real-time monitoring of the adsorption state of the adsorbent during the adsorption process, makes it difficult to accurately perceive the uniformity of contact between the adsorbent and the mixed liquid and the synchronicity of the adsorption reaction process, and easily leads to situations where the adsorbent is locally oversaturated and fails to switch to desorption in time or is not fully adsorbed locally, resulting in waste and ultimately low adsorption utilization rate of the adsorbent.

[0006] To achieve the above objectives, the present invention provides a separation apparatus for the production of m-p-cresol, comprising:

[0007] A fixed bed, which includes a bed frame and a bed layer;

[0008] The data acquisition module includes several fiber optic concentration sensors disposed inside the bed to acquire the concentration of p-cresol, and a distributed flow rate sensor to acquire the liquid flow rate.

[0009] An interface determination module is used to determine the concentration gradient of p-cresol based on the monitoring results of several optical fiber concentration sensors, and to determine the first interface between the saturation zone and the adsorption zone of the bed, and the second interface between the adsorption zone and the zone to be adsorbed based on the concentration gradient.

[0010] Interface monitoring module, which includes,

[0011] The level monitoring unit is used to determine whether the contact between the m-p-cresol mixture and the adsorbent is qualified based on the comparison between the interface level index and the preset level index. Based on the condition that the contact between the m-p-cresol mixture and the adsorbent is not qualified, several flow rate adjustment coefficients are set to adjust the spray flow rate of the m-p-cresol mixture.

[0012] A spacing monitoring unit is used to determine whether the adsorption process of p-cresol is qualified based on the spacing stability index of the first interface and the second interface, under the condition that the contact between the p-cresol mixed liquid and the adsorbent is qualified, so as to optimize the flow rate adjustment coefficient based on the condition that the adsorption process of p-cresol is unqualified.

[0013] An efficiency monitoring module is used to determine whether the separation efficiency of the m-p-cresol mixture is qualified based on the adsorption utilization rate of the adsorbent, and to optimize the preset level index based on the condition that the separation efficiency of the m-p-cresol mixture is unqualified.

[0014] Furthermore, the interface determination module determines the corresponding position of the concentration gradient as the interface feature position based on the comparison results of the concentration gradient of p-cresol within a preset gradient range, and fits several interface feature positions of different radial directions within the same cross section to obtain the first interface of the saturation region and the adsorption region, and the second interface of the adsorption region and the region to be adsorbed.

[0015] Furthermore, the levelness monitoring unit determines the coefficient of variation of the absolute distance between the first interface or the second interface and the horizontal plane as the interface level index of the corresponding interface.

[0016] Furthermore, the level monitoring unit determines that the contact between the p-cresol mixed liquid and the adsorbent is unqualified based on the comparison result that the interface level index is greater than the preset level index.

[0017] Furthermore, based on the comparison result that the interface level index of the first interface is greater than the preset level index, the level monitoring unit adjusts the spray flow rate of the m-p-cresol mixture in the corresponding area by setting several flow rate adjustment coefficients according to the first liquid flow velocity distribution deviation of the m-p-cresol mixture.

[0018] Furthermore, the spacing monitoring unit determines the spacing stability index by the coefficient of variation of several vertical distances between the spacing curve constructed based on the vertical spacing between the first interface and the second interface during the adsorption process and the standard spacing line.

[0019] Furthermore, the spacing monitoring unit determines that the adsorption process of p-cresol is unqualified based on the comparison result that the spacing stability index is greater than the preset stability index.

[0020] Furthermore, when the spacing monitoring unit determines that the adsorption process of p-cresol is unqualified, it determines to optimize the flow rate adjustment coefficient with a first flow rate correction coefficient based on the comparison result that the relative difference between the spacing stability index and the preset stability index is greater than the preset relative difference.

[0021] The spacing monitoring unit determines to optimize the flow adjustment coefficient with a second flow correction coefficient based on the comparison result that the relative difference is less than or equal to the preset relative difference.

[0022] Furthermore, the efficiency monitoring module determines that the separation efficiency of the p-cresol mixture is unqualified based on the comparison result that the adsorption utilization rate of the adsorbent is less than the preset utilization rate.

[0023] Furthermore, when the separation efficiency of the m-p-cresol mixed liquid is unqualified, the efficiency monitoring module determines to increase the preset level index by a first index adjustment coefficient based on the comparison result that the difference between the preset utilization rate and the adsorption utilization rate is greater than the preset difference.

[0024] The efficiency monitoring module determines to increase the preset level index by a second index adjustment coefficient based on the comparison result that the utilization difference is less than or equal to the preset difference.

[0025] Compared with existing technologies, the advantages of this invention lie in its ability to determine the interface position and levelness during adsorption by real-time monitoring of the concentration distribution and liquid flow rate of p-cresol in the fixed bed, thereby judging whether the contact between the p-cresol mixture and the adsorbent is uniform. This device, through a levelness monitoring unit comparing the interface level index with a preset level, adjusts the spray flow rate or drainage flow rate in a timely manner to ensure uniform contact between the liquid and the adsorbent, avoiding insufficient adsorbent utilization or product purity fluctuations caused by uneven local flow rates, thus guaranteeing separation efficiency and product purity. Only uniform contact can ensure that p-cresol is fully and synchronously retained by the adsorbent, maintaining a stable p-cresol purity of over 99% at the outlet, while preventing local oversaturation or idleness of the adsorbent, thereby further improving the adsorption utilization rate of the adsorbent.

[0026] Furthermore, this invention uses a spacing monitoring unit to track the thickness stability of the adsorption zone in real time, and judges whether the adsorption process is qualified based on the spacing stability index of the first and second interfaces. If the thickness of the adsorption zone fluctuates greatly, it indicates that the adsorption process is unstable, which may lead to insufficient adsorption of p-cresol or excessive consumption of the adsorbent. By optimizing the flow rate adjustment coefficient, the thickness of the adsorption zone is stabilized from the source, ensuring that p-cresol is fully retained and avoiding excessive p-cresol content at the outlet or fluctuations in product purity. Through spacing monitoring and flow rate optimization, the thickness of the adsorption zone is maintained within the standard range, achieving stable operation of the adsorption process, thereby improving the adsorption utilization rate of the adsorbent while ensuring separation purity.

[0027] Furthermore, this invention assesses separation efficiency based on the adsorption utilization rate of the adsorbent using an efficiency monitoring module, and optimizes a preset level index when the efficiency is unsatisfactory. By dynamically adjusting the preset level index, frequent adjustments and flow field disruptions caused by overly stringent interface level standards are avoided, thereby maximizing adsorbent utilization while ensuring contact uniformity. Ultimately, through multi-module collaborative monitoring and adjustment, efficient and energy-saving separation of m-p-cresol mixed liquids is achieved, ensuring product purity remains stable at 98.5%, extending adsorbent lifespan, and reducing overall operating costs. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the separation device used for the separation and production of p-cresol in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the fixed bed drain pipe assembly according to an embodiment of the present invention;

[0030] Figure 3 This is a structural block diagram of the separation device used for the separation and production of p-cresol in an embodiment of the present invention;

[0031] Figure 4 A flowchart for determining whether the contact between the m-cresol mixed liquid and the adsorbent is qualified in an embodiment of the present invention;

[0032] In the diagram: 1. Fixed bed, 2. Bed body, 3. Distributor, 4. Fiber optic concentration sensor, 5. Flow rate sensor, 6. Bottom support layer, 7. Drainage pipe assembly, 71. Annular drainage main pipe, 72. Drainage branch pipe, 73. Electric valve, 8. Bed layer, 9. Adsorbent layer. Detailed Implementation

[0033] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0034] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0035] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0036] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] Please see Figures 1-3 As shown, Figure 1 This is a schematic diagram of the separation device used for the separation and production of p-cresol in an embodiment of the present invention; Figure 2 This is a schematic diagram of the fixed bed drain pipe assembly according to an embodiment of the present invention; Figure 3 This is a structural block diagram of the separation device used for the separation and production of p-cresol in an embodiment of the present invention.

[0038] The present invention provides a separation apparatus for the production of p-cresol, comprising:

[0039] A fixed bed 1 includes a bed body 2 and a bed layer 8, a liquid distributor 3 disposed on the top of the bed body 2 for uniformly spraying material onto the surface of the adsorbent, a bed layer 8 disposed inside the bed body 2 and below the liquid distributor 3, the bed layer 8 consisting of an adsorbent layer 9 and a bottom support layer 6 from top to bottom, and a drain pipe assembly 7 disposed below the bottom support layer 6, wherein the bed body 2 is a vertical cylindrical body;

[0040] The data acquisition module includes several fiber optic concentration sensors 4 that are radially and uniformly arranged inside the bed 8 for acquiring the concentration of p-cresol, and a distributed flow rate sensor 5 for acquiring the liquid flow rate.

[0041] The interface determination module is used to determine the concentration gradient of p-cresol based on the monitoring results of several optical fiber concentration sensors 4, and to determine the first interface between the saturation zone and the adsorption zone of the bed 8, and the second interface between the adsorption zone and the zone to be adsorbed based on the concentration gradient.

[0042] The level monitoring unit is used to determine whether the contact between the m-cresol mixture and the adsorbent is qualified based on the comparison between the interface level index and the preset level index. Based on the condition that the contact between the m-cresol mixture and the adsorbent is not qualified, it sets several flow adjustment coefficients to adjust the spray flow rate of the m-cresol mixture, or sets several flow optimization coefficients to adjust the discharge flow rate of the m-cresol liquid.

[0043] A spacing monitoring unit is used to determine whether the adsorption process of p-cresol is qualified based on the spacing stability index of the first interface and the second interface, under the condition that the contact between the p-cresol mixed liquid and the adsorbent is qualified, so as to optimize the flow rate adjustment coefficient based on the condition that the adsorption process of p-cresol is unqualified.

[0044] An efficiency monitoring module is used to determine whether the separation efficiency of the m-p-cresol mixture is qualified based on the adsorption utilization rate of the adsorbent, and to optimize the preset level index based on the condition that the separation efficiency of the m-p-cresol mixture is unqualified.

[0045] Specifically, the bed 2 is a vertical cylindrical body with a diameter of 1000 mm and a height of 3000 mm. The bed layer 8 includes an adsorbent layer 9 and a bottom support layer 6. The adsorbent layer 9 uses a special adsorbent, such as a silicon-to-aluminum ratio of 50:1, a pore size of 0.55 nm, and a specific surface area of ​​380 m². 2 Modified ZSM-5 molecular sieve with a saturated adsorption capacity of 120 mg / g for p-cresol, an iodine adsorption value ≥1100 mg / g, a methylene blue adsorption value ≥180 mg / g, and a specific surface area ≥1200 m² / g. 2 / g, with pore size concentrated in the mesopore range of 2.0nm-3.0nm, and a saturated adsorption capacity of p-cresol ≥95mg / g; nitric acid-modified coal-based columnar activated carbon with a particle size of 3mm and a packing height of 1500mm, or a specific surface area ≥1100m². 2 The material is an amino-modified UiO-66-NH2MOFs material with a pore size of 0.8-1.2nm, a saturated adsorption capacity of ≥140mg / g for p-cresol, a particle size of 2mm-4mm after granulation, and a filling height of 1400mm. The adsorbent particle size is 2mm-5mm, and the filling height is 1.3-3 times the diameter of the bed. The bottom support layer 6 consists of a porous sieve plate and a quartz sand pad. The sieve plate has a pore size of 2mm-5mm, which is smaller than the diameter of the adsorbent particles. The quartz sand pad is located on the porous sieve plate and is filled in three layers: the lower layer is coarse sand with a particle size of 8mm-12mm, the middle layer has a particle size of 5-8mm, and the upper layer is fine sand with a particle size of 2mm-5mm. The total thickness is 1 / 4 of the diameter of the bed 2 to support the adsorbent, prevent loss, and allow the material to penetrate evenly.

[0046] Specifically, the drain pipe assembly 7 is located below the bottom support layer 6, and a ring-shaped drain main 71 is set around the bed body 2. Six radial drain branch pipes 72 are evenly distributed along the ring-shaped drain main 71. The drain branch pipes 72 are perpendicular to the ring-shaped drain main 71 and lead to the center of the bed body. Each drain branch pipe 72 is equipped with an electric valve 73.

[0047] Specifically, the fiber optic concentration sensor 4 is arranged in a cross shape along two mutually perpendicular radial directions, with 6 fibers evenly spaced along the height of the bed in each radial direction. The vertical spacing between adjacent sensors is 300mm, and the horizontal radial spacing is 250mm. The sensor range is 0-50mg / L, and the sampling frequency is 1 time / second. The fibers in the two radial directions correspond one-to-one in the same horizontal plane. The distributed flow rate sensor 5 is set below the liquid distributor 3 at the top of the bed 8 and above the drain pipe assembly 7 at the bottom of the bed. It divides the area below the liquid distributor 3 into 8 equal fan-shaped sub-regions. Each sub-region is equipped with a miniature differential pressure flow rate sensor with a range of 0-0.5m / s. Each area corresponding to the drain branch pipe is equipped with a flow rate sensor 5.

[0048] Specifically, the interface determination module constructs a p-cresol concentration distribution matrix along the radial and axial directions of the bed 8 based on the monitoring results of the fiber optic concentration sensor 4. It determines the concentration gradient distribution of p-cresol concentration in the radial and axial directions of the bed 8 according to the p-cresol concentration distribution matrix. Based on the comparison results of the concentration gradient within a preset gradient range, it determines the corresponding position of the concentration gradient as the interface feature position. By fitting several interface feature positions in different radial directions within the same cross section, the first interface of the saturation zone and the adsorption zone and the second interface of the adsorption zone and the zone to be adsorbed can be obtained.

[0049] Specifically, the preset gradient range of the first interface is 18mg / L-25mg / L, and the preset gradient range of the second interface is 5mg / L-8mg / L.

[0050] Specifically, the first and second interfaces are obtained by fitting several interface feature locations using the planar least squares method. First, the p-cresol concentration data of each fiber optic concentration sensor are collected to construct an axial-radial concentration distribution matrix. Second, the locations where the concentration gradient falls within a preset gradient range are selected as interface feature points. The concentration gradient range of the first interface is 18 mg / L-25 mg / L, and the concentration gradient range of the second interface is 5 mg / L-8 mg / L. The interface feature points of the same cross section are fitted using the planar least squares method, with the fitting formula being z=ax+by+c, to obtain the planar equations of the first and second interfaces. This is existing technology and will not be elaborated further.

[0051] Understandably, the principle of m- and p-cresol adsorption separation is selective adsorption. The adsorbent packed in fixed bed 1 has different adsorption affinities for m- and p-cresol, with p-cresol generally having a stronger adsorption capacity. When the m- and p-cresol mixed liquid flows from top to bottom through bed 8, p-cresol is preferentially captured by the active sites of the adsorbent, gradually forming an adsorption front within bed 8 as the flow progresses. Meanwhile, m-cresol, due to its weaker adsorption capacity, mostly permeates through bed 8 and flows out. Throughout the adsorption process, the concentration distribution of p-cresol within bed 8 is not a continuous gradual change, but rather, due to the balance between the adsorption rate and the flow rate, it forms three distinct regions: a saturation zone, an adsorption zone, and a zone to be adsorbed. The critical interfaces between these regions are accompanied by drastic changes in concentration. The saturation zone is located in the upper part of bed 8. The active sites on the adsorbent surface are completely occupied by p-cresol, and no more p-cresol can be adsorbed. Adsorption has reached a thermodynamic equilibrium state. The p-cresol concentration in this zone is basically the same as that in the feed solution. The adsorption zone is located below the saturation zone. It is the core area where p-cresol is dynamically captured from the fluid phase by the adsorbent. In this zone, the p-cresol concentration in the mixture is higher than the adsorption equilibrium concentration, and the adsorption rate is much greater than the desorption rate. A large amount of p-cresol is captured by the adsorbent, causing the p-cresol concentration in the fluid to drop sharply, forming a concentration change zone. The zone to be adsorbed is located below the adsorption zone. The active sites on the adsorbent surface are not occupied by p-cresol and are in a fresh state, with complete adsorption capacity. A large amount of p-cresol in the mixture has been captured in the adsorption zone. The amount of p-cresol that has not reached the zone to be adsorbed is very small. The adsorbent does not perform adsorption, and the p-cresol concentration in the fluid is maintained at an extremely low level.

[0052] Specifically, the levelness monitoring unit determines the interface levelness index of the corresponding interface as the ratio of the standard deviation to the average of the absolute distances between the first interface and / or the second interface and the horizontal plane.

[0053] It is understood that the horizontal plane is the horizontal plane with the geometric center of the first interface and / or the second interface located therein, and the smaller the interface level index, the higher the levelness of the interface.

[0054] Please see Figure 4 As shown, it is a flowchart for determining whether the contact between the m-cresol mixed liquid and the adsorbent is qualified in an embodiment of the present invention.

[0055] Specifically, the levelness monitoring unit determines that the contact between the p-cresol mixed liquid and the adsorbent is unqualified based on the comparison result that the interface level index is greater than the preset level index.

[0056] The levelness monitoring unit determines that the contact between the p-cresol mixed liquid and the adsorbent is qualified based on the comparison result that the interface level index is less than or equal to the preset level index.

[0057] Specifically, the preset level index is set to a value range of [0.2, 0.5], with 0.4 being preferred in this embodiment. The preset level index is determined through 5 sets of experiments, each with 10 parallel samples, totaling 50 sets of valid experimental data under different flow rate conditions. The experiments are conducted within a spray flow rate range of 0.10 m / s to 0.50 m / s, with a gradient of 0.10 m / s. Five core experimental conditions are set: 0.10 m / s, 0.20 m / s, 0.30 m / s, 0.40 m / s, and 0.50 m / s. Ten repeated experiments are performed under each condition to simulate different non-uniform flow field states, including uniform flow field, locally high / low flow velocity, and radial flow velocity deviation of ±0.05 m / s to ±0.12 m / s. A fiber optic concentration sensor with a range of 0–50 mg / L and a sampling frequency of 1 time / second is used to collect real-time data on the location of feature points at the first and second interfaces under each condition and calculate the corresponding interface level index. Simultaneously, the level index is also measured. Core indicators such as phenol product purity, adsorbent utilization rate, bed pressure drop, and operational stability were statistically fitted and screened using 50 sets of experimental data. It was determined that when the interface level index was in the range of 0.2–0.5, the m-cresol purity remained stable at ≥98.5%, the adsorbent utilization rate was ≥94%, the bed pressure drop fluctuation was ≤5 kPa, and there was no channeling or local overload. An interface level index below 0.2 easily led to frequent adjustments in automatic control and decreased flow field stability, while an index above 0.5 exacerbated flow field unevenness and significantly reduced separation purity and adsorption utilization rate. Considering the control precision, adjustment response speed, and operational stability of continuous industrial production, the preset level index range was ultimately determined to be [0.2, 0.5]. Among these, 0.4 was the optimal value balancing separation effect, adsorption utilization rate, and automatic control stability, and was thus selected as the preferred preset level index.

[0058] Specifically, a low interface level index indicates that within the same cross-section of bed 8, the material flow rate and distribution in different radial directions are completely uniform, the abrupt changes in the p-cresol concentration gradient are consistent, and the adsorbent particles and the m-p-cresol mixture can fully and synchronously contact each other, without any local insufficient or excessive contact. Only uniform contact can ensure that p-cresol can be uniformly and fully retained by the adsorbent, maintaining a stable p-cresol purity of over 99% at the outlet, without local premature penetration or purity fluctuations caused by unadsorbed p-cresol flowing out. Conversely, uneven contact can lead to localized oversaturation and idleness of the adsorbent, resulting in a decrease in overall adsorption capacity, forcing a shorter adsorption cycle and increased desorption frequency, ultimately reducing production efficiency, increasing energy consumption, and even easily causing localized channeling and abnormally high pressure drop in bed 8. Long-term operation may lead to adsorbent wear and agglomeration, shortening its service life and increasing equipment maintenance costs.

[0059] Specifically, when the level monitoring unit determines that the contact between the m-cresol mixture and the adsorbent is unqualified, based on the comparison result that the interface level index of the first interface is greater than the preset level index, it sets several flow rate adjustment coefficients according to the first liquid flow velocity distribution deviation of the m-cresol mixture to adjust the spray flow rate of the corresponding area.

[0060] The levelness monitoring unit adjusts the discharge flow rate of the corresponding discharge branch pipe 72 based on the comparison result that the interface level index of the first interface is less than or equal to the preset level index and the interface level index of the second interface is greater than the preset level index, and sets several flow rate optimization coefficients according to the second liquid velocity distribution deviation of m-cresol liquid.

[0061] Specifically, the levelness monitoring unit determines, based on the comparison result that the first liquid velocity distribution deviation is greater than the first preset velocity distribution deviation, to reduce the spray flow rate of the m-p-cresol mixed liquid in the corresponding area by the first flow rate adjustment coefficient;

[0062] The levelness monitoring unit determines, based on the comparison result that the first liquid velocity distribution deviation is less than the second preset velocity distribution deviation, to increase the spray flow rate of the m-p-cresol mixed liquid in the corresponding area by the second flow rate adjustment coefficient.

[0063] Specifically, the levelness monitoring unit determines, based on the comparison result that the second liquid velocity distribution deviation is greater than the first preset velocity distribution deviation, to reduce the drainage flow rate of the corresponding drainage branch pipe 72 by the first flow rate optimization coefficient;

[0064] The levelness monitoring unit determines to increase the drainage flow rate of the corresponding drainage branch pipe 72 by using the second flow rate optimization coefficient based on the comparison result that the second liquid flow rate distribution deviation is less than the second preset flow rate distribution deviation.

[0065] Specifically, the first preset flow velocity distribution deviation is 0.08 m / s, and the second preset flow velocity distribution deviation is -0.05 m / s; the value range of the first flow rate adjustment coefficient is set to [0.85, 0.93], preferably 0.9 in this embodiment of the invention; the value range of the second flow rate adjustment coefficient is set to [1.05, 1.12], preferably 1.1 in this embodiment of the invention; the value range of the first flow rate optimization coefficient is set to [0.89, 0.95], preferably 0.91 in this embodiment of the invention; and the value range of the second flow rate optimization coefficient is set to [1.08, 1.15], preferably 1.09 in this embodiment of the invention.

[0066] Specifically, the adjustment or optimization method for the flow rate adjustment coefficient and the flow rate optimization coefficient is to determine the adjusted flow rate or flow rate by multiplying the determined flow rate adjustment coefficient or flow rate optimization coefficient with the original spray flow rate or drainage flow rate.

[0067] Specifically, the value range and optimal values ​​of the first preset velocity distribution deviation, the second preset velocity distribution deviation, and each flow rate adjustment coefficient and flow rate optimization coefficient were determined through flow field adjustment matching experiments with 5 sets of flow rate conditions, 10 parallel samples per set, and a total of 50 sets of effective experimental data. Five sets of experimental conditions were set with a gradient of 0.10 m / s within the spray velocity range of 0.10 m / s to 0.50 m / s. Ten repeated experiments were conducted in parallel under each condition to artificially simulate different radial velocity deviations in the bed and apply different flow rate adjustment coefficients and flow rate optimization coefficients for closed-loop adjustment. Real-time data were collected on the purity of m-cresol, uniformity of radial velocity in the bed, interface levelness, bed pressure drop, adjustment response speed, and operational stability. Statistical fitting and validity verification of the 50 sets of experimental data showed that when the radial velocity distribution deviation exceeded +0.08 m / s, excessively high local velocity triggered rapid adsorption of the adsorbent. Saturation and the risk of cresol penetration increase dramatically. When the deviation is below -0.05 m / s, the local flow velocity is too low, leading to liquid accumulation and channeling, and a decrease in adsorbent utilization. Based on this, the first preset flow velocity distribution deviation is determined to be 0.08 m / s, and the second preset flow velocity distribution deviation is determined to be -0.05 m / s. When adjusting the spray flow rate, a coefficient in the range of 0.85 to 0.93 can smoothly reduce the flow velocity in the too-fast region and avoid flow field disturbance. Among them, 0.9 is the optimal value that balances adjustment range and stability. A coefficient in the range of 1.05 to 1.12 can effectively increase the flow velocity in the too-slow region and ensure uniform liquid distribution. Among them, 1.1 is the optimal value. When optimizing the drainage flow rate, a coefficient in the range of 0.89 to 0.95 can gently reduce the drainage volume of the too-fast branch pipe and eliminate bottom flow deviation. Among them, 0.91 is the optimal value. A coefficient in the range of 1.08 to 1.15 can reasonably increase the drainage volume of the too-slow branch pipe and ensure balanced drainage. Among them, 1.09 is the optimal value.

[0068] Specifically, the first liquid velocity distribution deviation refers to the difference between the actual liquid velocity in a certain radial region within the same cross-section at the top of the bed 8 and the average liquid velocity in all radial regions within that cross-section; the second liquid velocity distribution deviation refers to the difference between the actual liquid velocity in a certain radial region within the same cross-section at the bottom of the bed 8 and the average liquid velocity in all radial regions within that cross-section.

[0069] Specifically, the first interface is the upper boundary between the saturation zone and the adsorption zone, and its levelness is directly determined by the uniformity of the liquid distribution below the distributor 3. A tilted first interface is essentially due to an abnormal radial spray flow rate in the upper part. In areas with excessively fast flow rates, the high velocity leads to rapid adsorbent saturation and rapid interface downward movement; in areas with excessively slow flow rates, the low velocity results in lag in adsorption and slow interface downward movement, causing asynchronous adsorption processes in different radial directions. The spray flow rate is the control source of the upper flow field. By matching the flow rate adjustment coefficient to the first liquid velocity distribution deviation—decreasing if too fast and increasing if too slow—the liquid distribution in abnormal areas can be directly corrected, allowing the upper radial flow velocities to return to uniformity, fundamentally leveling the first interface. The second interface is the lower boundary between the adsorption zone and the zone to be adsorbed, and its levelness is determined by the liquid flow state in the lower part of the bed 8. A qualified first interface indicates that the upper spray flow field is uniform, and the root cause of the tilted second interface lies only in the lower part. For example, if the drainage from a branch pipe is too fast, the liquid flow accelerates, and the interface moves downward quickly; if the drainage is too slow, local liquid accumulation occurs, and the interface moves downward slowly, unrelated to the upper part. The discharge flow rate is an independent control source for the lower flow field. By matching the flow rate optimization coefficient with the second liquid velocity distribution deviation, it can be reduced too quickly or increased too slowly. This can independently correct the flow field in the abnormal area of ​​the lower part, flatten the second interface, and not affect the qualified flow field in the upper part and the first interface.

[0070] Specifically, the spacing monitoring unit collects the vertical spacing between the first interface and the second interface at different time points during the adsorption process in real time. Based on the vertical spacing and the corresponding time parameters, a spacing curve of the first interface and the second interface as the adsorption process changes is established. The coefficient of variation of several vertical distances between the spacing curve and the standard spacing line is determined as the spacing stability index. The standard spacing line is a straight line with the standard spacing value of 100cm between the first interface and the second interface as the vertical axis and parallel to the horizontal axis.

[0071] Specifically, when the standard spacing of the adsorption zones is 100cm, the effective adsorption sites of the adsorbent and the contact time of the p-cresol material are optimally matched, the purity of m-cresol is stable at ≥98.5%, there is no p-cresol breakthrough, the adsorbent utilization rate is ≥94%, and the bed pressure drop fluctuation is ≤5kPa. It is also compatible with the total bed filling height of 1300mm, with a buffer space reserved at the top for the saturation zone and a safety space reserved at the bottom for the waiting adsorption zone, meeting the requirements for continuous adsorption process. When the spacing is less than 100cm, the adsorption zone is too short, resulting in p-cresol breakthrough before it is fully adsorbed, and the product purity drops significantly. When the spacing is greater than 100cm, the adsorption zone is too long, resulting in adsorbent waste, increased bed pressure drop, uneven adsorption propulsion speed, and significantly reduced separation efficiency and operational stability. Based on the fixed bed structure dimensions, adsorbent filling parameters, and the process requirements of industrial continuous separation, the standard spacing value of the first interface and the second interface is determined to be 100cm.

[0072] Specifically, the spacing monitoring unit determines that the adsorption process of p-cresol is qualified based on the comparison result that the spacing stability index is less than or equal to the preset stability index;

[0073] The spacing monitoring unit determines that the adsorption process of p-cresol is unqualified based on the comparison result that the spacing stability index is greater than the preset stability index.

[0074] Specifically, the preset stability index is set to a range of [0.5, 0.7], with 0.6 being preferred in this embodiment. The preset stability index is determined using 50 sets of valid experimental data. Five core experimental conditions—low fluctuation, stable fluctuation, medium fluctuation, large fluctuation, and severe fluctuation—are set with the adsorption zone thickness fluctuation amplitude as the variable. Ten parallel experiments are conducted under each condition to eliminate random errors. The vertical distance between the first and second interfaces is tracked in real time using a fiber optic concentration sensor, and the corresponding distance stability index is calculated. Simultaneously, core indicators such as the purity of m-cresol, p-cresol penetration rate, adsorbent utilization rate, bed pressure drop fluctuation, and adsorption operation stability are detected. Statistical fitting and validity verification of the 50 sets of experimental data show that when the distance stability index is in the range of 0.5–0.7, the adsorption zone thickness fluctuation is ≤10 cm⁻¹. The parameters to be considered are: m-cresol purity ≥98.5%, adsorbent utilization rate ≥94%, bed pressure drop fluctuation ≤5kPa with no p-cresol breakthrough and no adsorbent local overload / idleness issues. A spacing stability index below 0.5 can easily lead to excessive adjustment of the adsorption zone thickness by the control system and a decrease in flow field stability. A value above 0.7 will result in excessive fluctuation of the adsorption zone thickness, insufficient p-cresol adsorption, and a risk of breakthrough. Considering the control precision, adjustment response speed, and separation stability of industrial continuous production, the preset stability index range was finally determined to be [0.5, 0.7]. Among them, 0.6 is the optimal value that takes into account the stability of the adsorption process, the separation effect, and the stability of control, and is used as the preferred preset stability index.

[0075] Specifically, the distance between the first and second interfaces represents the actual thickness of the adsorption zone. A smaller distance stability index indicates less change in the adsorption zone thickness during the adsorption process; conversely, a larger distance indicates frequent fluctuations in the adsorption zone thickness, resulting in thickening or thinning. The adsorption zone is the core area where p-cresol is captured from the fluid phase by the adsorbent. Its thickness stability is fundamental to the normal operation of the adsorption process. Maintaining the adsorption zone thickness within the standard range allows sufficient time for p-cresol to contact the active sites of the adsorbent as it flows through, ensuring adequate retention. This results in a stable p-cresol purity at the outlet of over 99%, eliminating the risk of premature p-cresol penetration. Frequent thickening / thinning of the adsorption zone can lead to several problems. If the thickness is too thin, p-cresol may not be fully adsorbed before entering the adsorption zone, resulting in excessive p-cresol content at the outlet. If the thickness is too thick, the p-cresol concentration at the end of the adsorption zone may be too low, causing excessive adsorbent consumption and potentially triggering local desorption, also leading to fluctuations in product purity.

[0076] Specifically, when the spacing monitoring unit determines that the adsorption process of p-cresol is unqualified, it determines to optimize the flow rate adjustment coefficient with a first flow rate correction coefficient based on the comparison result that the relative difference between the spacing stability index and the preset stability index is greater than the preset relative difference.

[0077] The spacing monitoring unit determines to optimize the flow adjustment coefficient with a second flow correction coefficient based on the comparison result that the relative difference is less than or equal to the preset relative difference.

[0078] Specifically, the preset range of relative difference is set to [10%, 20%], and in this embodiment of the invention, 15% is preferred.

[0079] Specifically, under the condition of reducing the spray flow rate, the value range of the first flow rate correction coefficient is set to [0.88, 0.92], preferably 0.89 in this embodiment of the invention, and the value range of the second flow rate correction coefficient is set to [0.93, 0.96], preferably 0.94 in this embodiment of the invention. Under the condition of increasing the spray flow rate, the value range of the first flow rate correction coefficient is set to [1.05, 1.08], preferably 1.06 in this embodiment of the invention, and the value range of the second flow rate correction coefficient is set to [1.02, 1.04], preferably 1.03 in this embodiment of the invention.

[0080] In this embodiment, the flow correction coefficient corrects the flow regulation coefficient by multiplying the determined flow correction coefficient by the original flow regulation coefficient to obtain the adjusted flow regulation coefficient.

[0081] Specifically, the preset relative difference and the optimal values ​​of each flow correction coefficient were determined through five sets of adsorption zone thickness fluctuation correction conditions and a closed-loop flow correction experiment with 10 parallel samples in each set. Using the relative difference between the spacing stability index and the preset stability index as the core variable, five gradient experimental conditions (5%, 10%, 15%, 20%, and 25%) were set. Ten repeated experiments were conducted in parallel under each condition to artificially simulate different thickness fluctuations in the adsorption zone. Different gradient flow correction coefficients were applied for closed-loop correction adjustment. Indicators such as adsorption zone thickness fluctuation, m-cresol product purity, p-cresol penetration rate, adsorbent utilization rate, bed pressure drop, adjustment response speed, and flow field recovery stability were collected in real time using fiber optic concentration sensors and flow velocity sensors. Statistical fitting and validity verification of 50 sets of experimental data showed that when the relative difference of the spacing stability index is in the 10%-20% range, flow correction can quickly suppress adsorption zone thickness fluctuations, restore a uniform flow field, and avoid over-adjustment. A relative difference below 10% leads to meaningless fine-tuning of the control system. Flow field stability decreases; a value exceeding 20% ​​results in excessive fluctuations, rendering conventional flow correction ineffective. Therefore, the preset relative difference range is determined to be [10%, 20%], with 15% being the optimal value balancing correction efficiency and control stability, and thus the preferred preset relative difference. Under the correction condition of reduced spray flow, a flow correction coefficient in the range of 0.88-0.92 can quickly reduce the velocity in excessively fast regions, curb excessive local propagation in the adsorption zone, and prevent flow field disturbance. 0.89 is the optimal correction value. A flow rate correction coefficient between 0.93 and 0.96 allows for smooth and fine-tuning of the flow rate, adapting to minor fluctuations in correction requirements. Among these, 0.94 is the optimal fine-tuning value. When increasing the spray flow rate, a flow rate correction coefficient between 1.05 and 1.08 can effectively increase the flow rate in slow areas, compensate for adsorption lag, and eliminate the risk of liquid accumulation. Among these, 1.06 is the optimal correction value. A flow rate correction coefficient between 1.02 and 1.04 allows for small and precise speed compensation, adapting to minor fluctuations in correction requirements. Among these, 1.03 is the optimal fine-tuning value.

[0082] Understandably, the essence of an unqualified adsorption process is excessive fluctuation in the adsorption zone over time. The stability of the adsorption zone is primarily determined by the advancement rate of the first interface, which is controlled by the upper spray flow rate. Uneven spray flow can cause localized excessively fast / slow advancement of the first interface, directly leading to narrowing / widening of the adsorption zone thickness, and is the main cause of spacing fluctuations. The second interface is the end of the adsorption zone; only when the first interface is stable will abnormal lower drainage flow rate individually affect the second interface. However, at this time, the spacing fluctuations are mostly localized and minor, and will not cause the overall adsorption process to fail. Therefore, optimizing the flow rate adjustment coefficient directly corrects the fluctuations at the beginning of the adsorption zone, curbing continuous spacing fluctuations at the source.

[0083] Specifically, the efficiency monitoring module determines that the separation efficiency of the p-cresol mixed liquid is unqualified based on the comparison result that the adsorption utilization rate of the adsorbent is less than the preset utilization rate.

[0084] The efficiency monitoring module determines that the separation efficiency of the p-cresol mixed liquid is qualified based on the comparison result that the adsorption utilization rate of the adsorbent is greater than or equal to the preset utilization rate.

[0085] Specifically, adsorption utilization rate refers to the percentage of the total amount of p-cresol actually adsorbed by the adsorbent to the saturated adsorption capacity of the adsorbent within a single adsorption cycle. The preset utilization rate is set to a range of [90%, 98%], with 94% being preferred in this embodiment of the invention. The preset utilization rate was determined through 5 sets of experiments, with 10 parallel samples in each set, totaling 50 sets of valid experimental data on adsorbent utilization efficiency under operating conditions. Within the spray flow rate range of 0.10 m / s to 0.50 m / s, with a gradient of 0.10 m / s, 5 core experimental operating conditions were set at 0.10 m / s, 0.20 m / s, 0.30 m / s, 0.40 m / s, and 0.50 m / s. Ten repeated experiments were conducted in parallel under each operating condition. The actual mass of p-cresol adsorbed by the adsorbent and the theoretical saturated adsorption capacity within a single adsorption cycle were collected in real time using an online concentration sensor and a weighing detection unit. Adsorption capacity data was collected and the adsorption utilization rate was accurately calculated. Simultaneously, indicators such as m-cresol product purity, adsorbent desorption energy consumption, local bed overload rate, and adsorbent lifespan decay rate were monitored. Through statistical fitting and effectiveness screening of 50 sets of experimental data, it was determined that when the adsorption utilization rate was in the range of 90%–98%, the m-cresol purity remained stable at ≥98.5%, desorption energy consumption decreased by 15%–20%, there was no local oversaturation / underutilization of the bed, and the adsorbent lifespan decay rate was ≤3% / month. An adsorption utilization rate below 90% would result in wasted adsorbent capacity, insufficient separation efficiency, and increased operating costs. A rate above 98% would easily lead to p-cresol breakthrough, product purity fluctuations, a surge in desorption load, and accelerated adsorbent aging. Considering the separation efficiency, energy consumption control, adsorbent lifespan, and operational economy in continuous industrial production, a preset utilization rate range of [90%, 98%] was ultimately determined. Among these, 94% was the optimal value balancing separation effect, adsorbent utilization efficiency, and production stability, and was selected as the preferred preset utilization rate.

[0086] Specifically, when the separation efficiency of the m-p-cresol mixed liquid is unqualified, the efficiency monitoring module determines to increase the preset level index by a first index adjustment coefficient based on the comparison result that the difference between the preset utilization rate and the adsorption utilization rate is greater than the preset difference.

[0087] The efficiency monitoring module determines to increase the preset level index by a second index adjustment coefficient based on the comparison result that the utilization difference is less than or equal to the preset difference.

[0088] Specifically, the preset difference is set to a range of [3%, 8%], preferably 5% in this embodiment of the invention; the first exponential adjustment coefficient is set to a range of [1.15, 1.3], preferably 1.2 in this embodiment of the invention; and the second exponential adjustment coefficient is set to a range of [1.11, 1.14], preferably 1.13 in this embodiment of the invention.

[0089] In this embodiment, the adjustment method of the index adjustment coefficient is to determine the adjusted preset level index by multiplying the determined index adjustment coefficient by the preset level index.

[0090] Specifically, the preset difference and the optimal values ​​of each index adjustment coefficient were determined through five sets of adsorption utilization rate deviation control conditions and an adaptive adjustment experiment of the preset level index with 10 parallel samples in each set. Using the difference between the preset utilization rate and the actual adsorption utilization rate as the variable, five gradient experimental conditions (1%, 3%, 5%, 8%, and 10%) were set. Ten repeated experiments were conducted in parallel under each condition to artificially simulate different levels of adsorption utilization rate deviation. Different gradient index adjustment coefficients were applied to adjust the preset level index. Key indicators such as adsorption utilization rate, m-cresol product purity, control adjustment frequency, flow field stability, bed pressure drop, and separation efficiency were collected in real time using fiber optic concentration sensors, flow rate sensors, and efficiency monitoring units. Statistical fitting and validity verification of 50 sets of experimental data showed that when the utilization rate difference is in the range of 3%-8%, adjusting the preset level index can effectively improve the adsorption utilization rate and separation efficiency. Efficiency is quickly achieved without over-adjustment. A difference of less than 3% will lead to ineffective fine-tuning of the control system and excessive adjustment frequency, which will disrupt the stability of the flow field. A difference of more than 8% will result in excessive utilization deviation, and small adjustments will not be able to make up for the shortfall. Based on this, the preset difference range is determined to be [3%, 8%]. Among them, 5% is the optimal value that balances regulation efficiency and control stability, and is selected as the preferred preset difference. For large deviations where the utilization difference is greater than the preset difference, the first index adjustment coefficient in the range of 1.15-1.3 can quickly amplify the preset level index and significantly widen the interface level qualification threshold, thus quickly correcting the problem of low utilization. Among them, 1.2 is the optimal large adjustment value. For small deviations where the utilization difference is less than or equal to the preset difference, the second index adjustment coefficient in the range of 1.11-1.14 can precisely fine-tune the preset level index and gently optimize the adsorption contact state, avoiding over-adjustment. Among them, 1.13 is the optimal precise adjustment value.

[0091] Specifically, if the preset level index is too small, a slightly tilted interface will be judged as unqualified, causing frequent adjustments, which in turn disrupts the flow field stability, leads to uneven contact, reduces adsorbent utilization, and ultimately reduces separation efficiency.

[0092] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A separation device for the production of m-p-cresol, characterized in that, include: A fixed bed, which includes a bed frame and a bed layer; The data acquisition module includes several fiber optic concentration sensors disposed inside the bed to acquire the concentration of p-cresol, and a distributed flow rate sensor to acquire the liquid flow rate. An interface determination module is used to determine the concentration gradient of p-cresol based on the monitoring results of several optical fiber concentration sensors, and to determine the first interface between the saturation zone and the adsorption zone of the bed, and the second interface between the adsorption zone and the zone to be adsorbed based on the concentration gradient. Interface monitoring module, which includes, The level monitoring unit is used to determine whether the contact between the m-p-cresol mixture and the adsorbent is qualified based on the comparison between the interface level index and the preset level index. Based on the condition that the contact between the m-p-cresol mixture and the adsorbent is not qualified, several flow rate adjustment coefficients are set to adjust the spray flow rate of the m-p-cresol mixture. A spacing monitoring unit is used to determine whether the adsorption process of p-cresol is qualified based on the spacing stability index of the first interface and the second interface, under the condition that the contact between the p-cresol mixed liquid and the adsorbent is qualified, so as to optimize the flow rate adjustment coefficient based on the condition that the adsorption process of p-cresol is unqualified. An efficiency monitoring module is used to determine whether the separation efficiency of the m-p-cresol mixture is qualified based on the adsorption utilization rate of the adsorbent, and to optimize the preset level index based on the condition that the separation efficiency of the m-p-cresol mixture is unqualified.

2. The separation apparatus for the production of m-p-cresol according to claim 1, characterized in that, The interface determination module determines the corresponding position of the concentration gradient as the interface feature position based on the comparison results of the concentration gradient of p-cresol within a preset gradient range. It then fits several interface feature positions of different radial directions within the same cross section to obtain the first interface of the saturation region and the adsorption region, and the second interface of the adsorption region and the region to be adsorbed.

3. The separation apparatus for the production of m-p-cresol according to claim 2, characterized in that, The levelness monitoring unit determines the coefficient of variation of the absolute distance between the first interface or the second interface and the horizontal plane as the interface level index of the corresponding interface.

4. The separation apparatus for the production of m-p-cresol according to claim 3, characterized in that, The levelness monitoring unit determines that the contact between the p-cresol mixed liquid and the adsorbent is unqualified based on the comparison result that the interface level index is greater than the preset level index.

5. The separation apparatus for the production of m-p-cresol according to claim 4, characterized in that, The levelness monitoring unit adjusts the spray flow rate of the m-p-cresol mixture in the corresponding area by setting several flow rate adjustment coefficients based on the comparison result that the interface level index of the first interface is greater than the preset level index, according to the first liquid flow velocity distribution deviation of the m-p-cresol mixture.

6. The separation apparatus for the production of m-p-cresol according to claim 5, characterized in that, The spacing monitoring unit determines the coefficient of variation of several vertical distances between the spacing curve constructed based on the vertical spacing between the first interface and the second interface during the adsorption process and the standard spacing line as the spacing stability index.

7. The separation apparatus for the production of m-p-cresol according to claim 6, characterized in that, The spacing monitoring unit determines that the adsorption process of p-cresol is unqualified based on the comparison result that the spacing stability index is greater than the preset stability index.

8. The separation apparatus for the production of m-p-cresol according to claim 7, characterized in that, When the spacing monitoring unit determines that the adsorption process of p-cresol is unqualified, it determines to optimize the flow rate adjustment coefficient with a first flow rate correction coefficient based on the comparison result that the relative difference between the spacing stability index and the preset stability index is greater than the preset relative difference. The spacing monitoring unit determines to optimize the flow adjustment coefficient with a second flow correction coefficient based on the comparison result that the relative difference is less than or equal to the preset relative difference.

9. The separation apparatus for the production of m-p-cresol according to claim 8, characterized in that, The efficiency monitoring module determines that the separation efficiency of the m-cresol mixed liquid is unqualified based on the comparison result that the adsorption utilization rate of the adsorbent is less than the preset utilization rate.

10. The separation apparatus for the production of m-p-cresol according to claim 9, characterized in that, When the separation efficiency of the m-p-cresol mixed liquid is unqualified, the efficiency monitoring module determines to increase the preset level index by a first index adjustment coefficient based on the comparison result that the difference between the preset utilization rate and the adsorption utilization rate is greater than the preset difference. The efficiency monitoring module determines to increase the preset level index by a second index adjustment coefficient based on the comparison result that the utilization difference is less than or equal to the preset difference.

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