Closed powder conveying device and closed powder conveying method for polyolefin catalyst powder

Abstract

This invention relates to the field of raw material conveying and feeding, and discloses a closed-loop conveying device for powder and a closed-loop conveying method for polyolefin catalyst powder. The closed-loop conveying device includes: an air supply unit, a reaction unit, a powder storage unit, and a monitoring unit; the powder storage unit is in a closed-loop connection with the reaction unit via a conveying pipe, and the conveying pipe is connected to the air supply unit, which provides airflow to the conveying pipe for transporting the powder; the monitoring unit includes a water content detection module and an oxygen content detection module installed on the powder path pipeline, used to detect the water content and oxygen content of the powder. The device and method provided by this invention use pneumatic conveying to isolate air and moisture, and ensure that the conveying process maintains a water-free and oxygen-free environment through online monitoring. The closed and continuous conveying process can significantly improve production efficiency.

Description

Technical Field

[0001] This invention relates to the field of raw material conveying and feeding, and discloses a closed conveying device for powder and a closed conveying method for polyolefin catalyst powder. Background Technology

[0002] In chemical, food, pharmaceutical, and bioengineering fields, substances that are easily deliquescent and denatured when exposed to water, easily oxidized and deteriorated upon contact with air, easily combustible upon contact with air, or unstable and easily decomposed at room temperature are frequently used. For example, in the industrial production of polyolefin catalysts, both powder and liquid raw materials must be isolated from air and moisture. Powder raw materials are prone to deliquescence upon contact with air, and contact with moisture will generate chloride ions, which can corrode equipment. In the industrial preparation process of polyolefin catalysts, the water content of the raw materials must be strictly controlled within the range of 50-200 μg / g. Using raw materials with a water content higher than this range will have a significant negative impact on the performance of the catalyst. The particle morphology and particle size distribution of polyolefin catalysts directly affect the performance of polyolefin resins. Factors such as the metering and transportation of powder raw materials, the feeding rate of the addition to the synthesis unit, the slurry mixing ratio, and the particle forming technology are key steps in determining the particle morphology of polyolefin catalysts. Furthermore, compared to batch production, continuous production processes can produce polyolefin catalysts with better performance and more stable quality. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem of difficulty in strictly controlling the water and oxygen content during the transportation of powder raw materials in existing technologies. This invention provides a closed-loop powder transportation device and a closed-loop transportation method for polyolefin catalyst powder. The device and method provided by this invention employ pneumatic conveying to isolate air and moisture, and ensure that the transportation process maintains an anhydrous and oxygen-free environment through online monitoring. Simultaneously, it transforms the intermittent powder transportation process into a closed, continuous transportation process. The device and method provided by this invention can significantly improve production efficiency, and the properties of the polyolefin catalyst product can be controlled by adjusting different operating conditions.

[0004] To achieve the above objectives, the present invention provides a closed conveying device for powder materials, comprising: an air supply unit, a reaction unit, a powder storage unit, and a monitoring unit; the powder storage unit is in closed communication with the reaction unit via a conveying pipe, the conveying pipe being connected to the air supply unit, the air supply unit being used to provide airflow to the conveying pipe for transporting the powder; the monitoring unit includes a water content detection module and an oxygen content detection module installed on the powder path pipeline, used to detect the water content and oxygen content of the powder.

[0005] A second aspect of the present invention provides a closed-loop conveying method for polyolefin catalyst powder, the method being carried out within the closed-loop powder conveying device described in the present invention, comprising: The activated polyolefin catalyst powder from the powder storage unit is transported to the reaction unit by the carrier gas provided by the gas replenishment unit, so that the powder and liquid raw materials are mixed in the reaction unit. The powder conveying process is monitored by the monitoring unit to maintain an anhydrous and oxygen-free environment.

[0006] The closed conveying device and closed conveying method for polyolefin catalyst powder provided by the present invention ensure that the conveying process maintains an anhydrous and oxygen-free environment through online monitoring. The closed and continuous pneumatic conveying method can significantly improve production efficiency. The properties of polyolefin catalyst products can also be controlled by adjusting different operating conditions. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a closed powder conveying device according to a specific embodiment of the present invention.

[0008] Explanation of reference numerals in the attached figures: 1. Ball mill; 2. Powder raw material silo; 3. Weighing module; 4. Powder receiving silo; 5. Pneumatic six-lobe valve; 6. Sending tank; 7. Visual monitoring system; 8. Oxygen content detection module; 9. Water content detection module; 10. Mass flow meter; 11. Switching ball valve; 12. Synthesis kettle; 13. Gas replenishment unit Detailed Implementation The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0009] This invention provides a closed conveying device for powder materials, comprising: an air supply unit, a reaction unit, a powder storage unit, and a monitoring unit; the powder storage unit is in closed communication with the reaction unit via a conveying pipe, the conveying pipe being connected to the air supply unit, the air supply unit being used to provide airflow to the conveying pipe for transporting the powder; the monitoring unit includes a water content detection module and an oxygen content detection module installed on the powder path pipeline, used to detect the water content and oxygen content of the powder.

[0010] According to a preferred embodiment of the present invention, the powder pathway pipeline is sequentially the outlet of the activation equipment 1, the powder raw material silo 2, the powder receiving silo 4, the sending tank 6, and the first raw material inlet of the synthesis kettle 12.

[0011] The closed conveying device provided by this invention ensures that the conveying process maintains an oxygen-free environment through online monitoring. It improves the powder conveying process into a closed and continuous process by using pneumatic conveying, which can significantly improve production efficiency.

[0012] According to a preferred embodiment of the present invention, the monitoring unit includes a control module and a visual monitoring module. The signal acquisition end of the visual monitoring module is used to acquire image signals of the gas-solid two-phase flow in the delivery pipeline in real time. The analysis server of the visual monitoring module stores a pre-established relationship model between the image signals and the flow patterns of the gas-solid two-phase flow. By comparing the image signals with those of the signal acquisition end, the flow pattern result is obtained, and the obtained flow pattern result is transmitted to the control module.

[0013] In this invention, the visual monitoring system can be a high-resolution high-speed camera, model FASTCAM NOVA R5-4K, purchased from Photron Corporation of Japan. The main equipment is a DN40 conveying pipe made of transparent plexiglass. The pipe is divided into two sections: a horizontal section (500mm) and a vertical section (500mm). The analysis system includes the ability to analyze and extract particle motion features from particle images during the conveying process, and a built-in intercorrelation algorithm to calculate the particle velocity based on particle image velocimetry technology. In this invention, the visual monitoring system can be an M3C capacitive tomography device purchased from ITS in the UK. The system includes a capacitive sensor surrounding the pipeline, a data acquisition system, an imaging computer and its interpretation software. The capacitive sensor is connected to the conveying pipeline through a flange. The sensor consists of a radial electrode, a shielding electrode, an outer shielding layer, an insulating pipe and a flange. The acquired image is reconstructed using the LBP algorithm. The conveying speed of the powder is calculated by the capacitive sensor using an intercorrelation method. The dielectric constant distribution of the image is used to identify the flow pattern of the powder.

[0014] In this invention, there are no special requirements for the method of collecting gas-solid two-phase flow pattern image signals in pipeline transportation lines. Commonly used collection methods are applicable to this invention. Those skilled in the art can choose according to actual needs. For example, high-speed imaging, capacitance tomography, or infrared cameras can be used to acquire gas-solid two-phase flow pattern image signals in pipeline transportation lines.

[0015] According to a preferred embodiment of the present invention, a relationship model between signal and flow pattern of gas-solid two-phase flow is established using machine learning and image processing techniques.

[0016] As needed, the control module can be connected to the pressure transmission, air replenishment unit, weighing module, rotary feed valve of the sending tank 6, powder receiving bin, and control valve circuit between the sending tanks.

[0017] In this invention, the reaction unit in the closed powder conveying device mainly includes a synthesis kettle.

[0018] In this invention, the powder storage unit in the closed powder conveying device includes a powder raw material silo. Preferably, the powder storage unit includes a powder raw material silo, a powder receiving silo, and a sending tank that are sequentially sealed and connected in series. A control valve is installed between the powder receiving silo and the sending tank. In this invention, the control valve has no special requirements and can be selected according to actual needs; for example, it can be a six-disc pneumatic valve.

[0019] In this invention, the first raw material inlet of the synthesis reactor is connected to a powder raw material silo, a powder receiving silo, or a sending tank via a conveying pipe. Preferably, the synthesis reactor is connected to a sending tank via a conveying pipe. The synthesis reactor is also equipped with a second raw material inlet. The conveyed powder enters the synthesis reactor through the first raw material inlet, and the liquid raw material enters the synthesis reactor through the second raw material inlet.

[0020] In this invention, a stirring element is provided in the synthesis reactor. The stirring element has no special requirements and can be selected according to the prior art. For example, a stirring paddle can be selected. The stirring paddle is connected to a motor installed at the top of the synthesis reactor.

[0021] In this invention, the closed conveying device is equipped with a weighing module for weight reduction measurement. This invention has no special requirements for the weighing module; commercially available models such as Mettler's EXPFA584, HBM's PW27A, and Yutesel's Model 102 are all suitable and will not be described in detail further. Specifically, the synthesis reactor is equipped with a synthesis reactor weighing module for weighing the materials inside the reactor. The powder raw material silo is equipped with a raw material silo weighing module for weighing the powder inside the silo. The sending tank is equipped with a sending tank weighing module for weighing the powder inside the sending tank.

[0022] In this invention, the feed end of the powder raw material silo is connected to the discharge end of the activation equipment. Preferably, the activation equipment is selected from at least one of a ball mill, a wet grinding mill, or a cone crusher. In the embodiments of this invention, a ball mill is used as an example, but this does not limit the scope of the invention.

[0023] In this invention, the bottom of the sending tank and the powder raw material silo are each equipped with an arch-breaking component. There are no special requirements for the type of arch-breaking component, and it can be selected according to the existing technology in the field. Preferably, the arch-breaking component is selected from one of the following: a stirrer, a rotary feeding valve, a flexible beater, or a pulse hammer.

[0024] In one specific embodiment of the present invention, the ball mill is provided with a ball mill inlet and a ball mill outlet. The ball mill outlet is connected to a powder raw material silo. The ball mill and the powder raw material silo are connected by a conveying pipeline to convey powder raw materials to the powder raw material silo. The powder raw material silo is provided with a raw material silo inlet, a raw material silo outlet, and a weighing module. The raw material silo inlet is connected to the ball mill, and the raw material silo outlet is connected to a powder receiving silo. The powder raw material silo and the powder receiving silo are connected by a conveying pipeline to convey powder raw materials to the powder receiving silo. The powder receiving silo is provided with a receiving silo inlet and a receiving silo outlet. The powder receiving silo inlet is connected to the raw material silo, and the powder receiving silo outlet is connected to a pneumatic six-disc valve. The powder receiving silo and the pneumatic six-disc valve are connected by a conveying pipeline. The sending tank is provided with a sending tank inlet, a sending tank outlet, and a weighing module. The sending tank inlet is connected to a pneumatic six-disc valve, and the sending tank outlet is connected to a gas replenishment unit. The sending tank and the gas replenishment unit are connected by a conveying pipeline.

[0025] In this invention, there are no special requirements for the volume of the powder raw material silo. It can be selected according to actual needs, such as designing it based on the bulk density, angle of repose, and other properties of the powder, as well as the storage capacity of the process. This will not be elaborated here.

[0026] In this invention, the sealed conveying device is equipped with a moisture content detection module, specifically including: a first moisture content detector for detecting the moisture content of powder in the powder raw material silo, a second moisture content detector for detecting the moisture content of powder in the powder receiving silo, and a third moisture content detector for detecting the moisture content of the powder feed to the synthesis reactor. The first moisture content detector is located on the side wall of the powder raw material silo at the contact point with the powder, the second moisture content detector is located on the side wall of the powder receiving silo at the contact point with the powder, and the third moisture content detector is located on the side wall of the synthesis reactor at the contact point with the powder.

[0027] This invention does not have special requirements for the water content analyzer; conventional online water content analyzers in the field can be used, such as the MS-204 model from Möss GmbH, Germany. The water content can be detected using online resistance detection, online microwave detection, or online infrared detection. The MS-204 model measures the moisture content of powder using online microwave detection. This is well known to those skilled in the art and will not be described in detail here.

[0028] In this invention, the closed conveying device is equipped with an oxygen content detection module for detecting oxygen content. The oxygen content detection module includes an oxygen concentration detector installed on the conveying pipeline and located between the third water content detector and the visual monitoring module.

[0029] This invention does not have special requirements for oxygen concentration detectors. Conventional oxygen concentration detectors in the field are all applicable to this invention. Those skilled in the art can choose according to actual needs. For example, the ERUN-QZ9220 online zirconia oxygen content analyzer from Winrun Environmental Protection Technology Group Co., Ltd. can be used for detection by fluorescence method, paramagnetic method, zirconia solid electrolyte oxygen measurement method or electrochemical reaction method, which will not be elaborated here.

[0030] In this invention, the gas replenishment unit includes a venting and gas replenishment pipeline connected to the powder path pipeline, wherein the venting and gas replenishment pipeline includes a first gas replenishment pipeline and a second gas replenishment pipeline. The discharge end of the sending tank is connected to the first gas replenishment pipeline; along the material flow direction, the conveying pipe located before the image signal acquisition point of the visual monitoring module on the conveying pipeline is connected to the second gas replenishment pipeline.

[0031] In this invention, there are no special requirements for the regulating device installed on the venting and replenishing gas pipeline. The existing pressure remote transmission, on / off regulating ball valve (or solenoid valve) and pulse device can be installed on the venting and replenishing gas pipeline according to actual needs. The pulse airflow is generated by opening and closing the solenoid valve at a set frequency according to the pressure change in the conveying pipeline, so as to push the material forward.

[0032] In this invention, the powder raw material silo and the powder receiving silo are each equipped with safety accessories, pressure transmitters, level gauges, and metal filters. The safety accessories mainly include rupture discs and safety valves installed on the top of the silos, and the pressure transmitter is a remote pressure gauge used to detect the pressure in the raw material silos.

[0033] This invention provides a closed-loop conveying method for polyolefin catalyst powder, which is carried out in the closed-loop conveying device of the present invention. The method includes: conveying activated polyolefin catalyst powder from the powder storage unit to the reaction unit through carrier gas provided by the gas replenishment unit, so that the powder and liquid raw materials are mixed in the reaction unit, wherein the powder conveying process is monitored by the monitoring unit to maintain an anhydrous and oxygen-free environment.

[0034] According to a preferred embodiment of the present invention, the closed-loop conveying method for the polyolefin catalyst powder includes the following steps: S1) The polyolefin catalyst powder is activated in the activation equipment to obtain activated powder, which is then transported to the powder raw material silo by a carrier gas. S2) The activated powder in the powder raw material silo is transported by carrier gas through the powder receiving silo and the sending tank, and then transported to the synthesis kettle to be mixed with the liquid raw material.

[0035] The closed conveying method provided by this invention uses pneumatic conveying to isolate air and moisture, and ensures that the conveying process maintains a water-free and oxygen-free environment through online monitoring. At the same time, it improves the intermittent powder conveying process into a closed and continuous conveying process, which can significantly improve production efficiency.

[0036] In this invention, a water content detection module sequentially monitors the moisture content of the powder feed into the powder raw material silo, powder receiving silo, and synthesis reactor, while an oxygen content detection module monitors the oxygen content at the synthesis reactor inlet. When the water content exceeds the raw material control threshold (greater than 2 wt%), the system issues an alarm, reminding operators to promptly check the system's sealing points. Upon receiving the alert, on-site operators immediately investigate any leaks. By implementing water and oxygen content detection modules to monitor the water and oxygen content within the conveying channel in real time, this invention ensures that the polyolefin catalyst powder conveying process maintains a water-free and oxygen-free environment.

[0037] In this invention, a visual monitoring system and a gas replenishment unit are used to regulate the pneumatic conveying flow rate and gas-solid two-phase flow pattern from the delivery tank to the synthesis reactor. For example, the visual monitoring system uses machine learning and image processing technology to determine the gas-solid two-phase flow pattern exhibited during the conveying of polyolefin catalyst powder. According to actual needs, the pneumatic conveying flow rate from the delivery tank to the synthesis reactor can be adjusted by regulating the control valve of the first gas replenishment pipeline located at the discharge end of the delivery tank in the gas replenishment unit, thereby transforming the gas-solid two-phase flow pattern into the desired form.

[0038] In this invention, the range of carrier gases that can be selected by the gas replenishment unit is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the carrier gas provided by the gas replenishment unit includes at least one of nitrogen and argon.

[0039] In this invention, the carrier gas flow rate in the second make-up gas pipeline can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the carrier gas flow rate in the second make-up gas pipeline is 1-15 m³ / h. 3 / h.

[0040] In this invention, the pressure of the sending tank can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the pressure of the sending tank is 0.1-0.8 MPa.

[0041] In this invention, the slurry mixing ratio can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the slurry mixing ratio is 0.5-2.0 L liquid / kg powder.

[0042] In this invention, the addition rate of the liquid raw material can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the addition rate of the liquid raw material is 1-10 L / min.

[0043] In this invention, the addition rate of the powder raw material can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the addition rate of the powder raw material is 10-25 kg / min.

[0044] In this invention, the stirring speed of the synthesis reactor can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the stirring speed of the synthesis reactor is 100-150 rpm.

[0045] In this invention, the heating rate of the synthesis vessel can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the heating rate of the synthesis vessel is 1-5℃ / min.

[0046] The apparatus and method provided by this invention improve the intermittent powder conveying process into a closed, continuous conveying process, which can significantly improve production efficiency. By adjusting different operating conditions, the properties of polyolefin catalyst products can be controlled.

[0047] Example 1 Please see Figure 1 In this invention, a method for metering and sealing the raw materials of a polyolefin catalyst is provided. The powdered raw material, magnesium chloride, is activated in a ball mill 1 under a slightly positive nitrogen pressure and then transported to the powder raw material silo 2 under a nitrogen pressure of 0.3~0.5 MPa. The activated magnesium chloride is stored in the powder raw material silo 2 under a sealed nitrogen atmosphere for 5-7 days. An online water content detector monitors the water content in the raw material silo 2 in real time. An alarm is triggered when the water content exceeds the raw material control index (greater than 2 wt%), and the operator promptly checks the system's sealing points.

[0048] When the polyolefin catalyst preparation process requires powder feeding, the operator calculates the required weight of magnesium chloride to be added to the synthesis reactor based on the polyolefin catalyst production process sheet. This calculation is then input into the powder raw material metering and conveying module and the synthesis reactor feeding module of the control system. The modules output feedback based on the input, determining the number of times magnesium chloride is fed from the powder raw material silo to the delivery tank and the amount fed each time. For example, if 100 kg of magnesium chloride needs to be added to the synthesis reactor, the powder raw material silo 2 uses a rotary star valve to control the feeding speed, and a weighing module is used for weight reduction and metering. Initially, 100 kg is weighed and enters the powder receiving silo 4. Based on the production feed amount of 100 kg of magnesium chloride, the operator adjusts the valve speed of the pneumatic six-valve valve 5 through the control system to regulate the magnesium chloride feeding speed. By adjusting the weight reduction in the powder receiving silo 4 weighing module and the weight increase in the delivery tank weighing module, the operator precisely controls the weight of magnesium chloride to be 100 ± 0.5 kg.

[0049] Powder conveying unit and pneumatic conveying flow control unit: The operator adjusts the gas-solid ratio of the pneumatic conveying process according to the properties of the material. The visual monitoring system 7 and the air replenishment unit 13, according to the logic loop of the control system, realize the control of the pneumatic conveying flow rate and flow pattern. In this embodiment, the nitrogen flow rate is 10m³ / h. 3 / h, the pressure of the sending tank is 0.2Mpa, and the flow pattern of magnesium chloride is determined by the visual monitoring system 7 to be a gas embolism flow pattern through machine learning and image processing technology. The control of the gas supply unit 13 and the control valve at the bottom of the sending tank can be converted into a dune flow pattern (under the visual monitoring system, magnesium chloride passes through the pipeline in a dune shape).

[0050] Synthesis reactor feeding module and suspension slurry preparation unit: Operators set the amount of liquid ethanol added in the control system according to the polyolefin catalyst production process sheet. Mass flow meter 10 and on / off regulating ball valve 11 control the ethanol addition. Before adding to the synthesis reactor, online water and oxygen content detectors are used to control the water content to be less than 100 μg / g and the oxygen content volume ratio to be less than 5%. Based on the weight of the magnesium chloride powder added to the synthesis reactor and the volume of the liquid raw material, a certain slurry preparation ratio of 1.5 L ethanol / kg magnesium chloride is maintained. Adjusting the liquid raw material addition rate to 5 L / min, the powder raw material addition rate to 20 kg / min, the stirring speed of the synthesis reactor to 110 rpm, and the heating rate to 1 °C / min, spherical magnesium chloride alcohols with a certain ethanol-to-magnesium ratio can be obtained. The formation of polyolefin catalyst particles in the synthesis reactor is controlled by the above conditions.

[0051] Example 2 Compared to Example 1, the only differences are in the powder conveying unit and the pneumatic conveying flow control unit: the operator adjusts the gas-solid ratio of the pneumatic conveying process according to the properties of the material. In this example, the nitrogen flow rate is 5m³ / h. 3 / h, the pressure of the sending tank is 0.4Mpa, and the flow pattern of magnesium chloride delivery is determined by the visual monitoring system 7 to be a plunger flow pattern through machine learning and image processing technology. The gas supply unit 13 and the control valve at the bottom of the sending tank are adjusted to maintain the pneumatic delivery process in a plunger flow pattern (under the visual monitoring system, magnesium chloride has a high concentration in the pipeline cross section and moves in a plunger shape).

[0052] Example 3 Compared with Example 1, the only difference lies in the feeding module of the synthesis reactor and the slurry preparation unit: the operator sets the amount of liquid raw material ethanol added in the control system according to the polyolefin catalyst production process sheet. The mass flow meter 10 and the switch regulating ball valve 11 control the amount of ethanol added. Based on the weight of the powdered magnesium chloride added to the synthesis reactor and the volume of the added liquid raw material, a certain slurry preparation ratio of 1.0 ethanol / kg magnesium chloride is maintained. The molar ratio of ethanol to magnesium chloride is adjusted to 2.50. The ethanol addition rate is controlled at 3L / min, the powdered raw material addition rate at 15kg / min, the stirring speed of the synthesis reactor at 120rpm, and the heating rate at 2℃ / min. Spherical magnesium chloride alcohol with a certain ethanol-magnesium ratio can be obtained. The formation of polyolefin catalyst particles in the synthesis reactor is controlled by the above conditions.

[0053] Comparative Example 1 Using the original intermittent feeding process, magnesium chloride is packaged in a stainless steel conical drum and protected with nitrogen. Before and after packaging, the water content of magnesium chloride must be tested to be less than 2wt%. When feeding, a certain amount of inert solvent is added to the synthesis reactor in advance. The water content of the inert solvent should be tested to be less than 50μg / g in advance. Before feeding into the synthesis reactor, the oxygen content volume ratio should be tested to be less than 5%. The conical drum is lifted using an electric hoist. Under nitrogen protection, magnesium chloride powder is added to the synthesis reactor. The mass of magnesium chloride added to the synthesis reactor is calculated using the platform scale weight reduction method. According to the slurry preparation ratio of 1.5L ethanol / kg magnesium chloride, ethanol is added. The water content of the ethanol is less than 100μg / g. Usually, multiple weighings and slurry adjustments are required. Ethanol is added to the synthesis reactor from a metering tank. The addition rate and amount of ethanol are determined based on the amount and rate of magnesium chloride added. The on-site operator manually times the process and controls the addition rate of ethanol (5L / min) and the addition rate of powder raw materials (20kg / min) by adjusting the valve opening. After the synthesis reactor is fully fed, samples are taken to test the water content, oxygen content, and slurry concentration of the suspension in the synthesis reactor. Based on the results, the next process is carried out. The stirring speed of the synthesis reactor is adjusted to 110rpm, and the heating rate is controlled within the range of 1℃ / min. Spherical magnesium chloride alcohols with a certain ethanol-to-magnesium ratio can be obtained. The polyolefin catalyst particles in the synthesis reactor are also controlled by the above conditions.

[0054] Table 1

[0055] A chemical plant produces and transports magnesium chloride. The original intermittent production process required six operators and five hours to complete the daily workload. However, using the conveying method of this invention, only two operators are needed, and the same workload can be completed in 40 minutes, significantly improving production efficiency. By adjusting the powder conveying rate, the amount of liquid raw material added, the powder-to-liquid slurry ratio, and the operating conditions of the synthesis reactor, this invention can also control the magnesium-to-alcohol ratio of the spherical magnesium chloride alcohol product, resulting in a product with a narrower particle size distribution and superior microstructure.

[0056] The preferred embodiments of the present invention have been described above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A closed conveying device for powder materials, characterized in that, The sealed conveying device includes: a gas replenishment unit, a reaction unit, a powder storage unit, and a monitoring unit; The powder storage unit is in a sealed connection with the reaction unit through a conveying pipe. The conveying pipe is connected to a gas supply unit, which provides airflow to the conveying pipe for transporting the powder. The monitoring unit includes a water content detection module and an oxygen content detection module installed on the powder path pipeline, used to detect the water content and oxygen content of the powder.

2. The closed powder conveying device according to claim 1, characterized in that, The monitoring unit includes a control module and a visual monitoring module. The signal acquisition end of the visual monitoring module is used to acquire image signals of the gas-solid two-phase flow in the delivery pipeline in real time. The analysis server of the visual monitoring module stores a pre-established relationship model between the image signals and the flow patterns of the gas-solid two-phase flow. By comparing the image signals with those of the signal acquisition end, the flow pattern result is obtained and transmitted to the control module.

3. The closed powder conveying device according to claim 1 or 2, characterized in that, The reaction unit includes a synthesis vessel; and / or The powder storage unit includes a powder raw material silo, and preferably the powder storage unit includes a powder raw material silo, a powder receiving silo and a sending tank that are sealed and connected in series in sequence, with a control valve installed between the powder receiving silo and the sending tank.

4. The closed powder conveying device according to claim 3, characterized in that, The first raw material inlet of the synthesis reactor is connected to a powder raw material silo, a powder receiving silo, or a sending tank via a conveying pipe. Preferably, the synthesis reactor is connected to a sending tank via a conveying pipe. The synthesis reactor is also equipped with a second raw material inlet; and / or The synthesis reactor is equipped with a stirring element; and / or The synthesis reactor is equipped with a synthesis reactor weighing module for weighing and measuring the weight of materials inside the reactor; and / or The powder raw material silo is equipped with a raw material silo weighing module for weighing and measuring the powder material inside the silo; and / or The sending tank is equipped with a sending tank weighing module for weighing and measuring the powder inside the sending tank.

5. The closed powder conveying device according to claim 3 or 4, characterized in that, The feed end of the powder raw material silo is connected to the discharge end of the activation equipment, preferably the activation equipment is selected from at least one of a ball mill, a wet grinding mill, or a cone crusher; and / or The bottom of the sending tank and the powder raw material silo are each equipped with an arch-breaking device, preferably selected from one of a stirrer, a rotary feed valve, a flexible beater, or a pulse hammer.

6. The closed powder conveying device according to claim 1, characterized in that, The water content detection module includes: A first moisture content analyzer for detecting the moisture content of powder materials in a powder raw material silo; and / or A second moisture content detector for detecting the moisture content of powder in a powder receiving bin; and / or A third moisture content analyzer used to detect the moisture content of powder feed into a synthesis reactor.

7. The closed powder conveying device according to claim 1, characterized in that, The oxygen content detection module includes an oxygen concentration detector installed on the delivery pipeline and located between the third water content detector and the visual monitoring module; and / or The gas supply unit includes a venting and gas supply pipeline connected to the powder path pipeline, wherein, The discharge end of the sending tank is connected to a first air supply line; and / or Along the material flow direction, the conveying pipe located before the image signal acquisition point of the visual monitoring module in the conveying pipeline is connected to a second air replenishment pipeline.

8. A closed-loop conveying method for polyolefin catalyst powder, characterized in that, The method is carried out in the closed powder conveying device according to any one of claims 1-7, comprising: The activated polyolefin catalyst powder in the powder storage unit is transported to the reaction unit by the carrier gas provided by the gas replenishment unit, so that the powder and liquid raw materials are mixed in the reaction unit. The powder conveying process is monitored by the monitoring unit to maintain an anhydrous and oxygen-free environment.

9. The closed conveying method according to claim 8, wherein, The method includes the following steps: S1) The polyolefin catalyst powder is activated in the activation equipment to obtain activated powder, which is then transported to the powder raw material silo by a carrier gas. S2) The activated powder in the powder raw material silo is transported by carrier gas through the powder receiving silo and the sending tank, and then transported to the synthesis kettle to be mixed with the liquid raw material for slurry preparation; Among them, the moisture content of the powder feed into the powder raw material silo, powder receiving silo and synthesis kettle is monitored sequentially by the moisture content detection module, and the oxygen content at the inlet of the synthesis kettle is monitored by the oxygen content detection module. The pneumatic conveying flow rate and gas-solid two-phase flow pattern from the delivery tank to the synthesis reactor are controlled by a visual monitoring system and a gas replenishment unit.

10. The closed conveying method according to claim 8 or 9, wherein, The carrier gas provided by the gas replenishment unit includes at least one of nitrogen and argon; and / or The carrier gas flow rate in the second replenishment gas pipeline is 1-15m³. 3 / h; and / or The pressure of the sending tank is 0.1-0.8 MPa; and / or The slurry mixing ratio is 0.5-2.0 L liquid / kg powder; and / or The liquid feedstock is added at a rate of 1-10 L / min; and / or The powder raw material is added at a rate of 10-25 kg / min; and / or The stirring speed of the synthesis reactor is 100-150 rpm; and / or The heating rate of the synthesis reactor is 1-5℃ / min.

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