CN115598430A - Gas-solid two-phase flow electrostatic charge detection system and method - Google Patents
Gas-solid two-phase flow electrostatic charge detection system and method Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/12—Measuring electrostatic fields or voltage-potential
- G01R29/14—Measuring field distribution
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- G—PHYSICS
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention discloses a system and a method for detecting electrostatic charge of a gas-solid two-phase flow, which belong to the fields of energy, chemical industry and pharmacy, and provide a novel system and a method for detecting electrostatic electrification of the gas-solid two-phase flow, wherein the system and the method are used for detecting induced current generated when air-borne particles in a pipeline rub with a pipe wall; the invention is a pipeline-shaped test section which has the same inner diameter as the tested pipeline and is divided into an electrode layer and a shielding layer, wherein the electrode layer is connected with test equipment, and the shielding layer is grounded; induced current caused by sliding on the inner wall of the single particle testing section, and continuous current is formed when a large number of particles pass through the testing section through pneumatic transmission; a self-designed static current testing section is used as a core to build a detection system for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in a pneumatic conveying system on static charges.
Description
Technical Field
The invention belongs to the field of energy, chemical industry and pharmacy, and particularly relates to a gas-solid two-phase flow electrostatic charge detection system and method.
Background
The gas-solid two-phase system is widely used in the industries of energy, chemical industry, pharmacy, metallurgy, material processing and the like. Static electricity is a ubiquitous phenomenon in a gas-solid two-phase system, and electrostatic charges are generated and accumulated due to friction and collision among particles and between particles and wall of a container, particularly in the petrochemical industry, a large amount of electrostatic charges are generated by a large number of insulating particles flowing at high speed in the process of violent collision. The accumulation of static charge can affect the hydrodynamic behavior in the reactor, cause the phenomena of wall adhesion, caking and the like, even cause the emergency stop of the reactor, and bring hidden danger to safe and stable production; the electrostatic flash risk and the secondary human body injury of the electrostatic electrode can be brought to the packaging process of the inflammable and explosive dust powder; in addition, electrostatic adsorption can affect the delivery quality of chemical powder products. The very low ambient humidity makes the generation and accumulation of static charge even more severe. Therefore, the research on the electrostatic electrification phenomenon in the gas-solid two-phase system has very important significance on the production efficiency of chemical powder, the product quality and the enterprise safety. At present, the static detection of a gas-solid two-phase system mainly comprises static potential measurement and static charge measurement. The electrostatic potential measurement comprises contact measurement and non-contact measurement; the electrostatic charge measurement is a multipurpose Faraday cup. The contact type electrostatic potential measurement mainly depends on electrostatic sensors arranged in a pipeline and a fluidized bed, and the non-contact type electrostatic potential measurement mainly depends on electrostatic induction of an annular induction electrode.
Patent CN101957385B discloses a method and a device for measuring the local particle velocity in a fluidized bed by electrostatic induction, wherein an electrostatic signal of gas-solid flow information is detected by an electric induction electrode array, and sent to a computer through a data acquisition card, and the difference electrostatic signal is subjected to spectrum analysis in the computer and the peak frequency on the spectrum is determined, so as to obtain the local particle velocity of the gas-solid two-phase flow.
Patent CN101839889B discloses an arc-shaped electrostatic sensor array measuring method and device for particle velocity distribution, which also detects electrostatic signals of gas-solid flow information through an electrode array;
patent CN105929260B discloses a method for detecting electrostatic level in a gas-solid system, which uses an induction electrode and pressure pulsation to obtain an induction electrostatic current signal generated in a particle fluidization process and a differential pressure signal at two sides of an annular induction electrode, and then obtains a particle charge-to-mass ratio through a quantitative correlation between the electrostatic current and the differential pressure signal.
Patent CN102608350B discloses a gas-solid two-phase flow velocity distribution detection method and device by multi-electrode electrostatic method, wherein a sensing part comprises electrodes distributed on 2 × C sections of a pipeline for detecting particle electrostatic voltage signals, the number of the electrodes on each section is set to be N, the N electrodes are uniformly distributed on the circumference along the inner wall of the pipeline to form an electrode circumference, two adjacent electrode circumferences are divided into a group from the electrode circumference on the most upstream section, the electrode circumferences are divided into C groups, the electrode arrangement positions on the two electrode circumferences of the same group are consistent, the electrodes on the electrode circumferences of different groups respectively use the axis of the pipeline as an axis, and the electrodes are sequentially rotated for a fixed angle. The invention is used for detecting the particle velocity distribution in different areas in the pipeline.
Patent CN109580716B discloses a method for identifying gas-solid flow pattern of lifting section of circulating fluidized bed based on electrostatic detection. The method comprises the steps of synchronously acquiring electrostatic signals at a plurality of axial positions of the lifting section, processing the acquired signals to obtain the axial distribution of electrostatic potential signals in the lifting section, and judging the flow pattern of gas-solid flow in the lifting section according to an electrostatic potential axial distribution curve. The criterion is that a dense phase region capable of detecting positive electrostatic potential exists in the fast fluidization flow pattern, but the pneumatic transmission flow pattern does not exist.
Patent CN101957385B discloses a method and an apparatus for electrostatic induction measurement of local particle velocity in a fluidized bed. The method comprises the steps of filling an insulating isolation material at one end of a metal shielding tube to form an insulating isolation block, uniformly and parallelly arranging a plurality of electrodes in the same plane in the insulating isolation block to form a first static induction electrode array and a second static induction electrode array, respectively connecting the electrodes in the two electrode arrays together by using a conducting wire, generating two groups of static signals reflecting gas-solid flow information when charged particles pass through the two static induction electrode arrays, connecting the static signals to a pre-charge differential circuit for amplification, sending the signals to a computer through a data acquisition card, carrying out spectrum analysis on the differential static signals in the computer, determining the peak frequency on a spectrum, and further obtaining the local particle velocity of the gas-solid two-phase flow.
The invention relates to a brand-new system and a method for detecting the gas-solid two-phase flow static electrification current, which can be widely used for the static prevention and control research of gas-solid two-phase conveying systems in various industries; the device is used for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in the pneumatic conveying system on static charges and the influence of different electrostatic effects on particle flow behaviors in the pneumatic conveying system; the device is used for detecting induced current generated when airborne particles in the pipeline rub against the pipe wall; the invention is a pipeline-shaped test section, has the same inner diameter as the tested pipeline, and is divided into an electrode layer and a shielding layer, wherein the electrode layer is connected with test equipment, and the shielding layer is grounded; induced current caused by sliding on the inner wall of the single particle testing section, and continuous current is formed when a large number of particles pass through the testing section through pneumatic transmission; a self-designed static current testing section is used as a core to build a detection system for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in a pneumatic conveying system on static charges. The method of the invention relates to the fields of energy, chemical industry, pharmacy and the like, can be widely used for the static prevention and control research of gas-solid two-phase conveying systems in various industries, and has very high academic research value.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a gas-solid two-phase flow static charge detection system and a method, which are used for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in a pneumatic conveying system on static charge and the influence of different static effects on particle flow behaviors in an airflow conveying system; reasonable in design has overcome prior art's not enough, has good effect.
In order to achieve the purpose, the invention adopts the following technical scheme:
a gas-solid two-phase flow electrostatic charge detection system comprises an air control valve, an air dryer, a flow meter, an electronic scale, a feed hopper, a feed control valve, a rotary valve, a computer, an electrometer, a conveying system and a recovery hopper;
the air dryer is installed at the downstream end of the air control valve, the feeding control valve is installed at the downstream end of the feeding hopper, the rotary valve is installed at the downstream end of the feeding control valve, and the rotary valve is installed at the downstream end of the flow meter;
the computer, the electrometer and the static current testing section are sequentially connected through a conveying pipeline, the static current testing section is respectively connected with the rotary valve, the Faraday cage and the recovery hopper through the conveying pipeline, the static current testing section is installed at the downstream end of the rotary valve, the Faraday cylinder is arranged at the downstream end of the static current testing section, and the recovery hopper is arranged at the downstream end of the Faraday cylinder;
an air control valve configured to control the flow rate of the gas flow and the flow rate of the material;
an air dryer configured to control the humidity of the airflow at a set dryness;
a flow meter, being a gas flow meter, configured to monitor the air delivery;
an electronic scale configured to measure a mass flow rate of a material being conveyed;
a feed hopper configured for entry of material to be conveyed;
a feed control valve configured to control the rate at which conveyed material enters the conveying system from the feed hopper;
a rotary valve configured for variable frequency control of feed volume;
a computer configured to store the electrostatically induced current;
an electrometer configured to store the electrostatically induced current in the computer at intervals of 0.1 s;
a recovery hopper configured for recovering the conveyed material;
the conveying system comprises an electrostatic current testing section and a Faraday cage;
the static current test section is configured to be used for measuring the static induction current of the conveyed material in the conveying pipeline;
a faraday cage configured for measuring a charge density of conveyed material within a conveying pipeline;
on one hand, compressed air sequentially passes through the air control valve, the air dryer and the flow meter to enter the rotary valve; the dryness of the compressed air can be controlled, and the flow rate of the compressed air is controlled by an air control valve; on the other hand, the materials sequentially pass through the feed hopper and the feed control valve to enter the rotary valve, and the mass flow of the conveyed materials is controlled by the feed control valve; the dried compressed air drives the conveyed materials to enter a conveying system; the conveying system comprises an electrostatic current testing section and a Faraday cylinder; the electrometer stores the detected static induced current data in a computer; the conveyed materials are finally circulated back to the recovery hopper.
Preferably, the system is characterized in that the conveying pipelines except the static current testing section are all metal pipelines and are grounded.
Preferably, the material to be conveyed is polypropylene granules or polyester chips.
Preferably, the electrostatic current test section has the same inner diameter as the conveying pipe.
Preferably, the air control valve is connected to the intake system.
Preferably, the feed hopper is made of metal and is grounded.
Preferably, the electrostatic current test section is, from inside to outside: the film layer, the conductive adhesive layer, the first metal layer, the non-conductive adhesive layer and the second metal layer; the first metal layer is connected to the electrometer and both the non-conductive adhesive layer and the second metal layer are grounded.
Preferably, the film layer is in direct contact with the material, the material is a non-metal material including PVC and PE, and the thickness is not more than 5mm.
Preferably, the first metal layer and the second metal layer are both made of copper and have a thickness of 0.10mm.
Preferably, the thickness of the conductive glue layer is 0.07mm.
Preferably, the non-conductive adhesive layer is 0.12mm thick.
Preferably, the first metal layer serves as an electrode layer.
Preferably, the non-conductive adhesive layer and the second metal layer act as a shielding layer.
Preferably, the recovery hopper is a metal shell and is grounded.
Preferably, the delivery conduit and faraday are provided with a manual valve therebetween.
Preferably, the rotary valve has eight rotary chambers and a fixed rotational speed.
In addition, the invention also provides a gas-solid two-phase flow static charge detection method, which adopts the gas-solid two-phase flow static charge detection system and specifically comprises the following steps:
step 1: compressed air enters the rotary valve through the air control valve, the air dryer and the flowmeter in sequence; the dryness of the compressed air can be controlled, and the flow rate of the compressed air is controlled by a control valve;
and 2, step: the materials sequentially pass through the feed hopper and the feed control valve to enter the rotary valve, and the mass flow of the conveyed materials is controlled by the feed control valve;
and step 3: the dried compressed air drives the conveyed material to enter an electrostatic current testing section of the conveying system;
and 4, step 4: the electrometer stores the detected static induced current data in a computer;
and 5: the conveyed materials are finally circulated back to the recovery hopper.
The invention has the following beneficial technical effects:
the invention provides a novel system and a novel method for detecting static electrification of a gas-solid two-phase flow, which are used for detecting induced current generated when gas-borne particles in a pipeline rub with a pipe wall; the invention is a pipeline-shaped test section which has the same inner diameter as the tested pipeline and is divided into an electrode layer and a shielding layer, wherein the electrode layer is connected with test equipment, and the shielding layer is grounded; induced current caused by sliding on the inner wall of the single particle testing section, and continuous current is formed when a large number of particles pass through the testing section through pneumatic transmission; a self-designed static current testing section is used as a core to build a detection system for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in a pneumatic conveying system on static charges.
The method of the invention relates to the fields of energy, chemical industry, pharmacy and the like, can be widely used for the static prevention and control research of gas-solid two-phase conveying systems in various industries, and has very high academic research value.
Drawings
FIG. 1 is a flow chart of a gas-solid two-phase flow electrostatic charge detection method according to the present invention;
wherein, 1-an air control valve; 2-an air dryer; 3-a flow meter; 4-an electronic scale; 5-a feed hopper; 6-feed control valve, 7-rotary valve; 8-a computer; 9-an electrometer; 10-an electrostatic current test section; 11-a faraday cage; 12-a recovery hopper;
FIG. 2 is a detailed view of an electrostatic current test section;
wherein, 101-a thin film layer; 102-a conductive adhesive layer; 103-a first metal layer; 104-a non-conductive adhesive layer; 105-second metal layer.
Detailed Description
The invention is described in further detail below with reference to the following figures and detailed description:
the embodiment of the invention provides a method for detecting electrostatic electrification current of a gas-solid two-phase flow, in particular to a method for detecting electrostatic induction current of solid particles in a pneumatic conveying system. The detection method can be used for researching the influence of the pipeline material, the environment humidity, the gas flow velocity, the particle component, the antistatic agent and the like in the pneumatic conveying system on the static charge and the influence of different static effects on the particle flow behavior in the pneumatic conveying system.
A detection system for gas-solid two-phase flow electrostatic electrification current comprises an air control valve 1, an air dryer 2, a flow meter 3, a feed hopper 5, an electronic scale 4, a feed control valve 6, a rotary valve 7, an electrostatic current testing section 10 (detailed in figure 2), an electrometer 9, a computer 8, a Faraday cage 11 and a recovery hopper 12.
The air control valve 1, the air dryer 2, the flowmeter 3, the rotary valve 7, the feeding control valve 6, the feeding hopper 5 and the electronic scale 4 are sequentially connected through a conveying pipeline, specifically, the air dryer 1 is installed at the downstream end of the air control valve 2, the feeding control valve 6 is installed at the downstream end of the feeding hopper 5, the rotary valve 7 is installed at the downstream end of the feeding control valve 6, and the rotary valve 7 is installed at the downstream end of the flowmeter 3;
an air control valve 1 configured to control a flow rate of the gas flow and a flow rate of the material;
an air dryer 2 configured to control the humidity of the air stream at a set dryness;
a flow meter 3, being a gas flow meter, configured to monitor the air delivery;
an electronic scale 4 configured to measure a mass flow rate of the conveyed material;
a feed hopper 5 configured for entry of material to be conveyed;
a feed control valve 6 configured to control the rate at which conveyed material enters the conveying system from the feed hopper;
a rotary valve 7 configured for variable frequency control of the feed amount;
a computer 8 configured to store the electrostatically induced current;
an electrometer 9 configured to store the electrostatically induced current in the computer at intervals of 0.1 s;
a recovery hopper 12 configured for recovering the conveyed material;
the conveying system comprises an electrostatic current testing section 10 and a Faraday cage 11;
an electrostatic current test section 10 configured to measure an electrostatic induction current of the conveyed material in the conveying pipeline;
a faraday cage 11 configured for measuring a charge density of a transported material within a transport pipe;
the computer 8, the electrometer 9 and the static current testing section 10 are sequentially connected through a conveying pipeline, the static current testing section 10 is respectively connected with the rotary valve 7, the Faraday cage 11 and the recovery hopper 12 through the conveying pipeline, the static current testing section 10 is installed at the downstream end of the rotary valve 7, the Faraday cage 11 is arranged at the downstream end of the static current testing section, and the recovery hopper 12 is arranged at the downstream end of the Faraday cage 11;
on one hand, compressed air enters the rotary valve 7 through the air control valve 1, the air dryer 2 and the flow meter 3 in sequence; the dryness of the compressed air can be controlled, and the flow rate of the compressed air is controlled by an air control valve 1; on the other hand, the materials sequentially pass through the feed hopper 5 and the feed control valve 6 to enter the rotary valve 7, and the mass flow of the conveyed materials is controlled by the feed control valve 6; the dried compressed air drives the conveyed materials to enter a conveying system; the conveying system comprises an electrostatic current testing section 10 and a Faraday cylinder 11; the electrometer 9 stores the detected static induction current data in the computer 8; the conveyed material is finally recycled back to the recovery hopper 12.
The conveying pipeline is a metal pipeline, and the conveying system is provided with an electrostatic current testing section 10 and a Faraday cylinder 11 which are respectively used for measuring the electrostatic induction current and the charge density of the materials in the conveying pipeline. The air flow rate, the dryness and the material mass flow of the whole system are controllable. The electrostatic current testing section comprises the following steps from inside to outside in sequence: a film layer 101, a conductive adhesive layer 102, a first metal layer 103, a non-conductive adhesive layer 104, and a second metal layer 105. The film layer 101 directly contacts with the material, and the material can be non-metallic material such as PVC, PE, etc. First metal layer 103 and second metal layer 105 are made of copper. The first metal layer 103 serves as an electrode and is connected to the electrometer 9. The second metal layer 105 acts as an electrical shield and is grounded. The method can research the rule of static electricity generation and different flowing states caused by different static electricity effects according to different experimental conditions, such as pipe wall materials, particle components, relative humidity, antistatic agents and other factors. See in particular the examples below:
example 1
Referring to fig. 1, an embodiment of the present invention provides a detection system for an electrostatic electrification current of a gas-solid two-phase flow, where the system includes an air control valve 1, an air dryer 2, a flow meter 3, a feed hopper 5, an electronic scale 4, a feed control valve 6, a rotary valve 7, an electrostatic current test section 10 (see fig. 2 in detail), an electrometer 9, a computer 8, a faraday cage 11, and a recovery hopper 12. The conveyed material is polypropylene particles. Compressed air enters the rotary valve 7 through the air control valve 1, the air dryer 2 and the flowmeter 3 in sequence, the air control valve is used for controlling airflow and material flow, and the air dryer controls the air flow humidity to be in the dryness set in the test. The recycling of polypropylene granules back to the granule hopper requires the passage of a feed control valve 6, which feed control valve 6 controls the rate of granules entering the conveying system from feed hopper 5, and an electronic scale 4 measures the granule mass flow. The polypropylene particles are introduced into the rotary valve 7 and are entrained by the gas flow from the compressor. The rotary valve 7 has eight rotary chambers and a fixed rotational speed. The conveying pipeline is made of copper, is grounded and has an inner diameter of 40mm. The electrostatic current testing section comprises the following steps from inside to outside in sequence: a film layer (PVC, thickness 5 mm), a conductive glue layer (thickness 0.07 mm), a copper electrode layer (thickness 0.10 mm), and a non-conductive adhesive layer (copper) (thickness 0.12 mm) and a shielding electrode layer (copper) (thickness 0.10 mm). The electrode layer is connected with the electrometer, and the shielding electrode layer is grounded. The static current test section 10 and the Faraday cylinder 11 are respectively used for measuring the static induction current and the charge density of the material in the conveying pipeline. The static current test section 10 is of the same inner diameter as the conveying pipe, and the static induced current is stored in the computer 8 at intervals of 0.1s using the electrometer 9. And a manual valve is arranged between the conveying pipeline and the Faraday 11. The material is recycled to the recycling hopper 12 at last, and the recycling hopper 12 is made of metal and is grounded. The adjustable variables of the whole conveying system are as follows: air pressure and flow rate, material flow rate, air dryness and material of the film layer.
Example 2
The embodiment of the invention provides a detection system for gas-solid two-phase flow electrostatic electrification current, which comprises an air control valve 1, an air dryer 2, a flow meter 3, a feed hopper 5, an electronic scale 4, a feed control valve 6, a rotary valve 7, an electrostatic current testing section 10 (shown in detail in figure 2), an electrometer 9, a computer 8, a Faraday cage 11 and a recovery hopper 12. The conveyed materials are polyester chips. Compressed air sequentially passes through the air control valve 1, the air dryer 2 and the flowmeter 3 to enter the rotary valve 7, the air control valve 1 is used for controlling airflow and material flow, and the airflow humidity is controlled at the dryness set in the test by the air dryer 2. The recycling of the polyester chips back to the recovery hopper 12 requires the passage of a feed control valve 6, the feed control valve 6 controlling the rate at which the pellets enter the conveyor system from the hopper, and an electronic scale 4 measuring the mass flow of the pellets. The polyester chips are led into a rotary valve and are driven by the airflow sprayed by a compressor. The rotary valve 7 has eight rotary chambers and the rotating speed is fixed. The conveying pipeline is made of copper, is grounded and has an inner diameter of 40mm. The electrostatic current testing section comprises the following steps from inside to outside in sequence: a film layer (PE, thickness 0.4 mm), a conductive glue layer (thickness 0.07 mm), a copper electrode layer (thickness 0.10 mm), and a non-conductive adhesive layer (copper) (thickness 0.12 mm) and a shielding electrode layer (copper) (thickness 0.10 mm). The electrode layer is connected with the electrometer, and the shielding electrode layer is grounded. The static current test section 10 and the Faraday cage 11 are respectively used for measuring the static induced current and the charge density of the material in the conveying pipeline. The static current test section 10 is of the same inner diameter as the conveying pipe, and the static induced current is stored in the computer 8 at intervals of 0.1s using the electrometer 9. And a manual valve is arranged between the conveying pipeline and the Faraday 11. The conveyed materials are finally circulated back to the recovery hopper 12, and the recovery hopper 12 is made of metal and is grounded. The adjustable variables of the whole conveying system are as follows: air pressure and flow rate, material flow rate, air dryness and material of the film layer.
In addition, the invention also provides a gas-solid two-phase flow static charge detection method, the flow of which is shown in figure 1, and the method specifically comprises the following steps:
step 1: compressed air enters the rotary valve through the air control valve, the air dryer and the flowmeter in sequence; the dryness of the compressed air can be controlled, and the flow rate of the compressed air is controlled by a control valve;
step 2: the materials sequentially pass through the feed hopper and the feed control valve to enter the rotary valve, and the mass flow of the conveyed materials is controlled by the feed control valve;
and step 3: the dried compressed air drives the conveyed materials to enter an electrostatic current testing section of the conveying system;
and 4, step 4: the electrometer stores the detected static induced current data in a computer;
and 5: the conveyed materials are finally circulated back to the recovery hopper.
The invention aims to provide a system and a method for detecting electrostatic electrification current of a gas-solid two-phase flow, which are used for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in a pneumatic conveying system on electrostatic charge and the influence of different electrostatic effects on particle flow behaviors in an airflow conveying system.
The invention provides a novel system and a novel method for detecting electrostatic electrification of a gas-solid two-phase flow, which are used for detecting induced current generated when gas-transported particles in a pipeline rub with a pipe wall; the invention is a pipeline-shaped test section which has the same inner diameter as the tested pipeline and is divided into an electrode layer and a shielding layer, wherein the electrode layer is connected with test equipment, and the shielding layer is grounded; induced current caused by sliding on the inner wall of the single particle testing section, and continuous current is formed when a large number of particles pass through the testing section through pneumatic transmission; a self-designed static current testing section is used as a core to build a detection system for researching the influence of pipeline materials, environment humidity, gas flow rate, particle components, antistatic agents and the like in a pneumatic conveying system on static charges.
The method of the invention relates to the fields of energy, chemical industry, pharmacy and the like, can be widely used for the static prevention and control research of gas-solid two-phase conveying systems in various industries, and has very high academic research value.
The above description is only for the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make various changes, modifications, additions and substitutions within the spirit and scope of the present invention.
Claims (17)
1. A gas-solid two-phase flow static charge detection system is characterized in that: comprises an air control valve, an air dryer, a flowmeter, an electronic scale, a feed hopper, a feed control valve, a rotary valve, a computer, an electrometer, a conveying system and a recovery hopper;
the air control valve, the air dryer, the flowmeter, the rotary valve, the feeding control valve, the feeding hopper and the electronic scale are sequentially connected through a conveying pipeline, specifically, the air dryer is installed at the downstream end of the air control valve, the feeding control valve is installed at the downstream end of the feeding hopper, the rotary valve is installed at the downstream end of the feeding control valve, and the rotary valve is installed at the downstream end of the flowmeter;
the computer, the electrometer and the static current testing section are sequentially connected through a conveying pipeline, the static current testing section is respectively connected with the rotary valve, the Faraday cage and the recovery hopper through the conveying pipeline, the static current testing section is installed at the downstream end of the rotary valve, the Faraday cylinder is arranged at the downstream end of the static current testing section, and the recovery hopper is arranged at the downstream end of the Faraday cylinder;
an air control valve configured to control the flow rate of the gas and the flow rate of the material;
an air dryer configured to control the humidity of the air stream at a set dryness;
a flow meter, being a gas flow meter, configured to monitor a wind delivery;
an electronic scale configured to measure a mass flow rate of a material being conveyed;
a feed hopper configured for entry of material to be conveyed;
a feed control valve configured to control the rate at which conveyed material enters the conveying system from the feed hopper;
a rotary valve configured for variable frequency control of feed volume;
a computer configured to store the electrostatically induced current;
an electrometer configured to store the electrostatically induced current in the computer at intervals of 0.1 s;
a recovery hopper configured for recovering the conveyed material;
the conveying system comprises an electrostatic current testing section and a Faraday cage;
the static current test section is configured to be used for measuring the static induction current of the conveyed material in the conveying pipeline;
a faraday cage configured for measuring a charge density of conveyed material within a conveying pipeline;
on one hand, compressed air enters the rotary valve through the air control valve, the air dryer and the flowmeter in sequence; the dryness of the compressed air can be controlled, and the flow rate of the compressed air is controlled by an air control valve; on the other hand, the materials sequentially pass through the feed hopper and the feed control valve to enter the rotary valve, and the mass flow of the conveyed materials is controlled by the feed control valve; the dried compressed air drives the conveyed materials to enter a conveying system; the conveying system comprises an electrostatic current testing section and a Faraday cylinder; the electrometer stores the detected static induced current data in a computer; the conveyed materials are finally circulated back to the recovery hopper.
2. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: except for the static current testing section, the conveying pipelines are all metal pipelines and are grounded.
3. The gas-solid two-phase flow electrostatic charge detection system of claim 2, characterized in that: the conveyed materials are polypropylene particles or polyester chips.
4. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: the static current test section and the conveying pipeline have the same inner diameter.
5. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: the air control valve is connected with an air inlet system.
6. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: the feed hopper is made of metal and is grounded.
7. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: the electrostatic current testing section comprises the following steps from inside to outside in sequence: the film layer, the conductive adhesive layer, the first metal layer, the non-conductive adhesive layer and the second metal layer; the first metal layer is connected to the electrometer and both the non-conductive adhesive layer and the second metal layer are grounded.
8. The gas-solid two-phase flow electrostatic charge detection system of claim 7, characterized in that: the film layer is in direct contact with the material, the material is non-metallic material including PVC and PE, and the thickness is not more than 5mm.
9. The gas-solid two-phase flow electrostatic charge detection system of claim 7, characterized in that: the first metal layer and the second metal layer are both made of copper, and the thickness of the first metal layer and the thickness of the second metal layer are both 0.10mm.
10. The gas-solid two-phase flow electrostatic charge detection system of claim 7, characterized in that: the thickness of the conductive adhesive layer is 0.07mm.
11. The gas-solid two-phase flow electrostatic charge detection system of claim 7, characterized in that: the thickness of the non-conductive adhesive layer was 0.12mm.
12. The gas-solid two-phase flow electrostatic charge detection system of claim 7, characterized in that: the first metal layer serves as an electrode layer.
13. The gas-solid two-phase flow electrostatic charge detection system of claim 7, characterized in that: the non-conductive adhesive layer and the second metal layer act as a shielding layer.
14. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: the recovery hopper is a metal shell and is grounded.
15. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: and a manual valve is arranged between the conveying pipeline and the Faraday.
16. The gas-solid two-phase flow electrostatic charge detection system of claim 1, characterized in that: the rotary valve has eight rotary chambers, and the rotating speed is fixed.
17. A gas-solid two-phase flow static charge detection method is characterized in that: the gas-solid two-phase flow electrostatic charge detection system of claim 1, comprising the following steps:
step 1: compressed air sequentially passes through the air control valve, the air dryer and the flow meter to enter the rotary valve; the dryness of the compressed air can be controlled, and the flow rate of the compressed air is controlled by a control valve;
and 2, step: the materials sequentially pass through the feed hopper and the feed control valve to enter the rotary valve, and the mass flow of the conveyed materials is controlled by the feed control valve;
and 3, step 3: the dried compressed air drives the conveyed materials to enter an electrostatic current testing section of the conveying system;
and 4, step 4: the electrometer stores the detected static induced current data in a computer;
and 5: the conveyed material is finally recycled to the recovery hopper.
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| CN202110716826.8A CN115598430A (en) | 2021-06-28 | 2021-06-28 | Gas-solid two-phase flow electrostatic charge detection system and method |
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| CN202110716826.8A CN115598430A (en) | 2021-06-28 | 2021-06-28 | Gas-solid two-phase flow electrostatic charge detection system and method |
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