Method and device for moisture content self-feedback drying of whole material

Abstract

The invention discloses a moisture content self-feedback drying method and device for full materials, and the method comprises the steps: monitoring the moisture content of materials in a feeding hopper in real time through a moisture content monitoring device, and selecting different feeding lines according to the moisture content: feeding the materials with the moisture content of 90-98% into a boiling bed filter for preliminary dehydration; the filtering medium-material mixture enters the next step along with the pulsating hot carrier gas; a material with the water content of 65-90% is stirred and mixed into the dispersion medium, and the obtained dispersion medium-material mixture enters the next step along with the pulsating heat carrier gas; materials with the water content of 30%-65% are granulated through a granulator to form material strips, and the material strips are cut into strips through hot carrier gas and brought to the next step; the materials with the water content of 10-30% are crushed through a crusher and enter the next step along with the hot carrier gas; then, through rotational flow drying, sorting and gas-solid separation, continuous automatic feeding and efficient drying treatment of materials with the water content of 10%-98% are achieved, the types of treatable materials are greatly widened, and the continuous drying device has the advantages of being continuous, automatic and stable.

Description

Technical Field

[0001] The invention belongs to the technical field of material drying, and in particular relates to a method and a device for self-feedback drying of moisture content of all materials. Background Art

[0002] With the progress of social economy and the growth of people's demand for a better life, social productivity has developed rapidly, but the large amount of pollutants generated in the production process has also brought environmental problems. The separation of pollutants in the process of environmental protection is at the expense of energy or material consumption. The energy consumed by global industry accounts for 32% of the global total energy consumption, of which the energy consumed in the separation process accounts for 45%-55% of the total energy consumption in industry, and the energy consumed by thermal separation (including distillation, drying and evaporation, etc.) in the separation process accounts for 80% of the total energy consumption of the separation process, and the energy consumed by non-thermal separation accounts for only 20% of the total energy consumption of the separation process. The energy consumed by thermal separation accounts for 36%-44% of the total energy consumption in industry, while the energy consumed by non-thermal separation accounts for only 9%-11% of the total energy consumption in industry. Therefore, replacing industrial thermal separation with feasible non-thermal separation will save a lot of energy and reduce the generation of environmental pollutants, which will help solve the problems of energy shortage and environmental pollution.

[0003] In industry, thermal separation is often used to dry materials that need to be dehydrated, such as sludge, distiller's grains, coal, crop products, waste residues, and waste catalysts. Since the latent heat of vaporization of water is very large, it consumes a lot of energy to dry it by phase change, which does not meet the goals of energy conservation, emission reduction, pollution reduction, and carbon reduction. However, non-phase change drying of water meets the main theme of the "dual carbon era". At the same time, normalizing the drying devices for different types of materials and materials with different moisture contents that need to be dried to achieve the effect of one machine for multiple uses is the only way to achieve the systematization, large-scale, and automation of industrial devices, which is of great significance to reducing energy consumption and carbon emissions.

[0004] CN110257089A discloses a method for drying and recycling wine lees, which uses pulsating gas as a carrier to make wine lees particles rotate while revolving in a cyclonic field to induce water to migrate out of the particles. After drying, the wine lees enter an oscillating drying column, and the pulsating drying airflow introduced causes the particles to vibrate and accelerate the drying speed. The wine lees particles after oscillation drying enter a secondary cyclonic rotation dehydration separator for further drying, and finally the dried wine lees are subjected to anaerobic pyrolysis and gasification. The moisture content of the dried wine lees particles obtained by this method is less than 10%, but it does not take into account that some relatively wet wine lees particles are deposited at the bottom of the oscillating drying column and need to be returned for reprocessing.

[0005] CN110183089A discloses a method and device for dehydrating excess sludge, wherein excess sludge with high water content is concentrated by a granular bed with a built-in cyclone, and the concentrated sludge enters the cyclone self-rotating dehydrator and the accelerated airflow sorting column in sequence with hot gas for deep dehydration and sorting of sludge and filter media, and the dried excess sludge enters the cyclone collector from the top of the sorting column with the gas, and the separated filter media is discharged from the bottom of the sorting column and recycled. The dehydration effect of the method and device is good, but the boiling bed filtration speed in the device is slow, the operation is complicated when refilling the filter media, the operation cycle is long, and it does not support continuous large-scale feeding. There is a phenomenon that sludge accumulates on the surface of the bed layer, causing the filter media in the lower layer to be not fully utilized.

[0006] CN110269094A discloses a method and device for drying and sorting grains. The wet grains enter the first-stage cyclone for cyclone self-rotation dehydration and drying to obtain a mixture of complete dry grains and impurities, and then they are separated by a sorter. The impurities are sent to the second-stage cyclone for separation to obtain air-dried grains and mud powder, and the mud powder is sent to the third-stage cyclone for gas-solid separation with air. This method can simultaneously realize the drying of wet grains and the sorting of dry grains with different specific gravities, and has a good application prospect, but the energy consumption of the electrically heated carrier gas is high, and the wet grains stay in the first-stage cyclone for a short time, which may cause the wet grain drying effect to be unstable. After entering the sorter, large particles of wet grains will be discharged from the bottom of the sorter and mixed with the complete dry grains.

[0007] CN113636737A discloses a method and device for dehydrating and drying excess sludge, wherein the excess sludge is concentrated by centrifugal dehydration, the concentrated sludge enters a mixer and is mixed with a dispersion medium, the sludge-dispersion medium mixture enters a cyclone for cyclone drying, and then a separation column separates the dispersion medium and dry sludge, and then a cyclone collector captures the dry sludge from the dry sludge and water-containing air mixture. The method has a good drying effect on the excess sludge, and at the same time, a sewage source heat pump is used to transfer the low-level heat energy in the sewage to the inlet gas to realize the recovery of heat energy, but the invention is only for the treatment of excess sludge, and cannot realize the drying treatment of sludge with different moisture contents and different materials.

[0008] In summary, the existing material drying methods and devices have the following problems: the existing drying technology and devices are only used to dry a single material or a material with a certain moisture content, and are not universally applicable to other materials. Different materials and the same material with different moisture contents cannot be processed at the same time, and different devices are required, resulting in excessive one-time investment, low drying efficiency, and waste of space and resources. Summary of the invention

[0009] In view of the above-mentioned problems existing in the prior art, the present invention provides a method and device for self-feedback drying of the moisture content of all materials. The moisture content of the material in the feed hopper is monitored in real time by a moisture content monitoring device, and different feeding routes are selected according to the moisture content. Then, through cyclone drying, sorting and gas-solid separation, continuous automatic feeding and efficient drying treatment of materials with a moisture content of 10%-98% are achieved, which greatly broadens the types of materials that can be processed and has the characteristics of continuity, automation and stabilization.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] The first aspect of the present invention is to provide a method for self-feedback drying of moisture content of all materials, the method comprising the following steps:

[0012] (1) Determination of moisture content: Infrared light is generated by an infrared light source, and infrared light of a characteristic wavelength is obtained through the filter on the spectrometer. After passing through the infrared transparent glass set at the bottom of the feed hopper, it is reflected by the material. The photoelectric sensor converts the optical signal of the reflected light into an electrical signal. The electrical signal is then processed by the processor to obtain the moisture content, and the feed line is adjusted according to the moisture content through self-feedback.

[0013] (2) Feeding line: (21) Materials with a moisture content of 90-98% enter the fluidized bed filter and are initially dehydrated using the filled filter medium. The filter medium-material mixture enters the cyclone dryer with the pulsating hot carrier gas, and the filter medium serves as a dispersion medium in the cyclone dryer; (22) Materials with a moisture content of 65-90% are stirred and mixed into the dispersion medium, and the resulting dispersion medium-material mixture enters the cyclone dryer with the pulsating hot carrier gas; (23) Materials with a moisture content of 30-65% are granulated by a granulator to form material strips, which are cut into strips by the hot carrier gas and then brought into the cyclone dryer; (24) Materials with a moisture content of 10-30% are crushed by a crusher and enter the cyclone dryer with the hot carrier gas;

[0014] (3) Cyclone drying: The wet materials from steps (21) and (22) are subjected to cyclone drying and separation in a cyclone dryer, and the obtained dispersion medium-dried materials are sent to a separation column with a pulsating hot carrier gas for accelerated separation; the wet materials from steps (23) and (24) are subjected to cyclone drying and separation in a cyclone dryer, and the obtained dried materials are sent to a gas-solid cyclone separator with a hot carrier gas through a separation column;

[0015] (4) Accelerated separation of mixed materials: In the separation column, the pulsating hot carrier gas has different cumulative accelerations on the dried material and the dispersed medium, and the dried material and the dispersed medium are separated.

[0016] (5) The dried material is then subjected to cyclone drying and gas-solid separation: The dried material enters the gas-solid cyclone separator for further cyclone drying and is then discharged, and water-containing gas is separated at the same time.

[0017] The present invention is further configured such that the hot carrier gas is a continuous flow of high-temperature flue gas; the pulsating hot carrier gas is a periodic oscillating flow of high-temperature flue gas;

[0018] The temperature of the high temperature flue gas is 40-80°C;

[0019] The pulsating hot carrier gas is a periodic oscillating airflow obtained by the periodic closing of a butterfly valve through which high-temperature flue gas passes. The periodic closing of the butterfly valve is controlled by an airflow pulsation generator.

[0020] The present invention is further configured that the method further comprises step (6) gas-liquid separation and heat energy recovery: the water-containing gas separated in step (5) is passed through a gas-liquid separator to separate hot waste water and hot waste gas;

[0021] When the flow rate of high-temperature flue gas is low, the hot exhaust gas is recycled as high-temperature flue gas, and whether to perform low-temperature heating is determined based on the recycling of the hot exhaust gas;

[0022] The hot wastewater is used to preheat the wet material in step (2), which is beneficial to improving the cyclone drying effect and realizing waste heat utilization.

[0023] The present invention is further configured such that the dispersion medium separated in step (4) is reused in steps (21) and (22).

[0024] The present invention is further configured that the method is applicable to materials with a moisture content within the range of 10-98%, and the materials include sludge, distiller's grains, coal, crop waste residues and waste catalysts.

[0025] The present invention is further configured such that the thickness of the ebullient bed layer in the ebullient bed filter is set between 0.4 and 1 m;

[0026] The filtering media used in the fluidized bed layer include perlite, quartz sand and sea sand;

[0027] The particle size of the filter medium is 0.5-2 mm.

[0028] The present invention is further configured that, in the step (22), the mixing mass ratio of the material having a moisture content of 65-90% and the dispersion medium is controlled to be 1:1-1:3;

[0029] The dispersion medium includes coal slag particles, quartz sand, perlite and sea sand;

[0030] The particle size of the dispersion medium is 2-4 mm.

[0031] The second aspect of the present invention is to provide a device for self-feedback drying of the moisture content of the whole material based on the above method, comprising a feed hopper, a feed system, a cyclone dryer, a sorting column and a gas-solid cyclone separator connected in sequence according to the material flow direction, and a moisture content monitoring system for real-time monitoring of the moisture content of the material, and a carrier gas generating unit, wherein:

[0032] The feed hopper is used for material feeding, and four parallel feed valves are arranged at the bottom of the hopper;

[0033] The moisture content monitoring device comprises an infrared light source, a light splitter, an infrared transparent glass arranged on a feed hopper, and a photoelectric sensor, which are arranged in sequence according to the direction of the light path, and a processor for converting an electrical signal received from the photoelectric sensor into moisture content information, wherein the processor is electrically connected to a feed valve of the feed hopper to transmit a control signal to the feed valve;

[0034] The feeding system comprises a first feeding line, a second feeding line, a third feeding line and a fourth feeding line respectively connected to four feeding valves;

[0035] The first feed line is provided with a fluidized bed filter; the second feed line is provided with a mixer; the third feed line is provided with a heat exchanger; the fourth feed line is provided with a crusher;

[0036] The cyclone dryer is used to perform cyclone drying on the wet material from the feed system to obtain a dried material or a dispersion medium-dried material mixture;

[0037] The separation column is used to separate the dried material and the dispersion medium in the dispersion medium-dried material mixture;

[0038] The gas-solid cyclone separator is used to perform cyclone drying again on the dried material from the separation column and obtain water-containing gas at the same time;

[0039] The carrier gas generating unit includes a heater, a first butterfly valve, an air flow pulsation generator and a hot air duct which are connected in sequence. The air flow pulsation generator is used to control the periodic closing of the first butterfly valve. The front and rear sides of the first butterfly valve are directly connected through a bypass pipeline, and a second butterfly valve is arranged on the bypass pipeline.

[0040] The present invention is further configured such that a heat exchanger is provided in the first feed line, the second feed line, the third feed line and the fourth feed line, respectively, after the fluidized bed filter, the mixer and the crusher, and before the granulator;

[0041] The device also includes a gas-liquid separator connected to the gas-solid cyclone separator, which is used to separate the water-containing gas from the gas-solid cyclone separator into hot waste water and hot waste gas. The water phase outlet and gas phase outlet of the gas-liquid separator are respectively connected to the heat exchanger and the heater.

[0042] The present invention is further configured such that the outlet of the granulator is vertically connected to the hot air duct, an extrusion plate is also provided at the outlet of the granulator, and a plurality of circular holes are evenly distributed on the extrusion plate; the cyclone dryer is one-stage or multi-stage series-connected.

[0043] The beneficial effects of the present invention are as follows:

[0044] (1) Compared with the traditional material drying method and device which only processes materials of a single type and a single moisture content, the present invention introduces a moisture content monitoring device to monitor the moisture content of the material in the feed hopper in real time. At the same time, four feeding routes are designed for materials with different moisture contents. The feeding routes are adjusted by moisture content information feedback to achieve automatic feeding and drying of materials to be dried with a moisture content of 10 to 98%. The present invention has a wide range of applications and is conducive to popularization.

[0045] (2) Compared with the traditional phase change drying method, the non-phase change drying method of the present invention has higher dehydration efficiency and lower energy consumption. It utilizes the huge centrifugal force generated by the self-corotation coupling motion of the wet material particles in the cyclone dryer (the rotation rate is as high as 20,000 r / min to 60,000 r / min) and the shear force exerted on the particles in the cyclone field to remove the moisture inside the particles. It has high dehydration efficiency and saves a large amount of energy required for vaporization in the phase change drying method.

[0046] (3) Compared with the traditional drying device, the device of the present invention operates stably and efficiently. The multi-stage cyclone dryer is connected in series to effectively extend the self-revolution coupling motion time of the wet material particles in the cyclone field, thereby improving the drying effect. This solves the problem of unstable drying effect of material particles caused by only using one stage of cyclone dryer, which affects the working efficiency of the drying device.

[0047] (4) The method and device of the present invention use high-temperature flue gas as carrier gas, and use the separated hot wastewater to preheat the wet material, and the hot waste gas is reused as carrier gas according to the situation. This realizes the utilization and recycling of waste heat, saves energy consumption, and can significantly reduce the operating cost of the drying process, which is in line with the concept of energy conservation, emission reduction, pollution reduction, carbon reduction and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a process flow chart of the present invention for self-feedback drying of moisture content of all materials.

[0049] Figure 2 It is a structural schematic diagram of a moisture content monitoring device.

[0050] Figure 3 It is a schematic diagram of the granulator principle.

[0051] Figure 4 This is a comparison chart of energy consumption between non-phase change drying and phase change drying.

[0052] In the figure:

[0053] 1-feed hopper; 11-feed valve;

[0054] 2-feeding system; 21-ebullating bed filter; 22-mixer; 23-granulator; 24-crusher; 25-heat exchanger; 26-extrusion plate;

[0055] 3- Cyclone dryer;

[0056] 4-Separation column;

[0057] 5-gas-solid cyclone separator;

[0058] 6- moisture content monitoring device; 61- infrared light source; 62- optical disc; 63- infrared transparent glass; 64- photoelectric sensor; 65- processor;

[0059] 71-heater; 72-first butterfly valve; 73-air flow pulsation generator; 74-hot air duct; 75-second butterfly valve; 76-fan;

[0060] 8-Gas-liquid separator. DETAILED DESCRIPTION

[0061] The technical scheme of the present invention is described clearly and in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only part of the embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of the present invention.

[0062] The test methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer. Unless otherwise specified, all percentages and fractions are by weight.

[0063] After extensive and in-depth research, the inventors of this case found that the existing material drying methods and devices can only dry a single material with a certain moisture content, and are not universally applicable to the drying of other materials. When drying different materials, different devices need to be replaced, resulting in excessive one-time investment and waste of space and resources.

[0064] Therefore, the present invention has developed a method and device for self-feedback drying of moisture content of all materials, which monitors the moisture content of materials in the feed hopper through a moisture content monitoring device, and designs four different feeding routes based on the characteristics of materials with different moisture contents, combined with processing efficiency and energy consumption, to achieve continuous and stable feeding of materials with full moisture contents. Then, the materials are dried by cyclone drying, sorting and gas-solid separation to achieve efficient drying of the materials.

[0065] Example 1

[0066] like Figure 1 As shown, a device for self-feedback drying of moisture content of all materials comprises a feed hopper 1, a feed system 2, a cyclone dryer 3, a sorting column 4 and a gas-solid cyclone separator 5 connected in sequence according to the material flow direction, and a moisture content monitoring system 6 for real-time monitoring of the moisture content of the material, and a carrier gas generating unit, wherein:

[0067] The feed hopper 1 is used for material feeding, and four parallel feed valves 11 are arranged at the bottom of the hopper;

[0068] Combination Figure 2 As shown, the moisture content monitoring device 6 comprises an infrared light source 61, a light-dispersing disc 62, an infrared-transmitting glass 63 and a photoelectric sensor 64 arranged in sequence according to the direction of the light path, and a processor 65 for converting the electrical signal received from the photoelectric sensor 64 into moisture content information. The processor 65 is electrically connected to the feed valve 11 of the feed hopper 1 to transmit a control signal to the feed valve 11;

[0069] The feeding system 2 includes a first feeding line, a second feeding line, a third feeding line and a fourth feeding line respectively connected to four feeding valves 11;

[0070] The first feed line is provided with an ebullated bed filter 21, which is used to preliminarily dehydrate the material with a moisture content of 90-98%, intercept and adsorb the material by using a filter medium, so that the material remains in the ebullated bed layer and the filtered clean water is discharged;

[0071] The second feeding line is provided with a stirrer 22, and the stirrer 22 is used to stir the material with a moisture content of 65-90% and the added dispersion medium to improve the dispersion of the material and the cyclone drying effect;

[0072] The third feeding line is provided with a granulator 23, which is used to granulate the material with a moisture content of 30-65% to form material strips, and directly feed the material, thereby maintaining a closed feeding environment and reducing air volume loss;

[0073] The fourth feeding line is provided with a crusher 24 for crushing materials with a moisture content of 10-30%;

[0074] The cyclone dryer 3 is used to perform cyclone drying on the material from the feeding system 2 to obtain a dried material or a dispersion medium-dried material mixture;

[0075] The separation column 4 is used to separate the dried material and the dispersion medium in the dispersion medium-dried material mixture;

[0076] The gas-solid cyclone separator 5 is used to perform cyclone drying again on the dried material from the separation column 4, and obtain water-containing gas at the same time;

[0077] The carrier gas generating unit includes a heater 71, a first butterfly valve 72, an air flow pulsation generator 73 and a hot air duct 74 which are connected in sequence, the air flow pulsation generator 73 is used to control the periodic closing of the first butterfly valve 72, the front and rear sides of the first butterfly valve 72 are directly connected through a bypass pipeline, and a second butterfly valve 75 is arranged on the bypass pipeline;

[0078] The hot air duct 74 is respectively connected to the outlets of the first feed line, the second feed line, the third feed line and the fourth feed line, and the inlet of the cyclone dryer 3 , so as to feed the wet material into the cyclone dryer 3 .

[0079] When the wet material enters the cyclone dryer 3 through the first feed line or the second feed line, the second butterfly valve 75 is closed, and the air flow pulsation generator 73 controls the first butterfly valve 72 to close periodically, thereby generating a periodic oscillating air flow (i.e., pulsating hot carrier gas) for separating the dried material and the dispersion medium in the separation column 4;

[0080] When the wet material enters the cyclone dryer 3 through the third feed line or the fourth feed line, the first butterfly valve 72 is closed and the second butterfly valve 75 is opened. At this time, a continuous airflow (ie, hot carrier gas) is generated, and the separation column 4 is equivalent to a straight channel.

[0081] In the present invention, a heat exchanger 25 is provided in the first feed line, the second feed line, the third feed line and the fourth feed line, respectively, after the fluidized bed filter 21, the mixer 22 and the crusher 24, and before the granulator 23;

[0082] The device also includes a gas-liquid separator 8 connected to the gas-solid cyclone separator 5, which is used to separate the water-containing gas from the gas-solid cyclone separator 5 into hot wastewater and hot waste gas. The water phase outlet of the gas-liquid separator 8 is connected to the heat exchanger 25, and the hot wastewater can be reused for preheating the wet material; the gas phase outlet of the gas-liquid separator 8 is connected to the heater 71, and the hot waste gas can be reused as high-temperature flue gas to achieve energy recovery.

[0083] In the present invention, Figure 3As shown, the outlet of the granulator 23 is vertically connected to the hot air duct 74, and an extrusion plate 26 is provided at the outlet of the granulator 23. A plurality of circular holes are evenly distributed on the extrusion plate 26, and the diameter D of the circular holes is preferably 6 mm.

[0084] The granulator 23 can continuously form strip materials through the extrusion action of the screw. While the strip materials are being formed, the continuous airflow in the hot air duct 74 can cut them off and bring them into the cyclone dryer 3. The feed rate can be controlled by controlling the extrusion rate of the granulator 23.

[0085] Since the drying time of the material particles in the primary cyclone dryer 3 is relatively short, much of the water inside the material particles with a higher moisture content has not yet completely migrated from the inside to the surface for removal, resulting in the deposition of the material with a higher moisture content at the lower end of the sorting column 4, which in turn requires the return of the material for reprocessing. Therefore, it is necessary to ensure that the material particles reach a lower moisture content before entering the sorting column 4 to improve the sorting efficiency.

[0086] Therefore, according to the actual processing situation, multiple stages of cyclone dryers 3 can be connected in series to improve the drying effect of wet material particles, reduce the amount of returned materials that need to be reprocessed, and greatly improve the processing efficiency of the material drying device.

[0087] The device also includes a material storage tank (not shown) arranged between the feed hopper 1 and the feed system 2, which is used to temporarily store the input wet material and stabilize the feed amount of the pipeline; and a fan 76 arranged before the heater 71, which is used to provide power for the high-temperature flue gas to move.

[0088] The method for self-feedback drying of moisture content of all materials based on the above device comprises the following steps:

[0089] (1) Determination of moisture content: Infrared light is generated by an infrared light source 61, and infrared light of a characteristic wavelength is obtained through a filter on a spectrophotometer 62. The infrared light passes through an infrared transparent glass 63 arranged at the bottom of the feed hopper 1 and is reflected by the material. The photoelectric sensor 64 converts the optical signal of the reflected light into an electrical signal, which is then processed by a processor 65 to obtain the moisture content. The feed line is adjusted according to the moisture content through self-feedback, so as to adapt a reasonable feeding method to different materials and realize a high degree of automation of continuous feeding.

[0090] (2) Feeding line:

[0091] (21) The material with a moisture content of 90-98% enters the fluidized bed filter 21 for preliminary dehydration. The filter medium filled in the fluidized bed filter 21 filters the material to remove moisture and achieve drying and reduction. The filter medium-material mixture enters the cyclone dryer 3 with the pulsating hot carrier gas. The filter medium serves as a dispersion medium in the cyclone dryer 3.

[0092] The fluidized bed filter 21 is used to preliminarily dehydrate the material with high moisture content to reduce the moisture content of the material, which can solve the feeding and transportation problems such as viscosity and bridging of the material with high moisture content, and can also improve the final drying treatment effect.

[0093] (22) The material with a moisture content of 65-90% is stirred and mixed into the dispersion medium, and the obtained dispersion medium-material mixture enters the cyclone dryer 3 along with the pulsating hot carrier gas;

[0094] Adding dispersing medium can improve the dispersion of materials and solve the feeding problem caused by strong viscosity of materials;

[0095] (23) The material with a moisture content of 30-65% is granulated by the granulator 23 to form material strips, which are cut into strips by the hot carrier gas and then brought into the cyclone dryer 3;

[0096] Granulation by the granulator 23 is beneficial to the subsequent cyclone drying process, and while achieving direct feeding, it also maintains a closed feeding environment, reduces air volume loss, and solves the problem of unsmooth feeding.

[0097] (24) The material with a moisture content of 10-30% is crushed by the crusher 24 and then enters the cyclone dryer 3 along with the hot carrier gas;

[0098] In view of the characteristics of low moisture content and high hardness of materials with a moisture content of 10-30%, crushing before feeding solves the feeding problem and increases the gas-liquid exchange area in the subsequent cyclone drying process.

[0099] (3) Cyclone drying:

[0100] (31) The wet materials from steps (21) and (22) are subjected to cyclone drying and separation in a cyclone dryer 3, and the obtained dispersion medium-dried materials enter a separation column 4 with a pulsating hot carrier gas for accelerated separation;

[0101] (32) The wet materials from steps (23) and (24) are subjected to cyclone drying and separation in the cyclone dryer 3, and the obtained dried materials are passed through the separation column 4 (which can be regarded as a straight channel at this time) along with the hot carrier gas to enter the gas-solid cyclone separator 5;

[0102] (4) Accelerated sorting of mixed materials:

[0103] In the separation column 4, due to the mass difference between the dried material and the dispersion medium, the pulsating hot carrier gas has different cumulative accelerations on the two, so that the total displacement direction of the dispersion medium is downward and discharged from the bottom of the separation column 4, and the total displacement direction of the dried material is upward and discharged from the top of the separation column 4 and enters the gas-solid cyclone separator 5;

[0104] (5) The dried material is further subjected to cyclone drying and gas-solid separation: The dried material enters the gas-solid cyclone separator 5 for further cyclone drying and is then discharged, and water-containing gas is separated at the same time.

[0105] In the present invention, the hot carrier gas is a continuous flow of high-temperature flue gas; the pulsating hot carrier gas is a periodic oscillating flow of high-temperature flue gas; the temperature of the high-temperature flue gas is 40-80°C, which can reduce the adhesion resistance of moisture and further improve the dehydration effect.

[0106] The pulsating hot carrier gas is a periodic oscillating airflow obtained by the periodic closing of the butterfly valve through which the high-temperature flue gas passes. The periodic closing of the butterfly valve is controlled by the airflow pulsation generator 73 .

[0107] In the present invention, the method further comprises step (6) gas-liquid separation and heat energy recovery: the water-containing gas separated in step (5) passes through a gas-liquid separator 8 to separate hot waste water and hot waste gas;

[0108] When the flow rate of high-temperature flue gas is low, the hot exhaust gas can be reused as high-temperature flue gas, and whether to perform low-temperature heating is determined based on the reuse of the hot exhaust gas;

[0109] The hot wastewater can be used to preheat the wet material in step (2), which is beneficial to improving the cyclone drying effect and realizing waste heat utilization.

[0110] In the present invention, the dispersion medium separated in step (4) can be reused in steps (21) and (22) to achieve resource recycling.

[0111] In the present invention, the method can be applied to the drying of materials within the entire moisture content range. Since there is less demand for drying materials with a moisture content below 10% in practical applications, the method is preferably applicable to the continuous and automated drying of all materials within the moisture content range of 10-98%, and the materials include but are not limited to sludge, wine lees, coal, crop waste residues, and waste catalysts.

[0112] In the present invention, in step (21), the thickness of the ebullient bed layer in the ebullient bed filter 21 is set between 0.4 and 1 m;

[0113] The filter medium used in the fluidized bed is preferably a granular material with high mechanical strength and high density, such as perlite, quartz sand and sea sand;

[0114] The particle size of the filter medium is 0.5-2 mm, and it acts as a dispersion medium in the subsequent cyclone drying process and can be recycled.

[0115] In the present invention, in step (22), the dispersion medium includes granular materials such as coal slag particles, quartz sand, perlite, sea sand, etc., which have a density difference with the dried material and a high mechanical strength;

[0116] The particle size of the dispersion medium is 2-4 mm;

[0117] The mixing mass ratio of the material with a moisture content of 65-90% and the dispersion medium is controlled at 1:1-1:3.

[0118] In the present invention, the material particles perform high-speed rotation and revolution in the cyclone dryer 3. The high-speed rotation of the material particles in the cyclone field induces non-phase change drying. The huge centrifugal force generated by the high-speed rotation of the material particles enables the interstitial water inside the material to overcome the viscous resistance and be removed. At the same time, the self-revolution coupling motion accelerates the mass transfer renewal rate on the surface of the material particles and enhances the removal of moisture from the material.

[0119] Figure 4 This is a comparison chart of energy consumption between non-phase change drying and phase change drying. As can be seen from the figure, the temperature required for the atmospheric pressure phase change drying process is higher than the boiling point of water. Water undergoes phase change during the evaporation process, and the phase change energy consumption (latent heat of vaporization) is higher than 2000kJ / kg.

[0120] The temperature required for the vacuum phase change drying process is lower than the boiling point of water. Water undergoes phase change during the evaporation process, and the energy consumption of the phase change is also higher than 2000kJ / kg, but it is lower than the energy consumption of the normal pressure phase change drying process.

[0121] The temperature required for the normal pressure non-phase change drying process is 60-90°C. Water does not undergo phase change during the drying process. The energy consumption during normal pressure non-phase change drying at 90°C is only 378kJ / kg.

[0122] Therefore, the energy consumption required for normal pressure non-phase change drying is one order of magnitude lower than that for normal pressure phase change drying and vacuum phase change drying, which has significant energy-saving advantages. Cyclone drying is achieved through cyclone rotation and revolution coupling oscillation, and the water does not undergo phase change. The energy consumption is 378 kJ / kg at 90°C, which greatly reduces the energy consumption of drying (the energy consumption of normal pressure and vacuum phase change drying is higher than 2600 kJ / kg).

[0123] Application Examples

[0124] The method and device of the above-mentioned embodiment 1 are used to dry the excess sludge and dewatered sludge, and the specific operation process and effect are described as follows:

[0125] 1. Source and nature of sludge

[0126] The residual sludge used in this embodiment was taken from the secondary sedimentation tank of the sewage treatment plant in Minhang District, Shanghai. The dewatered sludge 1 and the dewatered sludge 2 were taken from Shanghai Fujie Environmental Protection Technology Co., Ltd. Table 1 shows the measured properties of the three sludges.

[0127] Table 1 Properties of three sludges

[0128]

[0129] 2. Implementation process

[0130] The method of the above embodiment 1 is implemented as follows:

[0131] The materials used in this embodiment are residual sludge and dewatered sludge, and the gas carrying the sludge is high-temperature flue gas. Perlite with a particle size of 0.5-1mm is selected as the filter medium of the fluidized bed filter, and the bed thickness is set at 0.8m; the mixing ratio of dewatered sludge 1 and the dispersion medium is set to 1:2, the particle size of the dispersion medium is selected to be 2-3mm, and the dispersion medium is selected to be quartz sand; the granulator feed rate is set to 30kg / h.

[0132] The remaining sludge with a moisture content of 98.90% was sent to an ebullating bed separator using perlite as the filter medium for preliminary dehydration, and a sludge-perlite mixture was produced after concentration;

[0133] The dehydrated sludge 1 having a moisture content of 81.3% is mixed with quartz sand particles to obtain a sludge-quartz sand mixture;

[0134] The dehydrated sludge 2 with a moisture content of 53.4% ​​was granulated by a granulator to obtain 6 mm long strips of sludge.

[0135] (1) Drying process of sludge-perlite mixture and sludge-quartz sand mixture:

[0136] The high-temperature flue gas passes through the heater, the first butterfly valve, and the air flow pulsation generator in sequence to form a pulsating hot carrier gas, and the sludge-perlite mixture and the sludge-quartz sand mixture are sent to the cyclone dryer for drying; the heating temperature of the high-temperature flue gas in the experiment is 70°C.

[0137] In the cyclone dryer, the huge centrifugal force generated by the high-speed rotation of particles in the cyclone field is used to remove the interstitial water and capillary water of the sludge. The dehydrated sludge-perlite mixture or sludge-quartz sand mixture enters the sorting column from the bottom flow port of the cyclone dryer.

[0138] The pulsating hot carrier gas discharged from the overflow port of the cyclone dryer enters from the lower end of the sorting column, and uses the density difference between the sludge and the perlite and quartz sand particles to make the total displacement direction different in the pulsating air flow field, so that the sludge and the perlite and quartz sand particles are separated in the sorting column. The sorted perlite and quartz sand settle to the bottom of the sorting column, are discharged and recycled, and the sludge particles enter the gas-solid cyclone separator from the top of the sorting column.

[0139] In the gas-solid cyclone separator, the sludge particles and gas are separated, the dried sludge is discharged from the underflow port and collected, and the gas carrying the water phase enters the gas-liquid separator from the overflow port.

[0140] (2) Drying process of long strip sludge:

[0141] The high-temperature flue gas passes through the heater and the second butterfly valve in turn to form hot carrier gas, and the long strips of sludge are sent to the cyclone dryer for drying; the heating temperature of the high-temperature flue gas in the experiment is 70℃.

[0142] In the cyclone dryer, the huge centrifugal force generated by the high-speed rotation of particles in the cyclone field is used to remove the interstitial water and capillary water of the sludge. The dehydrated sludge enters the separation column from the bottom flow port of the cyclone dryer. The hot carrier gas discharged from the overflow port of the cyclone dryer enters from the lower end of the separation column and sends the dehydrated sludge to the gas-solid cyclone separator to separate the sludge particles and gas.

[0143] In the gas-solid cyclone separator, the sludge particles and gas are separated, the dried sludge is discharged from the underflow port and collected, and the gas carrying the water phase enters the gas-liquid separator from the overflow port.

[0144] 3. Implementation Effect

[0145] The comparison of sludge moisture content before and after drying is shown in Table 2 as follows:

[0146] Table 2 Comparison of sludge moisture content

[0147]

[0148] It can be seen from the results in Table 2 that the method and device of the present invention can realize automatic feeding and drying of materials to be dried with different moisture contents, and has excellent drying effect, and has the advantages of being able to process a wide variety of materials, and operating continuously, stably and efficiently.

[0149] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. That is, any equivalent replacement, change or modification made according to the content of the present invention should be within the protection scope of the present invention.

Claims

1. A method for drying the moisture content of all materials by self-feedback, characterized in that: The following steps are involved: (1) Determination of moisture content: Infrared light is generated by an infrared light source, and infrared light of a characteristic wavelength is obtained through the filter on the spectrometer. After passing through the infrared transparent glass set at the bottom of the feed hopper, it is reflected by the material. The photoelectric sensor converts the optical signal of the reflected light into an electrical signal. The electrical signal is then processed by the processor to obtain the moisture content, and the feed line is adjusted according to the moisture content through self-feedback. (2) Feeding line: (21) Materials with a moisture content of 90-98% enter the fluidized bed filter and are initially dehydrated using the filled filter medium. The filter medium-material mixture enters the cyclone dryer with the pulsating hot carrier gas, and the filter medium serves as a dispersion medium in the cyclone dryer; (22) Materials with a moisture content of 65-90% are stirred and mixed into the dispersion medium, and the resulting dispersion medium-material mixture enters the cyclone dryer with the pulsating hot carrier gas; (23) Materials with a moisture content of 30-65% are granulated by a granulator to form material strips, which are cut into strips by the hot carrier gas and then brought into the cyclone dryer; (24) Materials with a moisture content of 10-30% are crushed by a crusher and enter the cyclone dryer with the hot carrier gas; (3) Cyclone drying: The wet materials from steps (21) and (22) are subjected to cyclone drying and separation in a cyclone dryer, and the obtained dispersion medium-dried materials are sent to a separation column with a pulsating hot carrier gas for accelerated separation; the wet materials from steps (23) and (24) are subjected to cyclone drying and separation in a cyclone dryer, and the obtained dried materials are sent to a gas-solid cyclone separator with a hot carrier gas through a separation column; (4) Accelerated separation of mixed materials: In the separation column, the pulsating hot carrier gas has different cumulative accelerations on the dried material and the dispersed medium, and the dried material and the dispersed medium are separated. (5) The dried material is then subjected to cyclone drying and gas-solid separation: The dried material enters the gas-solid cyclone separator for further cyclone drying and is then discharged, and water-containing gas is separated at the same time.

2. The method for drying the moisture content of all materials by self-feedback according to claim 1, characterized in that: The hot carrier gas is a continuous flow of high-temperature flue gas; the pulsating hot carrier gas is a periodic oscillating flow of high-temperature flue gas; The temperature of the high temperature flue gas is 40-80°C; The pulsating hot carrier gas is a periodic oscillating airflow obtained by the periodic closing of a butterfly valve through which high-temperature flue gas passes. The periodic closing of the butterfly valve is controlled by an airflow pulsation generator.

3. The method for drying the moisture content of all materials by self-feedback according to claim 2, characterized in that: The method further comprises step (6) gas-liquid separation and heat energy recovery: the water-containing gas separated in step (5) is passed through a gas-liquid separator to separate hot waste water and hot waste gas; When the flow rate of high-temperature flue gas is low, the hot exhaust gas is recycled as high-temperature flue gas, and whether to perform low-temperature heating is determined based on the recycling of the hot exhaust gas; The hot wastewater is used to preheat the wet material in step (2).

4. The method for drying the moisture content of all materials by self-feedback according to claim 1, characterized in that: The dispersion medium separated in step (4) is reused in steps (21) and (22).

5. The method for drying the moisture content of all materials by self-feedback according to claim 1, characterized in that: The method is applicable to materials with a moisture content within the range of 10-98%, and the materials include sludge, wine dregs, coal, crop waste residues and waste catalysts.

6. The method for drying the moisture content of all materials by self-feedback according to claim 1, characterized in that: The thickness of the ebullient bed layer in the ebullient bed filter is set between 0.4 and 1 m; The filtering media used in the fluidized bed layer include perlite, quartz sand and sea sand; The particle size of the filter medium is 0.5-2 mm.

7. The method for drying the moisture content of all materials by self-feedback according to claim 1, characterized in that: In the step (22), the mixing mass ratio of the material with a moisture content of 65-90% and the dispersion medium is controlled at 1:1-1:3; The dispersion medium includes coal slag particles, quartz sand, perlite and sea sand; The particle size of the dispersion medium is 2-4 mm.

8. A device for self-feedback drying of moisture content of all materials, characterized in that: It includes a feed hopper, a feed system, a cyclone dryer, a sorting column and a gas-solid cyclone separator connected in sequence according to the material flow direction, a moisture content monitoring system for real-time monitoring of the moisture content of the material, and a carrier gas generating unit, wherein: The feed hopper is used for material feeding, and four parallel feed valves are arranged at the bottom of the hopper; The moisture content monitoring device comprises an infrared light source, a light splitter, an infrared transparent glass arranged on a feed hopper, and a photoelectric sensor, which are arranged in sequence according to the direction of the light path, and a processor for converting an electrical signal received from the photoelectric sensor into moisture content information, wherein the processor is electrically connected to a feed valve of the feed hopper to transmit a control signal to the feed valve; The feeding system comprises a first feeding line, a second feeding line, a third feeding line and a fourth feeding line respectively connected to four feeding valves; The first feed line is provided with a fluidized bed filter; the second feed line is provided with a mixer; the third feed line is provided with a heat exchanger; the fourth feed line is provided with a crusher; The cyclone dryer is used to perform cyclone drying on the wet material from the feed system to obtain a dried material or a dispersion medium-dried material mixture; The separation column is used to separate the dried material and the dispersion medium in the dispersion medium-dried material mixture; The gas-solid cyclone separator is used to perform cyclone drying again on the dried material from the separation column and obtain water-containing gas at the same time; The carrier gas generating unit includes a heater, a first butterfly valve, an air flow pulsation generator and a hot air duct which are connected in sequence. The air flow pulsation generator is used to control the periodic closing of the first butterfly valve. The front and rear sides of the first butterfly valve are directly connected through a bypass pipeline, and a second butterfly valve is arranged on the bypass pipeline.

9. The device for drying the moisture content of all materials by self-feedback according to claim 8, characterized in that: In the first feed line, the second feed line, the third feed line and the fourth feed line, heat exchangers are respectively arranged after the fluidized bed filter, the mixer and the crusher, and before the granulator; The device also includes a gas-liquid separator connected to the gas-solid cyclone separator, which is used to separate the water-containing gas from the gas-solid cyclone separator into hot waste water and hot waste gas. The water phase outlet and gas phase outlet of the gas-liquid separator are respectively connected to the heat exchanger and the heater.

10. The device for drying the moisture content of all materials by self-feedback according to claim 8, characterized in that: The outlet of the granulator is vertically connected to the hot air duct, and an extrusion plate is also arranged at the outlet of the granulator, and a plurality of circular holes are evenly distributed on the extrusion plate; the cyclone dryer is one-stage or multi-stage series-connected.

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