CN107314621A - A kind of method for microwave drying and its device of use - Google Patents

A kind of method for microwave drying and its device of use Download PDF

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Publication number
CN107314621A
CN107314621A CN201710672499.4A CN201710672499A CN107314621A CN 107314621 A CN107314621 A CN 107314621A CN 201710672499 A CN201710672499 A CN 201710672499A CN 107314621 A CN107314621 A CN 107314621A
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CN
China
Prior art keywords
temperature
wind
microwave
seal cavity
heat
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Pending
Application number
CN201710672499.4A
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Chinese (zh)
Inventor
彭虎
夏广斌
刘建平
刘忠
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Hunan Yuan Chuan High-Tech Industrial Technology Co Ltd
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Hunan Yuan Chuan High-Tech Industrial Technology Co Ltd
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Priority to CN201710672499.4A priority Critical patent/CN107314621A/en
Publication of CN107314621A publication Critical patent/CN107314621A/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00Drying solid materials or objects by processes involving the application of heat
    • F26B3/32Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action
    • F26B3/34Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects
    • F26B3/347Electromagnetic heating, e.g. induction heating or heating using microwave energy
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/02Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
    • F26B21/04Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure partly outside the drying enclosure
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/06Controlling, e.g. regulating, parameters of gas supply
    • F26B21/10Temperature; Pressure
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/22Controlling the drying process in dependence on liquid content of solid materials or objects
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26DRYING
    • F26BDRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B9/00Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards
    • F26B9/06Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards in stationary drums or chambers

Abstract

The present invention provides a kind of method for microwave drying, including herein below:Product to be dried is placed in the seal cavity of microwave dryer;Microwave dryer transmitting microwave carries out microwave drying, while the gas in seal cavity is carried out into forced convertion;The temperature and the surface temperature of product to be dried of the gas in seal cavity are monitored, at the same time the gas in seal cavity is post-processed and seal cavity is recycled back into.The inventive method adds the temperature and humid control to gas medium in seal cavity on the basis of conventional microwave dry technology, while being familiar with the marrow of dry materials principle, reaches the purpose that microwave drying is efficiently carried out using microwave energy;Microwave drying process can be prevented effectively from and cause the technological problemses such as dry materials are excessive, deform, burn, being denatured;Microwave drying process is carried out by approach such as complete moisture cycles recycling, cavity insulations simultaneously energy-saving enhanced.Invention additionally discloses the device that the above method is used, part is readily available, is easy to implement.

Description

A kind of method for microwave drying and its device of use
Technical field
The present invention relates to technical field of microwave drying, and in particular to a kind of method for microwave drying and its device of use.
Background technology
Method for microwave drying takes full advantage of microwave firing rate soon, and the advantage of efficiency high substantially reduces dry products The required time, significantly, microwave drying has obtained abundant accreditation to energy saving and efficiency increasing effect in social production.
Microwave drying is a kind of method of internal heating, is specifically:Wet stock is in cycle of oscillation extremely short microwave high-frequency In electric field, polarization can occur for its internal hydrone and along the direction proper alignment of microwave electric field, then be handed over high frequency rapidly The interaction of power transformation field direction changes and rotated, and produces violent collision and friction (each second is up to more than one hundred million times), as a result one The kinetic energy for dividing microwave energy to be hydrone in material, makes the temperature of water raise up to gasification disengaging material, so that material is obtained To drying.That is, after microwave enters material and absorbed, its energy is directly changed into heat energy inside material dielectric.
Microwave drying is used in the prior art, probably there are following several ways:(1) product to be dried is directly placed into microwave It is dried in drying equipment;(2) using the drying side disclosed in the utility model patent of Application No. 200920234330.1 Method is dried;(3) it is dried with the drying means disclosed in the patent of invention of Application No. 201410025343.3.
In the prior art, there is following the problem of solving of still needing in microwave drying process:
First, the efficiency of heating surface of microwave drying is relatively low.The key of commercial microwave technical energy saving is because microwave energy is to sample Heating from inside to outside is carried out, without carrying out indirect heat transfer by gas medium and sample to be heated as conventional art, plus The sample of the same yield of heated drying, microwave heating technique can significantly reduce the thermic load of system, and capacity usage ratio is able to significantly Improve, realize energy-conservation.Existing commercial microwave dry technology payes attention to the high-efficiency heating effect that microwave treats dry products, ignores this The lower-temperature atmosphere environment on periphery when a little materials are heated by microwave, the substantial amounts of heat energy from microwave passes through convection current, radiation, conduction etc. Approach is transferred in the cold air in microwave drying cavity from material, causes the reduction slowed down with microwave efficiency of programming rate.
Secondly, it is excessive with the heat loss of existing microwave drying technology.With the progress of drying process, microwave drying cavity Interior air humidity gradually increases, and temperature is also gradually stepped up, when existing microwave drying process is higher than threshold values using timing or humidity The hydrofuge method of pumping by force, a large amount of to carry sensible heats and the damp and hot wind of steam latent heat is emptied by dehumidifier, loss gas is then outside to be mended Fill, although can reach the purpose of hydrofuge water outlet, cost is a large amount of losses of hot blast in drying chamber and being greatly reduced for temperature, The compensation of the heat of loss can directly increase energy consumption, reduce the benefit of microwave drying process.
Finally, existing commercial microwave drying means fails original to dock with the optimal drying process of material, it is impossible to give full play to Microwave drying is quick, efficiently, feature, do not make to meet material shapes, form, physicochemical properties in microwave rapid draing Occur harmful change with lower, can only take and suppress microwave heating contribution, the scheme such as reduction microwave input power, these all make microwave Dry efficiency is had a greatly reduced quality, it is impossible to " making the best use of everything ".
In summary, being badly in need of exploitation one kind has drying efficiency height, energy consumption appropriate and the measured drying side of dry products matter Method is to solve the deficiencies in the prior art.
The content of the invention
Present invention aims at providing, a kind of easy to operate, drying efficiency is high, energy consumption is low and dry products matter is measured Method for microwave drying, concrete technical scheme is as follows:
A kind of method for microwave drying, including following key element:
Product to be dried is placed in the closed and heat-insulated seal cavity in microwave dryer;
Microwave dryer transmitting microwave carries out microwave drying, while the gas in seal cavity is carried out into forced convertion;
The temperature and the surface temperature of product to be dried of the gas in seal cavity are monitored, is at the same time extracted out incessantly Part in seal cavity is back in seal cavity after being post-processed containing humid gas.
Preferred in above technical scheme, the post processing comprises the following steps:
Step a, by cool processing the temperature containing wet wind extracted out out of seal cavity is down to below its dew-point temperature, Now moisture condensation in part turns into aqueous water and removed from containing wet wind, obtains wet wind;
Step b, wet wind will be gone to be heated, and obtain the warm wind that dries.
Preferred in above technical scheme, gas temperature and the principle with dry products table temperature are in monitoring cavity: The temperature T of gas during microwave drying in seal cavity1Relation with the dry environment temperature To using conventional drying methods is: T1≤ To+10 DEG C, this measure can realize that material microwave drying process is connected with the quick, correct of conventional drying process;It is to be dried The surface temperature T of product2The surface temperature T of the material allowed with constant speed constant temperature stage highest in common processmaxRelation be T2 ≤Tmax+ 5 DEG C, the temperature T of gas during with microwave drying in seal cavity1Relation be T2≤T1+ 20 DEG C, this measure is used to ensure Microwave input power makes material surface temperature be defined to from beginning to end in the framework, can reach outside to material internal moisture Migrate to have and suitably migrate speed;
Cool heat-transfer surface temperature T during to carrying out cooling processing containing wet wind3With the dew-point temperature T containing wet windLRelation be TL- 10℃≤T3≤TL;Dry the temperature T of warm wind4With the dew-point temperature T containing wet windLRelation be T4≥TL+ 1 DEG C, this measure then can be with Control the temperature of recyclegas, humidity to be in favourable gaseous state, maintain the suitable evaporation rate of surface of material moisture film.
Preferred in above technical scheme, the mode of forced convertion is to be stirred using the fan of controllable convection current;Gas Value relative to the wind speed V of material is when carrying out forced convertion:0.5m/s≤V≤4m/s;The rotating speed of the fanIn formula:NmaxAnd NminFan when respectively relative wind velocity is 4m/s and 0.5m/s Rotating speed, it is allowed to which maximum deviation is 20r/min;T1The temperature of gas during for microwave drying in seal cavity;T2For product to be dried Surface temperature.
Preferred in above technical scheme, the volume for the gas extracted out and post-processed out of seal cavity per hour is 1/4~2.5 times of the volume of airtight cavity.
Preferred in above technical scheme, the cooling is processed as natural air cooled heat exchanger, heat exchanger air blast cooling, water cooling Or heat pump cooling;Described heat is microwave heating, electric heating, industrial exhaust heat heat exchange, geothermal heating, solar energy heating or heat pump Heating.
It is preferred in above technical scheme, using heat pump cold end as low-temperature receiver to it is described containing wet wind carry out cooling processing and While dehumidification treatments, using the hot junction of the heat pump to the hot junction for going wet wind heat the either heat pump The thermal source heat that also cold end including heat pump is obtained from air, industrial smoke, natural water body, the water body containing underground heat;
The microwave drying is that continuous-type microwave is dried or/and intermittent type microwave is dried, and the microwave is heated to be continous way Microwave is heated or/and intermittent type microwave heating.
Apply the technical scheme of the present invention, combine the physical chemistry rule of dry materials process, dried in conventional microwave Added in technical foundation in microwave dryer in seal cavity gas medium property control, add for being done The monitoring of dry material, microwave drying process of forgoing causes the technological problemses such as dry materials are excessive, deform, burn, being denatured, and reaches height Imitate the purpose that rapid microwave drying is carried out using microwave energy;Simultaneously recycled by moisture cycles, cavity insulation etc. approach to micro- Ripple drying process carried out it is energy-saving enhanced, have the advantages that high-quality, efficiently, energy-conservation.Details as Follows:
1st, in terms of energy-conservation, it is specifically:The present invention emphasizes to dry the tightness properties of system, is in particular in logistics and energy stream Two aspects:A, heat loss control:The Insulation of drying means and seal cavity in equipment and pipeline is dropped to the full extent Heat causes radiation loss through metal material cavity wall, tube wall in low dry system, measure one side lifting drying Mean temperature in system, accelerates drying process, on the other hand may also reach up the technological effect of directly economize on electricity 5~10%;b、 UTILIZATION OF VESIDUAL HEAT IN:The present invention has abandoned the scheme for forcing to extract damp-heat air and directly empty in traditional microwave drying process, but Damp-heat extraction will persistently be contained, then this portion gas is all sent back to system after partial condensation dehumidifies and carries out circulation profit With, because these gas phases are much higher for environment temperature, compared to after forced-ventilated dehumidifier hot blast directly with gas in air supplement system Body, it is possible to decrease energy consumption 20~35%.
2nd, technological effect is good, and the present invention is familiar with the marrow of microwave drying and drying process physics, dry compared to traditional microwave The more quick high-quality of drying method, be specifically:The characteristics of heating present invention incorporates conventional drying processes and with reference to microwave, preheating rises Thermophase is based on circulating air, few high moisture material for heating seal cavity body as heater meanses with or without microwave, it is to avoid micro- Ripple, which is directly heated, to be caused to ftracture, deforms;Constant speed drying section and falling rate of drying section, by controlling dried material surface temperature T2With gas Atmosphere temperature T1(temperature of gas during microwave drying in seal cavity), can make moisture from the migration of exterior surface inside material The evaporation rate of speed and surface of material matches, and can improve moisture evaporation speed with maximum likelihood on this basis, carry The yield of high unit installed power, may insure that the structure with dried material exempts from destruction in microwave environment again, cause deformation, Dry core, the production accident of black core occur, and thoroughly solution microwave drying yield is big but poor quality, or produced under the conditions of guaranteed quality Amount industry sex chromosome mosaicism not up to standard, therefore, the present invention directly docking material conventional drying processes, using close to traditional drying work Environment (atmosphere) process conditions of skill, unique atmosphere temperature, temperature of charge are monitored simultaneously, it is ensured that microwave highly effective drying is avoided simultaneously Material temperature in microwave field is too high to cause structure to destroy, while ensureing to have given play to the quick-drying characteristic of microwave as far as possible, really Protect high-quality drying effect.
3rd, both sides advantage effectively lifts dry production capacity, is specifically:
In terms of a, material stream, the principle for material evaporation is evaporated the design of process, and the present invention is except continuing to use microwave Accelerate outside dry theory, emphasize the forced ventilation in drying process, high temperature and forced convertion venting practice greatly improve pin Evaporation to surface of material moisture film, actual effect is quick heat energy input of the microwave due to penetration effect realization to material, is completed Entire body heating to material, accelerates the precipitation of internal structure water and outwards migrating for Free water, and two aspects are combined, greatly promoted Moisture removal efficiency, improves the production capacity of unit installed power.
In terms of b, energy stream, on the one hand, material heats up and moisture is straight from the required heat of exterior surface migration inside material Connect from microwave energy, without by the conduction of traditional kiln, convection current, radiate these inefficient modes and supply required heat; On the other hand, migrated from material to the vaporization institute calorific requirement of the free water of surface of material, on the one hand can pass through microwave It can convert and be rapidly heated, on the other hand ensure material surface temperature T2Than atmosphere temperature T1On the premise of height, inside material By microwave energy Lai heat energy and pass to by conduction the moisture film of surface of material, the third aspect, recyclegas is in thing When material surface moisture film is flowed through with appropriate speed, the evaporation of moisture film can be accelerated, the evaporation process can be strong due to highly endothermic effect The temperature of moisture film is reduced, until water film temperature is near or below atmosphere temperature T1, forced convertion can also be passed through by now flowing atmosphere To Water film heating.Being precisely controlled for the cooperations of three aspects and three temperature can be in controllable and efficient mode to being precisely controlled moisture Transition process and evaporation process, accomplish that quality and yield are minored.
4th, effective moisture content and useful volatile matter can be obtained, is specifically:The present invention reduces atmosphere water content using condensation method, cold Solidifying obtained aqueous water and condensable useful volatile matter can be recycled directly.The feature lacks the life in area for water resource Produce great economic value.As there is other useful volatilizable byproducts in volatile matter, economic benefit more preferably, can during such as processing bamboo product The high added value byproduct such as bamboo vinegar is obtained, is increased economic efficiency.
5th, wide application, technique is grafted good, is specifically:The method and device that the present invention is provided be conventional drying methods with The perfect adaptation of conventional microwave seasoning, takes two to grow and abandon that its is not enough, has put into practice fully showing that its is superior, Ji Nengman The common powdery of foot, graininess, bulk etc., again can be to ceramic body, art sculptures etc. to the dry materials of product design no requirement (NR) There is the drying of the object of strict demand to appearance and size and internal structure, the fast rapid-curing cutback of the material of high moisture content can be met It is dry, the harsh application scenario to PPM grades of the water content upper limit such as plastic particles can be also met, the good of its adaptability is reflected.
Invention additionally discloses the device that a kind of above-mentioned drying means is used, specifically include:Including microwave dryer, for institute State circulated air regulator control system, temperature sensor group and auxiliary circulating equipment that microwave dryer provides circulating air;
The microwave dryer includes the seal cavity provided with heat-insulation layer, and the seal cavity is provided with containing wet wind outlet And warm wind import of drying;
The circulation regulator control system includes runner pipe containing wet wind, to the processing component that is post-processed containing wet wind and dry Warm wind runner pipe, the arrival end of the processing component passes through runner pipe containing wet wind and outlet containing wet wind, the processing component The port of export pass through to dry and warm wind runner pipe and dry warm wind inlet communication;The warm wind runner pipe that dries, which is provided with, to be used to contain Wet wind is passed through by seal cavity and exports the circulated air extracted out and the warm wind that dries is blasted to seal cavity through warm wind import of drying containing wet wind Machine;
The temperature sensor group include the first temperature sensor, second temperature sensor, three-temperature sensor and 4th temperature sensor, first temperature sensor is used to monitor the temperature containing wet wind, the second temperature sensor Temperature for monitoring the gas in the seal cavity, the three-temperature sensor is used for the surface for monitoring product to be dried Temperature, the 4th temperature sensor is used for the temperature for monitoring dry warm wind runner pipe or warm wind import of drying;
The auxiliary circulating equipment is arranged on the inside of the seal cavity, is carried out for strengthening the gas in seal cavity Convection current, it is ensured that the temperature and homogeneity of ingredients of the gas in the seal cavity, and the evaporation rate moisturized.
Preferred in above technical scheme, the processing component includes condenser and heater, and the condenser is used for pair Described to carry out cooling processing and dehumidification treatments containing wet wind, the heater is used to go wet wind to heat to described;
The air inlet of the condenser passes through runner pipe containing wet wind and outlet containing wet wind, the air outlet of the condenser Connected with the air inlet of the heater, the air outlet of the heater passes through warm wind runner pipe and the warm wind import company of drying of drying It is logical;
The 5th temperature sensor for being used for monitoring heat-transfer surface temperature is provided with the cooling heat-transfer surface of the condenser;It is described cold Condenser is for the natural air cooled condenser by low-temperature receiver of air, the air blast cooling condenser by low-temperature receiver of air or using recirculated water as low-temperature receiver Condenser;
Either, the processing component is heat pump, and the cold-side inlet of the heat pump is by runner pipe containing wet wind and containing wet wind Outlet, the hot junction outlet of the heat pump passes through warm wind runner pipe and the warm wind inlet communication that dries of drying.
Preferred in above technical scheme, the auxiliary circulating equipment includes forced convertion fan group;
First temperature sensor, second temperature sensor, the 4th temperature sensor and the 5th temperature sensor are equal For contact temperature-measuring device, the three-temperature sensor is infrared temperature sensor;The runner pipe containing wet wind, dry warm wind Heat-insulation layer is equipped with the outer wall of runner pipe, condenser and heater.
Using the device of the present invention, device is simply easily realized, equipment input at initial stage is low.
In addition to objects, features and advantages described above, the present invention also has other objects, features and advantages. Below with reference to figure, the present invention is further detailed explanation.
Brief description of the drawings
The accompanying drawing for constituting the part of the application is used for providing a further understanding of the present invention, schematic reality of the invention Apply example and its illustrate to be used to explain the present invention, do not constitute inappropriate limitation of the present invention.In the accompanying drawings:
Fig. 1 is the schematic device of the preferred embodiment of the present invention 1;
Fig. 2 is the drying process schematic diagram of the device using Fig. 1;
Fig. 3 is the structural representation for circulating regulator control system in the device of the preferred embodiment of the present invention 2;
Fig. 4 is the drying process schematic diagram of the device using Fig. 3;
Wherein, 1, microwave dryer, 1.1, seal cavity, 1.11, containing wet wind outlet, 1.12, warm wind import of drying, 2, Circulate regulator control system, 2.1, runner pipe containing wet wind, 2.2, processing component, 2.21, condenser, 2.22, heater, 2.3, dry it is warm Distinguished and admirable siphunculus, 3, temperature sensor group, the 3.1, first temperature sensor, 3.2, second temperature sensor, the 3.3, the 3rd temperature is passed Sensor, the 3.4, the 4th temperature sensor, the 3.5, the 5th temperature sensor, 4, auxiliary circulating equipment, 5, product to be dried, 6, dry Product, 7, conveyer.
Embodiment
Embodiments of the invention are described in detail below in conjunction with accompanying drawing, but the present invention can be limited according to claim Fixed and covering multitude of different ways is implemented.
Embodiment 1:
A kind of method for microwave drying (exemplified by drying full-size 30mm building blocks, aqueous 21.5% to moisture content 2%), Its device used refers to Fig. 1, specifically includes microwave dryer 1, provides following for circulating air for the microwave dryer 1 Ring wind regulator control system 2, temperature sensor group 3 and auxiliary circulating equipment 4, Details as Follows:
The microwave dryer 1 includes the seal cavity 1.1 provided with heat-insulation layer, and the seal cavity 1.1, which is provided with, to be contained Wet wind outlet 1.11 and warm wind import 1.12 of drying.
The circulation regulator control system 2 includes runner pipe containing wet wind 2.1, the processing component 2.2 to being post-processed containing wet wind And the warm wind runner pipe 2.3 that dries, the arrival end of the processing component passes through runner pipe containing wet wind and outlet containing wet wind, institute The port of export of processing component is stated by warm wind runner pipe and the warm wind inlet communication that dries of drying, above-mentioned processing component is using heat herein Pump, specific annexation is:The cold-side inlet of the heat pump is connected by runner pipe containing wet wind 2.1 with containing wet wind outlet 1.11, The hot junction outlet of the heat pump is connected by the warm wind runner pipe 2.3 that dries with warm wind import 1.12 of drying.The heated airflow that dries Siphunculus, which is provided with, to be used to that wet wind will to be contained by seal cavity through exporting warm wind of extracting out and will dry containing wet wind through the warm wind import drum that dries Enter the circulating fan (not shown) of seal cavity.
The temperature sensor group 3 includes the first temperature sensor 3.1, second temperature sensor 3.2, the 3rd TEMP The temperature sensor 3.4 of device 3.3 and the 4th, first temperature sensor 3.1 is arranged in the runner pipe containing wet wind 2.1 Portion, the temperature for monitoring the runner pipe containing wet wind 2.1;The second temperature sensor 3.2 is arranged on the seal cavity 1.1 inside, for monitoring the temperature inside the seal cavity 1.1;The three-temperature sensor 3.3 is arranged on described close On the inwall for sealing cavity 1.1, the surface temperature for monitoring product 5 to be dried;4th temperature sensor 3.4 is arranged on institute The inside of wet warm wind runner pipe 2.2 is stated, the temperature for monitoring the warm wind runner pipe 2.2 that dries.
The auxiliary circulating equipment 4 is arranged on the inside of the seal cavity, and it includes multiple forced convertion fans, is used for The gas strengthened in seal cavity carries out convection current, it is ensured that the temperature and homogeneity of ingredients of the gas in the seal cavity, and increases The evaporation rate added water point.
First temperature sensor, second temperature sensor and the 4th temperature sensor are contact temperature-measuring device, described Three-temperature sensor is infrared temperature sensor (contactless).
Heat-insulation layer is equipped with the outer wall of the runner pipe containing wet wind and the warm wind runner pipe that dries.
The device of the present embodiment can also be used in combination with conveyer 7.Conveyer 7 can use following structure:Including Transmit the feed belt of product 5 to be dried and dry products 6, drive power source and support that the feed belt moved The support frame of the feed belt.
The method for microwave drying of the present embodiment refers to Fig. 2, specifically includes following steps:
Product to be dried is placed in the closed and heat-insulated seal cavity in microwave dryer;
Microwave dryer transmitting microwave carries out microwave drying, while the gas in seal cavity is subjected to forced convertion, Microwave drying is that continuous-type microwave is dried or/and intermittent type microwave is dried;
The temperature and the surface temperature of product to be dried of the gas in seal cavity are monitored, at the same time incessantly to close The part in cavity is sealed to carry out in post processing Posterior circle to seal cavity containing humid gas.
Above-mentioned post processing comprises the following steps:
Step a, by cool processing the temperature containing wet wind extracted out out of seal cavity is down to below its dew-point temperature, Now moisture condensation in part turns into aqueous water and removed from containing wet wind, obtains wet wind;
Step b, wet wind will be gone to be heated, and obtain the warm wind that dries.
Gas temperature and the principle with dry products table temperature are in monitoring cavity:During microwave drying in seal cavity The temperature T of gas1Relation with the dry environment temperature To using conventional drying methods is:T1≤ To+10 DEG C, this measure can be real Existing material microwave drying process is connected with the quick, correct of conventional drying process;The surface temperature T of product to be dried2With routine The surface temperature T for the material that constant speed constant temperature stage highest allows in techniquemaxRelation be T2≤Tmax+ 5 DEG C, during with microwave drying The temperature T of gas in seal cavity1Relation be T2≤T1+ 20 DEG C, this measure is used to ensure that microwave input power makes surface of material Temperature is defined in the framework from beginning to end, can be reached that material internal moisture is outwards migrated to have and suitably be migrated speed Degree;Cool heat-transfer surface temperature T during to carrying out cooling processing containing wet wind3With the dew-point temperature T containing wet windLRelation be TL-10℃≤ T3≤TL;Dry the temperature T of warm wind4With the dew-point temperature T containing wet windLRelation be T4≥TL+ 1 DEG C, this measure can then control to follow Temperature, the humidity of ring gas are in favourable gaseous state, maintain the suitable evaporation rate of surface of material moisture film.
The mode of forced convertion is to be stirred using the fan of controllable convection current;Relative to thing during gas progress forced convertion The wind speed V of material value is:0.5m/s≤V≤4m/s;The rotating speed of the fan In formula:NmaxAnd NminThe rotating speed of fan when respectively relative wind velocity is 4m/s and 0.5m/s, it is allowed to which maximum deviation is 20r/min; T1The temperature of gas during for microwave drying in seal cavity;T2For the surface temperature of product to be dried.
The volume for the gas extracted out and post-processed out of seal cavity per hour for airtight cavity volume 1/4~ 2.5 again.
Cooling processing containing wet wind is carried out and while dehumidification treatments to described as low-temperature receiver using the cold end of heat pump, using this The hot junction of heat pump to it is described go wet wind to be heated (herein, the heat in the hot junction of the heat pump can also include heat pump The heat that cold end is obtained from air, industrial smoke, natural water body, the water body containing underground heat).
Table 1 is referred to using the performance of dry products obtained by the drying means and device of the present embodiment.
Embodiment 2:
The concrete scheme of the present embodiment refers to Fig. 3 and Fig. 4, and its difference from Example 1 is following two aspects:
Apparatus structure is different, is specifically:(1) processing component includes condenser 2.21 and heater 2.22, described cold Condenser 2.21 is used for described containing wet wind progress cooling processing and dehumidification treatments, and the heater 2.22 is used to go wet wind to described Heated (heater can be the part that heat exchanger, heat pump etc. can be heated, during using heat pump, be specifically:Heat pump Cold end obtains heat from air, industrial smoke, natural water body, the water body containing underground heat and passes to hot junction, the heat of the heat pump End is used as heater);The air inlet of the condenser by runner pipe containing wet wind and outlet containing wet wind, the condenser Air outlet is connected with the air inlet of the heater, and the air outlet of the heater passes through warm wind runner pipe and the warm wind that dries of drying Inlet communication;(2) the 5th temperature sensor for being used for monitoring heat-transfer surface temperature, institute are provided with the cooling heat-transfer surface of the condenser The 5th temperature sensor is stated for contact temperature-measuring device;(3) condenser (can be with root for the condenser using recirculated water as low-temperature receiver According to actual conditions, the natural wind or air blast cooling condenser using air as low-temperature receiver are used).
1st, technique is slightly different, and details are:Go wet wind to be cooled and dried into condenser through runner pipe containing wet wind, obtain To going wet wind;Wet wind is gone to be returned after being heated into heater through the warm wind runner pipe that dries in seal cavity (in the association of circulating fan Under same-action).
Table 1 is referred to using the performance of dry products obtained by the drying means and device of the present embodiment.
Performance comparision table (the sampling Detection capacity 500 of dry products obtained by the embodiment 1-2 of table 1 and comparative example 1-3 Part)
Case/parameter Unit microwave installed power production capacity kg/ (kW.h) Energy consumption for drying (kWh/kg) Yields %
Embodiment 1 7.11 0.565 96.5
Embodiment 2 6.95 0.785 97.4
Comparative example 1 5.16 2.16~2.42 78.4
Comparative example 2 5.56 1.86~2.08 83.3
Comparative example 3 5.74 1.78~1.97 85.2
As known from Table 1:
Examples 1 and 2 are the implementation results of the present invention in table 1, and comparative example 1 is that the popular microwave in market is done at this stage The implementation result of drying process;The side that comparative example 2 and comparative example 3 are all used using extraction section hot blast as circulated air Case, difference be the extraction section of comparative example 2 circulated air directly heat after return for drying, while discharge part mix wind Carry out hydrofuge;Comparative example 3 is then screened to circulated air, and wind-warm syndrome, which is higher than just to return after some threshold values, to be used, and return is used Part hot blast carry out dehumidification treatments, otherwise directly discharge.
Microwave energy belongs to secondary energy sources, i.e., the electric energy converted prime energy is converted into microwave energy through microwave device to be used for Article is heated, the efficiency that electric energy is converted into microwave is about 70%, and its complementary energy is converted into the heat energy of microwave component and dissipated.Contrast Embodiment 1 is by the way of microwave heating joint electric heating, and using the relative humidity containing damp and hot wind is directly screened, humidity over limit is then straight Connect mode hydrofuge of the extraction containing damp and hot wind serious without doing any recycling, heat-energy losses.Comparative example 2 is followed using part The mode that ring wind is directly heated but do not dehumidified, reduces the relative humidity of circulated air, while temperature is improved, overall measure ratio Comparative example 1 is more favorably with improving drying efficiency, at the same time, and the program is added using the uninterrupted part that recycles containing wet wind Heat returns to the mode recycled, while uninterrupted discharge unit contains wet wind, is conducive to the entirety of microwave drying atmosphere parameter to put down Surely, therefore drying quality is higher than comparative example 1.Comparative example 3 is similar with comparative example 2, therefore both energy consumptions refer to Mark is lower than comparative example 1, and dry mass is also higher than the latter.Comparative example 3 relative contrast's embodiment 2, mainly more pair The examination of air-out wind-warm syndrome, the too low air-out economic value of temperature is low, can directly extract discharge out, heat loss is relatively small;Temperature Higher than the air-out of threshold values, return again to and use after dehumidifying, so do to make full use of returning to the higher hot blast of this portion temperature, And dehumidify and advantageously reduce the humidity of overall wind, the efficiency dried in drying chamber is improved, therefore program relative contrast implements Significantly, its indices has also been lifted the improvement effect of example 2.
Using the embodiment 2 and embodiment 1 of the present invention program in base of the comparative example 2,3 using this advantage of circulated air On plinth, the physics essence of drying process is further digested and assimilated, recyclegas 100% had been recycled before this, circulated air The dehumidification treatments for passing through condensing mode before drying chamber before this are returned to, dehumidifying degree is smart due to liquid phase-gas-liquid equilibrium condition of water It is really controllable, that is, accomplish the accurate control to circulated air humidity, and easily realize that condensation process temperature drop is as small as possible, i.e., heat loss is use up May be small, therefore with respect to three comparative example schemes of energy consumption index of the two schemes improve huge.In addition, the present invention two Scheme also carries out Precision measurement to the surface temperature of building blocks material to be dried, prevents microwave over-heating from causing to be damaged by drying sample Hinder, therefore the yields based on certified products number is more than contrast scheme.
The main distinction of embodiment 1 and embodiment 2 is that the latter is directly coordinated to circulation using condenser and heater respectively Gas carries out circulated air humidity and temperature adjusting, and the former directly serves as condenser and heater using the cold end and hot junction of heat pump, The heat energy lost when being condensed this have the effect that circulated air, includes the latent heat of most of water vapor condensation release, due to heat The hot junction that the effect of pump is directly transferred to heat pump is used to heat the low temperature drying wind by dehumidifying, along with from heat pump itself machine The heat energy that tool can be transformed, the energy efficiency of heat pump and the heat loss of wall radiating are not considered, can accomplish that circulated air is removed Wet-heating link heat utilization rate 100%, it is considered to which the actual effect of Heat Pump contribution, energy utilization rate can even exceed 100%, can such as utilize heat pump from environment crawl heat be used for heating to recyclegas, therefore embodiment 1 energy consumption index compared with Embodiment 2 is more preferable;Test proves that:The yields difference very little of embodiment 1 and embodiment 2, only phase during quantity of reckoning by the piece 500 Poor 4, it is believed that in phase same level).
Comparative example 1:
Product to be dried is directly placed into microwave dryer and is dried.
Comparative example 2:
It is dried using the drying means disclosed in the utility model patent of Application No. 200920234330.1.
Comparative example 3:
It is dried using the drying means disclosed in the patent of invention of Application No. 201410025343.3.
The preferred embodiments of the present invention are the foregoing is only, are not intended to limit the invention, for the skill of this area For art personnel, the present invention can have various modifications and variations.Within the spirit and principles of the invention, that is made any repaiies Change, equivalent substitution, improvement etc., should be included in the scope of the protection.

Claims (10)

1. a kind of method for microwave drying, it is characterised in that including following key element:
Product to be dried is placed in the closed and heat-insulated seal cavity in microwave dryer;
Microwave dryer transmitting microwave carries out microwave drying, while the gas in seal cavity is carried out into forced convertion;
The temperature and the surface temperature of product to be dried of the gas in seal cavity are monitored, sealing is at the same time extracted out incessantly Part in cavity is back in seal cavity after being post-processed containing humid gas.
2. method for microwave drying according to claim 1, it is characterised in that the post processing comprises the following steps:
Step a, by cool processing the temperature containing wet wind extracted out out of seal cavity is down to below its dew-point temperature, now Part moisture condensation turns into aqueous water and removed from containing wet wind, obtains wet wind;
Step b, wet wind will be gone to be heated, and obtain the warm wind that dries.
3. method for microwave drying according to claim 2, it is characterised in that gas temperature and with drying in monitoring cavity The principle of product table temperature is:
The temperature T of gas during microwave drying in seal cavity1With the relation of the dry environment temperature To using conventional drying methods For:T1≤To+10℃;The surface temperature T of product to be dried2The material allowed with constant speed constant temperature stage highest in common process Surface temperature TmaxRelation be T2≤Tmax+ 5 DEG C, the temperature T of gas during with microwave drying in seal cavity1Relation be:T2 ≤T1+20℃;
Cool heat-transfer surface temperature T during to carrying out cooling processing containing wet wind3With the dew-point temperature T containing wet windLRelation be TL-10℃ ≤T3≤TL;Dry the temperature T of warm wind4With the dew-point temperature T containing wet windLRelation be T4≥TL+1℃。
4. the method for microwave drying according to claim 2-3 any one, it is characterised in that the mode of forced convertion is to adopt It is stirred with the fan of controllable convection current;Value relative to the wind speed V of material is when gas carries out forced convertion:0.5m/s≤ V≤4m/s;The rotating speed of the fanIn formula:NmaxAnd NminRespectively relative wind velocity The rotating speed of fan during for 4m/s and 0.5m/s, it is allowed to which maximum deviation is 20r/min;T1Gas during for microwave drying in seal cavity The temperature of body;T2For the surface temperature of product to be dried.
5. method for microwave drying according to claim 4, it is characterised in that extract out and carry out out of seal cavity per hour The volume of the gas of post processing is 0.25~2.5 times of the volume of airtight cavity.
6. method for microwave drying according to claim 4, it is characterised in that the cooling is processed as heat exchanger natural wind Cold, heat exchanger air blast cooling, water cooling or heat pump cooling;The heating is microwave heating, electric heating, industrial exhaust heat exchange heat, Heat heating, solar energy heating or heat pump.
7. method for microwave drying according to claim 6, it is characterised in that using the cold end of heat pump as low-temperature receiver to described Cooled containing wet wind and while dehumidification treatments, go wet wind to be heated either to described using the hot junction of the heat pump The heat in the hot junction of the heat pump also cold end including heat pump is obtained from air, industrial smoke, natural water body, the water body containing underground heat The heat taken;
The microwave drying be continuous-type microwave dry or/and intermittent type microwave dry, it is described be heated to be continous way heating or/and Batch (-type) is heated.
8. the device that a kind of method for microwave drying as claimed in claim 6 is used, it is characterised in that set including microwave drying Circulated air regulator control system, temperature sensor group and the auxiliary circulation dress standby, circulating air is provided for the microwave dryer Put;
The microwave dryer include provided with heat-insulation layer seal cavity, the seal cavity be provided with containing wet wind outlet and Dry warm wind import;
The circulation regulator control system includes runner pipe containing wet wind, to the processing component post-processed containing wet wind and the warm wind that dries Runner pipe, the arrival end of the processing component is by runner pipe containing wet wind and outlet containing wet wind, and the processing component goes out Mouth end passes through dry warm wind runner pipe and the warm wind inlet communication that dries;The warm wind runner pipe that dries, which is provided with, is used to that wet wind will to be contained Passed through by seal cavity and export the circulating fan extracted out and the warm wind that dries is blasted to seal cavity through warm wind import of drying containing wet wind;
The temperature sensor group includes the first temperature sensor, second temperature sensor, three-temperature sensor and the 4th Temperature sensor, first temperature sensor is used to monitor the temperature containing wet wind, and the second temperature sensor is used for The temperature of the gas in the seal cavity is monitored, the three-temperature sensor is used for the surface temperature for monitoring product to be dried Degree, the 4th temperature sensor is used for the temperature for monitoring dry warm wind runner pipe or warm wind import of drying;
The auxiliary circulating equipment is arranged on the inside of the seal cavity, for strengthening the progress pair of the gas in seal cavity Stream, it is ensured that the temperature and homogeneity of ingredients of the gas in the seal cavity, and the evaporation rate moisturized.
9. device according to claim 8, it is characterised in that the processing component includes condenser and heater, described Condenser is used for described containing wet wind progress cooling processing and dehumidification treatments, and the heater is used to go wet wind to be added to described Heat treatment;
The air inlet of the condenser is by runner pipe containing wet wind and outlet containing wet wind, the air outlet of the condenser and institute The air inlet connection of heater is stated, the air outlet of the heater passes through warm wind runner pipe and the warm wind inlet communication that dries of drying;
The 5th temperature sensor for being used for monitoring heat-transfer surface temperature is provided with the cooling heat-transfer surface of the condenser;The condenser For the natural air cooled condenser by low-temperature receiver of air, the air blast cooling condenser by low-temperature receiver of air or using recirculated water as the cold of low-temperature receiver Condenser;
Either, the processing component is heat pump, and the cold-side inlet of the heat pump is exported by runner pipe containing wet wind with containing wet wind Connection, the hot junction outlet of the heat pump passes through warm wind runner pipe and the warm wind inlet communication that dries of drying.
10. device according to claim 9, it is characterised in that the auxiliary circulating equipment includes forced convertion fan group;
First temperature sensor, second temperature sensor, the 4th temperature sensor and the 5th temperature sensor are to connect Touch thermal detector, the three-temperature sensor is infrared temperature sensor;The runner pipe containing wet wind, the warm wind that dries circulation Heat-insulation layer is equipped with the outer wall of pipe, condenser and heater.
CN201710672499.4A 2017-08-08 2017-08-08 A kind of method for microwave drying and its device of use Pending CN107314621A (en)

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CN109341303A (en) * 2018-10-11 2019-02-15 山东奥福环保科技股份有限公司 A kind of ceramic honey comb green body rapid drying device and drying means
CN112696915A (en) * 2020-12-18 2021-04-23 中国农业科学院油料作物研究所 Oil heat pump microwave coupling tempering method and system
CN113758168A (en) * 2021-09-22 2021-12-07 山西悦凌空调有限公司 Waste heat recovery device of yellow flower dryer

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CN109341303A (en) * 2018-10-11 2019-02-15 山东奥福环保科技股份有限公司 A kind of ceramic honey comb green body rapid drying device and drying means
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CN113758168A (en) * 2021-09-22 2021-12-07 山西悦凌空调有限公司 Waste heat recovery device of yellow flower dryer
CN113758168B (en) * 2021-09-22 2022-08-16 山西悦凌空调有限公司 Waste heat recovery device of yellow flower dryer

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