CN108239483A - A kind of low temperature drying method of bleaching shellac - Google Patents
A kind of low temperature drying method of bleaching shellac Download PDFInfo
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- CN108239483A CN108239483A CN201711427375.6A CN201711427375A CN108239483A CN 108239483 A CN108239483 A CN 108239483A CN 201711427375 A CN201711427375 A CN 201711427375A CN 108239483 A CN108239483 A CN 108239483A
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- lac
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- bleaching shellac
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09F—NATURAL RESINS; FRENCH POLISH; DRYING-OILS; DRIERS (SICCATIVES); TURPENTINE
- C09F1/00—Obtaining purification, or chemical modification of natural resins, e.g. oleo-resins
- C09F1/02—Purification
Abstract
The invention discloses a kind of methods of Vac-dry sheliac, including carrying out fluidized drying processing under the conditions of low temperature and low humidity to washing after bleaching lac particle, remove the moisture in bleaching shellac particle.The method of the present invention operates operation at a lower temperature, and the dry working time is short, easy to operate, and high degree of automation, the bleaching shellac moisture content of preparation is low, and appearance color and physical and chemical index meet and exceed National Standard of the People's Republic of China's bleaching shellac【GB/T8140‑2009】Defined refined bleached lac standard.
Description
Technical field
The present invention relates to a kind of production method of natural resin, more particularly to a kind of production method of bleaching shellac.
Background technology
Lac be the natural resin mixture with property that lac insect secrets out of after water is drawn also known as
Shellac, main component are lac resin, account for about the 65%~80% of gross weight, in addition with wax, pigment, the hydrotrope and machinery
Impurity etc..The main place of production of lac is the Indian subcontinent and Southeast Asia, including India, Bangladesh, China, Pakistan, Thailand
State and Burma etc..
The lactone that the main component of lac is made of hydroxy fatty acid (aleuritic acid) and sequiterpene olefin(e) acid (shelloic acid)
And lactide, it is a kind of natural resin of macromolecular.Lac is gone through as the application that a kind of pure natural resin has 2000~3000 years
History, lac resin have the characteristics that cementability is strong, insulation, moisture-proof, film is smooth, bright, and nontoxic, tasteless, are important work
Industry raw material is widely used in the industries such as military project, electronics, medicine, food and chemical industry, and in fruit freshness preserving, egg product film, candy
Food covering with paint, pill coating etc. then need more use refined bleached lac.
Bleaching shellac is one kind in lac intensely processed products.There are two kinds of pigments in lac：One kind is water-soluble purple
Glue color acid can be substantially removed in pimpled rubber production process；Another kind is with almost identical with lac resin
The erythrolaccin of solubility property.Erythrolaccin is difficult to be removed, therefore yellow even brown is presented in product.However in food, doctor
The industrial aspects such as medicine and Furniture manufacture often need light color or colourless lac resin product, it is necessary to remove this pigment.Industry
Upper application bleaching agent carries out lac resin bleaching resulting product and is known as bleaching shellac.
Bleaching shellac is made by seed lac after dissolving, dewaxing, bleach, be acidified precipitating, washing, centrifugation, drying.
In bleaching shellac production process, bleaching shellac is analysed by being acidified in the case where being acidified kettle blender forceful action with threadiness or sheet
Go out, and be condensed into larger glue core when mutually colliding, bleaching shellac particle is caused to have flourishing hole and a specific surface area, and
Flourishing hole has been formed simultaneously during granulation and has included abundant hygroscopic water, flourishing hole and specific surface area to bleach
The a large amount of acid of lac granular absorption, micro free chlorine and water soluble salt.Therefore, the bleaching shellac obtained from aqueous slkali
Often containing a large amount of physical-mechanical combination water, and cannot mechanically remove；Simultaneously because lac to heat more
Sensitivity, the restrictive condition of drying process are more.The drying means applied in present industrial production is mainly tunnel type drying,
And temperature is controlled in the drying process at 30 DEG C hereinafter, drying time is not shorter than 7d generally.Traditional bleaching shellac dry technology
Because the time is long, take up a large area, labor intensity is high, climate is affected, to norm controllings such as the color indexes of product
Property it is not strong, directly affect the realization of the quality and large-scale industrial production of bleaching shellac product, become restriction its development
" bottleneck ".
At present, the method for external Vac-dry sheliac is based on the framed bent drying of hot-air, wherein simplest is wet
Glue paves allows it to spontaneously dry in threshing ground that is outdoor or having overcover, also has plenty of equipped with steam-heating pipe or cooling fin
Framed bent on or have hot-air by drying chamber or tunnel kiln in be dried.Though above-mentioned drying mode is simple and practicable, labor is spent
It is power, inefficient.The biography equipped with wet grain glue e.g., is mostly made using continuous dryer in the modernization processing factory of the states such as India
Dynamic band is made moisture evaporation and is dried using cocurrent or the hot-air of convection current, according to device type and heat by heating furnace
Air pressure difference can be divided into rectangle Horizontal vibration drier and pneumatic conveyer dryer.The crucial factor of drying process is dry temperature
Degree, if temperature is too low to be not achieved drying purpose, and it is excessively high can cause a gum softening even melt and adhere on the dryer, also
It can make the color burn of lac, quality deteriorates.
The dry link of domestic bleaching shellac production and foreign countries are essentially identical, usually have hot-air by plate rail or tunnel
Then road drying mode 168 hours continues to dry to water content at low temperature below 3%.The drying time of bleaching shellac is long, energy
Consumption is high, and drying efficiency is low, and effect is poor, and moisture content is higher.
The dehydration and drying of bleaching shellac has become the mistake for expending maximum in manpower in bleaching shellac production process, the energy and working hour
Cheng Huanjie, it is therefore desirable to it is a kind of efficiently, the dehydration of low temperature, dry technology break through prior art bottleneck.
Invention content
It, should it is an object of the invention in view of the problems of the existing technology provide a kind of method of Vac-dry sheliac
Method is simple for process, quick, easy to operate, and drying condition is mild, and bleaching shellac drying time is short, significantly reduces bleaching shellac
Moisture, bleaching shellac appearance color and physical and chemical index reach National Standard of the People's Republic of China-bleaching shellac【GB/
T8140-2009】Defined refined bleached lac standard.
Purpose to realize the present invention, the drying means of the bleaching shellac provided according to an aspect of the present invention are included to bleaching purple
Glue wet feed carries out fluidized drying processing.
Wherein, the moisture content of the bleaching shellac wet feed is 60-75%；It is wet to bleaching shellac during the fluidized drying
It is 25-50 DEG C to expect the temperature of dry gas being dried, preferably 30 DEG C~46 DEG C, further preferably 38 DEG C；To bleaching
The content of vapor is excellent to contain 5-10g vapor in per kilogram dry gas in the dry gas that lac wet feed is dried
5.4-7.6g vapor is selected as, is steamed preferably in per kilogram dry gas containing 5-10g vapor, preferably 5.4-7.6g water
Gas.
Particularly, the flow velocity that dry gas passes through fluid bed during the fluidized drying is 0.29~0.50m/s, preferably
For 0.35~0.40m/s.
Wherein, the step of carrying out in the following order prepares the dry gas during the fluidized drying：
1) cooling treatment in confined conditions, is carried out to air, air is reduced to 5-10 DEG C, in cooling procedure air
Middle condensation vapor Cheng Shui removes the water of condensation, and the cold air of water-vapo(u)r saturation is made；
2) in confined conditions, the cold air of water-vapo(u)r saturation is heated, makes temperature rise to 25-50 DEG C, i.e.,
.
Particularly, the temperature of the cold air of the water-vapo(u)r saturation described in step 1) is preferably 7-8 DEG C, and further preferably 8
℃；In the water-vapo(u)r saturation cold air in per kilogram air the quality containing vapor be 5-10g, preferably 5.4-7.6g, i.e.,
The moisture content of the water-vapo(u)r saturation cold air is 5-10g/kg；Preferably 5.4-7.6g, further preferably 6.2-6.7g/kg,
The quality containing vapor is 6.2-6.7g i.e. in per kilogram water-vapo(u)r saturation cold air.
Especially, the cooling treatment carries out air under confined conditions using refrigeration unit or heat pump, by air
Temperature is reduced to 5-10 DEG C.
Wherein, the cooling treatment described in step 1), the pressure in heat-treatment process described in step 2) are 0.1MPa
(absolute pressure).
Particularly, it is carried out in step 2) using using hot water, steam, heat medium oil, heat pump or electric heater heating air
The heat treatment.
Especially, the device for realizing heating is heat exchanger, and heat exchanger may be selected as finned heat exchanger, casing type heat exchanging
It is one or more in device, pipe heat exchanger.
Particularly, it further includes and is carried out again at the fluidized drying after centrifugal dehydration treatment is carried out to bleaching shellac wet feed
Reason.
Wherein, the rotating speed during the centrifugal dehydration treatment is 3000-5000rpm, centrifugation time 15-30min.
Another aspect of the present invention provides a kind of drying means of bleaching shellac, the step of progress including order below：
A) centrifugal treating
Bleaching shellac wet granular is placed in a centrifuge carry out centrifugal dehydration treatment, removing bleaching is purple under the action of the centrifugal force
The intergranular moisture of glue obtains centrifugation bleaching shellac particle；
B) fluidized drying is handled
Centrifugation bleaching shellac particle is placed in fluidized bed dryer, is passed through dry gas, dry gas is bleached with centrifugation
Lac particle comes into full contact with, and forms fluidisation state, and caloic is carried out between dry gas and bleaching shellac granular solids and is exchanged, dry gas
Absorb the moisture in centrifugation bleaching shellac particle, Vac-dry sheliac particle.
Wherein, step A) described in rotating speed during centrifugal dehydration treatment be 3000-5000rpm, centrifugation time 15-
30min。
Particularly, the moisture content for drifting lac wet granular is 60-75%.
Wherein, step B) described in dry gas the step of carrying out in the following order be prepared：
1) cooling treatment in confined conditions, is carried out to air, air is reduced to 5-10 DEG C, in cooling procedure air
Middle condensation vapor Cheng Shui removes the water of condensation, and the cold air of water-vapo(u)r saturation is made；
2) in confined conditions, the cold air of water-vapo(u)r saturation is heated, makes temperature rise to 25-50 DEG C, i.e.,
.
Particularly, air themperature is reduced to 7-8 DEG C, further preferably 8 DEG C in step 1)；Steam made of described is satisfied
With the quality containing vapor in per kilogram cold air in cold air be 5-10g, preferably 5.4-7.6g, further preferably
6.2-6.7g。
Wherein, step B) in dry gas by the flow velocity of fluid bed be 0.29~0.50m/s, preferably 0.35~
0.40m/s。
Particularly, step B) described in dry gas temperature for 25-50 DEG C, contain 5-10g in per kilogram dry gas
Vapor, preferably 5.4-7.6g, further preferably 6.2-6.7g.
Another aspect of the invention provide it is a kind of be prepared according to the method described above drift lac.
Bleaching shellac obtained has advantages below after the method for the present invention dehydration and drying：
1st, bleaching shellac finished product made from present invention drying is milk yellow, and color index is 0.89~No. 0.97；Bleaching is purple
Glue volatile matter (moisture) content 1~2%；The thermmohardening time reaches 130-150, more than National Standard of the People's Republic of China
【8140-2009 bleaching shellacs of GB/T】Middle refined bleached lac (1 grade) relevant criterion.Bleaching shellac【GB/T8140-
2009】Standard is shown in Table 1.
1 bleaching shellac of table【GB/T8140-2009】Bleaching shellac technical indicator and specification requirement are taken passages following：
2nd, the method for the present invention is simple for process, quick, easy to operate, and drying time is short, it is only necessary to which 28~30min is ensureing to float
It is short to the drying time of the bleaching shellac particle of acidification precipitating in the case of the quality of trillium glue, obvious drying effect, preparation
The moisture content of lac is low, reaches 3%, considerably improves the rate of drying of bleaching shellac, reduces labor intensity, shortens
Working hour.
3rd, the method time of Vac-dry sheliac particle of the present invention is short, and low energy consumption, (dry using the method for the present invention drying 1kg
Weight) bleaching shellac particle, the thermal losses of fluidized drying is only 987-1269kJ, is (wet using vacuum drying method drying 1kg
0.59-0.75 times of bleaching shellac particle consumption energy again)；It is to be disappeared using fixed bed drying 1kg (weight in wet base) bleaching shellac particle
0.61-0.78 times of energy consumption；It is that energy is consumed using microwave drying 1kg (weight in wet base) bleaching shellacs particle under vacuum conditions
0.56-0.72 times；It is the 0.48- using vacuum freeze-drying method drying 1kg (weight in wet base) bleaching shellacs particle consumption energy
0.62 times.
4th, the method for the present invention mechanization and high degree of automation significantly reduce artificial labor intensity, and the present invention
Combined type dehydration and drying technique do not have to by spreading drying out, not only processing method is simple and fast, but also saves bleaching shellac
Dry land area further reduced the production cost of bleaching shellac.
Specific embodiment
In being produced with bleaching shellac, it is acidified the bleaching shellac that the bleaching shellac after precipitating, washing obtains after solid-liquor separation
Particle is raw material.The bleaching shellac used in the embodiment of the present invention is by State Administration of Forestry's characteristic forest reserves engineering and technological research
Heart refined bleached lac pilot plant manufactures.In bleaching shellac production process, the bleaching shellac that acidified precipitating obtains passes through
The bleaching shellac particle obtained after solid-liquor separation is raw material, i.e., in bleaching shellac production, Sticklac or seed lac is molten
In sodium carbonate liquor or other weak caustic solutions, mechanical admixture contained by removing or shellac wax stand in filtrate after cooling and add in
Bleaching agent is bleached, then to bleaching glue carry out acidizing crystal, precipitating, then will acidification precipitating in glue through vibrating screen into
Row separation of solid and liquid obtains the bleaching shellac particle with flourishing hole and specific surface area, and it is washed with removing
The impurity such as the water-soluble hydrochlorate that intragranular is included.The present invention is done using the bleaching shellac particle wet feed obtained after washing as raw material
It is dry, wherein, the moisture content of raw material bleaching shellac particle is 60-75%.
It is surveyed in the embodiment of the present invention using the quick halogen moisture teller of HR83-P types (Mettler Toledo Inc. of Switzerland)
Determine the moisture content of lac particle.
Embodiment 1
1st, centrifugal treating
The bleaching shellac particle that moisture content is 65% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 5000rpm, centrifugation time
For 15min.
2nd, dry gas is prepared
A) under normal pressure (0.1MPa) state, the air under the conditions of room temperature (15-35 DEG C) is carried out by refrigeration unit cold
But it handles, the relative humidity of air gradually rises in cooling procedure, until reaching saturation, when the cold air for reaching saturation continues
Cooling, during cooling, condensation vapor Cheng Shui removes the water of condensation, to remove the steam in air, water-vapo(u)r saturation cold air is made.
B) by air cooling to 8 DEG C, the water-vapo(u)r saturation cold air that temperature under normal pressure (0.1MPa) is 8 DEG C, cold air is made
Relative humidity for 100%, the moisture content of cold air is 6.7g/kg, and it is the water that 8 DEG C of moisture contents are 6.7g/kg to obtain temperature
The quality of vapor contained in vapour saturation cold air, i.e. per kilogram water-vapo(u)r saturation cold air is 6.7g.
C) in closed air induction system, temperature is reduced to 8 DEG C, moisture content is that the water-vapo(u)r saturation of 6.7g/kg is cold
Air is heated to 38 DEG C by heat medium oil, and dry gas is made, and the wherein temperature of dry gas is 38 DEG C；Moisture content is
The quality of vapor contained in 6.7g/kg, i.e. per kilogram dry gas be 6.7g, saturation degree 0.16.
Wherein, the saturation degree means the saturation vapour content of moisture content and the temperature air in air at a certain temperature
The ratio between.It is to express the capacity of water that air absorbs moisture in the drying process.Such as under normal pressure, 38 DEG C of moisture in air are reachable
Saturation moisture is 44.1g, 6.7/44.1=0.16 in 44.1g/kg, the i.e. air of 38 DEG C of per kilogram, is theoretically located in this way
Air per kilogram after reason can absorb the moisture that material transfer comes：44.1-6.7=37.4g.
3rd, fluidized drying is handled
1.0kg centrifugation lac particles are placed in fluidized bed dryer (TG200, German Lai Chi companies), are passed through step 2)
The dry gas of preparation makes dry gas be come into full contact with centrifugation lac particle, forms fluidisation state, reaches dry gas and lac
Caloic between granular solids exchanges, and dry gas absorbs the moisture in centrifugation lac particle, achievees the purpose that dry lac particle,
Wherein, the temperature for the dry gas being passed through is 38 DEG C, moisture content 6.7g/kg, and the flow velocity that dry gas passes through fluid bed is
0.35m/s。
Centrifuge lac particle in fluidized bed dryer dry to moisture content be 3% when, stop drying, obtaining moisture content is
3% drying lac, fluidized drying processing used time 28min, wherein the energy consumption for often drying 1kg (dry weight) lac particle is
987.03kJ。
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.
The performance indicator measurement result of bleaching shellac is as shown in table 2.
Embodiment 2
Other than without centrifugal treating, remaining is same as Example 1, and the drying lac moisture content of preparation is 3%, stream
Change and be dried the used time as 45min, wherein the energy consumption for often drying 1kg (dry weight) lac particle is 1500kJ.
Explanation：To bleaching shellac wet feed carry out centrifugal treating, mainly by intergranular moisture centrifugation get rid of (but cannot will
Intragranular moisture abjection).
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.The performance indicator measurement result of bleaching shellac is as shown in table 2.
Embodiment 3
1st, centrifugal treating
The bleaching shellac particle that moisture content is 75% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 4500rpm, centrifugation time
For 20min.
2nd, dry gas is prepared
A) under normal pressure (0.1MPa) state, the air under the conditions of room temperature (25 DEG C) is carried out by refrigeration unit at cooling
Reason, the relative humidity of air gradually rises in cooling procedure, until reaching saturation, when the cold air for reaching saturation continues to cool down
During cooling, condensation vapor Cheng Shui removes the water of condensation, to remove the steam in air, water-vapo(u)r saturation cold air is made.
B) by air cooling to 5 DEG C, the water-vapo(u)r saturation cold air that temperature under normal pressure (0.1MPa) is 5 DEG C, cold air is made
Relative humidity for 100%, the moisture content of cold air is 5.4g/kg, and it is the water that 5 DEG C of moisture contents are 5.4g/kg to obtain temperature
The quality of vapor contained in vapour saturation cold air, i.e. per kilogram water-vapo(u)r saturation cold air is 5.4g.
C) in closed air induction system, temperature is reduced to 5 DEG C, moisture content is the cold sky of water-vapo(u)r saturation of 5g/kg
Gas is heated to 30 DEG C by hot steam, and dry gas is made, and the wherein temperature of dry gas is 30 DEG C, and moisture content is
The quality of vapor contained in 5.4g/kg, i.e. per kilogram dry gas be 5.4g, saturation degree 0.20.3rd, at fluidized drying
Reason
1kg centrifugation lac particles are placed in fluidized bed dryer, are passed through dry gas, make dry gas and centrifugation lac
Particle comes into full contact with, and forms fluidisation state, and the caloic reached between dry gas and lac granular solids exchanges, dry gas absorb from
Moisture in heart lac particle achievees the purpose that dry lac particle, wherein, the temperature of the dry gas being passed through is 30 DEG C, wet
Content 5.4g/kg, the flow velocity that dry gas passes through fluid bed are 0.50m/s.
Centrifuge lac particle in fluidized bed dryer dry to moisture content be 3% when, stop drying, obtaining moisture content is
3% drying lac, fluidized drying processing used time 35min, wherein the energy consumption for often drying 1kg (dry weight) lac particle is
1100kJ/kg。
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.
The performance indicator measurement result of bleaching shellac is as shown in table 2.
Embodiment 4
Other than without centrifugal treating, remaining is same as Example 3, and the drying lac moisture content of preparation is 3%, stream
Change and be dried the used time as 50min, wherein the energy consumption for often drying 1kg (dry weight) lac particle is 1300kJ.
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.The performance indicator measurement result of bleaching shellac is as shown in table 2.
2 bleaching shellac performance indicator testing result of table
| Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 | |
| Color index/number | 0.95 | 0.96 | 0.94 | 0.95 |
| Hot ethanol insoluble matter/% | 0.091 | 0.095 | 0.091 | 0.095 |
| Volatile matter (moisture)/% | 1.68 | 1.77 | 1.72 | 1.91 |
| Thermmohardening time (170 DEG C ± 0.5 DEG C)/s | 125 | 122 | 132 | 126 |
Embodiment 5
1st, centrifugal treating
The bleaching shellac particle that moisture content is 60% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 3000rpm, centrifugation time
For 30min.
2nd, dry gas is prepared
A) under normal pressure (0.1MPa) state, the air under the conditions of room temperature (35 DEG C) is carried out by refrigeration unit at cooling
Reason, the relative humidity of air gradually rises in cooling procedure, until reaching saturation, when the cold air for reaching saturation continues to cool down
During cooling, condensation vapor Cheng Shui removes the water of condensation, to remove the steam in air, water-vapo(u)r saturation cold air is made.
B) by air cooling to 10 DEG C, the water-vapo(u)r saturation cold air that temperature under normal pressure (0.1MPa) is 10 DEG C, cold sky is made
The relative humidity of gas is 100%, and the moisture content of cold air is 7.6g/kg, and it is 7.6g/kg's that obtain temperature, which be 10 DEG C of moisture contents,
The quality of vapor contained in water-vapo(u)r saturation cold air, i.e. per kilogram water-vapo(u)r saturation cold air is 7.6g.
C) in closed air induction system, temperature is reduced to 10 DEG C, moisture content is that the water-vapo(u)r saturation of 7.6g/kg is cold
Air is heated to 46 DEG C by hot steam, and dry gas is made, and the wherein temperature of dry gas is 46 DEG C, and moisture content is
The quality of vapor contained in 7.6g/kg, i.e. per kilogram dry gas be 7.6g, saturation degree 0.12.3rd, at fluidized drying
Reason
1kg centrifugation lac particles are placed in fluidized bed dryer, are passed through dry gas, make dry gas and centrifugation lac
Particle comes into full contact with, and forms fluidisation state, and the caloic reached between dry gas and lac granular solids exchanges, dry gas absorb from
Moisture in heart lac particle achievees the purpose that dry lac particle, wherein, the temperature of the dry gas being passed through is 46 DEG C, wet
Content 7.6g/kg, the flow velocity that dry gas passes through fluid bed are 0.29m/s.
Centrifuge lac particle in fluidized bed dryer dry to moisture content be 3% when, stop drying, obtaining moisture content is
3% drying lac, fluidized drying processing used time 22min, wherein the energy consumption for often drying 1kg (dry weight) lac particle is
1000kJ/kg。
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.
The performance indicator measurement result of bleaching shellac is as shown in table 3.
Embodiment 6
1st, centrifugal treating
The bleaching shellac particle that moisture content is 65% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 5000rpm, centrifugation time
For 15min.
2nd, dry gas is prepared
A) under normal pressure (0.1MPa) state, the air under the conditions of room temperature (20 DEG C) is carried out by refrigeration unit at cooling
Reason, the relative humidity of air gradually rises in cooling procedure, until reaching saturation, when the cold air for reaching saturation continues to cool down
During cooling, condensation vapor Cheng Shui removes the water of condensation, to remove the steam in air, water-vapo(u)r saturation cold air is made.
B) by air cooling to 7 DEG C, the water-vapo(u)r saturation cold air that temperature under normal pressure (0.1MPa) is 7 DEG C, cold air is made
Relative humidity for 100%, the moisture content of cold air is 6.2g/kg, and it is 7 DEG C to obtain temperature, and moisture content is the water of 6.2g/kg
The quality of vapor contained in vapour saturation cold air, i.e. per kilogram water-vapo(u)r saturation cold air is 6.2g.
C) in closed air induction system, temperature is reduced to 7 DEG C, moisture content is the saturation cold air of 6.2g/kg
35 DEG C are heated to by hot steam, dry gas is made, the wherein temperature of dry gas is 35 DEG C, and moisture content is
The quality of vapor contained in 6.2g/kg, i.e. per kilogram dry gas be 6.2g, saturation degree 0.18.3rd, at fluidized drying
Reason
1kg centrifugation lac particles are placed in fluidized bed dryer, are passed through dry gas, make dry gas and centrifugation lac
Particle comes into full contact with, and forms fluidisation state, and the caloic reached between dry gas and lac granular solids exchanges, dry gas absorb from
Moisture in heart lac particle achievees the purpose that dry lac particle, wherein, the temperature of the dry gas being passed through is 35 DEG C, wet
Content 6.2g/kg, the flow velocity that dry gas passes through fluid bed are 0.40m/s.
Centrifuge lac particle in fluidized bed dryer dry to moisture content be 3% when, stop drying, obtaining moisture content is
3% drying lac, fluidized drying processing used time 36min, wherein the energy consumption for often drying 1kg (dry weight) lac particle is
1080kJ/kg。
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.
The performance indicator measurement result of bleaching shellac is as shown in table 3.
3 bleaching shellac performance indicator testing result of table
| Embodiment 5 | Embodiment 6 | |
| Color index/number | 0.99 | 0.95 |
| Hot ethanol insoluble matter/% | 0.092 | 0.091 |
| Volatile matter (moisture)/% | 1.98 | 1.70 |
| Thermmohardening time (170 DEG C ± 0.5 DEG C)/s | 121 | 126 |
Reference examples 1
1st, centrifugal treating
The bleaching shellac particle that moisture content is 65% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 4500rpm, centrifugation time
For 20min.
2nd, vacuum drying treatment
Centrifugation lac particle is placed in vacuum drying chamber, carries out vacuum drying treatment, wherein, in process of vacuum drying absolutely
It is 30KPa to pressure, drying temperature is 45 DEG C, pays attention to observing the variation of bleaching shellac particle, and test drift at regular intervals
The moisture content of trillium glue particle after the moisture content of bleaching shellac particle reaches quality standards, takes out dried material, closes vacuum
Pump and adding thermal resistance power supply.The drying that moisture content is 3% is made and drifts lac, the vacuum drying treatment time is 510min, is often done
The energy consumption of dry 1kg (dry weight) lac particle is 1685.74kJ.
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.The performance indicator measurement result of bleaching shellac is as shown in table 4.
Reference examples 2
1st, centrifugal treating
The bleaching shellac particle that moisture content is 65% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 4500rpm, centrifugation time
For 20min.
2nd, fixed bed drying is handled
Centrifugation lac particle is placed on material disc, and be positioned in aeration cabinet, bed drying process is fixed,
In, drying temperature is 50 DEG C during fixed bed drying, pays attention to observing the variation of bleaching shellac particle, and is surveyed at regular intervals
The moisture content of bleaching shellac particle is tried, after the moisture content of bleaching shellac particle reaches quality standards, dried material is taken out, closes
Drying box power supply.The drying that moisture content is 3% is made and drifts lac, fixed bed drying processing time is 45min, often dries 1kg
The energy consumption of (dry weight) lac particle is 1624.18kJ.
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.The performance indicator measurement result of bleaching shellac is as shown in table 4.
Reference examples 3
1st, centrifugal treating
The bleaching shellac particle that moisture content is 65% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 4500rpm, centrifugation time
For 20min.
2nd, vacuum freeze drying is handled
Centrifugation lac particle is placed in material disc, and be positioned in vacuum freezing drying oven, carries out vacuum freeze drying
Processing, wherein, absolute pressure is 0.09mba during vacuum freeze drying, and drying temperature is -40 DEG C, notices that observation bleaching is purple
The variation of glue particle, and the moisture content of bleaching shellac particle is tested at regular intervals, treat that the moisture content of bleaching shellac particle reaches
To after quality standard, dried material is taken out, closes drying box power supply.The drying that moisture content is 3% is made and drifts lac, vacuum is cold
Dry processing time is lyophilized as 1800min, the energy consumption for often drying 1kg (dry weight) lac particle is 2037.32kJ.
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.The performance indicator measurement result of bleaching shellac is as shown in table 4.
Reference examples 4
1st, centrifugal treating
The bleaching shellac particle that moisture content is 65% is sent into centrifuge, power supply is opened and carries out centrifugal treating, in centrifugal force
Under the action of remove the intergranular moisture of lac, obtain centrifugation lac particle, wherein, centrifugal rotational speed 4500rpm, centrifugation time
For 20min.
2nd, micro-wave vacuum is handled
Centrifugation lac particle is placed in material disc, and be positioned in micro-wave vacuum case, carries out micro-wave vacuum
Processing, wherein, absolute pressure is 4.5KPa, microwave power 600W in microwave-vacuum drying, pays attention to observing bleaching shellac
The variation of particle, and the moisture content of bleaching shellac particle is tested at regular intervals, treat that the moisture content of bleaching shellac particle reaches
After quality standard, dried material is taken out, closes drying box power supply.The drying that moisture content is 3% is made and drifts lac, microwave vacuum
The drying process time is 30min, and the energy consumption for often drying 1kg (dry weight) lac particle is 1762.56kJ.
The bleaching shellac of preparation is according to National Standard of the People's Republic of China【GB/T 8142-2008 lac products sampling side
Method】With【GB/T 8143-2008 Methods of testing lac products】Measure the color index of lac, hot ethanol insoluble matter, volatile matter,
Wax, chlorinity, thermmohardening time, ash content, the hydrotrope and acid value.The performance indicator measurement result of bleaching shellac is as shown in table 4.
4 bleaching shellac performance indicator testing result of table
| Reference examples 1 | Reference examples 2 | Reference examples 3 | Reference examples 4 | |
| Color index/number | 1.00 | 1.90 | 1.01 | 0.90 |
| Hot ethanol insoluble matter/% | 0.085 | 0.085 | 0.076 | 0.075 |
| Volatile matter (moisture)/% | 2.87 | 0.92 | 1.63 | 2.89 |
| Thermmohardening time (170 DEG C ± 0.5 DEG C)/s | 122 | 121 | 151 | 129 |
Testing result shows：
1st, using the method for the present invention to being acidified the bleaching shellac product purity obtained after the bleaching shellac particle drying of precipitating
Height, impurity content is low, and the color index of lac is No. 0.89-0.97；Bleaching shellac moisture is low, reaches 3%, less than country
Standard, other performances are more than National Standard of the People's Republic of China【8140-2009 bleaching shellacs of GB/T】Middle refined bleached
Lac (1 grade) relevant criterion.
2nd, the method for the present invention is short to the drying time for being acidified the bleaching shellac particle of precipitating, dry whole (including centrifugation and
Fluidized drying handle) temporal summation be less than 90min, the fluidized drying time is short, and less than 40min, drying effect is apparent, significantly contract
The short drying process time, lac rate of drying is improved, reduce labor intensity, shorten working hour.
3rd, the thermmohardening time of bleaching shellac prepared by the method for the present invention is long, reaches 130-150s, shows the bleaching prepared
Lac is long in the heated dehydration polymerization time, i.e. the thermal life of bleaching shellac or thermal polymerization time is long, improves lac
Performance.
4th, the entire drying process temperature of the method for the present invention Vac-dry sheliac particle is low, heated time is short, bleaching shellac
Product colour index is low, and energy consumption for drying is relatively low, and the energy consumption for often drying 1kg (dry weight) lac particle is less than 1300kJ, only
987-1269kJ is 0.59-0.75 times using vacuum drying method drying 1kg (weight in wet base) bleaching shellacs particle consumption energy；
It is 0.61-0.78 times using fixed bed drying 1kg (weight in wet base) bleaching shellacs particle consumption energy；It is to use under vacuum conditions
0.56-0.72 times of microwave drying 1kg (weight in wet base) bleaching shellacs particle consumption energy；It is to be dried using vacuum freeze-drying method
0.48-0.62 times of 1kg (weight in wet base) bleaching shellacs particle consumption energy significantly reduces the production cost of bleaching shellac.
Claims (10)
1. a kind of drying means of bleaching shellac, including carrying out fluidized drying processing to bleaching shellac wet feed.
2. the method as described in claim 1, it is characterized in that using temperature as 25-50 DEG C, contain 5.4- in per kilogram air
The dry gas of 7.6g vapor carries out the fluidized drying.
3. method as claimed in claim 2, it is characterized in that dry gas passes through fluid bed during the fluidized drying
Flow velocity is 0.29~0.50m/s.
4. the method as described in claim 1, it is characterized in that, the step of progress in the following order prepares the fluidized drying
Dry gas in journey：
1) cooling treatment in confined conditions, is carried out to air, air themperature is reduced to 5-10 DEG C, in cooling procedure air
Middle saturation condensation vapor Cheng Shui removes the water of condensation, and the cold air of water-vapo(u)r saturation is made；
2) in confined conditions, the cold air of water-vapo(u)r saturation is heated, make temperature rise to 25-50 DEG C to get.
5. method as claimed in claim 4, it is characterized in that the temperature of cold air described in step 1) is preferably 7-8 DEG C.
6. method as claimed in claim 4, it is characterized in that using refrigeration unit or heat pump to described in air progress in step 1)
Cooling treatment.
7. method as claimed in claim 4, it is characterized in that in step 2) using using hot water, steam, heat medium oil, heat pump or
Electric heater heats air, carries out the heat treatment.
8. the method as described in claim 1, it is characterized in that further include bleaching shellac wet feed is centrifuged, after dehydration again
Carry out the fluidized drying processing.
9. method as claimed in claim 8, it is characterized in that the rotating speed in the centrifugation, dehydration process is 3000-
5000rpm, centrifugation time 15-30min.
10. a kind of bleaching shellac, it is characterized in that being dried according to any the methods of above-mentioned 1-9.
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