CN115350656A - Drying cylinder heating and concentrating device and method for cellulose nanofibril gel and application - Google Patents
Drying cylinder heating and concentrating device and method for cellulose nanofibril gel and application Download PDFInfo
- Publication number
- CN115350656A CN115350656A CN202211087504.2A CN202211087504A CN115350656A CN 115350656 A CN115350656 A CN 115350656A CN 202211087504 A CN202211087504 A CN 202211087504A CN 115350656 A CN115350656 A CN 115350656A
- Authority
- CN
- China
- Prior art keywords
- drying cylinder
- cnf
- gel
- concentration
- scraper
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001035 drying Methods 0.000 title claims abstract description 238
- 229920002678 cellulose Polymers 0.000 title claims abstract description 47
- 239000001913 cellulose Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 43
- 238000010438 heat treatment Methods 0.000 title claims abstract description 34
- 239000011248 coating agent Substances 0.000 claims abstract description 43
- 238000000576 coating method Methods 0.000 claims abstract description 43
- 238000003860 storage Methods 0.000 claims abstract description 41
- 238000007790 scraping Methods 0.000 claims abstract description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 32
- 230000008719 thickening Effects 0.000 claims 1
- 238000009776 industrial production Methods 0.000 abstract description 3
- 239000000499 gel Substances 0.000 description 124
- 238000001704 evaporation Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 230000008020 evaporation Effects 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 8
- 239000002028 Biomass Substances 0.000 description 7
- 239000000835 fiber Substances 0.000 description 7
- 238000003763 carbonization Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000000017 hydrogel Substances 0.000 description 5
- 230000002195 synergetic effect Effects 0.000 description 5
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 description 4
- 239000004964 aerogel Substances 0.000 description 4
- 229910052809 inorganic oxide Inorganic materials 0.000 description 4
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 238000005189 flocculation Methods 0.000 description 3
- 230000016615 flocculation Effects 0.000 description 3
- 238000000265 homogenisation Methods 0.000 description 3
- 239000002121 nanofiber Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000021736 acetylation Effects 0.000 description 1
- 238000006640 acetylation reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000002134 carbon nanofiber Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 235000015110 jellies Nutrition 0.000 description 1
- 239000008274 jelly Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- 238000000643 oven drying Methods 0.000 description 1
- 238000004094 preconcentration Methods 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000000527 sonication Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/0052—Preparation of gels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
- B01D1/24—Evaporating by bringing a thin layer of the liquid into contact with a heated surface to obtain dry solids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/30—Accessories for evaporators ; Constructional details thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/0052—Preparation of gels
- B01J13/0065—Preparation of gels containing an organic phase
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
The invention discloses a drying cylinder heating and concentrating device, a drying cylinder heating and concentrating method and application of cellulose nanofibril gel, wherein the method comprises the following steps of: adding the CNF gel into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder; the temperature of the outer surface of the drying cylinder is changed by adjusting the steam pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder; scraping and collecting the CNF coating film concentrated in the step 2 by a second scraper. The method has the advantages of simple operation, short concentration time, high concentration efficiency, easy realization of industrial production and the like. Meanwhile, the concentration of the CNF gel can be greatly improved after the concentration treatment by a drying cylinder, and the CNF gel is convenient to transport and store.
Description
Technical Field
The invention belongs to the technical field of concentration treatment of nano-cellulose, and particularly relates to a drying cylinder heating and concentrating device and method for cellulose nano-fibril gel and application.
Background
The Cellulose Nanofibrils (CNF) have the advantages of good physical and mechanical properties, high hydrophilicity, reproducibility, easy degradation, greenness, no toxicity, high reaction activity and the like, become a green reinforced material with great development potential, and have wide application in the fields of medicine, food, papermaking, oil exploitation, electronic products and the like. CNFs are generally less than 100nm in diameter, have a length of between a few microns and a few tens of microns, contain both crystalline and amorphous regions, and have a high aspect ratio. CNF is typically prepared by mechanical methods assisted by biological or chemical pre-treatment, such as high pressure homogenization, freeze-pulverization, sonication, and the like. Currently, high pressure homogenization is the most common method. In the process of preparing the cellulose nanofibrils through high-pressure homogenization treatment, in order to prevent the fibers from generating gel and blocking a high-pressure homogenizing pipeline due to strong water absorption and retention capacity in the process of nanofibrillation, the concentration of the prepared pulp suspension cannot be too high and is generally about 0.01wt% -1wt%, the prepared CNF hydrogel is in a transparent jelly shape and has very high water content (99 wt% -99.99 wt%) and viscosity value, the subsequent storage and use of the CNF are seriously influenced, and the transportation cost is greatly increased. The bottleneck problems of nonuniform heating, low concentration efficiency and the like of cellulose nanofibril gel cannot be solved by conventional drying and concentrating in an oven, dense and firm fiber aggregates can be generated under the action of hydrogen bonds by excessive concentration and drying of the nanofibers, the redispersion performance of the nanofibers is seriously influenced, in addition, because CNF hydrogel has excellent water retention, the water content of the hydrogel cannot be effectively removed by using the conventional drying and drying methods in the oven and the like to improve the concentration of the hydrogel, the concentration efficiency is extremely low, the CNF hydrogel is likely to be locally heated unevenly to cause CNF film formation and even carbonization by the conventional drying method, the quality and subsequent application of CNF products are seriously influenced, a large amount of heat and energy can be consumed by the conventional drying method, and the realization of targets of carbon peak reaching and carbon neutralization is not facilitated under the background of 'double carbon'. In view of this, it is of great practical significance to develop a CNF gel concentration method that is simple in operation, short in concentration time, uniform in water evaporation, high in concentration efficiency, low in energy consumption, and easy to implement industrial production.
Through searching, the following two patent publications related to the patent application of the invention are found:
1. the invention discloses a method for preparing an inorganic oxide aerogel by taking biomass nano fibrillated cellulose as a template (CN 103112830A), and aims to solve the problems of complex process, high cost and low yield of the existing method for preparing the inorganic oxide aerogel. The method comprises the following steps: 1. preparing a biomass nano fibrillated cellulose aqueous solution; 2. preparing an absolute ethanol solution of biomass nano fibrillated cellulose; 3. mixing to obtain inorganic/biomass nano fibrillated cellulose mixed solution; 4. preparing inorganic/biomass nano fibrillated cellulose composite dispersion liquid; 5. performing replacement concentration to obtain an inorganic/biomass nano fibrillated cellulose composite/tertiary butanol suspension; 6. drying to obtain the tert-butyl alcohol/inorganic/biomass nano fibrillated cellulose composite material; 7. and (4) carrying out demoulding plate treatment to obtain the inorganic oxide aerogel. The method is mainly used for preparing the inorganic oxide aerogel.
2. A method for improving thermal properties of nanofibrillar cellulose (CN 107216396A) is completed by four steps of 1) preparation of toluene suspension of nanofibrillar cellulose, 2) preparation of acetic anhydride reaction system, 3) preparation of acetylated nanofibrillar cellulose and 4) acetylation modification treatment of nanofibrillar cellulose. The invention obviously improves the thermal performance of the nanofibrillar cellulose and greatly widens the research and application range of the nanofibrillar cellulose.
By contrast, the present patent application is substantially different from the above patent publications.
Disclosure of Invention
The invention aims to overcome the problems in the prior art and provides a drying cylinder heating and concentrating method for cellulose nano-fibril gel.
The technical scheme adopted by the invention for solving the technical problem is as follows:
a drying cylinder heating and concentrating device for cellulose nanofibril gel comprises a low-concentration CNF gel storage tank, a drying cylinder, a motor, a first scraper and a second scraper, wherein the low-concentration CNF gel storage tank is arranged along the horizontal direction and can contain the low-concentration CNF gel to be concentrated;
the drying cylinder is arranged above the bottom of the low-concentration CNF gel storage tank, the lower part of the drying cylinder is arranged in the low-concentration CNF gel storage tank, the outer surface of the drying cylinder arranged in the low-concentration CNF gel storage tank can be in contact with the low-concentration CNF gel, the low-concentration CNF gel can be adsorbed on the outer surface of the drying cylinder, and the drying cylinder can concentrate the CNF coating film adsorbed on the outer surface of the drying cylinder; the drying cylinder is connected with a motor, and the motor can drive the drying cylinder to rotate along the circumferential direction;
the first scraper and the second scraper are respectively arranged on two horizontal sides of the drying cylinder, the first scraper is arranged at intervals close to the outer surface of the drying cylinder, the first scraper can adjust the thickness of a CNF film, the second scraper is arranged in contact with the outer surface of the drying cylinder, and the second scraper can film and scrape the CNF film on the outer surface of the drying cylinder after concentration treatment.
Further, the low concentration CNF gel can be uniformly adsorbed on the outer surface of the drying cylinder.
Further, the drying cylinder is internally provided with water vapor which can control the temperature of the outer surface of the drying cylinder.
Further, the device further comprises a finished product concentrated CNF gel storage tank which is arranged below the second scraper and can be used for collecting the CNF coating film scraped by the second scraper.
Use of a device as described above for concentrating a cellulose nanofibril gel.
The drying cylinder heat concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding the CNF gel into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
step 2: the temperature of the outer surface of the drying cylinder is changed by adjusting the water vapor pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step 2 by a second scraper.
Further, the concentration of the CNF gel before concentration in the step 1 is 0.1wt% -2wt%, and the concentration of the CNF gel after concentration in the step 3 is 1.2wt% -100wt%.
Further, the distance between the first scraper and the outer surface of the drying cylinder in the step 2 is 0.2-0.6cm, and the running speed of the drying cylinder is 0.01-0.5r/min.
Further, the pressure of the water vapor in the drying cylinder in the step 2 is 0.2-1.5MPa.
Use of a method as described above for concentrating a cellulose nanofibril gel.
The beneficial effects obtained by the invention are as follows:
1. the drying cylinder heating method of the cellulose nanofibril gel has the advantages of simple operation, short concentration time, uniform water evaporation, high concentration efficiency and low energy consumption, and is easy to realize industrial production. The device and the method can overcome the bottleneck problems of uneven heating, low concentration efficiency, easy generation of agglomeration and carbonization of the nano fibers and the like of the traditional concentration drying method.
2. The concentration method of the CNF gel is simple to operate, short in concentration time, capable of being calculated according to the rotating speed of 0.1-0.5r/min, and capable of controlling the process and low in energy consumption (the method utilizes the adsorption force (hydrogen bond force, van der Waals force and the like) between the surface of the drying cylinder and the cellulose nanofibril gel, when the drying cylinder rotates and the surface of the drying cylinder is in uniform contact with the low-concentration cellulose nanofibril gel, the low-concentration cellulose nanofibril gel can be uniformly adhered to the surface of the drying cylinder, and the gel surface is further flattened under the action of the first scraper so as to further control the thickness of the dried gel layer. Is particularly suitable for the concentration process of fluid with high viscosity and high water content such as CNF and the like.
3. The concentration method of the invention realizes the high concentration of the CNF gel, can greatly improve the concentration of the CNF gel after the concentration treatment by the drying cylinder, is convenient for storage and transportation, and reduces the storage and transportation cost.
Drawings
FIG. 1 is a schematic view of the structural connection of the apparatus of the present invention and a process diagram of cylinder heating and condensation of CNF gel.
Detailed Description
The present invention will be further described in detail with reference to examples for better understanding, but the scope of the present invention is not limited to the examples.
The raw materials used in the invention are all conventional commercial products unless otherwise specified, the methods used in the invention are all conventional in the field, and the quality of each substance used in the invention is conventional quality.
A drying cylinder heating and concentrating device for cellulose nanofibril gel, as shown in fig. 1, the device comprises a low-concentration CNF gel storage tank 1, a drying cylinder 5, a motor (not shown in the figure), a first scraper 2 and a second scraper 4, wherein the low-concentration CNF gel storage tank is arranged along the horizontal direction, and the storage tank can contain low-concentration CNF gel 6 to be concentrated;
the drying cylinder is arranged above the bottom of the low-concentration CNF gel storage tank, the lower part of the drying cylinder is arranged in the low-concentration CNF gel storage tank, the outer surface of the drying cylinder arranged in the low-concentration CNF gel storage tank can be in contact with the low-concentration CNF gel, the low-concentration CNF gel can be adsorbed on the outer surface of the drying cylinder, and the drying cylinder can carry out concentration operation on the CNF coating film 3 adsorbed on the outer surface of the drying cylinder; the drying cylinder is connected with a motor, and the motor can drive the drying cylinder to rotate along the circumferential direction;
the first scraper and the second scraper are respectively arranged on two horizontal sides of the drying cylinder, the first scraper is arranged at intervals close to the outer surface of the drying cylinder, the first scraper can adjust the thickness of a CNF film, the second scraper is arranged in contact with the outer surface of the drying cylinder, and the second scraper can film and scrape the CNF film on the outer surface of the drying cylinder after concentration treatment.
In this embodiment, the low concentration CNF gel can be uniformly adsorbed on the outer surface of the drying cylinder.
In this embodiment, the drying cylinder is provided with water vapor, and the temperature of the outer surface of the drying cylinder can be controlled by adjusting the pressure of the water vapor.
In this embodiment, the apparatus further comprises a finished concentrated CNF gel reservoir (not shown in the figure) disposed below the second doctor blade, which can be used to collect the CNF coating film scraped off by the second doctor blade.
Use of a device as described above for concentrating a cellulose nanofibril gel.
The drying cylinder heat concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding the CNF gel into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
step 2: the temperature of the outer surface of the drying cylinder is changed by adjusting the water vapor pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step 2 by a second scraper.
Preferably, the concentration of the CNF gel before concentration in step 1 is 0.1wt% to 2wt%, and the concentration of the CNF gel after concentration in step 3 is 1.2wt% to 100wt%.
Preferably, the distance between the first scraper (4) and the outer surface of the drying cylinder in the step 2 is 0.2-0.6cm, and the running speed of the drying cylinder is 0.1-0.5r/min
Preferably, the pressure of the water vapor in the drying cylinder in the step 2 is 0.2-1.5MPa.
One working principle of the drying cylinder heating and concentrating device provided by the invention can be as follows:
step 1: adding low-concentration CNF gel with a certain concentration into a CNF storage tank below the equipment, installing a drying cylinder with a certain water vapor pressure above the storage tank, driving the drying cylinder to rotate through the rotation of a motor, contacting the CNF gel through the surface of the drying cylinder and uniformly adsorbing a layer of CNF gel, moving the CNF gel coated on the surface of the drying cylinder along with the rotation of the drying cylinder, and simultaneously uniformly transferring the heat on the surface of the drying cylinder to the CNF gel layer to promote the evaporation of the water in the CNF gel layer and improve the concentration of the CNF gel.
And 2, step: the surface temperature of the drying cylinder is changed by adjusting the steam pressure inside the drying cylinder; the heating evaporation concentration time of the CNF gel coating on the surface of the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF gel coat applied on the cylinder surface is adjusted by adjusting the distance between the first doctor blade 2 and the cylinder surface.
And 3, step 3: the CNF gel coating concentrated in step 2 is collected by the second doctor blade 4, for example, into the final concentrated CNF gel storage tank on the right side of the apparatus.
The concentration of the CNF gel before concentration is 0.1wt% -2wt%. The concentration efficiency of the CNF gel and the concentration (1.2 wt% -100 wt%) of the final CNF gel can be adjusted by adjusting the steam pressure (0.2-1.5 MPa) in the drying cylinder, the rotating speed (0.01-0.5 r/min) of the drying cylinder and the coating thickness (0.2-0.6 cm) of the CNF gel on the surface of the drying cylinder.
Example 1
The drying cylinder heat concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the concentration of the initial CNF gel is 1 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
step 2: the temperature of the outer surface of the drying cylinder is changed by adjusting the steam pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step (2) by a second scraper;
wherein the distance from the first doctor to the surface of the drying cylinder is 0.5cm.
The running speed of the drying cylinder is 0.2r/min.
The pressure of the steam in the drying cylinder is 0.4MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 1.7wt%.
Example 2
The drying cylinder heat concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the concentration of the initial CNF gel is 1 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
and 2, step: the temperature of the outer surface of the drying cylinder is changed by adjusting the water vapor pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and 3, step 3: scraping and collecting the CNF coating film concentrated in the step (2) by a second scraper;
wherein the distance from the first doctor to the surface of the drying cylinder is 0.5cm.
The running speed of the drying cylinder is 0.1r/min.
The pressure of the steam in the drying cylinder is 0.6MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 3wt%.
Example 3
The drying cylinder heating concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the initial CNF gel concentration is 1.8 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
step 2: the temperature of the outer surface of the drying cylinder is changed by adjusting the steam pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and 3, step 3: scraping and collecting the CNF coating film concentrated in the step (2) by a second scraper;
wherein the distance from the first doctor to the surface of the drying cylinder is 0.3cm.
The running speed of the drying cylinder is 0.05r/min.
The pressure of the steam in the drying cylinder is 1MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 50wt%.
Example 4
The drying cylinder heating concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the initial CNF gel concentration is 1.2 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
and 2, step: the temperature of the outer surface of the drying cylinder is changed by adjusting the steam pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step 2 by a second scraper;
wherein the distance from the first doctor to the surface of the drying cylinder is 0.35cm.
The running speed of the drying cylinder is 0.2r/min.
The vapor pressure inside the drying cylinder is 0.8MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 31%.
Example 5
The drying cylinder heating concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the concentration of the initial CNF gel is 1 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
and 2, step: the temperature of the outer surface of the drying cylinder is changed by adjusting the water vapor pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step (2) by a second scraper;
wherein the distance from the first doctor to the surface of the drying cylinder is 0.5cm.
The running speed of the drying cylinder is 0.3r/min.
The vapor pressure inside the drying cylinder is 0.5MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 1.9wt%.
Example 6
The drying cylinder heat concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the initial CNF gel concentration is 1 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
step 2: the temperature of the outer surface of the drying cylinder is changed by adjusting the water vapor pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step (2) by a second scraper;
wherein the distance from the first doctor to the surface of the drying cylinder is 0.4cm.
The running speed of the drying cylinder is 0.2r/min.
The vapor pressure inside the drying cylinder is 0.4MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 2.3wt%.
Example 7
The drying cylinder heating concentration method of cellulose nanofibril gel using the apparatus as described above comprises the steps of:
step 1: adding CNF gel (the concentration of the initial CNF gel is 1.5 wt%) into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
step 2: the temperature of the outer surface of the drying cylinder is changed by adjusting the steam pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step (2) by a second scraper;
wherein the distance of the first doctor to the cylinder surface is 0.35cm.
The running speed of the drying cylinder is 0.1r/min.
The vapor pressure inside the drying cylinder is 0.5MPa.
Adding the CNF gel into a CNF storage tank below the device, driving the CNF gel to flow by a rotating drying cylinder, drying and concentrating by the drying cylinder, wherein the concentration of the collected concentrated CNF is 18wt%.
The correlation test of the present invention is as follows:
1. compared with the drying equipment in the prior art, the device and the method have the advantages of convenient operation, simple parameter control and higher drying efficiency, and overcome the defects of nonuniform drying, fiber agglomeration and flocculation when local heating is too high, even fiber carbonization and the like of the traditional oven drying, and the quality, redispersion performance and the like of the product are seriously influenced.
2. In the method, the distance between the first scraper and the surface of the drying cylinder, the running speed of the drying cylinder and the vapor pressure in the drying cylinder have the related detection of the synergistic effect
The preferred scheme is as follows: the distance (0.2-0.6 cm) between the first scraper and the surface of the drying cylinder, the running speed of the drying cylinder is 0.01-0.5r/min, and the steam pressure in the drying cylinder is 0.2-1.5MPa.
TABLE 1 table of conditions and results of inventive examples 1 to 7 and comparative examples
Wherein, the relevant detection methods, parameters and the like of comparative examples 1 and 2 in table 1 are the same as those of example 1 except for the differences described in table 1; the relevant test methods, parameters and the like of comparative example 3 in table 1 were the same as those of example 3 except for the differences described in table 1; the relevant test methods, parameters and the like of comparative example 4 in Table 1 were the same as those of example 7 except for the differences described in Table 1.
As can be seen from Table 1, the CNF concentration before concentration is the same (1 wt%) as compared with the results of example 1 and example 2, and the distance from the first doctor blade to the surface of the drying cylinder is 0.5cm, and since the cylinder running speed in example 2 is 0.1r/min, which is lower than the cylinder running speed in example 1 by 0.2r/min, the speed of rotation in example 2 is slower and the time for evaporating water at high temperature is longer in the same time, and the water vapor inside the drying cylinder is 0.6MPa in example 2, which is higher than 0.4MPa in example 1, which indicates that the water content evaporated in the unit time is more. In summary, the concentration of the concentrated CNF gel obtained in example 2 is 3wt% higher than the concentration of the concentrated CNF in example 1.7wt%. Therefore, increasing the dryer speed and the steam pressure inside the dryer can result in a 1.3wt% increase in solids content of the concentrated CNF gel.
In addition, comparing the results of example 6 and example 1, both examples had the same pre-concentration CNF concentration (1 wt%), the same cylinder speed (0.2 r/min), the same cylinder internal water vapor pressure (0.4 MPa), the only different factors being the distance of the first blade from the cylinder surface, 0.5cm for example 1 and 0.4cm for example 6, indicating that the CNF gel coating was thinner and the water evaporation rate was greater for example 6, resulting in a post-concentration CNF concentration of 2.3wt% for example 6, 1.7wt% higher than for example 1, and a difference of 0.6wt%. Therefore, combining the two sets of comparisons, one can conclude that: the result of the superposition of the two factors (i.e. the enhancement of the cylinder running speed and the steam pressure inside the cylinder) can improve the CNF gel concentration difference by 1.3wt% and is higher than the CNF gel concentration difference caused by a single factor (the distance from the first scraper to the surface of the cylinder) by 0.6wt%, which shows that when a certain condition is used alone or replaced by other conditions with similar functions, the two factors can exert a synergistic superposition effect, and the double-factor superposition can generate an evaporation concentration effect better than the single factor.
Comparing the examples and the comparative examples in table 1, it can be seen that the experimental parameters in the comparative examples exceed the parameter range protected by the present invention, and when the distance from the first doctor blade 2 to the surface of the drying cylinder is too small, the thickness of the CNF film is small, the CNF film is easy to lose water, and fiber flocculation, coagulation and carbonization phenomena occur, which are not favorable for redispersion of the CNF. If the distance is too large, the CNF membrane is large, dehydration and concentration are not easy to occur, and the concentration effect is influenced. When the operation speed of the drying cylinder is too low, the evaporation time is too long, the CNF film loses too much water, so that the water in the CNF film is not uniformly evaporated, the fiber is flocculated and condensed, and the local carbonization phenomenon occurs. When the pressure of water vapor in the drying cylinder is too low, the surface temperature of the drying cylinder is too low, the dehydration amount of the CNF film is small, the evaporation and concentration effects are poor, and the concentration purpose cannot be achieved; when the pressure of water vapor in the drying cylinder is too high and the temperature is too high, the CNF film is locally heated to cause the rapid dehydration of the fiber to generate flocculation, condensation and carbonization phenomena, thereby influencing the dispersion effect of the CNF. Therefore, the conditions in the examples are within the parameters protected by the present invention, and the related test results are within the expected concentration effect, while the concentration results obtained when the conditions in the comparative examples are beyond the range protected by the present invention are not within the expected concentration effect. The test results of these comparative examples can be significantly lower than those of the corresponding examples.
As can be seen from Table 1, when the preferred solution, that is, the distance (0.2-0.6 cm) from the first scraper to the surface of the drying cylinder, the running speed of the drying cylinder is 0.01-0.5r/min, and the steam pressure in the drying cylinder is 0.2-1.5MPa, is used for the synergistic concentration treatment, the quality and the redispersibility performance of the obtained concentrated treatment product are obviously higher than those of the single treatment or the effect of the two-factor simultaneous treatment. Therefore, the preferable proposal of the invention has the synergistic effect that the distance (0.2-0.6 cm) from the first scraper to the surface of the drying cylinder, the running speed of the drying cylinder is 0.01-0.5r/min, and the water vapor pressure in the drying cylinder is 0.2-1.5MPa.
In conclusion, the evaporation and concentration efficiency of the CNF gel and the concentration of the final CNF gel can be effectively improved by adjusting the three factors of the distance from the first scraper to the surface of the drying cylinder and the water vapor pressure inside the drying cylinder at the running speed of the drying cylinder. Moreover, the change of two factors can produce an additive synergistic effect, and the evaporation concentration effect is better than that of a single factor.
Although the embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the embodiments disclosed.
Claims (10)
1. A dryer heating and concentrating device for cellulose nanofibril gel is characterized in that: the device comprises a low-concentration CNF gel storage tank, a drying cylinder, a motor, a first scraper and a second scraper, wherein the low-concentration CNF gel storage tank is arranged along the horizontal direction and can contain the low-concentration CNF gel to be concentrated;
the drying cylinder is arranged above the bottom of the low-concentration CNF gel storage tank, the lower part of the drying cylinder is arranged in the low-concentration CNF gel storage tank, the outer surface of the drying cylinder arranged in the low-concentration CNF gel storage tank can be in contact with the low-concentration CNF gel, the low-concentration CNF gel can be adsorbed on the outer surface of the drying cylinder, and the drying cylinder can carry out concentration operation on the CNF coating film adsorbed on the outer surface of the drying cylinder; the drying cylinder is connected with a motor, and the motor can drive the drying cylinder to rotate along the circumferential direction;
the first scraper and the second scraper are respectively arranged on two horizontal sides of the drying cylinder, the first scraper is arranged at intervals close to the outer surface of the drying cylinder, the first scraper can adjust the thickness of a CNF film, the second scraper is arranged in contact with the outer surface of the drying cylinder, and the second scraper can film and scrape the CNF film on the outer surface of the drying cylinder after concentration treatment.
2. The drying cylinder heating and concentrating apparatus of cellulose nanofibril gel according to claim 1, characterised in that: the low concentration CNF gel can be uniformly adsorbed on the outer surface of the drying cylinder.
3. The cellulose nanofibril gel dryer heating and condensing unit according to claim 1, characterized by: the drying cylinder is internally provided with water vapor which can control the temperature of the outer surface of the drying cylinder.
4. The drying cylinder heating and concentrating device of cellulose nanofibril gel according to any of claims 1 to 3, characterised in that: the device further comprises a finished product concentrated CNF gel reservoir disposed below the second scraper, which can be used to collect CNF coating films scraped by the second scraper.
5. Use of a device according to any one of claims 1 to 4 for concentrating cellulose nanofibrillar gel.
6. Drying cylinder thermal thickening of cellulose nanofibril gel using an apparatus according to any of claims 1 to 4, characterised in that: the method comprises the following steps:
step 1: adding the CNF gel into a low-concentration CNF gel storage tank, and driving the CNF gel to flow by a rotating drying cylinder;
and 2, step: the temperature of the outer surface of the drying cylinder is changed by adjusting the steam pressure in the drying cylinder; the heating time of the CNF coating on the drying cylinder is adjusted by adjusting the rotating speed of the drying cylinder; the thickness of the CNF coating film is adjusted by adjusting the distance between the first scraper and the outer surface of the drying cylinder;
and step 3: scraping and collecting the CNF coating film concentrated in the step 2 by a second scraper.
7. The method of claim 6, wherein: the concentration of the CNF gel before concentration in the step 1 is 0.1wt% -2wt%, and the concentration of the CNF gel after concentration in the step 3 is 1.2wt% -100wt%.
8. The method of claim 6, wherein: in the step 2, the distance from the first scraper to the outer surface of the drying cylinder is 0.2-0.6cm, and the running speed of the drying cylinder is 0.01-0.5r/min.
9. The method according to any one of claims 6 to 8, wherein: the pressure of the water vapor in the drying cylinder in the step 2 is 0.2-1.5MPa.
10. Use of a method according to any one of claims 6 to 9 for concentrating a cellulose nanofibrillar gel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211087504.2A CN115350656A (en) | 2022-09-07 | 2022-09-07 | Drying cylinder heating and concentrating device and method for cellulose nanofibril gel and application |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211087504.2A CN115350656A (en) | 2022-09-07 | 2022-09-07 | Drying cylinder heating and concentrating device and method for cellulose nanofibril gel and application |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115350656A true CN115350656A (en) | 2022-11-18 |
Family
ID=84006194
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211087504.2A Pending CN115350656A (en) | 2022-09-07 | 2022-09-07 | Drying cylinder heating and concentrating device and method for cellulose nanofibril gel and application |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115350656A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1837434A1 (en) * | 2006-03-21 | 2007-09-26 | Electrolux Home Products Corporation N.V. | Clothes tumble dryer |
| CN105239184A (en) * | 2015-10-23 | 2016-01-13 | 南京荣之盛生物科技有限公司 | Bacterial cellulose/graphene/ferroferric oxide composite film and preparation method thereof |
| CN106346531A (en) * | 2016-08-29 | 2017-01-25 | 贵州苗仁堂制药有限责任公司 | Slicing mechanism of hydrogel coating machine |
| CN217383642U (en) * | 2022-06-15 | 2022-09-06 | 焦作广瑞净水材料有限公司 | A cylinder drying device for polyaluminium chloride production |
-
2022
- 2022-09-07 CN CN202211087504.2A patent/CN115350656A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1837434A1 (en) * | 2006-03-21 | 2007-09-26 | Electrolux Home Products Corporation N.V. | Clothes tumble dryer |
| CN105239184A (en) * | 2015-10-23 | 2016-01-13 | 南京荣之盛生物科技有限公司 | Bacterial cellulose/graphene/ferroferric oxide composite film and preparation method thereof |
| CN106346531A (en) * | 2016-08-29 | 2017-01-25 | 贵州苗仁堂制药有限责任公司 | Slicing mechanism of hydrogel coating machine |
| CN217383642U (en) * | 2022-06-15 | 2022-09-06 | 焦作广瑞净水材料有限公司 | A cylinder drying device for polyaluminium chloride production |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107840988B (en) | Preparation method of nano-cellulose aerogel and heat-insulating material | |
| Jiang et al. | Assembling and redispersibility of rice straw nanocellulose: effect of tert-butanol | |
| CN105239184A (en) | Bacterial cellulose/graphene/ferroferric oxide composite film and preparation method thereof | |
| CN104497322B (en) | A kind of method that nano lignin is prepared using liquid-phase deposition technique | |
| CN104611995A (en) | Air filter paper and preparation method thereof | |
| WO2018054212A1 (en) | Graphene composite, preparation method therefor and use thereof, method for preparing nanocellulose and resultant nanocellulose, and high-performance graphene composite nanocellulose and preparation method therefor | |
| CN1948347A (en) | Drying method of bearing blue polysaccharide | |
| CN105802589A (en) | High-strength heat-conducting film and preparation method thereof | |
| Ching et al. | Ultrasound-assisted conversion of cellulose into hydrogel and functional carbon material | |
| CN107473217A (en) | A kind of preparation method and application of sunflower seed shell activated carbon | |
| CN105561955A (en) | Method for preparing hydrophobic cellulosic organic nano clay composite heavy-metal ion adsorbing ceramsites | |
| Dinesh et al. | Fabrication of transparent paper devices from nanocellulose fiber | |
| CN105070522B (en) | Graphene/titania nanotube prepares flexible bending folding thin-film electrode | |
| CN113996287A (en) | Method for preparing structured solid acid catalyst by coupling ultrasonic wave with microwave | |
| CN115350656A (en) | Drying cylinder heating and concentrating device and method for cellulose nanofibril gel and application | |
| Yang et al. | Preparation of nanocellulose and its applications in wound dressing: A review | |
| Wang et al. | In situ regulation of bacterial cellulose networks by starch from different sources or amylose/amylopectin content during fermentation | |
| Gu et al. | Study on preparation of lignin-containing nanocellulose from bamboo parenchyma | |
| CN111073029A (en) | Preparation method of cellulose nanofibril-based hydrophobic oleophilic recyclable aerogel | |
| CN108727638B (en) | High-strength graphene/graphene oxide film and production method and equipment thereof | |
| He et al. | Chitin nanocrystals scaffold by directional freezing for high-efficiency water purification | |
| CN110935325A (en) | Ultrahigh-flux nanofiber filtering membrane and preparation method thereof | |
| CN112876716B (en) | Method for rapidly preparing high-strength bacterial cellulose paper in large area | |
| Wang et al. | Review on the strategies for enhancing mechanical properties of bacterial cellulose | |
| CN115445225A (en) | Flat plate drying and concentrating device, method and application of nanofibrillar cellulose gel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |