Boiling dryer, also known as fluidized bed, has been used for more than 30 years. It is now more and more important in pharmaceutical, chemical, food, food and other aspects. However, the performance of different types of boiling dryers And the application is different. This paper starts with the basic idea of ​​boiling dryer, analyzes the difference between several types of boiling drying, and expounds the characteristics of boiling drying equipment, so that people can better use such equipment and make such equipment manufacture and application. More complete, more reliable and safer, and at the same time make such equipment better serve our industry.
1. The basic idea of ​​boiling and drying
1.1 The basic principle of boiling drying The definition of boiling drying: boiling drying, commonly known as fluidized drying, refers to the drying medium to dry the solid particles in a fluidized state.
The principle of boiling and drying: refers to the drying medium to dry the solid particles in the fluidized state. The basis of the material drying process is the boiling of the powder. At the same time, under the action of exhausting, the fine powder in the container is filtered through the collecting bag. The rear row is outdoors. During drying, due to gas-solid two-phase countercurrent contact, vigorous agitation. The solid particles are suspended in a drying medium and have a large contact surface area, which is excellent in heat transfer, mass transfer, volume dry strength, and thermal efficiency.
Because the boiling drying has better adaptability to various materials, it has smaller floor space, larger production capacity, higher thermal efficiency, easier operation control and less particle damage than other dryers. It is widely used at present, especially in the pharmaceutical industry. in.
1.2 boiling and drying characteristics
1.2.1 Because the contact area between the material and the drying medium is large, and the material is continuously stirred vigorously in the bed, the heat transfer effect is good and the heat capacity coefficient is large;
1.2.2 Due to the uniform temperature distribution in the fluidized bed, any local overheating of the product is avoided, so it is especially suitable for drying certain heat sensitive materials;
1.2.3 Continuous operation can be carried out in the same equipment, and intermittent operation can also be performed;
1.2.4 The residence time of the material in the dryer can be adjusted as needed, so the moisture content of the product is stable;
1.2.5 The drying device itself does not include mechanical moving parts, so the investment cost of the equipment is low and the maintenance workload is small.
1.3 Application range of boiling drying in the pharmaceutical industry Boiling drying can be widely used in the production of raw materials. The applicable varieties are: amoxicillin, ampicillin, acocillin, dihydrostreptomycin, kanamycin, ampicillin. Penicillin, penicillin, tetracycline, streptavidin, chloramphenicol, sulfathiazole, vitamin A, vitamin E, vitamin B12, aluminum oxychloride, aluminum sulfate, amylase, barium sulfate, calcium lactate, calcium pantothenate , hormones, L-lysine, niacin, protease, rutin derivatives, liver essence and so on.
2. The difference between boiling type and comparison with other equipment
2.1 Type difference of boiling and drying With the continuous development of application technology, the types and applications of boiling dryers are more and more, and the classification methods of equipment are also different. According to the materials to be dried, they can be divided into three categories: * is a granular material; the second is a paste material; and the third is a fluid material such as a suspension and a solution. According to the operating conditions, they can basically be divided into two categories: continuous and intermittent. According to the state of the structure, there are generally fluidized, stirred fluidized, and vibrational.
The boiling drying equipment produced by the drying equipment manufacturer is briefly introduced from the above three aspects. From the operating conditions: GFG series high-efficiency boiling dryer, FG series boiling dryer is intermittent, the granularity of the material to be dried has certain requirements, generally not less than 30 microns, not less than 4mm is appropriate. When several materials are mixed and dried, the specific gravity of each material should be close. The XF series box type boiling dryer and ZLG series vibrating fluidized bed dryer are continuous type, which can meet the requirements of continuous production.
2.2 Comparison with other equipment Because of the better adaptability of boiling drying to various materials, it is smaller than the hot air circulation oven, with small floor space, large production capacity, high thermal efficiency, and uniform humidity after drying. Compared with the airflow drying, the product can reach the desired moisture content by adjusting the length of time the material stays in the fluidized bed.
3. Brief description of the characteristics of several commonly used boiling drying equipments Due to the different material requirements and different requirements for finished products, different types of fluidized drying machines have emerged. The following several fluidized drying equipments combined with one company are used in the pharmaceutical industry. The characteristics, a brief description, can enable users to have a better understanding, and also make our company's products better applied and serve the pharmaceutical industry.
3.1 GFG series high efficiency boiling dryer GFG series high efficiency boiling dryer is suitable for drying mechanism screw extrusion granules,
Rocking granules, wet high-speed mixed granules; wet granules and powdery materials in the fields of medicine, food, feed, chemical, etc.; large granules, small pieces, viscous granules; konjac, polyacrylamide, etc. Material.
3.2 FG series vertical boiling dryer FG vertical boiling dryer is mainly used for drying powder or granular materials in the pharmaceutical, food, chemical and other industries.
Features of FG vertical boiling dryer:
1 fluidized drying, fast heat and mass transfer;
2 operating under closed negative pressure, no dust flying;
3 Anti-static filter material is used for safe operation;
4 equipment has no dead angle, clean thoroughly, no cross-contamination;
5 meet the requirements of GMP regulations.
3.3 XF series box type boiling dryer XF series box type boiling dryer is composed of air filter, bubbling bed main air cyclone, bag filter, high pressure centrifugal fan and operation console. Due to the different nature of the dry materials, when the dust removal equipment is matched, it can be carried out as needed. At the same time, the cyclone separator can be selected and the dust collector can be disposed. You can also choose one of them. In general, a material with a large specific gravity only needs to select a cyclone separator. The lighter weight material needs to be equipped with a bag filter and the spare pneumatic feeding device is selected.
XF series box type boiling dryer is mainly used for drying of medicines, chemical raw materials, food, grain processing and feed. Such as: raw material medicine, tablet granules, Chinese medicine granules, health food, beverage granules, corn germ, feed, plastic resin, citric acid and other granular materials dry and dehumidified. The suitable material particle size is generally 0.1-6mm, and the good particle size is 0.5-3mm.
XF series box boiling dryer works:
The clean hot air is distributed into the bed through the valve plate, and the wet material entering from the feeder is boiled by the hot air. Due to the extensive contact between hot air and materials, the process of heat and mass transfer is increased, so it can be dried in a short time. Entering from one end of the bed, boiling and drying after tens of seconds to several minutes, automatically flows out from the other end of the bed. This equipment is generally operated under negative pressure. Features of XF series horizontal boiling dryer: It can be automated production and is a continuous drying equipment. The drying speed is fast and the temperature is low, which can ensure the product quality and meet the GMP requirements of pharmaceutical production. Steam, electricity and hot air furnace can be used together.
3.4 ZLG series vibrating fluidized bed dryer When the granular material is dried in a common fluidized bed dryer, the material particles should be uniform and have certain specifications, otherwise the groove flow and the stagnation zone will be formed. When the particle size distribution is wide, The entrainment is serious, the agglomeration is easy when the humidity is large, and the particle residence time distribution range is large due to the back mixing of the particles, and the moisture content of the particles is uneven, thereby limiting the use range of the ordinary fluidized bed dryer. In order to overcome its shortcomings, a lot of research has been done abroad to improve the performance of fluidized bed dryers. Especially in today's energy shortage, the mass transfer heat transfer process is strengthened, energy conservation and quality are improved, and the fluidized bed dryer has wide adaptability and economic rationality. The vibrating fluidized bed dryer has great significance. The vibrating fluidized bed dryer has the advantages of advanced design, reliable quality, wide application range, remarkable energy conservation and the ability to dry materials that are difficult to dry on other dryers. Therefore, the vibrating fluidized bed dryer is widely welcomed by various industries.
3.4.1 Working principle of ZLG series vibrating fluidized bed:
The vibrating fluidized bed dryer (see the right figure) is generated by the vibration motor to excite the machine, and the material jumps forward under the action of the exciting force in a given direction, while the vibrating fluidized bed dries the hot air input at the bottom of the machine. The material is in a fluidized state, and the material particles are in full contact with the hot air to achieve the desired drying effect. The material enters from the mouth of the vibrating fluidized bed dryer. The material on the vibrating bed of the vibrating fluidized bed dryer is in orthogonal contact with the hot air passing through the lower part of the vibrating trough. The humid air is led out by the induced air, and the dry material is discharged from the discharge port. discharge.
3.4.2 Scope of application:
ZLG series vibrating fluidized bed dryer is suitable for drying materials that are not easy to flow (such as particles are too thick or too fine, easy to bond or agglomerate, etc.) and special requirements (such as requiring crystal integrity, crystal brightness, etc.) . At present, this equipment has been successfully used for the drying of citric acid, monosodium glutamate, borax, ammonium sulfate, compound fertilizer, radish, soybean meal, distiller's grains, seeds, slag, sugar and other materials.
3.4.3 Features:
3.4.3.1 Vibrating fluidized bed dryer is driven by vibration motor, which has stable operation, low noise, long service life and convenient maintenance.
3.4.3.2 Vibrating fluidized bed dryer vibration makes the material easy to reach the fluidized state and increases the effective heat transfer coefficient, so the thermal efficiency is high. The bed temperature distribution is uniform and there is no local overheating. Uniform fluidization, no dead angles and blow through. Vibration plays a role in transportation and is also conducive to energy conservation. It can save 30-60% energy compared to general drying equipment.
3.4.3.3 The thickness of the material layer and the moving speed and amplitude of the machine can be adjusted steplessly. The adjustability is good and the speed is wide.
3.4.3.4 The surface damage of the material is small, it can be used for the drying of fragile materials, and the material particles can be used when irregular, without affecting the effect.
3.4.3.5 The vibrating fluidized bed dryer adopts a fully enclosed structure, which effectively prevents cross-contamination of materials from the outside, cleans the environment and improves working conditions.
3.4.3.6 Vibration promotes fluidization, reducing air demand and reducing particle entrainment rate;
3.4.3.7 By adjusting the frequency and amplitude of the vibration, it is easy to control the residence time distribution of the powder pellets to achieve continuous operation;
4. Summary This article starts with the basic concept of boiling and drying, so that people have a better understanding of different types of boiling drying. At the same time, the characteristics of the boiling drying equipment developed in recent years are comprehensively described. The boiling drying technology has its own particularity. Different products have different drying processes and powder rules. There is no single spray drying machine that can be applied to various requirements. Boiling and drying is still regarded as a skill, and the experiment is the basis of correct modeling. The company has experimental equipment for the user to carry out the technical test of the material, and also can complete the turnkey project of such equipment. The purpose of this article is to provide better service for the industrialization of the spray drying series of equipment, and also look forward to the introduction of newer and better boiling drying equipment. | |
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