Abstract:Drying equipment is widely used in industrial testing. Many fields require the use of drying equipment. Similarly, drying equipment also plays an important role in the pharmaceutical industry. Today, the author will bring the application of eight kind…
Drying equipment is widely used in industrial testing. Many fields require the use of drying equipment. Similarly, drying equipment also plays an important role in the pharmaceutical industry. Today, the author will bring the application of eight kinds of drying equipment in the chemical and pharmaceutical industry. Analysis of the application of eight kinds of drying equipment in the chemical and pharmaceutical industry.
(1) Belt dryer
The belt dryer is composed of several independent unit sections. Each unit segment includes a circulating fan, heating unit, separate or shared fresh air intake system and exhaust system. The operating parameters of the amount of drying medium, temperature, humidity and exhaust gas circulation can be independently controlled, so as to ensure the reliability of the dryer and optimize the operating conditions. With a dryer, the operation is flexible, the wet material is fed, and the drying process is performed in a completely sealed box. The working conditions are better, and the leakage of dust is avoided. It is used for drying sheet, strip and granular materials with good air permeability. It is especially suitable for materials with high water content such as dehydrated vegetables and Chinese medicine decoction pieces, which do not allow high material temperature.
(2) Drum scraper dryer
Roller scraper dryer is a continuous operation equipment for drying liquid-phase materials or belt-shaped materials attached to the outer wall of the cylinder through a rotating cylinder in a heat conduction manner. The material liquid to be dried flows from the high-level tank into the receiving tank of the drum dryer. Driven by the transmission device, the drying drum rotates at a specified speed. The material is formed by a film distribution device to form a material film on the wall of the drum. A heating medium is continuously introduced into the cylinder, the cylinder is heated, and the moisture of the material film is vaporized by heat transfer from the cylinder wall, and then the materials that meet the drying requirements are scraped off by a scraper, and then conveyed to the storage tank by a spiral for packaging. Moisture removed by evaporation, depending on its nature, can be introduced into the corresponding processing device through a closed cover; generally, water vapor can be directly released into the atmosphere through the exhaust pipe on the top of the cover. This machine is mainly used for processing liquid materials. It can be heated and dried by steam, hot water or hot oil, and cooled by cold water. According to different material properties and process requirements, immersion, spray, milling and auxiliary feeding methods can be used.
(3) Hollow paddle dryer (blade dryer)
Hollow blade dryer is also called blade dryer, which is mainly composed of W-shaped shell with jacket, two hollow blade shafts and transmission device. Hollow blades are arranged on the shaft, and a rotary joint for introducing a heat medium is installed at the shaft end. The heat required to dry the moisture is conducted to the material by the inner wall of the jacketed W-shaped groove and the hollow blade wall. During the drying of the material, the hollow shaft with hollow blades stirs the material while heating the material, thereby renewing the heating surface. It is a continuous conduction heating dryer. The heating medium is steam, hot water or thermal oil. The heating medium is introduced into the shell jacket and the two hollow blade shafts, and the materials are heated and dried by conduction heating. The hollow blade shaft structure of different materials is different.机 The machine is suitable for processing various paste-like, granular, powdery materials with good thermal stability. It can also dry heat-sensitive materials under special conditions and recover solvents during the drying process. Commonly used in the drying or cooling of carbon black, light calcium carbonate, titanium dioxide, barium carbonate, nitrile uric acid, gypsum, clay, manganese dioxide, nylon and polyester chips, polyethylene, polypropylene (recycled solvent) and other materials.
(4) Vacuum harrow dryer
The drying material is added from the middle of the vacuum rake dryer. Under the stirring of the continuously rotating rake teeth, the surface is continuously updated when the material contacts the housing wall, and the dried material is subject to steam (or hot water, thermal oil). ) Indirect heating, but the material moisture is vaporized, and the vaporized moisture is pumped away by the vacuum pump in time. The dried material is indirectly heated by the heat carrier, so that the water in the material is vaporized, and the vaporized water is discharged by the vacuum pump in time.
Due to the high operating vacuum, generally within the range of 400-700mmHg, the water vapor pressure on the surface of the material to be dried is much greater than the water vapor pressure in the evaporation space in the dryer casing. Therefore, it is beneficial for the drainage of the internal moisture and surface moisture of the material to be dried, and for the movement of water molecules of the material to be dried to achieve the purpose of drying. The vacuum harrow dryer is suitable for materials that are thermally sensitive, easily oxidized at high temperatures, or materials that tend to compact during drying, and materials that must be recovered from the steam discharged during drying. Typical dry materials are sodium propylene sulfonate, CMC, phthalocyanine blue, dye intermediates, carboxymethyl starch, maltodextrin, and anthraquinone sulfonic acid.
5 (5) Double cone rotary vacuum dryer
The double cone rotary vacuum dryer is slightly olive-shaped, with two ends covered, and two shafts in the middle to support the body. The device body has a jacket for heating, and the device body can be rotated during drying, so that the material and the device wall are often replaced and contacted, which overcomes the shortcomings of the material in the vacuum oven which mainly relies on the conduction of the heating cylinder and the thermal efficiency is low. Rotary vacuum dryers have been widely used in fine chemicals and medicine, and are not suitable for materials with high viscosity or strong adhesion during the rotation process. This equipment is mainly used for the concentration, mixing, drying and low temperature drying of powdery, granular and fibrous materials in the pharmaceutical, chemical, food and other industries (such as biochemical products). It is more suitable for easy oxidation, volatility and heat sensitivity. Drying of strongly irritating, toxic materials and materials that do not allow crystal damage.
(6) Spray dryer
Spray drying is a widely used process in the liquid process forming and drying industry. It is especially suitable for generating powdery and granular solid products from solutions, emulsions, suspensions and pasty liquid raw materials. Therefore, when the particle size distribution, residual moisture content, bulk density and particle shape of the finished product must meet high standards, spray drying is a better process.
(7) Vacuum oven
Because of the reduced pressure, the evaporation temperature of the volatiles contained in the material can be reduced, which is suitable for the drying of various heat-sensitive and easily oxidizable materials. This device is usually a cylinder or other housing that can be operated under vacuum. The electric heating or hot water and heat-conducting oil are used to supply heat through a heating plate or a heating tube, which is suitable for batch production in small batches.
Oven is a general-purpose drying equipment with a wide application area. It belongs to a disc-type intermittent drying equipment and is used in pharmaceutical, chemical, and food. Heat curing, drying and dehydration of materials and products in industries such as light industry and heavy industry. Such as raw materials, crude drugs, Chinese medicine pieces, extracts, powders, granules, granules, water pills, packaging bottles, pigments and dyes, dehydrated vegetables, dried fruits, sausages, plastic resins, electrical components, baking paint, etc.
(8) Rotary flash dryer
The dried material enters the drying chamber through the screw input device, and is pulverized by the stirring blade at the lower part of the dryer. The pulverized material is in full contact with the hot air, flows upward and is dried under the dual action of the stirring blade and the air flow distributor. The materials with qualified particle size and humidity will be dried downward until they pass.
Features: fast drying speed. The dryer can be completed in 1-10 seconds; the residence time of the material can be adjusted. Adjustable between 1-500s, suitable for drying of heat-sensitive materials; a variety of feeding devices are available for continuous and stable feeding without bridging; high ambient air velocity in the drying chamber, short material residence time, and effective prevention of materials Deterioration of sticky walls and heat-sensitive materials; the drying chamber is equipped with grading rings and swirl plates, the fineness and final moisture of the materials can be adjusted and controlled; and the drying strength is high.