Analysis on the application of eight kinds of drying equipment in the chemical and pharmaceutical industry

  Drying equipment is very 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 on the application of eight kinds of drying equipment in the chemical and pharmaceutical industry.

  (1) Belt dryer

  Belt dryer is composed of several independent unit sections. Each unit section includes a circulating fan, a heating device, a separate or public fresh air intake system and a tail gas exhaust system. The operating parameters of the quantity of drying medium, temperature, humidity and exhaust gas circulation can be independently controlled to ensure the reliability of the dryer and the optimization of operating conditions. The belt dryer is flexible in operation, wet material is fed, and the drying process is carried out in a completely sealed box. The working conditions are good and the leakage of dust is avoided. It is used for drying flakes, strips and granular materials with good air permeability. It is especially suitable for materials with high water content and high temperature of materials such as dehydrated vegetables and Chinese herbal medicine pieces.

  (2) Roller scraper dryer

  Drum Scraper Dryer is a continuous operation device that uses a rotating cylinder to dry the liquid phase material or ribbon material attached to the outer wall of the cylinder by means of heat conduction. The material liquid to be dried flows from the high tank into the material receiving tank of the drum dryer. The drying drum is driven by the transmission device and rotates at the specified speed. The material is formed by a film cloth device, which forms a material film on the wall of the drum. The heating medium is continuously fed into the cylinder to heat the cylinder, and the moisture of the material film is vaporized by heat transfer from the cylinder wall, and then the material that meets the drying requirements is scraped off by a scraper, and then conveyed to the storage tank through a screw for packaging. The moisture removed by evaporation, depending on its nature, can be introduced into the corresponding treatment device through a closed cover; generally it is water vapor, which can be directly discharged into the atmosphere from the exhaust pipe on the top of the cover. This machine is mainly used to process liquid materials. It can be heated and dried by steam, hot water or hot oil, and cold water can be used for cooling and flake formation. Feeding methods such as immersion type, spray type, and grinding auxiliary type can be adopted according to different material properties and process requirements.

  (3) Hollow paddle dryer (blade dryer)

  Hollow blade dryer, also known as blade dryer, is mainly composed of a W-shaped shell with a jacket, two hollow blade shafts and a transmission device. Hollow blades are arranged on the shaft, and the end of the shaft is equipped with a rotary joint into which the heat medium is introduced. The heat required to dry the moisture is conducted to the material by the inner wall of the W-shaped groove with a jacket and the wall of the hollow blade. During the drying process of the material, the hollow shaft with hollow blades heats the material and stirs the material at the same time, so as to update the heating surface. It is a continuous conduction heating dryer. The heating medium is steam, hot water or heat transfer oil. The heating medium is passed 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.    This machine is suitable for processing various paste, granular, powder and other thermally stable materials. Under special conditions, it can also dry heat-sensitive materials and recover solvents during the drying process. Commonly used for drying or cooling materials such as carbon black, light calcium carbonate, titanium dioxide, barium carbonate, nitriuric acid, gypsum, clay, manganese dioxide, nylon and polyester chips, polyethylene, polypropylene (recovered solvent), etc.

  (4)Vacuum rake dryer

The drying material is added from the top and middle of the shell of the vacuum rake dryer. Under the stirring of the continuously rotating rake teeth, when the material contacts the shell wall, the surface is constantly updated, and the dried material is subjected to steam (or hot water, heat transfer oil). ) Indirect heating, but the material moisture is vaporized, and the vaporized moisture is pumped away by the vacuum pump in time. The material to be dried is indirectly heated by the heat carrier to vaporize the moisture in the material, and the vaporized moisture is discharged in time by the vacuum pump.

  Due to the relatively high operating vacuum, generally within the range of 400-700mmHg, the water vapor pressure on the surface of the dried material is much greater than the water vapor pressure in the evaporation space in the dryer shell. Thereby it is beneficial to the discharge of the internal moisture and surface moisture of the material to be dried, and it is beneficial to the movement of water molecules of the material to be dried to achieve the purpose of drying. The vacuum rake dryer is suitable for heat-sensitive materials that are easily oxidized at high temperatures or materials that are easy to harden during drying, as well as materials whose steam exhausted during drying must be recovered. Typical drying materials include sodium propylene sulfonate, CMC, phthalocyanine blue, dye intermediates, carboxymethyl starch, maltodextrin, anthraquinone sulfonic acid, etc.

  (5) Double cone rotary vacuum dryer

  The body of the double-cone rotary vacuum dryer is slightly olive-shaped, with covers at both ends, and two shafts in the middle to support the body. The body has a jacket for heating, and the body can be rotated during drying, so that the material and the wall are frequently replaced and contacted, which overcomes the shortcomings of low thermal efficiency due to the low heat efficiency of the material in the vacuum oven that mainly depends on the heating cylinder. Rotary vacuum dryers have been widely used in fine chemicals, medicine, etc., 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 and drying of powdery, granular and fibrous materials in the pharmaceutical, chemical, and food industries, and materials that require low-temperature drying (such as biochemical products, etc.). It is more suitable for easy oxidation, volatile, and heat sensitivity. Drying of strongly irritating, toxic materials and materials that are not allowed to destroy crystals.

  (6) spray dryer

  Spray drying is a more 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 materials. Therefore, when the particle size distribution, residual moisture content, bulk density and particle shape of the finished product must meet the standard of ^, spray drying is a very ideal process.

  (7) Vacuum oven

  Because the evaporation temperature of the volatiles contained in the material evaporation can be reduced after the pressure is reduced, it is suitable for the drying of various heat-sensitive and easy-to-oxidize materials. This device is often a cylinder or other shell that can withstand vacuum operation, and it uses electric heating or hot water, and heat transfer oil to supply heat through a heating plate or heating tube. It is suitable for small batch intermittent production.

  Oven is a general-purpose drying equipment with a wide range of applications. It is a tray-type intermittent drying equipment and is used in pharmacy, chemical industry, and food. Heat curing, drying and dehydration of materials and products in light industry, heavy industry and other industries. Such as raw materials, crude drugs, Chinese herbal medicines, extracts, powders, granules, granules, water pills, packaging bottles, pigments and dyes, dehydrated vegetables, dried fruits, sausages, plastic resins, electrical components, baking paint, etc.

  (8) Spin flash dryer

The material to be dried enters the drying chamber through the screw feeder, and is crushed by the stirring blade at the lower part of the dryer. The crushed material is fully in contact with the hot air, and flows upward and dried under the dual action of the stirring blade and the air distributor, and passes through the classifier. The materials with qualified particle size and humidity are screened and turned down and dried until they are qualified.

  Product features: fast drying speed. The dryer can be completed in 1-10 seconds; the residence time of the material can be adjusted. It can be adjusted between 1-500s and is suitable for the drying of heat-sensitive materials; a variety of feeding devices are available, and the feeding is continuous and stable without bridging; the circumferential air velocity in the drying chamber is high, and the material residence time is short, which effectively prevents materials Adhesive wall and heat-sensitive materials deteriorate; the drying chamber is equipped with a grading ring and swirling sheet, the fineness of the material and the final moisture can be adjusted and controlled; the drying strength is high.