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

Drying equipment is widely used in industry. In many fields, the use of drying equipment is required. 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 section includes a circulation fan, heating device, separate or common fresh air intake system and exhaust gas exhaust system. The operating parameters of the amount of drying medium, temperature, humidity and exhaust gas circulation can be independently controlled to ensure the reliability of the operation of the dryer and the optimization of operating conditions. The belt dryer is flexible in operation, the 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 suitable for drying sheets, strips and granules with good air permeability. It is especially suitable for materials with high water content, such as dehydrated vegetables, Chinese herbal medicines, and high temperature.

  (2) Roller scraper dryer

  Roller scraper dryer is a continuous operation equipment that uses the rotating cylinder to dry the liquid material or band material attached to the outer wall of the cylinder in the form of heat conduction. The material liquid to be dried flows into the receiving tank of the drum dryer from the high-level tank. Driven by the transmission device, the drying drum rotates at the specified speed. The material is formed by the film distribution device to form a film on the wall of the drum. The heating medium is continuously fed into the cylinder to heat the cylinder body, the moisture of the material film is vaporized by the heat transfer of the cylinder wall, and then the material that meets the drying requirements is scraped off by the scraper, and then conveyed into the storage tank through the 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 released into the atmosphere through the exhaust pipe on the top of the cover. This machine is mainly used to process liquid materials. It can be heated by steam, hot water or hot oil to dry, and can also be cooled by cold water. According to different material properties and process requirements, immersion type, spray type, grinding auxiliary type and other feeding methods can be used.

  (3) Hollow blade dryer (blade dryer)

  Hollow blade dryer, also known as blade dryer, is mainly composed of a W-shaped shell with jacket, two hollow blade shafts and a transmission device. Hollow blades are arranged on the shaft, and a rotary joint for introducing heat medium is installed at the shaft end. The heat required for drying 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 process of the material, the hollow shaft with hollow blades stirs the material while heating the material, thereby updating the heating surface. It is a continuous conduction heating dryer. The heating medium is steam, hot water or thermal oil. The heating medium is passed into the casing jacket and the two hollow blade shafts, and the materials are heated and dried by conduction heating, and the structure of the hollow blade shafts of different materials is different.

  The machine is suitable for processing various pastes, granules, powders and other materials with good thermal stability. Under special conditions, it can also dry heat-sensitive materials and recover solvents during the drying process. Commonly used for drying or cooling carbon black, light calcium carbonate, titanium dioxide, barium carbonate, nitrile uric acid, gypsum, clay, manganese dioxide, nylon and polyester chips, polyethylene, polypropylene (recovered solvent) and other materials.

  (4) Vacuum rake dryer

The dry materials are added from the middle of the shell of the vacuum rake dryer. Under the stirring of the continuously rotating rake teeth, when the materials contact the shell wall, the surface is constantly updated, and the dried materials are subject to steam (or hot water, thermal oil) ) Indirect heating, but the material moisture vaporizes, the vaporized moisture is pumped away in time by the vacuum pump. The dried material is indirectly heated by the heat carrier, so that the moisture in the material is vaporized, and the vaporized moisture is discharged in time by the vacuum pump.

   Due to the high degree of vacuum operation, generally in 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 housing. Therefore, it is beneficial to the discharge of the internal moisture and surface moisture of the dried material, and to the movement of the water molecules of the dried material, so as to achieve the purpose of drying. The vacuum rake dryer is suitable for materials that are sensitive to heat, easily oxidized at high temperature or materials that are easy to harden 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, anthraquinone sulfonic acid, etc.

  (5) Double cone rotary vacuum dryer

   The double cone rotary vacuum dryer body 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 of the container are frequently replaced and contacted, which overcomes the disadvantage that the material in the vacuum oven mainly depends on the conduction of the heating cylinder and the thermal efficiency is low. 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 rotation. This equipment is mainly used for the concentration, mixing, drying of powdery, granular and fibrous materials in the pharmaceutical, chemical, food and other industries, and materials that require low temperature drying (such as biochemical products), and is more suitable for easy oxidation, volatility, and heat sensitivity Strong irritation, toxic materials and materials that do not allow crystals to dry.

  (6) spray dryer

   Spray drying is a widely used process in the liquid process forming and drying industries. It is suitable for producing 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 accurate standards, spray drying is an ideal process.

  (7) Vacuum oven

  After the decompression, the evaporation temperature of the volatiles contained in the material evaporation can be reduced, which is suitable for the drying of various heat-sensitive and easily oxidized materials. This device is often a cylinder or other housing that can handle vacuum operation. It is heated by electric heating or hot water and heat conduction oil 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 application area. It is a tray-type intermittent drying equipment and is used in pharmaceuticals, chemicals and food. Heating and solidification, 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 melons and fruits, sausages, plastic resins, electrical components, baking paint, etc.

  (8) Rotary flash dryer

The dried material enters the drying chamber through the screw feeder, and is crushed by the stirring paddle at the lower part of the dryer. The crushed material and hot air are fully contacted, and flow upward and dry under the dual action of the stirring paddle and the airflow distributor. The materials with qualified particle size and humidity are 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. Adjustable between 1-500s, suitable for the drying of heat-sensitive materials; a variety of feeding devices are available, the feeding is continuous and stable, and no bridging phenomenon will occur; the peripheral gas velocity in the drying chamber is high, the material stays short, and the material is effectively prevented The sticky wall and heat-sensitive materials are deteriorated; the drying chamber is equipped with a grading ring and a cyclone, the fineness of the material and the final moisture can be adjusted and controlled; the drying strength is high.