Spray Dryer The spray dryer is a dryer that processes solutions, suspensions or slurry materials. It is sprayed to make the material into droplets dispersed in the hot gas stream. The materials are in contact with the hot air in a cocurrent, countercurrent or mixed flow manner, so that the water evaporates quickly to achieve the drying purpose. By adopting this drying method, the chemical unit operation such as concentration or filtration can be omitted, and a granular product of 30-50up can be obtained, and the drying time is extremely short. The general drying time is 5-30s, which is suitable for the drying of materials which are easily decomposed in the process of high heat sensitive materials and liquid concentration, and the product has good fluidity and fast solubility. In the spray dryer, the gas-solid two-phase contact surface area is large, but the gas-solid two-phase lean ladder phase flows, so the volumetric heat transfer coefficient is small, generally 23-116, and the hot air temperature is 250-500 degrees Celsius in the cocurrent operation, countercurrent The operation is 200-300 degrees Celsius. Industrial-scale spray dryers typically have thermal efficiencies ranging from 40% to 50%. Foreign spray dryers with waste heat recovery can achieve a thermal efficiency of 70%. This equipment is only economical when it is larger than the production capacity of '100kg (water) / h.
There are three forms of spray methods used in industry:
1. Centrifugal atomizer. The rotation speed is generally 4000-20000r/min, and the Zui height is up to 50000r/min.
2. Pressure atomizer. The pump is used to pressurize the liquid to 10000000-200000000Pa and send it to the atomizer to spray the liquid into a mist.
3. Airflow atomizer. The feed liquid is sprayed into a mist by a nozzle using compressed air or superheated steam having a pressure of 2,000,000 to 5,000,000 Pa.
In China, pressure and centrifugal atomizers are used more, and small spray drying devices are also useful for airflow atomizers. The flow of the spray drying device is as follows: the feed liquid passes through the atomizer, and the spray mist is dispersed in the hot air flow. The air is sent to the air heater by the blower, then enters the spray drying tower and is dried in contact with the mist. The product part falls into the bottom of the tower, and part of it is sucked into the first-stage cyclone dust collector by the first-stage exhaust fan. After separation, the exhaust gas is vented. The product from the bottom of the tower and the product collected by the cyclone are taken out by a secondary blower and separated by a secondary cyclone.
The products of spray drying are fine particles. In order to meet the requirements of the Environmental Protection Law, it is not enough to use the cyclone to separate the products and purify the exhaust gas. It is generally necessary to use a bag filter to purify and combine the exhaust gases. The dust content is less than 50 gas (standard state), or the wet scrubber can reduce the dust content of the exhaust gas to 15-35 gas (standard state).
There are three forms of spray methods used in industry:
1. Centrifugal atomizer. The rotation speed is generally 4000-20000r/min, and the Zui height is up to 50000r/min.
2. Pressure atomizer. The pump is used to pressurize the liquid to 10000000-200000000Pa and send it to the atomizer to spray the liquid into a mist.
3. Airflow atomizer. The feed liquid is sprayed into a mist by a nozzle using compressed air or superheated steam having a pressure of 2,000,000 to 5,000,000 Pa.
In China, pressure and centrifugal atomizers are used more, and small spray drying devices are also useful for airflow atomizers. The flow of the spray drying device is as follows: the feed liquid passes through the atomizer, and the spray mist is dispersed in the hot air flow. The air is sent to the air heater by the blower, then enters the spray drying tower and is dried in contact with the mist. The product part falls into the bottom of the tower, and part of it is sucked into the first-stage cyclone dust collector by the first-stage exhaust fan. After separation, the exhaust gas is vented. The product from the bottom of the tower and the product collected by the cyclone are taken out by a secondary blower and separated by a secondary cyclone.
The products of spray drying are fine particles. In order to meet the requirements of the Environmental Protection Law, it is not enough to use the cyclone to separate the products and purify the exhaust gas. It is generally necessary to use a bag filter to purify and combine the exhaust gases. The dust content is less than 50 gas (standard state), or the wet scrubber can reduce the dust content of the exhaust gas to 15-35 gas (standard state).
Yunnan NBC Agricultural Development Co., Ltd deals in (heat pump air drying) Yunnan Plateau agricultural products. Including Flowers And Leaves, fruits, rhizomes, poultry meat, aquatic products and other drying products. All products are free of additives, agricultural residues and phosphorus and sulfur. It has obtained the national SC food safety production certification, and at the same time, it is produced according to the international standards, reaching the export level, and can be OEM.
Fruits,Dry Fruits,Dried Fruits,Free of Additives
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