Spray dryer is a form with rapid development and wide application in drying field, which is suitable for liquid raw materials such as solution, emulsion and pumpable suspension to generate powder, granular or block solid products. The different drying characteristics of dry materials, such as thermal sensitivity, viscosity, and flowability, as well as the different quality requirements of product particle size, particle size distribution, residual water content, bulk density, particle shape, etc., determine the use of different atomizers, airflow movement modes, and structural forms of drying rooms.
The slurry after ball milling is further stirred evenly and heated to above 35 ℃ in the mixing tank. Then, pressure is applied to the mixing tank, and under the action of pressure, the slurry is sent to the atomizer. After atomization by the atomizer, it is sprayed into the tower from the lower part of the tower. The N2 heated by the oil and gas heat exchanger is sent by the blower to the gas distributor at the top of the tower. After passing through the gas distributor, N2 enters the tower uniformly and in a whirlwind shape, drying and granulating the atomized slurry. After the material particles come into contact with hot gas, the liquid on their surface quickly evaporates, while the internal gas migrates to the surface during the subsequent drying process and is carried away by the hot gas. The dried material particles fall to the bottom of the tower and are recovered through a pair of disc valves in a gap type.
The gas after drying the slurry contains vaporized hexane and a small amount of small dust. This gas is first sent to the cyclone separator by the pressure fan for preliminary separation of the dust, and then sent to the condensate washing tower. In the rinsing tower, the gas is thoroughly washed, and the hexane gas contained in the gas is condensed and collected at the bottom of the rinsing tower. The washed gas is then sent to the oil gas heat exchanger for heating and reuse. During operation, the system maintains a slightly positive pressure state and is automatically controlled by an air supply valve and an exhaust valve. Avoiding the drawbacks of hot air eddy currents and axial flow, a hot air rectification chamber is installed. At the blowing outlet of the rectification chamber, a honeycomb shaped fixed blade similar to a propeller turbine guide impeller is installed. Hot air flows out from the radius direction of the fixed blade, further changing the direction of the hot air and blowing towards the drying tower. In this way, the fixed blades convert the hot air from the vortex into the axial supply of the drying tower, achieving the purpose of rectification, and the effect is very obvious in solving the problem of product adhesion inside the drying tower. And after rectification, it prevents the hot air from rotating, so that when the fog drops, it is evenly heated, and the thermal change of the finished product can be maintained within a small limit, thus improving the quality of the finished product.
The spray dryer is a thermal process that enables liquid materials to be atomized into fine atomized droplets through nozzles, and then contact with hot media in the drying tower to dry into powder. The feed can be a solution, suspension, or paste, and atomization can be achieved through rotary atomizers, pressure atomizers, and airflow atomizers. The operating conditions and design of drying equipment can be selected based on the required drying characteristics of the product and the specifications of the powder particles. The spray dryer spray, drying and collection system is made of transparent high-quality high borosilicate heat-resistant glass material, so that the drying process can be carried out in a pollution-free environment. Equipped with an imported oil-free air compressor, the particle size of the powder spray follows a normal distribution, with excellent fluidity and very low noise, less than 60dB. The atomization structure of two fluid spray, the whole machine is made of high-quality stainless steel materials, and the design is compact without auxiliary equipment. Equipped with a nozzle cleaner (needle pass), it will automatically clear when the nozzle is blocked, and the frequency of needle pass can be automatically adjusted.
