Application of small spray dryer in alumina production

Application of small spray dryer in alumina production Drying habits of many varieties of alumina are drying methods such as box type, belt type or rotary drum These drying materials are mostly in static or semi dynamic drying process, with long drying time and high energy consumption After drying, the materials need to be crushed and graded, resulting in low product quality, high energy consumption, serious waste of products, and dust pollution The machine is full dynamic drying mode The high humidity material enters the dryer for a few seconds, and then pulverized and dried The drying, dispersing and grading process is completed The small spray dryer driers the heat medium and the dry material to exhibit instantaneous heat transfer and drying characteristics under the large surface area heat transfer state, which makes the energy utilization rate obviously improve, and the apparent appearance, fluidity and uniformity of the products are outstanding In the closed state, it can improve the product recovery rate and reduce the environmental pollution This drying method has obvious characteristics in the drying of various alumina products The hot air enters the mouth of the experimental spray dryer at the appropriate spouting velocity at the inlet and enters the mixing and drying chamber The material is strongly cut, collided and rubbed and is micronized, which strengthens the mass transfer and heat transfer At the bottom of the dryer, the larger and wetter particles are mechanically broken under the action of the agitator, and the particles with lower moisture content and smaller particle size are entrained and lifted by the rotating air flow, and further dried in the rising process Due to the rotating flow of gas-solid phase, the inertia of solid phase is larger than that of gas phase, and the relative velocity of solid-gas phase is larger, which strengthens the mass transfer and heat transfer between the two phases The drying process of a variety of alumina products, small spray drying machine first filter or centrifuge dehydration products, from the adjustable speed feeder into the experimental spray dryer, the feeding device has stable feeding and can overcome the stickiness of different materials, the heat source of the dryer can be directly or indirectly fired heater Fuel is natural gas, diesel and liquefied petroleum gas For example, coal-fired hot blast stove should be used in coal combustion to ensure stable coal temperature and tail gas to meet environmental requirements The setting of system stability is selected according to the physical properties of drying products Excessive temperature can cause surface sintering of individual materials, crystallization water precipitation and thermal color change After the drying and particle size grading process, the gas-solid separation is carried out by the rear gas capture system The selection of separation parameters depends on the particle size of the material For ultra-fine materials, it is advisable to limit the air speed into the bag filter to no more than 1 m / s to prevent the material from running away The experimental spray dryer has the following advantages: operation, dynamic, continuous, fast, uniform product quality, stable system operation, energy saving, consumption reduction and no pollution It will be widely used in drying many kinds of alumina and in light metal products