Project Overview:

Lignite has a high chemical reactivity, is prone to weathering in air, and is difficult to store and transport. During direct combustion, it causes significant air pollution. Lignite has become one of the main types of coal used in China; however, due to its low degree of coalification, it cannot burn completely, resulting in the generation of large amounts of black smoke. If not processed through drying and refinement, the extensive use of inferior lignite will lead to severe air pollution issues.

Lignite – The Primary Coal Used in China

Lignite is the mineral coal with the lowest degree of coalification, between peat and bituminous coal. Appearance and Color: Lignite typically appears in brownish-black or grayish-black, lacks luster, and its texture varies by type. There are loose, soft, soil-like lignites, as well as denser, harder dark-colored varieties. Lignite has high chemical reactivity, is prone to weathering in the air, and is difficult to store and transport. To improve the combustion performance of lignite and reduce environmental pollution, it is necessary to dry the coal to reduce its moisture content, thereby increasing its calorific value and combustion efficiency.

Lignite drying involves safety hazards, dust pollution, material combustion issues, and many other technical challenges. Through research into the characteristics of lignite materials, Hangzhou Qianjiang Drying Equipment has innovatively developed a new type of superheated steam fluidized bed dryer specifically designed for lignite. This is a multifunctional horizontal fluidized bed dryer suitable for drying both powders and granular materials. The development represents a breakthrough in addressing the difficulties encountered by conventional lignite drying equipment, allowing for precise control over the moisture content and properties of the product. After drying, lignite can be transformed from brown coal to hard coal, significantly improving its calorific value, storage, and transportation performance, thus meeting the quality standards for commercial thermal coal.

Lignite-Specific Superheated Steam Fluidized Bed Dryer – Working Principle

The superheated steam closed-loop horizontal fluidized bed dryer is a continuous-type drying equipment. It operates in a sealed environment, with superheated steam as the drying medium. After filtration, dehumidification (optional), and heating, the steam enters the dryer. The inlet air temperature can be precisely controlled to ensure the stability and efficiency of the lignite drying process. This equipment is also suitable for drying materials that can be processed by any horizontal fluidized bed.

Wet materials are evenly fed into the first chamber of the fluidized bed via a feeder. This chamber is equipped with a rake dispersing device to promote full contact between the material and the hot air. After passing through the first chamber, the semi-dried product is loosely distributed, which helps maintain the fluidization quality throughout the drying process and ultimately achieves the required dryness of the product.