subject: The Latest Technoloy Used In Belt Dryer [print this page] The mesh belt dryer of the present invention includes at least one substantially vertically orientated elongate container having an upper inlet, for receiving the charge of moisture containing particulate material, and a lower outlet for discharging the particulate material after drying. The inlet and outlet are typically open to allow for substantially continuous throughput of the particulate material.
The mesh belt dryer of the invention also includes at least one substantially vertical gas permeable wall through which a drying gas can pass to contact, and dry, the particulate material. Preferably, the dryer includes at least two opposed, substantially vertical permeable walls. Depending on the nature of the particulate material, the walls may advantageously be at a slight angle to the vertical such that the cross-sectional interior area of the container increases from its top to its bottom. Such an arrangement is preferred where the particulate material does not shrink upon drying because it minimises or prevents "bridging" of the material and consequential obstruction of material flow. However, angled vertical walls may not be necessary where the particulate material comprises low rank carbonaceous material, because such material shrinks upon drying and the bridging effect is minimised.
The at least one gas permeable wall preferably includes a plurality of openings therethrough. The openings are preferably of a size such that the drying gas is able to pass into and out of the container but such that the particulate material cannot pass through the openings. The following discussion will focus on the use of air as the drying gas, however, it is to be understood that other suitable gases (for example, CO2, N2, etc. which may be derived from combustion waste gases) could instead be used. Preferably the drying gas is either directly derived from another industrial process that produces suitable gas or is recycled from earlier use in the mesh belt dryer or from use in another section of the drying plant. If using recycled drying gas it is preferred to incorporate a desiccator or refrigerator within the gas flow after exit from the air outlet to de-humidify the gas. This is also a convenient way of recovering water that may then be put to another use. In the case where the drying gas is heated above ambient temperature this will preferably be achieved using waste heat from another industrial process.
