DRY MIXTURES

[:ru]Сизиков С. А.[:en]Sizikov S. A.[:] [:ru]генеральный директор ЗАО НИПКБ «Стройтехника»[:en]general Director of CJSC Research and development bureau «Stroytechnika»[:]

[:ru]Вяткин Г. М.[:en]Vyatkin G. M.[:] [:ru]заместитель генерального директора ЗАО НИПКБ «Стройтехника»[:en]deputy General Director of CJSC Research and development bureau «Stroytechnika»[:]

Alitinform №5 (06) 2008 г. 68-78 p.

Abstract

Drying of bulk materials is the most common process in almost all industries.

Dryers are used to obtain product with low residual moisture. The dryers’ operation is based on moisture removal from the material due to water phase transformation under heat. This type of drying called ‘heat drying’ is most widely used in industrial production. Basic methods of heat transfer to dehydrated material are: conductive (heat transfer from hot surface), convective (heat transfer by gaseous medium), radiant-heat drying (radiant heat exchange), dielectric (placing wet material in the high radio frequency electromagnetic field), as well as cold or sublimation drying. In large-tonnage production with capacity of 1 up to 500 tons of dried bulk per hour, the most commonly used are continuous convective dryers due to their relatively simple design and efficiency as compared to the dryers based on other methods of drying. Convective dryers for bulk (granular) materials vary in construction as follows: tower dryers, air tube dryers, rotary dryers, flash dryers, fluidized-bed dryers and vibrofluidized-bed dryers. Each of the above mentioned dryers has certain advantages and disadvantages and appropriate application area. In order to make a correct choice of convective dryer, brief and comprehensible analysis of convective bulk dryers’ efficiency is provided below. This integrated assessment of dryers’ effectiveness includes costs related to fuel consumption (dryer performance), electric power consumed to transit material and gaseous medium, capital expenditures on the dryer and dust-cleaning system, overall dimensions and amount of metal required to build the equipment.