Fluidization has its beginning in the forties of the 20th century.However production activities using fluidization technology

such as washing of rice and winnowing of grain

have existed for a long time even before the word "fluidization" appeared.That is

human activities involving fluidization began well before the 16th century.Coal gasification and catalytic cracking of petroleum are representatives of recent industrial applications of fluidization.Theories were proposed by J.F.Davidson on bubbling fluidization and by Mooson Kwauk on generalized fluidization and on bubbleless gas-solids contact.Current theoretical studies of fluidization are focused on quantitative prediction and optimum control

involving multi-scale heterogeneous structures consisting of gas bubbles

particle agglomerates

and liquid drops distributed in size and in concentration; modeling for predicting relationships between heterogeneous structure and transport of momentum

heat

mass

as well as chemical reactions; and computer simulation for the prediction and optimization of process operation and scale-up for fluidization technologies in the process industries

such as chemicals

metallurgy

energy

new materials and environment

particularly in China due to its fast development of economy.Computer simulation involving the two-fluid model combined with the structure-effect model of fluidization is currently a highly efficient method for solving problems of optimization and scale-up of fluidized bed reactors.However this method still faces many challenges and hard work needs yet to be done.Chinese industries are undergoing a period of transformation in adjusting current structure

and eliminating backward technologies

to realize lower energy consumption

lower pollution

and cleaner production.Backward equipment

such as rotary kilns

moving beds

and fixed beds are being replaced by fluidized beds

offering good opportunities for developing fluidization science and technology.