Rotary Kiln Incineration. Comparison and Scaling of Field-Scale and Pilot-Scale Contaminant Evolution Rates from Sorbent Beds

A comparison is made, for the first time, between the evolution of hydrocarbons from clay sorbent beds in a field-scale rotary kiln incinerator and in a pilot-scale rotary kiln simulator. To relate the data from the different sized units, due allowance is made for bed dynamical similitude, bed geometrical factors, and bed heat-up. To minimize the effects of disturbances caused by foreign matter in the field-scale bed and differences in loading techniques, the rate of evolution is characterized by an “evolution interval” defined as the time required for the middle 80% of the ultimate contaminant evolution to occur. A comparison of evolution intervals with reciprocal bed temperature reveals that the data are consistent with an analysis that assumes a uniform bed temperature (at any instant of time) and a desorption-controlled evolution rate. Furthermore, the evolution intervals scale inversely with a modified Froude number, which characterizes bed dynamics. The success in comparing field and simulator results indicates that pilot-scale rotary kilns may be used to simulate certain features of industrial-scale units if dynamical, geometrical, and thermal parameters are matched appropriately.