CFD Modeling of Meat and Bone Meal Combustion in a Rotary Cement Kiln

Abstract

Abstract-This paper presents a three-dimensional computational fluid dynamics (CFD) modeling study carried out for a rotary cement kiln withal multi-channel burner with swirl and high momentum air components. The simulations are performed using the commercial CFD software ANSYS FLUENT, version 13.0, and are carried out for coal as well as for meat and bone meal (MBM) combustion using the eddy-dissipation model for combustion. Steady-state solutions are obtained using the Lagrangian approach for the particle phase and the Eurasian approach for the continuous phase. The turbulence is modeled by the RNG k-ε model, and gas-phase radiation is modeled by the P1 radiation model. The effect of MBM fuel properties on combustion characteristics such as temperature, fuel devolatilization, volatiles and char burning, in comparison with coal, are presented and discussed. It was found that MBM combustion products temperatureis300K lower than that of coal, and the char burnout of MBM is 83%. This poor burnout is mainly due to bigger MBM particles.Index Terms-CFD, combustion, meat and bone meal, rotary cement kiln.

CFD Modeling of Multi-fuel Combustion of Coal and Meat and Bone Meal (MBM) in a Cement Rotary Kiln

“…In this case, the positive effect of the latter two factors is outweighed by the two former factors. The higher ash and moisture content in MBM (Table I) also contribute to reduced temperature, since the ash and evaporated water vapour must be heated up to the equilibrium temperature [10]. Table IV summarizes the devolatilization and char burnout percentages at the kiln end.…”

“…The solution strategy is explained elsewhere [3], [10] and not repeated here. For the level of accuracy, the limited residual values for convergence are 10 -3 for continuity and 10 -4 for the other equations.…”

“…3. Some of fuel properties are presented in Table I and gas properties are described in elsewhere [3], [10]. Default model parameters are used for the char combustion of both fuels [12].…”

“…Moreover, the authors of the current study used CFD to carry out simulations of MBM combustion. The first publication mainly discusses the impacts of fuel characteristics on combustion properties such as gas temperature, devolatilization, char burnout [10], while the second paper investigates the effect of fuel feeding position and fuel particle size on the combustion characteristics [3]. Both publications discuss the effects of replacing 100% of the coal by MBM, i.e.…”

Experimental and numerical studies of rotating drum grate furnace

“…[14] have investigated process of meat and bone meal (MBM) combustion in a cement rotary kiln, using a three-dimensional, steady state CFD model. The authors have carried out set of simulations, to find out an effect of various fuel feeding positions and fuel particle size for combustion characteristics.…”