Kinetic study of pulverized coal devolatilization for boiler CFD modeling

Global Kinetic Modeling of Coal Devolatilization in a Thermogravimetric Balance and Drop-Tube Furnace

“…8 Furthermore, the values of parameter n are selected to obtain a differential reaction model value close to the standard first-to third-order model (Figure 2). In the case of the additional simplex search method, the starting point is defined as the converged output value of the genetic algorithm to start in an adequate basin of attraction.…”

“…6,7 Thus, experimental studies still seem to be a reliable way to assess kinetic parameters of coal devolatilization. 8 The kinetic analysis of pulverized coal devolatilization under an inert gaseous atmosphere has been carried out under various thermal analytical methods at laboratory scale, by measuring the mass loss when the sample is heated or held at a constant temperature. The temperature-controlled thermogravimetric balance (TGA) is usually used to study pulverized coal devolatilization from low to moderate final temperatures at relatively slow programmed linear heating rates, with high accuracy and time resolution.…”

Using a genetic algorithm and CFD to identify low NOx configurations in an industrial boiler

“…When coal characterization on a drop tube furnace is available, the kinetic parameters of the Kobayashi scheme are determined using an optimization routine based on genetic algorithm and simplex method [22]. However, since no characterization for this particular coal has been performed, default kinetics parameters (activation energies E 1 and E 2 and the pre-exponential factors A 1 and A 2 ) given in Code_Saturne have been used.…”

Temperature and heating rate of solid particles undergoing a thermal decomposition. Which criteria for characterizing fast pyrolysis?

“…-Transient processes: a small sample of particles at T S0 is rapidly introduced in a reactor at T H .This situation is encountered, for example, in the case of horizontal hot walls tubes inside which is suddenly pushed a crucible containing a small mass of particles [7,8] ; or of vertical tubes (drop tubes) with introduction of a pulse of particles at the top [9]. Etc.…”

“…-The reaction rate r (kg s -1 ) is defined as: km r  (9) Where m is the particle mass at time t defined as:…”