Fuel Particle Conversion of Pulverized Biomass during Pyrolysis in an Entrained Flow Reactor

Abstract

This study addresses the change of char morphology and fuel conversion during pyrolysis in a laminar entrained flow reactor by experiments and particle simulation. Three experimental parameters were examined: reaction temperature (1073 and 1273 K); particle size (125−250, 250−500, and 500−1000 μm); and the length of reaction zone (650 and 1885 mm). The scanning electron microscopic (SEM) images showed that biomass swelled during heating and shrank during initial stage of pyrolysis. Then, char morphology transformed to cenospheres after the plastic stage. The yields of solid residue from the experiments were reasonably predicted by particle simulation. To give a guideline for the design of laminar entrained flow pyrolysis reactors, the required reactor length for complete conversion of biomass was also calculated for the pyrolysis. High reaction temperature, small particles, and slower gas flow were favorable for high fuel conversion.

Atmospheric entrained-flow gasification of biomass and lignite for decentralized applications

“…3(A). The residence times of 1 mm and 0.25 mm particles amounted to 1.4 ± 0.1 s and 3.3 ± 0.2 s, respectively, while the gas residence time was about 50.7 s. These measurements indicate a strong dependence of the particle residence time on the diameter of the fluidized particles and support theoretical predictions of Dupont et al [23], Umeki et al [52] and Kirtania and Bhattacharya [53]. This will be discussed in the following with the help of a general model.…”

“….2-4 but used α = 0.15 and β = 0.687 (Schiller-Naumann expression [57]) in order to calculate the drag force coefficient. Residence times of 9 and 0.7 s for 0.1 mm and 1 mm particles, respectively, were calculated for a reactor length of 1.9 m at 1000°C by Umeki et al [52]. These residence times are higher than the ones presented in Fig.…”

“…Flow rate gasification agent in m 3 Umeki et al [52] and Kirtania and Bhattacharya [53] also applied Eq. .2-4 but used α = 0.15 and β = 0.687 (Schiller-Naumann expression [57]) in order to calculate the drag force coefficient.…”

High‐temperature pyrolysis and CO2 gasification of Victorian brown coal and Rhenish lignite in an entrained flow reactor

“…The method for calculation of the entrained flow parameters, including Reynolds number, particle drag coefficient, slip velocity and particle residence time, is described elsewhere. 15 The particle residence time, within certain ranges depending on particle properties, can also be controlled by the gas flow rate.…”

Influence of fast pyrolysis conditions on yield and structural transformation of biomass chars

“…The rapid heating of small biomass particles and the short residence time at high temperatures minimize the char yield and increase char reactivity [5]. The majority of previous investigations [3,[6][7][8][9][10][11][12][13][14][15][16][17][18][19] referred to low-ash containing feedstocks (softwood, hardwood). The effects of heating rate and temperature on the morphological transformations at both slow (b 10 ∘ C/s) and intermediate and fast pyrolysis environments (N 100 ∘ C/s) of the same feedstock were rarely studied.…”