Influence of H 2 O, CO 2 and O 2 addition on biomass gasification in entrained flow reactor conditions: Experiments and modelling

Abstract

. Influence of H2O, CO2 and O-2 addition on biomass gasification in entrained flow reactor conditions: Experiments and modelling. Fuel, Elsevier, 2016, 166, pp.166-178. 10 Experiments were modelled with a 1D-model using detailed chemical scheme. Gas, char, tar + soot were satisfactorily simulated in the whole range of conditions. ysis reaction, gas phase reaction with a detailed chemical scheme (176 species, 5988 reactions), char gasification by steam and CO 2 and soot formation. H 2 O or CO addition has no influence on gasification product yields at 800 and 1000 °C, while at 1200 and 1400 °C the char gasification is significantly enhanced and soot formation is certainly inhibited by OH radical which reacts with soot precursors. The modification of output gas phase composition is mostly due to WGS reaction which reaches thermodynamic equilibrium from about 1200 °C. As expected, O 2 has a significant influence on gas and tar yields through combustion reactions. Char and soot yields decrease as ER increases. The GASPAR model allows a good prediction of gas and char and gives relevant evolution of soot and tar yields on the large majority of conditions studied.

Biomass Chars: The Effects of Pyrolysis Conditions on Their Morphology, Structure, Chemical Properties and Reactivity

“…This behavior can be explained by the sublimation/boiling of potassium during pyrolysis performed at 1400 • C (boiling point 1420 • C, sublimation at 1500 • C), leading to the appearance of large porosity at the surface of the char particle, or again to the char gasification by H 2 O/CO 2 formed during the pyrolysis stage. This is consistent with other results obtained under similar conditions [23], which also showed that potassium released from char at 1400 • C was incorporated into soot particles. The samples Char-500 and Char-600 present a smooth surface, comparable to the one of the raw biomass.…”

“…Furthermore, at high temperatures, the formation of soot was observed, starting from 1000 °C. A deep analysis of the operating conditions' effect on the pyrolysis product distribution can be found in previous investigations [23,26]. The main focus of the present study was to identify the effect of the operating conditions on the char characteristics.…”

“…The EFR experimental set-up was previously described in detail by Billaud et al [23]. It consists of an alumina tube inserted in a vertical electrical heater with three independent heating zones.…”

“…This takes into account the particle density and size, and their evolution as pyrolysis proceeds, between the density and size of wood particles and those of char particles [24]. The robustness and accuracy of the model is validated over a wide range of temperatures, atmospheres and particle sizes [23,25]. The particle residence time varies more at low temperatures, while it remains almost the same for temperatures above 600 • C. This is not obvious at first glance, but it has to do with the change in particle slip velocity during the pyrolysis process.…”

CO2 gasification of microalgae (N. Oculata) – A thermodynamic study

“…For instance, [7] investigated the gasification of pine sawdust using CO2 over Ni/Al precipitation catalyst. [8] studied the gasification of beech sawdust in the entrained flow reactor. [9] developed a model to investigate the performance of biomass gasification with CO2 using fluidized bed gasifier.…”