Thick wood particle pyrolysis in an oxidative atmosphere

Abstract

The oxidative pyrolysis was studied in thermally thin and thick regimes. The oxygen has a significant influence on oxidative pyrolysis. The effect of particle size was studied in thermally thick regime conditions. The temperatures inside a particle highlighted the exothermicity of the process. t r a c tOxidative pyrolysis of pine wood particles was analysed thermo-gravimetrically. The effects of the concentration of oxygen in the surrounding gas and of particle size were investigated. Three different oxygen concentrations (0%, 10% and 20% v/v) and three different sized cylindrical pine wood samples (4 mm, 8 mm and 12 mm in diameter and 15 mm long) were tested. Two types of Macro-TG apparatuses were used; the first was non-isothermal and was used at a heating rate of 20 1C/min, and the second was isothermal used at two temperatures, 400 1C and 600 1C. In the low heating rate non-isothermal apparatus, results showed that oxygen had a strong influence on pyrolysis behaviour, but particle size did not. In the high heating rate isothermal apparatus, particle size had a significant influence on conversion: transfer phenomena limit oxidative pyrolysis.

Numerical models for thermochemical degradation of thermally thick woody biomass, and their application in domestic wood heating appliances and grate furnaces

“…1) implies that the bed model was decoupled from the gas phase model, as the temperature at the boundaries of the wood log were set to constant values. 2) RSM refers to Reynolds-Stress Model, 3) refers to the Eddy Dissipation Model (EDM), 4) refers to the Eddy Break-Up model (EBU), 5) refers to the Eddy Dissipation Concept (EDC), 6) refers to probability density function modeling approach. The references refer to current state-of-the-art models, that included certain key aspects of a specific feature.…”

“…Overall, there is a large difference between thermally thin and thermally thick particles, which is classified by the Biot (Bi) number. The Biot number is defined as [6] Bi…”

Regenerated isotropic wood

“…9a). Both show three main stages during pyrolysis in air, defined as dehydration, oxidative pyrolysis and char oxidation, respectively [ 27 ]. RGI-wood loses less weight during oxidative pyrolysis as its compact structure results in a higher yield of char and less volatilization.…”

Comparison of the oxidative pyrolysis behaviors of black liquor solids, alkali lignin and enzymatic hydrolysis/mild acidolysis lignin

“…3 that there are three main stages in the DTG curves of AL and EMAL, which can be divided into dehydration, oxidative pyrolysis and char oxidation. 5,7 The obvious peak at 731.8 C in BLS represents the decomposition of metal salt in it. 15 The DTG curve of AL appears to be more uniform and identical in distribution.…”

“…5 Because this biomass fast pyrolysis is an endothermic process 6 and therefore requires an external energy input, considerable attention has been paid to reducing the energy consumption during the pyrolysis process. Oxidative pyrolysis greatly simplies the reactor design to reduce the energy input and improves the conversion rate of biomass, [7][8][9][10][11][12][13] as shown in these studies. On the other hand, carefully controlled oxygen concentration in partial oxidative pyrolysis would be benecial to the decomposition of biomass and reduce the content of oligomers or pyrolytic lignin in bio-oil.…”