Pyrolysis Characteristics of Undervalued Wood Varieties in the Portuguese Charcoal Sector

Abstract

Charcoal production in Portugal is mostly based on the valorization of woody residues from cork oak and holm oak, the latter being considered a reference feedstock in the market. Nevertheless, since wildfire prevention became a priority in Portugal, after the recent dramatic wildfires, urgent actions are being conducted to reduce the fuel load in the forests, which is increasing the amount of biomass that is available for valorization. Additionally, biomass residues from agriculture, forest management, control of invasive species, partially burnt wood from post-fire recovery actions, and waste wood from storm devastated forests need also to be considered within the national biomass valorization policies. This has motivated the present work on whether the carbonization process can be used to valorize alternative woody biomasses not currently used on a large scale. For this purpose, slow pyrolysis experiments were carried out with ten types of wood, using a fixed bed reactor allowing the controlled heating of large fuel particles at 0.1 to 5 °C/min and final temperatures within 300–450 °C. Apart from an evaluation of the mass balance of the process, emphasis was given to the properties of the resulting charcoals considering its major market in Portugal—barbecue charcoal for both recreational and professional purposes.

Oak Biomass in the Form of Wood, Bark, Brushwood, Leaves and Acorns in the Production Process of Multifunctional Biochar

“…The observed significant ash increase may result from the analysis method used and the occurrence of additional charcoal incineration. The literature on the subject also noted an increase in ash recovery after the pyrolysis process [ 38 , 92 , 102 , 113 , 114 ] Ash increase during the pyrolysis process has been observed by scientists in earlier studies. Ulusal et al noted an increase in ash in willow sawdust depending on the temperature of pyrolysis (400, 500, 600 °C) and its time (15, 30, 60, 120 min.).…”

Variability on the energy properties of charcoal and charcoal briquettes for barbecue

“…A high ash content in charcoal briquettes can represent a serious problem during their use both for the environmental repercussions and potentially also for human health due to the inhalation of fine dust [ 39 ]. In addition, the high ash content charcoal causes the need for frequent cleaning and frequent maintenance of barbecues with the possibility of forming layers of ash above the embers that could transfer to the food [ 40 ].

Figure 2 Average ash content, standard deviation and range of variations of all samples analyzed.

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Numerical Study of Cylindrical Tropical Woods Pyrolysis Using Python Tool

“…Vapor and liquid states are highly related. In effect, Figures 21 and 22 show that the evolutions of these two pyrolysis products are directly opposite because the concentration [31,32].…”

“…Commandré et al [30] confirm this ratio of gas density obtained during pyrolysis process and show experimentally that this ratio can reach up to 40%. [31,32].…”

“…RH = 0.3%/100, R = 25 mm and Ho = 20%. Works of Widiyannita et al and Charvet et al permit us to notice that the percentage of each component given by the pyrolysis depends on the product used[31,32].Vapor and liquid states are highly related. In effect, Figures21 and 22show that the evolutions of these two pyrolysis products are directly opposite because the concentration…”