EFFECT OF PYROLYSIS HEATING RATE ON THE CHEMICAL COMPOSITION OF WOOD VINEGAR FROM EUCALYPTUS UROGRANDIS AND MIMOSA TENUIFLORA

Lúcio César Dantas De Medeiros,Pedro Nico Medeiros Neto,Alexandre Santos Pimenta,Renata Martins Braga,Tatiane Kelly De Azevedo Carnaval,Dulce Maria De Araújo Melo

doi:10.1590/1806-90882019000400008

Lúcio César Dantas De Medeiros, Pedro Nico Medeiros Neto + Show 4 more

Open Access

https://doi.org/10.1590/1806-90882019000400008

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Abstract

ABSTRACT Among the parameters used in the biomass carbonization process, the heating rate is one of the most important. The objective of the present work was to assess the influence of different heating rates on the chemical composition of wood vinegar (WV) from two wood species. Dried disks of Eucalyptus grandis and Mimosa tenuiflora wood were used as raw material. Carbonization runs were carried out in a laboratory muffle furnace at three heating rates (0.7, 1.0 and 1.4 °C/min), with 10 runs at each heating rate, reaching 450 °C. Yields of charcoal, pyrolysis liquids and gases were determined for all carbonization conditions. Crude pyrolysis liquid from each wood species and each heating rate was bi-distilled, yielding purified WV samples. These samples were extracted with ethyl acetate and the organic fraction was analyzed by gas chromatography-mass spectrometry to obtain qualitative and semi-quantitative data. Results showed that lower heating rates produce higher yields of charcoal, while higher heating rates lead to higher yields of pyrolysis liquids and gases. Totals of 57 and 42 chemical compounds were identified in the WV of Eucalyptus and Mimosa, respectively, divided into the following groups: alcohols, ketones, furans and pyrans, and phenolic compounds. In general, higher heating rates led to greater contents of furans and pyrans and lower concentrations of phenolic compounds.

Highlights

In Brazil, about 7.8 million hectares are occupied by planted forests, of which almost 5.6 million hectares are eucalyptus forests
The objective of the present work was to assess the influence of different heating rates on the chemical composition of wood vinegar (WV) from two wood species
Crude pyrolysis liquid from each wood species and each heating rate was bi-distilled, yielding purified WV samples. These samples were extracted with ethyl acetate and the organic fraction was analyzed by gas chromatography-mass spectrometry to obtain qualitative and semi-quantitative data

Summary

Introduction

In Brazil, about 7.8 million hectares are occupied by planted forests, of which almost 5.6 million hectares are eucalyptus forests Of this total, 1.1 million hectares are dedicated exclusively to the production of wood for making charcoal (Indústria Brasileira de Árvores, 2017). Brazil produced 4.5 million metric tons of charcoal in 2016, and the country is unique in the world in having sustainable production by using wood from planted forests. Most of the industrial charcoal plants use large or small masonry kilns that do not recover the byproduct gases and condensable fractions. In this production technology, mass and energy yields are very low in relation to the initial mass of dry wood. Every year in Brazil millions of tons of usable chemicals are virtually lost to the atmosphere as smoke without recycling

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