Chemical properties of bio-oils produced by fast pyrolysis of bamboo

Abstract

Bamboo powder was analytically pyrolyzed using pyrolysis-gas chromatography (Py-GC), and the effects of fast pyrolysis conditions on the product distribution of bio-oil were evaluated. 4-Vinylphenol (4VP) was identified as a major product of bamboo fast pyrolysis by 1 H-NMR and 13 C-NMR spectrometry. The formation pathway of 4VP demonstrated that p-coumarate esters are present in bamboo lignin, and 4VP is likely to be derived from these p-coumarate structures. The evaluation of the effect of fast pyrolysis temperature on the product distribution of bio-oil revealed that increasing pyrolysis temperature resulted in high yields of compounds containing a furan structure and reduced yields of phenolic compounds, except catechol. The fast pyrolysis of Klason lignin produced 4VP in lower yield than that from bamboo powder, even though the yield of 4-vinylguaiacol from acid lignin was greater than that from bamboo powder. In comparison with fast pyrolysis, slow pyrolysis of bamboo produced simple phenols, such as phenol, guaiacol, methyl guaiacol, syringol, and methyl syringol, in higher yields, whereas the yield of 4VP was lower than that from fast pyrolysis. The chemical characteristics of bio-oil depend on the biomass source, pyrolysis conditions, and the type of pyrolyzer.

OH-Initiated Reactions of para-Coumaryl Alcohol Relevant to the Lignin Pyrolysis. Part II. Kinetic Analysis

“…There exists controversy in the identification of DHBF in lignin pyrolysis. , Qu et al and later Kato at al . have particularly found that GC/MS procedures can be misleading because of the closely resembling mass-spectroscopic spectra of DHBF and 4-vinylphenol ( 4VP ).…”

“…28,171 Qu et al 171 and later Kato at al. 28 have particularly found that GC/MS procedures can be misleading because of the closely resembling mass-spectroscopic spectra of DHBF and 4-vinylphenol (4VP). Furthermore, the isolation and reanalysis of this very major product using NMR and other methods allowed its identification as 4-vinylphenol.…”

“…Monolignols are the most important primary products of lignin pyrolysis. ,,,− Their primary formation and decomposition are currently the dominating view on the decomposition mechanisms and depolymerization of lignin during fast pyrolysis. ,,− This makes the pyrolysis of monolignols a very challenging process to be studied kinetically. A fundamentally based pyrolysis mechanism of these key intermediates is necessary to develop detailed kinetic models of lignin pyrolysis so as to accomprehend the kinetic models of biomass pyrolysis because the pyrolysis kinetics of other two biomass components, viz., cellulose and hemicellulose is much more developed (see, e.g., refs − ).…”

“…The pyrolysis of monolignols as aromatic nuclei, mimicking the primary products of the lignin pyrolysis as well as the structural motifs of the lignin side groups, is actively explored only in recent years. ,,− ,− , In our previous studies, we have shown that the pyrolysis of p -CMA and its bare model CnA generates a large variety of phenolic compounds and benzene derivatives such as phenol, p -cresol, 4-vinylphenol, indene, styrene, benzaldehyde, 1-propynyl benzene, and 2-propenyl benzene and corresponding para -hydroxy-derivatives depending on pyrolysis conditions by utilizing both conventional and fractional pyrolysis approaches. ,− Remarkably, the yields of a small set of phenolics in low-temperature fractional pyrolysis of p -CMA constitute as high as 70% of the total gas-phase products …”

Pyrolysis characteristic of kenaf studied with separated tissues, alkali pulp, and alkali lignin

“…In addition, many researchers have studied the pyrolysis conversion of switch grass and have evaluated the obtained bio-oil with respect to its chemical composition (Charles et al, 2008), energy-conversion efficiency (Boateng et al, 2007), and effect of milling (Bridgman et al, 2007). Several studies on the pyrolysis conversion of crops other than switch grass, such as wheat straw (Fidalgo et al, 1993), rice husks (Gai et al, 2013), tobacco residue (Cardoso and Ataide, 2013), orange waste (Lopez-Velazquez et al, 2013), giant cane (Temiz et al, 2013), microalgae (Wang et al, 2013), and bamboo (Kato et al, 2014), have also been reported. These plants consist of cellulose, hemicellulose, and lignin.…”