Comparative study of bio-oils obtained by fast and slow pyrolysis of peach stone

ABSTRACT The processing of pickled peaches generates the peach stone as an agro-industrial residue that is difficult to dispose of. Thus, the woody endocarp pyrolysis technique is an efficient treatment for converting biomass into value-added products. Among the products, bio-oil is composed of two immiscible phases (organic and aqueous), with potential to supply the production of chemical products in different industrial sectors. The objective of this study was to obtain and evaluate the constitution of the organic phase of the bio-oils based on the fast (quartz reactor) and slow (stainless steel reactor) pyrolysis of the woody endocarp, both with fixed bed at 700°C, thus evidencing the influence of processes in the constitution of the obtained bio-oils. As liquid fractions, they were derived with N-methyl-N-trimethylsilyltrifluoracetamide for further characterization in gas chromatography coupled with mass spectrometry. Through the methodology employed, a total of 59 and 41 compounds were detected in the organic phases of the fast and slow pyrolysis bio-oils, respectively; Phenols are the majority, with 59.9 and 67.2% by weight, where the methoxyphenol (fast) and cresols (slow) are the predominant compounds. It is concluded that the derivatization stage and the gas chromatography/mass spectrometry technique were satisfactory for the qualitative and semi-quantitative characterization of bio-oils, which they can potentially use as a source of chemical products and to benefit from reuse of residue.

摘要 桃罐头加工过程中会产生桃核这一难以处置的农业工业废弃物。因此，木质内果皮热解技术是将生物质转化为高附加值产物的高效处理手段。所得生物油由互不相溶的两相（有机相与水相）组成，具备为不同工业领域的化学品生产提供原料的潜力。本研究旨在基于均采用固定床反应器、热解温度为700℃的快速热解（石英反应器）与慢速热解（不锈钢反应器）工艺，获取并分析桃核木质内果皮热解生物油的有机相组成，以此阐明两种热解工艺对所得生物油组成的影响。针对所得液相馏分，采用N-甲基-N-三甲基硅基三氟乙酰胺（N-methyl-N-trimethylsilyltrifluoracetamide）进行衍生化处理，随后通过气相色谱-质谱联用法（gas chromatography coupled with mass spectrometry）完成后续表征。通过所采用的分析方法，在快速热解与慢速热解生物油的有机相中分别检出总计59种和41种化合物；酚类为主要组分，质量占比分别为59.9%与67.2%，其中快速热解产物中以甲氧基苯酚为主，慢速热解产物中则以甲酚类为优势化合物。研究表明，衍生化步骤与气相色谱/质谱联用技术可较好地实现生物油的定性与半定量表征，这类生物油可作为化学品生产的原料来源，并实现该农业废弃物的资源化再利用。