Abstract
This study assessed the pyrolysis liquids obtained by slow pyrolysis of industrial hemp leaves, hurds, and roots. The liquids recovered between a pyrolysis temperature of 275–350 °C, at two condensation temperatures 130 °C and 70 °C, were analyzed. Aqueous and bio-oil pyrolysis liquids were produced and analyzed by proton nuclear magnetic resonance (NMR), gas chromatography–mass spectrometry (GC-MS), and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). NMR revealed quantitative concentrations of the most abundant compounds in the aqueous fractions and compound groups in the oily fractions. In the aqueous fractions, the concentration range of acetic acid was 50–241 gL−1, methanol 2–30 gL−1, propanoic acid 5–20 gL−1, and 1-hydroxybutan-2-one 2 gL−1. GC-MS was used to compare the compositions of the volatile compounds and APPI FT-ICR MS was utilized to determine the most abundant higher molecular weight compounds. The different obtained pyrolysis liquids (aqueous and oily) had various volatile and nonvolatile compounds such as acetic acid, 2,6-dimethoxyphenol, 2-methoxyphenol, and cannabidiol. This study provides a detailed understanding of the chemical composition of pyrolysis liquids from different parts of the industrial hemp plant and assesses their possible economic potential.
Highlights
IntroductionIndustrial hemp is an annual, non-psychoactive plant selected for its low concentration of the psychoactive compound, delta-9-tetrahydrocannabinol (∆-9-THC), i.e., not more than 0.3% on a dry wet basis
Hurd contained the highest concentration of alcohols, esters/sugars, and phenols, leaves were rich with aromatics
The findings of this study showed that pyrolysis liquid of hemp leaves obtained at pyrolysis stage 275–350 ◦C and condensation temperature at 70 ◦C have similar chemical concentrations of acetic acid when compared to pyrolysis liquids obtained from hemp hurds at torrefaction stage 135–275 ◦C and the condensation temperature at 70 ◦C studied earlier
Summary
Industrial hemp is an annual, non-psychoactive plant selected for its low concentration of the psychoactive compound, delta-9-tetrahydrocannabinol (∆-9-THC), i.e., not more than 0.3% on a dry wet basis. Industrial hemp is characterized as a second-generation lignocellulosic biomass [1] and is mainly composed of cellulose (39–50%), hemicelluloses (18–25%), and lignin (21–24%) [2,3,4]. Hemp is a fast-growing crop that provides high quantity biomass in a short time with 10–15 t·ha−1 of hemp dry matter yields, a short vegetation period of 3–4 months, and a rapid growth up to 4 m in height. The short rotation nature of this crop and its fast growth are closely linked to the potential of using this biomass [5]. According to the European Industrial Hemp Association’s (EIHA) report published in 2017, hemp cultivation and its market have increased considerably and undergone a remarkable development since the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
