Based on experimental and literature research, the influence of pyrolysis temperature and raw materials on the components of wood vinegar solution
Wood vinegar, also known as wood vinegar, is a brownish yellow to dark brown liquid obtained by condensing the flue gas mixture produced by the thermal cracking of waste biomass from agricultural, forestry, and agricultural product processing enterprises such as straw, wood, and sawdust. Wood vinegar has antioxidant, bactericidal, deodorizing and other effects, and is often used as an antioxidant, biological fertilizer additive, antibacterial agent, deodorizer, food preservative and other aspects. Therefore, it is widely used in agriculture, food, animal husbandry industry, environment and daily chemical industry.

The components of wood vinegar are complex, and the physicochemical properties and components of wood vinegar vary depending on the type of raw material and collection method. There are research reports that pyrolysis temperature is an important factor affecting the composition and content of wood vinegar. Zheng et al. found that as the pyrolysis temperature increased from 250 ℃ to 350 ℃, the content of acetic acid in the vinegar solution of reed bamboo decreased, while the content of ketones and phenolic substances increased. Wei et al. found through analysis of walnut branch vinegar that acidic substances showed a decreasing trend in the temperature range of 230-450 ℃. Some scholars have compared and studied the differences in the types and contents of wood vinegar components from different raw material sources. For example, Li et al. analyzed the components of wood vinegar from five different raw materials: oak, walnut shell, peanut shell, corn cob, and rice husk, and found that woody oak and walnut shells, as well as herbaceous plants (corn cob, peanut shell, rice husk), have differences in the presence or absence of low content components such as hexanedione and furfuryl alcohol. In the past, research mainly focused on the application of wood vinegar in agriculture, food, and component analysis, and there were few studies on the relationship between wood vinegar and raw materials, temperature, and the components of wood vinegar.

This study is based on GC-MS analysis of eucalyptus wood vinegar components in the low-temperature range (270-340 ℃) and high-temperature range (370-400 ℃), as well as 75 domestic and foreign data on wood vinegar components in the past 26 years. Statistical analysis methods such as cluster heatmap analysis, linear regression analysis, NMDS analysis, correlation analysis, and random forest model are used to explore the relationship between wood vinegar components and temperature, raw materials, and wood vinegar components, in order to provide reference or inspiration for biomass resource utilization, wood vinegar processing and preparation, application, and research.

This article is based on experimental and literature data, and uses multivariate statistical analysis methods to explore the effects of different raw materials and temperatures on the components of eucalyptus wood vinegar and their interrelationships. There is a significant difference in the components of eucalyptus wood vinegar at low and high temperatures, and the content of acidic substances in eucalyptus wood vinegar decreases and the content of phenolic substances increases with increasing temperature. Ketones, esters, and aldehydes do not show significant differences with temperature changes. There is a significant difference in the composition of wood vinegar with pyrolysis temperatures below 350 ℃ and above 350 ℃. Wood vinegar with pyrolysis temperatures below 350 ℃ has a higher content of acidic substances, while wood vinegar with pyrolysis temperatures above 350 ℃ has an increased content of phenolic substances and a decreased content of acidic substances. Acetic acid is the main substance of acidic substances, phenolic substances mainly include phenol, guaiacol, and 2,6-dimethoxyphenol, aldehyde and ketone substances mainly include furfural and 1-hydroxy-2-acetone, and alcohol substances mainly include furfuryl alcohol and methanol. There is a significant negative correlation between acidic substances and phenolic substances, as well as phenolic substances and ester substances in the components of wood vinegar; Acid substances are significantly positively correlated with esters, alcohols, and ketones. The pyrolysis temperature is an important factor affecting the composition of wood vinegar.