The Catalytic Pyrolysis of Herb Residue from the Chinese Medicine Industry

Abstract

Catalytic pyrolysis of herb residue with different catalyst (pure TiO₂, Cu/TiO₂, La/TiO₂, and Al/TiO₂) was carried out in a fixed-bed to obtain upgraded bio-oils. The effects of catalysts on chemical composition of bio-oils were investigated. According to the result of gas chromatography-mass spectrometry, the bio-oil containing the highest amount of aliphatics and aromatics and the lowest amount of oxygenated fractions was obtained with La/TiO₂ catalyst. Moreover, it was found that the bio-oil with La/TiO₂ catalyst had lower oxygen content and higher high heating value compared with the case without catalyst or with other catalysts. The effect of catalyst ratio (catalyst/cellulose mass ratio) on the product yields was also observed, which showed that the use of La/TiO₂ led to a higher quality but a lower quantity for the bio-oil. Based on the quality and quantity of bio-oil, 10 wt% is the optimal catalyst ratio.

Keywords:

• biomass
• bio-oil
• catalytic pyrolysis
• doping TiO₂
• herb residue

Notes

^aOn dry basis.

^bCalculated by difference.

^cExtracted with 95% ethanol/toluene (1/2, by volume), followed by 95% ethanol and hot water.

^aObtained at 450°C without catalyst and with La/TiO₂ by 10 wt%.

^aCalculated by difference.