Catalytic pyrolysis of Alcea pallida stems in a fixed-bed reactor for production of liquid bio-fuels

• Catalytic pyrolysis of Alcea pallida stems was conducted in a fixed-bed reactor.
• Calcium hydroxide, zinc chloride, tincal, alumina and ulexite were used as catalysts.
• The maximum bio-oil yield (39.35%) was obtained with alumina catalyst at 500 °C.
• 160 different compounds were identified by GC–MS in bio-oils produced at 500 °C.

Pyrolysis of Alcea pallida stems was performed in a fixed-bed tubular reactor with and without catalyst at three different temperatures. The effects of pyrolysis parameters including temperature and catalyst on the product yields were investigated. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts had different effects on product yields and composition of bio-oils. Liquid yields were increased in the presence of zinc chloride and alumina but decreased with calcium hydroxide, tincal and ulexite. The highest bio-oil yield (39.35%) by weight including aqueous phase was produced with alumina catalyst at 500 °C. The yields of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by elemental analysis, TGA, FT-IR and GC–MS. 160 different compounds were identified by GC–MS in the bio-oils obtained at 500 °C.