Bio-oil production via catalytic pyrolysis of Anchusa azurea: Effects of operating conditions on product yields and chromatographic characterization

• Catalytic pyrolysis of Anchusa azurea stalks was performed in a fixed-bed reactor.
• Alumina, calcium hydroxide, sodium carbonate and zinc chloride were used as catalysts.
• The highest bio-oil yield (34.05%) was obtained in the presence of sodium carbonate at 450 °C.
• 124 and 164 different compounds were identified in the bio-oils obtained at 350 and 550 °C respectively.

Pyrolysis of Anchusa azurea, a lignocellulosic gramineous plant, was carried out in a tubular, fixed-bed reactor in the presence of four catalysts (Ca(OH)2, Na2CO3, ZnCl2, Al2O3). The influences of pyrolysis parameters such as catalyst and temperature on the yields of products were studied. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts effected the yields of products differently and the composition of bio-oils. Liquid yields were increased in the presence of Na2CO3, ZnCl2 and Al2O3 and decreased with Ca(OH)2. The highest bio-oil yield (34.05%) by weight including aqueous phase was produced with Na2CO3 catalyst at 450 °C. The yields of products (bio-char, bio-oil and gas) and the compositions of the resulting bio-oils were determined by GC–MS, FT-IR and elemental analysis. GC–MS identified 124 and 164 different compounds in the bio-oils obtained at 350 and 550 °C respectively.