Abstract:
The catalytic hydropyrolysis of pine wood was conducted in a fixed bed reactor under a H
2 pressure of 5 MPa at different temperatures (600-700 ℃) to investigate the effects of two iron salts, Fe(NO
3)
3 and FeSO
4, on the upgrading of bio-oil and gaseous products. Fe(NO
3)
3 is found to promote the conversion of biomass to bio-oil and gaseous products, with a carbon conversion rate as high as 97.4%, a CH
4 yield of 21.2%, and a bio-oil yield of 32.8% (daf. biomass basis). Moreover, the oxygen content in the bio-oil decreases, the yield of light aromatic hydrocarbon increases and the yield of BTX (benzene, toluene and xylene) reaches 2.6%. In contrast, FeSO
4 has an inhibitory effect on the production of gaseous hydrocarbons and bio-oil. The XRD analysis shows that Fe(NO
3)
3 is transformed to
α-Fe during hydropyrolysis, with the amorphous and porous structures of bio-char being formed. This is highly conducive to the catalytic hydrogenation and methanation of bio-char. But FeSO
4 is converted to Fe
2S
3 during the hydropyrolysis, which might poison the catalytic activity.