Comparative investigation of rice husk, thermoplastic bituminous coal and their blends in production of value-added gaseous and liquid products during hydropyrolysis/co-hydropyrolysis

Abstract

The hydropyrolysis/co-hydropyrolysis of rice husk (RH) and thermoplastic bituminous coal (BC) was carried out using a fixed-bed reactor to investigate the effects of atmosphere and hydrogen pressure on product distributions. RH produced more carbon oxides, phenolics and acids. BC yielded more methane and BTX (benzene, toluene and xylene) during hydropyrolysis. Compared with hydropyrolysis of RH, the co-hydropyrolysis promoted the higher heating value of gaseous product and the yield of BTX by 19% and 57% respectively, while it reduced the yield of corrosive acids by 89% under 5 MPa H₂. The yields of methane, BTX and phenolics during co-hydropyrolysis were 1.5, 6.4 and 4.0 times as much as those obtained during co-pyrolysis under 5 MPa. The co-hydropyrolysis reformed the structure of heavy oil/tar, benefiting the development of aromaticity. High hydrogen pressure synergistically reduced yields of char and acids, and enhanced yields of tar and light aromatics via the secondary reactions.

Keywords: Co-hydropyrolysis; Rice husk; Synergistic effect; Thermoplastic bituminous coal.