Weiming Yi

Enhancing biogas production of corn stover by fast pyrolysis pretreatment

A new thermo-chemical pretreatment by a lower temperature fast pyrolysis (LTFP) was applied to promote anaerobic digestion (AD) efficiency of corn stover (CS). The pretreatment experiment was performed by a fluidized bed pyrolysis reactor at 180, 200 and 220°C with a carrier gas flow rate of 4 and 3m(3)/h. The components characteristics, Scanning Electron Microscope (SEM) images and Crystal Intensity (CrI) of the pretreated CS were tested to explore effectiveness of the pretreatment. The results showed that the cumulative methane production at 180°C for 4 and 3m(3)/h were 199.8 and 200.3mL/g TS, respectively. As compared to the untreated CS, the LTFP pretreatment significantly (a<0.05) increased the methane production by 18.07% and 18.33%, respectively. Methane production was well fitted by the Gompertz models, and the maximum methane potential and AD efficiency was obtained at 180°C for 3m(3)/h.

Supercritical CO2 Extraction of Corn Stalk Pyrolysis Oil

Supercritical CO 2 extraction was employed to separate simulated and real bio-oil. Effects of adsorbents on enrichment were investigated for a simulated bio-oil, which is composed of acetic acid (AC), propanoic acid (PA), furfural (FR), acetylacetone (AA) and 2-methoxyphenol (MP). Extraction of spiked bio-oil shows adsorbents are able to influence extraction efficiency and selectivity. Appropriate water content in the simulated bio-oil favors in improving extraction efficiency. Extraction with methanol (or ethanol)-modified CO 2 affords higher extraction efficiency than that with pure CO 2 , but might lead to lower extraction selectivities. Using 5A molecular sieve as adsorbent, the extraction efficiencies for MP, FR, PA, AA and AC under 45°C and 20.0 MPa respectively reach up to 100%, 84.9%, 57.8%, 57.1% and 22.8%. In addition, supercritical CO 2 extraction of a real bio-oil showed that water content and acidity of the bio-oil after extraction dropped significantly, suggesting remarkable upgrading in heat value and corrosiveness of the bio-oil.