Liquid Biofuel Production From The Thermochemical Conversion Of Algae

Firstly, the thermochemical conversion behaviors of microalgae and macroalgae were studied, respectively; Secondly, direct hydrothermal catalytic upgrading and two-step catalytic hydrothermal upgrading of microalgal biocrude were examined. The main research content and results are summarized as follows:(1) Thermochemical conversion of microalgaeInfluence of temperature(150-450°C), time(5-120min), hydrogen pressure(1atm-8MPa) on the product distribution and properties of the bio-oil from the pyrolysis of microalgae were explored. Temperature was the most influential factor to the relative amount of each product and properties of the hydropyrolysis oil. About 85% of energy originally present in the microalgae was recovered as oil under the optimal conditions.(2) Thermochemical conversion of macroalgaeInfluences of temperature(250-390°C), time(10-120min), reactor loading(0.5/8.4-5.5/8.4), and K2CO3 loading(0-30 wt.%) on the product distribution and properties of the liquefied oil from the hydrothermal liquefaction of Enteromorpha prolifera were determined. The results suggest that temperature and K2CO3 loading amount are more influential on the product distribution, and modest loading amount of K2CO3 can promote the conversion of Enteromorpha prolifera, however, it would has negative effect as its loading amount is higher than 20 wt.%.(3) Direct catalytic upgrading of the crude microalgal bio-oilUnder conditions of 400°C and 1h, influence of catalyst loading(varied from 0 to40 wt.%), water density(varied from 0 to 0.1 g/cm3), and formic acid(HCOOH) loading(varied from 2 to 37 mmol) on the product yields and properties of the treated oil were examined. In the presence of Pt/?-Al2O3, a product oil, which was a freely flowing liquid, was obtained. Compared to SCW + H2, the presence of SCW + HCOOH effectively controls the coke formation.(4) Two-step catalytic upgrading of the crude microalgal bio-oilInfluence of 5% Pt/C, 5% Pd/C, 5% Ru/C, 5% Pt/C(sulfided), Mo2 C, Mo S2,alumina, Co Mo/?-Al2O3(sulfided), Ni/Si O2–Al2O3, HZSM-5, activated carbon, and Raney-Ni on the product distribution and the properties of the upgraded oil from the upgrading of pretreated algal oil at 400°C, 4h, and ?H2O=0.025g/cm3 were determined.The results suggest that the upgraded oil produced from the Ru/C catalyzed reaction had the highest yield and higher heating value. Compared to the single-compoent catalyst catalyzed reaction, two-component catalyst catalyzed reaction not only can produce higher upgraded oil yield, but also can achieved higher energy recovery.