RESUMEN
Upgrading of bio-oil obtained from hydrothermal liquefaction (HTL) of algae is necessary for it to be used as a fuel. In this study, bio-oil obtained from HTL of Nannochloropsis sp. was upgraded using five different catalysts (Ni/C, ZSM-5, Ni/ZSM-5, Ru/C and Pt/C) at 300⯰C and 350⯰C. The upgraded bio-oil yields were higher at 300⯰C; however, higher quality upgraded bio-oils were obtained at 350⯰C. Ni/C gave the maximum upgraded bio-oil yield (61â¯wt%) at 350⯰C. However, noble metal catalysts (Ru/C and Pt/C) gave the better upgraded bio-oils in terms of acidity, heating values, and nitrogen values. The higher heating value of the upgraded bio-oils ranged from 40 to 44â¯MJ/kg, and the nitrogen content decreased from 5.37 to 1.29â¯wt%. Most of the upgraded bio-oils (35-40â¯wt%) were in the diesel range. The major components present in the gaseous products were CH4, CO, CO2 and lower alkanes.
Asunto(s)
Biocombustibles , Aceites de Plantas , Catálisis , Polifenoles , Temperatura , AguaRESUMEN
Hydrothermal liquefaction (HTL) of nine algae species were performed at two reaction temperatures (280 and 320°C) to compare the effect of their biomass composition on product yields and properties. Results obtained after HTL indicate large variations in terms of bio-oil yields and its properties. The maximum bio-oil yield (66wt%) was obtained at 320°C with a high lipid containing algae Nannochloropsis. The higher heating value of bio-oils ranged from 31 to 36MJ/kg and around 50% of the bio-oils was in the vacuum gas oil range while high lipid containing algae Nannochloropsis contained a significant portion (33-42%) in the diesel range. A predictive relationship between bio-oil yields and biochemical compositions was developed and showed a broad agreement between predictive and experimental yields. The aqueous phases obtained had high amount of TOC (12-43g/L), COD (35-160g/L), TN (1-18g/L), ammonium (0.34-12g/L) and phosphate (0.7-12g/L).
Asunto(s)
Biocombustibles , Chlorophyta , Biomasa , Cromatografía de Gases y Espectrometría de Masas , Aceites , TemperaturaRESUMEN
Removal of nutrients (phosphorus and nitrogen) as struvite from bio-oil aqueous phase generated via hydrothermal liquefaction of algae was evaluated in this study. Effect of process parameters such as pH, temperature and reaction time on struvite formation was studied. More than 99% of phosphorus and 40-100% ammonium nitrogen were removed under all experimental conditions. X-ray diffraction analysis confirmed the formation of struvite, and the struvite recovered from bio-oil aqueous phase can be used as a slow-release fertilizer. Biogas production from struvite recovered bio-oil aqueous phase showed 3.5 times higher CH4 yield (182±39mL/g COD) as compared to non-struvite recovered aqueous phase. The results from this study indicate that both struvite and methane can be produced from bio-oil aqueous phase.
Asunto(s)
Biocombustibles , Biotecnología/métodos , Microalgas/metabolismo , Nitrógeno/aislamiento & purificación , Fósforo/aislamiento & purificación , Aceites de Plantas/química , Temperatura , Agua/química , Compuestos de Amonio/análisis , Anaerobiosis , Análisis de la Demanda Biológica de Oxígeno , Biotecnología/economía , Fertilizantes , Metano/análisis , Fosfatos/análisis , Estruvita/análisis , Aguas Residuales/químicaRESUMEN
Hydrothermal liquefaction of wet biomass such as algae is a promising thermochemical process for the production of bio-oil. Bio-oil aqueous phase generated during liquefaction process is rich in complex organics and can be utilized for biogas production following its pre-treatment with granular activated carbon. In our study, use of 30% activated carbon resulted in higher chemical oxygen demand (COD) reduction (53±0.3%) from aqueous phase. Higher CH4 production (84±12mL/gCOD) was also observed in 30% carbon-treated aqueous phase fed cultures, whereas only 32±6mLCH4/gCOD was observed in control (non-carbon treated) cultures. The results from this study indicate that almost 67±0.3% initial COD of aqueous phase can be reduced using a combination of both carbon treatment and biogas production. This study shows that aqueous phase can be utilized for CH4 production.