Optimization of process parameters for conventional pyrolysis of algal biomass into bio-oil and bio-char production

The current study involves the conventional pyrolysis of algal biomass under a batch fixed-bed reactor for the analysis of temperature, retention time, N2 flow rate on pyrolysis product yields Response Surface Methodology by Box-Behnken Design method was used for obtaining optimum parameters. The operating conditions were varied in the range of 450-575 degrees C, 30-60 min and 0.1-0.5 l/min, respectively. The regression model with 95% confidence level resulted in the high value of R2=98.42% with R2 adjusted=95.59% indicating excellent fit of the data to the model. A maximum yield of 20.1% (organic) + 20.62% (aqueous) by weight of bio-oil obtained at a pyrolysis temperature 575 degrees C, retention time 45 min and N2 flow rate 0.5 l/min. The Fourier transform infrared analysis study represents a reduction in the quantities of O-H (hydroxyl), C-H (alkanes), C--O (esters), -C-H (alkenes), and C-O (primary alcohol) groups, under algal biomass at the expanding pyrolysis temperatures. The gas chromatography-mass spectroscopy investigation showed highest concentrations of 4-Methylpentanamide, n-Heptadecane, 2-Methyl naphthalene and n-Hexadecanoic acids in bio-oil.

Automated summary

In this study, the conventional pyrolysis of algal biomass was conducted in a batch fixed-bed reactor to analyze the effects of temperature, retention time, and N2 flow rate on pyrolysis product yields. The Box-Behnken Design method was used to obtain optimum parameters. The regression model showed a high R2 value of 98.42% and R2 adjusted value of 95.59%, indicating a good fit of the data to the model. The analysis revealed that the maximum yield of bio-oil was obtained at a pyrolysis temperature of 575 degrees C, retention time of 45 min, and N2 flow rate of 0.5 l/min. Fourier transform infrared analysis showed a reduction in various functional groups, while gas chromatography-mass spectroscopy identified specific compounds in the bio-oil.