Produção de gás de síntese a partir da glicerina / Syngas production from glycerol

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Biodiesel (alkyls esters) is a clean burning fuel derived from renewable lipid feedstock such as vegetable oil or animal fat. Glycerin is a by-product from the biodiesel production which represents nearly 10% of product total mass. As the biodiesel production is increasing there exist incentives to use the glycerin as raw material for other processes. The glycerin pyrolysis is a promising way to produce biofuels such as hydrogen and syngas (feedstock used in synthetic fuels production via Fisher-Tropsch reaction) and at same time avoids its accumulation in the environment. Glycerin pyrolysis was carried out in a fixed bed reactor filled with silica-quartz and/or alumina oxide. The raw material considered in this work was pure glycerin and crude glycerin from biodiesel production. Experimental designs were carried out in specific conditions to identify the impact of the main process variables. At first, a fractional factorial experimental design was chosen to analyze the most significant factors (reaction temperature, reaction time, glycerin quantity and flow rate of carrier gas) on the conversion glycerin to hydrogen and syngas. The glycerin quantity was the least significant factor, so it was excluded from further investigation. Afterwards, the experiments were carried out according to a 23 complete factorial design plus three central points. Two first-order models were obtained to predict the crude glycerin conversion in hydrogen and syngas as a function of reaction temperature, reaction time and flow rate of carrier gas. From the surface methodology analysis, high conversions of glycerin into hydrogen and syngas, around 45% mol/mol and 85% mol/mol, respectively, can be obtained under the following conditions 850 º C, 30 min and flow carrier gas, 50ml/min. The best glycerin conversion to gas products was 80% v/v of glycerin. The main gás products were H2 and CO. Besides these gases, CO2, CH4, C2H4 and C3H8 were also obtained in smaller proportions. The liquid product compositions were methanol, ethanol, acetone and acetaldehyde. Through the energy calculations, it becomes clear that production of H2 from this process is energetically feasible. For one mole of glycerol, computed net energy of the reaction was around 293kJ.

ASSUNTO(S)

gás - síntese glicerina pirólise syngas glycerin pyrolysis

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