4-E (Environmental, Economic, Energetic and Exergetic) analysis of slow pyrolysis of lignocellulosic waste

E. TORRES; L. RODRIGUEZ-ORTIZ; D. ZALAZAR GARCÍA; M. ECHEGARAY; R. RODRIGUEZ; H. ZHANG; G. MAZZA

RENEWABLE ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2020 vol. 162 p. 296 - 307

0960-1481

The bio-waste slow pyrolysis process is assessed by fourindicators to determine its energetic, exergetic, economic and environmentalperformance. The influence of the pyrolysis temperature (300-800 ºC) on theseparameters, but also on the biochar, bio-oil and gas production, is analysed.The biochar yield decreased 10.5% and the gas yield increased 17.2% between 300and 800 ºC. The bio-oil yield increased about 2.1 % between 300 and 500 ºC and decreasedabout 8 %between 500 and 800 ºC. Within the temperaturerange 300-800 ºC, the H2, CO and CH4 molar fractionsincreased 51.4, 6.6 and 0.3 %, respectively. CO2 content decreasedabout 58.3%. The exergy efficiency varied between 81.16 and85.33 %in this temperature range. The exergy-based economic factor revealed that 15.38 - 19.16 % of the total cost was associated with theexergy destruction. The environmental impact was lower at higher temperatures.The recommended temperature range is 300-400 ºC to produce biochar, andtemperatures of over 700 ºC to produce gas. When the interest focus is on thebio-oil, it is recommended to work close to 500 ºC.