Computer-aided environmental and exergy analysis as decision-making tools for selecting bio-oil feedstocks

Abstract

In recent decades, there is an increasing interest to gradually replace fossil energy sources because of the environmental concerns associated to their use. Therefore, promising renewable energy sources such as bio-oil have attracted great attention. The aim of this work is to provide insights into the application of computer-aided tools for decision-making related to renewable energy-based projects. The influence of feedstocks on the process design for producing bio-oil is evaluated from environmental and exergy viewpoints. To this end, two different feedstocks were selected: (i) mixture of banana empty fruit bunches/corn stover, and (ii) microalgae Chlorella sp. The processing topologies for bio-oil production were simulated using Aspen Plus ®, considering parameters such as operating conditions (temperature, pressure, among others). Exergy analysis was developed based on extended mass/energy balances, heat of reactions, work, among other parameters derived from process simulation. The Waste Reduction (WAR) algorithm was then applied to perform environmental analysis calculating potential environmental impacts. Thus, this work presented the exergetic and environmental comparison of two different low-cost feedstocks for renewable energy production. Results revealed that algal processing topology is the most convenient alternate based on exergy efficiency (⁓24%) and environmental performance (2.13×10-2 PEI output/kg; −3.22×10+1 PEI generated/kg).