We have developed a novel thermal carbon analysis (TCA) method that provides both carbon mass balance and thermal fractionation profiles. Though not providing chemical structural information, this method enables a comprehensive characterization of both lignin and its degradation products, potential renewable and sustainable feedstocks. TCA is essential as a complement to a qualitative chemical speciation by thermal desorption–pyrolysis gas chromatography–mass spectrometry (TD–Py–GC–MS). Mono- and diaromatic oxygenated compounds were used as model compounds to optimize the method. The influence of various parameters such as solvents, amounts of sample loaded, and temperature ramp configuration, were investigated. A multistep temperature program with TD and pyrolytic temperatures with and without oxygen was employed for analysis of untreated lignin, where up to 55 wt % evolved in the presence of oxygen only, this fraction being unaccounted for by currently used methods. The TCA results were supported by thermogravimetric analysis with a matching heating ramp resulting in a similar mass distribution; however, TCA has the advantage of being selective for carbon. For lignin degradation products, the TD steps of TCA yielded similar recoveries as a solvent extraction followed by GC–MS. Thus, TCA may be used for screening significant product fractions to quantify the previously uncharacterized oligomer/polymer and char fractions.

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The production of microalgae as a fatty acid oil resource for use in biofuels production is a widespread research topic at the lab scale. Microalgae contain a higher lipid content on a dry-weight basis compared to oilseeds such as soybeans. Additionally, the growth and cultivation cycle of microalgae is 15 days, in comparison to soybeans, for which the cycle occurs once or twice annually. However, to date, it has been uneconomical to produce microalgae oils in a world-scale facility due to limitations in cultivating microalgae at commercial scales. Recent developments suggest that the use of heterotrophic microalgae may be economically feasible for large-scale oil production. To assess this feasibility, a comparative scoping study was performed analysing the feasibility of an industrial-scale process plant for the growth and extraction of oil from microalgae. Processes were developed at the preliminary design level using heterotrophic subspecies and autotrophic subspecies of Chlorella vulgaris. AACE Class 4 cost estimates and economic analyses were performed. This study concludes that processes based on heterotrophic microalgae are more likely to reach economic feasibility than processes using autotrophic microalgae. However, a few barriers still remain to achieving free-market economic viability.