Pyrolysis Products Separation of Lignin via Molecular Distillation and Liquid–Liquid Extraction

In this communication, two sets of experimental data on lignin pyrolysis were proposed to design processes for product separation through Aspen Plus V12.1. After simulation, a comprehensive analysis was undertaken, encompassing both techno-economic evaluations and energy analyses, utilizing Aspen Process Economic Analyzer (APEA) V12 and Aspen Energy Analyzer (AEA) V12.1. The initial phase involved the development of processes via molecular distillation, facilitating components separation. Subsequent modifications incorporated liquid–liquid-extraction technique, with a comparative assessment of system performances. Techno-economic analysis revealed that, for the first dataset, solvent extraction resulted in an 8.9% and 10.3% reduction in total capital cost and equipment cost. Conversely, for the second dataset, one-step solvent extraction incurred a 25.0% and 26.0% increase in total capital cost and equipment cost, while two-stage solvent extraction led to a more substantial rise of 52.1% and 55.4%. In parallel, energy analysis outcomes indicated that, for the first dataset and the first scenario of the second dataset, peak values were observed for heating, with ratios of heating values to the sum of cooling and process exchanger values at 55.5, 44.8, and 1.0. In alternate scenarios, cooling values surpassed cumulative sum of heating and process exchanger values, yielding ratios of 1.6 and 1.5 for cooling values to the sum of heating and process exchanger values.