Kraft lignin fast (catalytic) pyrolysis for the production of high value-added chemicals (HVACs): A techno-economic screening of valorization pathways

This paper presents a techno-economic analysis (TEA) of six (6) scenarios of the kraft lignin catalytic (CFP) and thermal (TFP) fast pyrolysis towards the production of high value-added chemicals (HVACs) and electric energy, based on experimental data from our previous work. ASPEN PLUS was used to simulate the proposed plants/scenarios and retrofitted custom-based economic models that were developed in Microsoft EXCEL. The results showed that scenarios 1 and 2 in which the produced bio-oil is used as fuel for electricity production are the most cost-deficient. On the other hand, scenarios 3 and 6 that utilize the light bio-oil fraction to recover distinct HVACs, along with the use of heavier fractions for electricity production, have showed a significant investment viability, since profitability measures are high. Furthermore, scenarios 4 and 5 that refer to the recovery of mixtures (fractions) of HVACs, are considered an intermediate investment option due to the reduced cost of separation. All the proposed scenarios have a substantial total capital investment (TCI) which ranges from 135 MM€ (scenario 4) to 380 MM€ (scenario 6) with a Lang factor of 6.08, which shows that the CAPEX results are within reason. As far as the comparison of lignin CFP and TFP goes, it is shown that lignin CFP leads to the production of aromatic and phenolic monomers which have a substantial market value, while TFP can lead to important value-added chemicals with a lower OPEX than CFP. A target of return of investment (ROI) of 32% has been set for the selling prices of the HVACs. In summary, this study aims at listing and assessing a set of economic indicators for industrial size plants that use lignin CFP and TFP towards the production of high value-added chemicals and energy production and to provide simulation data for comparative analysis of three bio-oil separation methods, i.e. distillation, liquid-liquid extraction and moving bed chromatography.