Exergoeconomic analysis of Kraft Lignin oxidative depolymerization in a biorefinery

Lignin as a plentiful biopolymer with an aromatic structure is proper for producing biobased chemical materials in the biorefinery. Inasmuch as optimal energy consumption is necessary for community development, exergoeconomic and sensitivity analyses are done to decrease waste production and increase energy efficiency in this unit. So in this study, an exergoeconomic analysis is performed on a process for oxidative lignin depolymerization through exergy, cost, energy, and mass method. A thermodynamic model is made in Aspen-plus simulation software to simulate this process and also for the investigation of exergy and energy analyses. Then, equipment exergoeconomic variables such as cost rate of exergy destruction, exergoeconomic factor, and relative cost difference are calculated. According to the common exergy analyses, the highest destruction of exergy takes place in a cooler (E - 2) with a value of 685.4 kW. Also, the most efficiencies of exergy are pertaining to the Heater with cooler and mixer with separation with the values of 51.17% and 21.88%, respectively. Also, the results of exergy analyses show cooler (E - 2) (4.94 $/h) and one of the separator (S - 4) (0.0023 $/h) have the greatest and smallest destruction of exergy cost rate, respectively. Also, the outcomes indicate that separator (S - 4) (99.46%) and condenser (E - 4) (7.03%) have the greatest and smallest exergoeconomic factor, respectively.

Automated summary

This study conducted an exergoeconomic analysis on the process of oxidative lignin depolymerization, aiming to reduce waste production and increase energy efficiency. The results showed that the cooler and one of the separators had the highest and lowest destruction of exergy cost rate, respectively, and the heater with cooler and mixer with separation had the highest efficiencies of exergy.