Technology assessment of a chemical looping-integrated biorefinery for green urea from kraft lignin: Pinch-based energy efficiency and probabilistic techno-economics

This study evaluates, at a conceptual screening level, an integrated biorefinery converting 200 tons/day of kraft lignin into green urea through gasification, chemical looping (CL), Haber-Bosch ammonia synthesis (HB), and urea production. The assessment combines ASPEN PLUS modelling, pinch-based heat integration, techno-economic analysis (TEA), and Monte Carlo analysis (MCA). At a minimum temperature approach of 10 °C, heat integration reduces external utility demand by 33.4%, from 63.3 to 42.2 Gcal/hr, and utility-related CO 2 emissions by 38.1%, providing annual operating-cost savings of $4.55 million. On an exported-product basis excluding internally consumed NH 3 , the process-level energy efficiency increases from 11.8% to 14.6%. The process produces 45.28 tons/day of net urea, together with recovered H 2 , N 2 , and lignin-derived solids. Approximately 33.2 tons/day of biogenic CO 2 is incorporated into the urea product within the defined gate-to-gate boundary. The minimum selling price of green urea is estimated at $0.53/kg, with a fixed capital investment (FCI) of $43.0 million and annual operating expenses (OPEX) of $15.37 million. MCA yields a mean net present value of $12.0 million and a 71.2% probability of positive financial performance at the MSP. Overall, the results indicate promising process-level emission-reduction and economic potential, while further kinetic, equipment-level, and life-cycle validation is required.