H2-rich syngas production from gasification involving kinetic modeling: RSM-utility optimization and techno-economic analysis

Abstract

In this research article, H₂ rich syngas production is optimized using response surface methodology (RSM) and a utility concept involving chemical kinetic modeling considering eucalyptus wood sawdust (CH_1.63O_1.02) as gasification feedstock. By adding water gas shift reaction, the modified kinetic model is validated with lab scale experimental data (2.56 ≤ root mean square error ≤ 3.67). Four operating parameters (i.e., particle size “d_p”, temperature “T”, steam to biomass ratio “SBR”, and equivalence ratio “ER”) of air–steam gasifier at three levels are used to frame the test cases. Single objective functions like H₂ maximization and CO₂ minimization are considered whereas for multi-objective function a utility parameter (80% H₂ : 20% CO₂) is considered. The regression coefficients (R_H2² = 0.89, R_CO2² = 0.98 and R_U² = 0.90) obtained during the analysis of variance (ANOVA) confirm a close fitting of the quadratic model with the chemical kinetic model. ANOVA results indicate ER as the most influential parameter followed by T, SBR, and d_p. RSM optimization gives H₂|_max = 51.75 vol%, CO₂|_min = 14.65 vol% and utility gives H₂|_opt. = 51.69 vol% (0.11%↓), CO₂|_opt. = 14.70 vol% (0.34%↑). The techno-economic analysis for a 200 m³ per day syngas production plant (at industrial scale) assured a payback period of 4.8 (∼5) years with a minimum profit margin of 142% when syngas selling price is set as 43 INR (0.52 USD) per kg.