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

In this research article, H<INF>2</INF> rich syngas production is optimized using response surface methodology (RSM) and a utility concept involving chemical kinetic modeling considering eucalyptus wood sawdust (CH<INF>1.63</INF>O<INF>1.02</INF>) 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<INF>p</INF>", 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 H<INF>2</INF> maximization and CO<INF>2</INF> minimization are considered whereas for multi-objective function a utility parameter (80% H<INF>2</INF> : 20% CO<INF>2</INF>) is considered. The regression coefficients (R<INF>H<INF>2</INF></INF>2 = 0.89, R<INF>CO<INF>2</INF></INF>2 = 0.98 and R<INF>U</INF>2 = 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<INF>p</INF>. RSM optimization gives H<INF>2</INF>|<INF>max</INF> = 51.75 vol%, CO<INF>2</INF>|<INF>min</INF> = 14.65 vol% and utility gives H<INF>2</INF>|<INF>opt.</INF> = 51.69 vol% (0.11%down arrow), CO<INF>2</INF>|<INF>opt.</INF> = 14.70 vol% (0.34%up arrow). The techno-economic analysis for a 200 m3 per day syngas production plant (at industrial scale) assured a payback period of 4.8 (similar to 5) years with a minimum profit margin of 142% when syngas selling price is set as 43 INR (0.52 USD) per kg.