Supercritical Water Gasification of glycerol: Continuous reactor kinetics and transport phenomena modeling

Supercritical Water Gasification of glycerol is carried out on a continuous tubular reactor at 25 MPa and 610 degrees C. A design of experiments is performed at three levels of glycerol concentration (2.5; 5; and 10%) and three levels of inflow rate (125; 250; and 375 mL/min). The process outputs are the molar production of H-2; CH4; CO2; CO; and C2H6. The influence of Stainless Steel 316 and Inconel-625 as reactor materials is compared. A compartment model is implemented considering the system as a heat exchanger in series with a wall reactor. Heat transfer influence on reactivity is successfully captured. The results are useful and accurate in describing global stoichiometry. H-2, CH4, and CO2 productivity are fairly predicted. The catalytic effect of Inconel-625 manifests from the CO2 to CO ratio when compared with Stainless Steel 316. Inconel-625 is 50% more productive in terms of C-2 hydrocarbons and 40% more active towards CH4 production, which is detrimental in 50% of the H-2 yield. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Automated summary

In this study, glycerol was gasified under supercritical water conditions using a continuous tubular reactor. The effects of glycerol concentration and inflow rate on the reaction products were investigated, and the performance of different reactor materials was compared. The results showed that heat transfer had a significant influence on reactivity, and the molar production of H-2, CH4, and CO2 could be accurately predicted. In terms of catalytic effect, Inconel-625 outperformed Stainless Steel 316 with higher productivity of C-2 hydrocarbons and CH4, but at the expense of H-2 yield.