Combined Partial Oxidation and Carbon Dioxide Reforming Process: A Thermodynamic Study
DOI : 10.3844/ajassp.2011.9.14
American Journal of Applied Sciences
Volume 8, Issue 1
Problem statement: CO2 reforming is one of the methods to utilize a greenhouse gas to produce syngas, an important feed for methanol and Fischer-Tropsch synthesis. However, CO2 reforming is strong endothermic reaction requiring large amount of supplied energy. Partial oxidation, an exothermic reaction, is combined with CO2 reforming to serve the energy requirement. Thus, the optimum ranges of O2 and CO2 fed to the process corresponding to feedstock are needed to find. Moreover, one of the most important problems found in this process is solid carbon formation. Therefore, the operating range in which the carbon formation can be avoided is also required to study. Approach: In this study CH4 was used as feedstock. The optimum rage of O2 and CO2 fed to the process was found by using thermodynamic equilibrium method based on minimization of Gibbs free energy. The Lagrange multiplier method was conducted to form the equations and they were solved by the Newton-Raphson method. The solid carbon formation zone was also simulated. Results: The simulation showed that higher reaction temperature caused higher CH4 and CO2 conversions. Syngas production increased with increasing temperature. Operating the process with high temperature or high O2/CH4 and CO2/CH4 rations could eliminate solid carbon formation. Increase of O2/CH4 ration higher than 0.1 led decreasing syngas while increase of CO2/CH4 ration caused increasing H2 and CO. However, when CO2/CH4 ration was higher than 0.85, increasing CO2/CH4 ration showed insignificant change of syngas concentration. Conclusion: The combined partial oxidation and CO2 reforming of method should be operated with reaction temperature of 1050 K. The optimum range of CH4:CO2:O2 for this process is 1: 0.85-1.0:0.1-0.2.
© 2011 Sompop Jarungthammachote. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.