Affiliation:
1. University of South Africa (UNISA)
Abstract
The innovative G-H graphical technique, a plot of Enthalpy vs Gibbs free energy was utilized to obtain a thermodynamically attainable region (AR) for the gasification of waste tyres. The AR is used to examine the interaction between the competing reactions in a gasifier and used to identify optimal targets for the conversion of waste tyres. The objective is to investigate the effect of temperature on the product selectivity. a temperature range of 25-1500°C at 1 bar was used for the analysis. The results show that at temperatures from 200°C to 600°C methane and carbon dioxide are dominant products at minimum Gibbs free energy. However, as the temperature increases, methane production decreases and hydrogen production become more favourable. Between 600°C and 700°C, carbon dioxide and hydrogen are dominant products. The AR results show that the products of gasification (CO and H2) are preferred products at minimum Gibbs free energy only at temperatures from 800°C to 1500°C, when both water and oxygen are used as oxidants. Therefore, syngas production from tyres is only feasible at high temperatures. Temperatures above 1000°C are recommended to prevent the formation of intermediate radicals.
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics,General Materials Science
Reference14 articles.
1. Mavukwana, A. E. (2016). Development of a simulation model for gasification of South African solid waste: waste tyres and agricultural residue (Doctoral dissertation, University of Johannesburg).
2. Oboirien, B.O., & North, B.C. (2017). A review of waste tyre gasification. Jour of Environ-mental Chemical Engineering, 5(5), 5169-5178. https://doi.org/10.1016/j.jece.2017.09.057.
3. Van Staden, P.A.J. (2012). A feasibility study to establish the preferred environmentally-friendly utilisation option in respect of waste tyre materials in South Africa (Doctoral dissertation, Stellenbosch: Stellenbosch University).
4. Portofino, S., Casu, S., Iovane, P., Russo, A., Martino, M., Donatelli, A., & Galvagno, S. (2011). Optimizing H2 Production from Waste Tires via Combined Steam Gasification and Catalytic Reforming. Energy & Fuels, 25(5), 2232-2241. https://doi.org/10.1021/ef200072c.
5. Sempuga, B.C., Hausberger, B., Patel, B., Hildebrandt, D., & Glasser, D. (2010). Classification of Chemical Processes: A Graphical Approach to Process Synthesis to Improve Reactive Process Work Efficiency. Industrial & Engineering Chemistry Research, 49(17), 8227-8237. https://doi.org/10.1021/ie100288h.