Modeling and Simulation of a Waste Tire to Liquefied Synthetic Natural Gas (SNG) Plant

Thermochemical conversion of solid wastes through gasification offers the dual benefit of production of high-value fuels from the recovered energy and environmentally friendly waste disposal. Waste tires in particular may be a suitable feedstock for gasification as a result of their high energy content (LHV of 34 MJ/kg, higher than coal), high volatile matter, and low ash content. Rotary kilns for steam gasification are a promising and technologically mature option to handle such difficult solid wastes that have a wider range of compositions, particle sizes, and moisture contents. In this paper, we propose a novel process for production of liquefied synthetic natural gas (SNG) and electricity from waste tires through the syngas route. We use experimental data available in the open literature to represent the complex steam gasification unit operation and use modeling and simulation techniques for the other units to evaluate the technological feasibility and thermodynamic performance of the proposed process. The process has an energy efficiency of 57.1%LHV and as such shows promise as an alternative for recovery of energy and material from waste. However, further technoeconomic and life cycle analyses are required prior to process optimization in order to improve performance.