A pyrolysis process coupled to a catalytic cracking stage: A potential waste-to-energy solution for mattress foam waste

Abstract

Pyrolysis coupled to either thermal or catalytic cracking of mattress foam waste was performed in a laboratory-scale facility consisting of a fixed-bed reactor joined to a tubular cracking reactor. The results showed a great potential for the production of syngas specially at high cracking temperatures. Particularly, fixing 800 °C in the cracking reactor, a CO and CH₄ rich gas with a remarkable amount of H₂ was obtained. The addition of catalysts (dolomite, olivine or HiFUEL®) significantly decreased undesirable tar formation, (below 10 wt%), simultaneously increasing the gas yield and keeping CO and CH₄ as the main components in the stream, becoming a preferable route that the non-catalytic process. Accordingly, this stream could be used preferably for further applications in energy generation because its heating value ranged between 15.7 MJ/Nm³ and 19.6 MJ/Nm³. In particular, the gas obtained by the use of dolomite could be advantageous for the production of organic compounds such as dimethyl ether (DME) as well as its use an engine or boiler to generate electricity in small facilities. In addition, the solid fraction obtained after de process could be used as a medium quality refused derived fuel (LHV ~ 12 MJ/kg) in order to support the internal energy requirements of the process.

Keywords: Mattress foam; Pyrolysis; Refuse-derived fuel; Syngas; Waste.