(444a) Production of Levulinic Acid in Integrated Biorefineries from Municipal Solid Waste

Demand for material goods is expected to increase due to rising human population and managing municipal solid waste (MSW) resulting after consumption will be challenging. This will require holistic integration of waste processing for efficient resource use, and minimisation of environmental impacts, through pursuit of a circular economy [1]. Integrated waste biorefinery systems are a promising solution for profitable and sustainable waste valorisation [2]. This paper reports an integrated conceptual mechanical biological chemical treatment (MBCT) system in the form of an advanced biorefinery system, for the production of levulinic acid to increase economic margin of municipal solid waste processing by 110-150% [3]. After mechanical separation recovering recyclables, metals (iron, aluminium, copper) and refuse derived fuel (RDF), lignocelluloses from remaining municipal solid waste (MSW) are extracted by supercritical-water. This lignocellulosic stream is then valorised by a chemical process comprising hydrolysis in dilute H₂SO₄ catalyst producing LA as main product and an effluent stream containing some furfural and formic acid (FA). This effluent and the pulping effluent are anaerobically digested into biogas and fertiliser. Produced biogas (6.4 MWh/t), RDF (5.4 MWh/t), char (4.5 MWh/t) are combusted, heat recovered into steam generation in boiler (efficiency: 80%); on-site heat/steam demand is met; balance of steam is expanded into electricity in steam turbines (efficiency: 35%). The economic margin (product prices â?? annual cost â?? MSW cost) of the system is 118 Euro/t MSW, with margin of various products, decreasing in the order chemical > metals > fuel > energy > composting, respectively. Value analysis shows diversion of compost like output into chemical eliminates needs for gate fees. This conceptual system demonstrates how the judicious application of process integration combined with economic value and life cycle analyses allows generating competitive and environmentally friendly municipal solid waste biorefinery systems and can contribute to the development of a circular economy.

[1] Satchatippavarn S, Martinez-Hernandez E, Hang MYLP, Leach M, Yang A. Urban biorefinery for waste processing. Chemical Engineering Research and Design 2015; 107, 81-90.

[2] Sadhukhan J, Ng KS, Martinez-Hernandez E, Biorefineries and Chemical Processes: Design, Integration and Sustainability Analysis. Wiley, Chichester, UK, 2014.

[3] Sadhukhan J, Ng KS, Martinez-Hernandez E, Novel integrated mechanical biological chemical treatment (MBCT) systems for the production of levulinic acid from fraction of municipal solid waste: A comprehensive techno-economic analysis. Bioresource Technology 2016. In press.