Optimization of Combustion Behavior and Producer Gas Quality from Reclaimed Landfill Through Highly Densify RDF-Gasification

Abstract

The growth in population, technology, and economy are resulting in the rapid increase of Municipal Solid Waste (MSW), which has a significant direct impact to the environment. MSW is generally disposed by landfill, which requires a lot of land space. Moreover, it is considered as a non-sustainable solution, by which only decomposable material is decayed where plastic and paper still remain inside. In order to provide the land space for recently large amount of waste, the old MSW need to be reclaimed and used as alternative fuel for sustainable disposal and converted into green and clean energy through gasification process. However, using an as-receive reclaimed product faces the challenges of combustion behaviour because it is non-homogeneous and loosens. This study discusses the improvement of the characteristics of the as-received reclaimed product by converting it into high density Refuse Derived Fuel (RDF). The surrogate reclaimed landfill RDF used has been made of waste plastic (polyethylene) and paper with a ratio of 75:25%-wt. After densification by extrusion, RDF-5 has a density higher than 600kg/m3. The experiment was conducted in a laboratory scale downdraft gasifier by feeding surrogate RDF 10kg/hr with the air flow rate 12, 15 and 18 Nm3/hr, respectively. Charcoal was added as an additive at the same weight of RDF in order to increase the fraction of fixed carbon and improve concentration of producer gas. The influences of the additive on the producer gas concentration and combustion characteristics were investigated. Results showed highest CO% and LHV were affected by air flow rate of 12 Nm3/hr at 22.02%-vol and 4.39MJ/Nm3, respectively, whereas highest H2% was obtained with air flow rate of 15 Nm3/hr. It was found that the densification of the reclaimed landfill and the mixing of the additive optimized the combustion behavior in terms of temperature distribution along the gasifier height and improved the producer gas quality.