Pyrolysis and Gasification of a Real Refuse-Derived Fuel (RDF): The Potential Use of the Products under a Circular Economy Vision

Abstract

Refuse-Derived Fuels (RDFs) are segregated forms of wastes obtained by a combined mechanical–biological processing of municipal solid wastes (MSWs). The narrower characteristics, e.g., high calorific value (18–24 MJ/kg), low moisture content (3–6%) and high volatile (77–84%) and carbon (47–56%) contents, make RDFs more suitable than MSWs for thermochemical valorization purposes. As a matter of fact, EU regulations encourage the use of RDF as a source of energy in the frameworks of sustainability and the circular economy. Pyrolysis and gasification are promising thermochemical processes for RDF treatment, since, compared to incineration, they ensure an increase in energy recovery efficiency, a reduction of pollutant emissions and the production of value-added products as chemical platforms or fuels. Despite the growing interest towards RDFs as feedstock, the literature on the thermochemical treatment of RDFs under pyrolysis and gasification conditions still appears to be limited. In this work, results on pyrolysis and gasification tests on a real RDF are reported and coupled with a detailed characterization of the gaseous, condensable and solid products. Pyrolysis tests have been performed in a tubular reactor up to three different final temperatures (550, 650 and 750 °C) while an air gasification test at 850 °C has been performed in a fluidized bed reactor using sand as the bed material. The results of the two thermochemical processes are analyzed in terms of yield, characteristics and quality of the products to highlight how the two thermochemical conversion processes can be used to accomplish waste-to-materials and waste-to-energy targets. The RDF gasification process leads to the production of a syngas with a H2/CO ratio of 0.51 and a tar concentration of 3.15 g/m3.

The Future of Graphene: Preparation from Biomass Waste and Sports Applications

“…MSW is a heterogeneous waste stream, which is an inevitable part of daily life [120], characterized by complex components and a high organic content. On average, 0.74 kg of waste is generated per person per day globally.…”

Use of By-Products from Gasification and Carbonization from Polymeric Residues and Biomass for Application in Liquid Phase Adsorption

“…Reactivity and mass variation occur with incidence in the range between 250 • C and 550 • C, and the final residual mass reaches very high values, around 50%. It is worth noting the appearance of a peak in the higher temperature range, around 725 • C, which is related to the final mass loss around 700 • C, due to the decomposition of carbonates [22].…”

“…This reality is leading the scientific community to continue to look for applications for this type of by-product, which may involve the use of physical and chemical modification processes, such as activation processes, to improve their physical and chemical properties. When biomass materials are used in these thermochemical processes, the large amounts of char become a good precursor to produce activated char [7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Another stage of the process that is sometimes important to consider and explore is the pre-treatment of waste, particularly biomass, which can influence these results [12,13].…”

Physical Chemistry Supports Circular Economy: Toward a Viable Use of Products from the Pyrolysis of a Refuse-Derived Fuel and Granulated Scrap Tire Rubber as Bitumen Additives

“…Pyrolysis products were characterized by elemental and proximate analyses, thermogravimetry (both in inert and oxidative atmospheres) and gas-chromatography coupled with mass spectrometry (GC-MS) as reported elsewhere [67].…”

“…The bio-oil sample from RDF was rich in plastic derived species [67] and oxygenated species derived from cellulose-containing materials (paper and wood), while the one from WTR was richer in aromatic species such as stable monoterpenes like limonene [72].…”