Plasma gasification of refuse derived fuel in a single-stage system using different gasifying agents

Abstract

The renewable evolution in the energy industry and the depletion of natural resources are putting pressure on the waste industry to shift towards flexible treatment technologies with efficient materials and/or energy recovery. In this context, a thermochemical conversion method of recent interest is plasma gasification, which is capable of producing syngas from a wide variety of waste streams. The produced syngas can be valorized for both energetic (heat and/or electricity) and chemical (ammonia, hydrogen or liquid hydrocarbons) end-purposes. This paper evaluates the performance of experiments on a single-stage plasma gasification system for the treatment of refuse-derived fuel (RDF) from excavated waste. A comparative analysis of the syngas characteristics and process yields was done for seven cases with different types of gasifying agents (CO2+O2, H2O, CO2+H2O and O2+H2O). The syngas compositions were compared to the thermodynamic equilibrium compositions and the performance of the single-stage plasma gasification of RDF was compared to that of similar experiments with biomass and to the performance of a two-stage plasma gasification process with RDF. The temperature range of the experiment was from 1400 to 1600 K and for all cases, a medium calorific value syngas was produced with lower heating values up to 10.9 MJ/Nm(3), low levels of tar, high levels of CO and H2 and which composition was in good agreement to the equilibrium composition. The carbon conversion efficiency ranged from 80% to 100% and maximum cold gas efficiency and mechanical gasification efficiency of respectively 56% and 95%, were registered. Overall, the treatment of RDF proved to be less performant than that of biomass in the same system. Compared to a two-stage plasma gasification system, the produced syngas from the single-stage reactor showed more favourable characteristics, while the recovery of the solid residue as a vitrified slag is an advantage of the two-stage set-up.

An overview of advances in biomass gasification

“…3 An example of a novel HGCU process is the use of plasma torches to crack tars; this differs from plasma gasification where the plasma is used for energy generation by gasifying biomass, MSW and refuse derived fuel (RDF). 51,52 Relevant features, advantages and limitations of these technologies are presented in Table 3.…”

The role of plasma in syngas tar cracking

“…Another advantage is the relatively low tar content of the syngas produced. Although tar is generated in the pyrolysis zone and leave the reactor before they can pass through the gasification zone in most configurations, tar-yields as high as 543 mg Nm −3 [35], and as low as <10 mg Nm −3 have been reported [36]. This is a tar-content much lower than the one found in fluidized gasifiers, where the tar yield is in the range of 1-100 g Nm −3 .…”

The Current Status of Hazardous Waste Management in China: Identification, Distribution, and Treatment

“…Thermal treatment of HW. Thermal treatments, including but not limited to incineration, smelting, and combustion, and so on, refer to the processing of HW at high temperature to destroy or reduce the toxicity of HW (Wang et al, 2009;Agon et al, 2016;Li et al, , 2018b. Thermal treatment of HW is mostly preferred to treat HW in China because of its superiorities like volume and mass reduction, energy recovery, and high efficiency (Yu et al, 2012(Yu et al, , 2015Chen et al, 2020).…”