Entrained Flow Plasma Gasification of Sewage Sludge–Proof-of-Concept and Fate of Inorganics

Abstract

Sewage sludge is a residue of wastewater processing that is biologically active and consists of water, organic matter, including dead and living pathogens, polycyclic aromatic hydrocarbons, and heavy metals, as well as organic and inorganic pollutants. Landfilling is on the decline, giving way to more environmentally friendly utilisation routes. This paper presents the results of a two-stage gasification–vitrification system, using a prototype-entrained flow plasma-assisted gasification reactor along with ex situ plasma vitrification. The results show that the use of plasma has a considerable influence on the quality of gas, with a higher heating value of dry gas exceeding 7.5 MJ/mN3, excluding nitrogen dilution. However, dilution from plasma gases becomes the main problem, giving a lower heating value of dry gas with the highest value being 5.36 MJ/mN3 when dilution by nitrogen from plasma torches is taken into account. An analysis of the residues showed a very low leaching inclination of ex-situ vitrified residues. This suggests that such a system could be used to avoid the problem of landfilling significant amounts of ash from sewage sludge incineration by turning inorganic residues into a by-product that has potential use as a construction aggregate.

Conversion of Syngas from Entrained Flow Gasification of Biogenic Residues with Clostridium carboxidivorans and Clostridium autoethanogenum

“…Possibilities to increase the H 2 content in a syngas can be the addition of steam to the gasification agent, but might not be sufficient to reach 2:1 [63]. Plasma entrained flow gasification with steam as gasification agent could possibly achieve the necessary H 2 :CO ratio, but is still at a rather low technology readiness level [64][65][66]. Additionally, hydrogen addition to the syngas from other sources such as chloralkali electrolysis, polymer electrolyte membrane electrolysis (PEM) or a subsequent water-gas shift reactor could be applied to achieve the necessary H 2 :CO ratio.…”

Advancing Sustainable Decomposition of Biomass Tar Model Compound: Machine Learning, Kinetic Modeling, and Experimental Investigation in a Non-Thermal Plasma Dielectric Barrier Discharge Reactor

“…A dual technique for calculating the apparent decomposition constant is using the regression technique by analyzing the experimentation results using Equation (12). The other method is the differentiation method for a model in MATLAB R-21 for dC a /dt Vs t. The reaction rate constant by the regression technique is 0.040 (L/kJ), as shown in Figure 5.…”

“…It is a predominant resource in thermochemical processes, i.e., gasification and pyrolysis, to simultaneously produce heat and clean energy [5][6][7][8]. Typically, producer gas consists of H 2 , CO, CO 2 , CH 4 , as well as other hydrocarbons, and N 2 if air is used as a gasifying agent [9][10][11][12]. Among the variety of hydrocarbons produced during gasification, one should distinguish tars, which are problematic in terms of downstream processing of the producer gas [13][14][15][16].…”

Investigation of plasma parameters, distributions, and optical emission for the anti-microbial performance of non-woven fabric under direct current glow discharge

“…Over the past two decades, numerous articles have been published on non-thermal plasma glow discharges using atmospheric pressure of plasma jet (APPJ), radiofrequency (RF), and Direct Current (DC) for various applications such as etching, coating, disinfection, sterilization, medical applications, and woven and non-woven fabric treatment [ [6] , [7] , [8] ]. Additionally, many studies have focused on thermal plasma using plasma gasification reactors for the treatment of different wastes, solid, plastic, scrap tires, medical, and grey water, and plasma gasification is considered a source for energy recovery by converting different wastes into syngas, pyrolysis oil, diesel oil, carbon, and slug [ [9] , [10] , [11] , [12] ].…”