Sewage sludge gasification in a bench scale rotary kiln

Freda, Cesare; Cornacchia, Giacinto; Romanelli, Assunta; Valerio, V.; Grieco, Massimiliano

doi:10.1016/j.fuel.2017.10.013

Cited by 68 publications

(39 citation statements)

References 20 publications

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“…The abundancy of sewage sludge is now a major concern in many countries [6][7][8]. The development of sewage treatment plants, being a result of directives and large financial expenditures of the European Union [8,9], results in a significant increase in the production of sewage sludge [7,8,10]. Moreover, there are directives that significantly limit or even completely prohibit landfilling of the sewage sludge [7,11].…”

Section: Introductionmentioning

confidence: 99%

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Sewage Sludge-Derived Producer Gas Valorization with the Use of Atmospheric Microwave Plasma

Wnukowski

Kordylewski

Łuszkiewicz

et al. 2019

Waste Biomass Valor

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Atmospheric microwave plasma was applied to the processing of the partially cleaned producer gas obtained from sewage sludge gasification. The plasma processing resulted in residual tar compounds conversion and changes in the gas composition. During the tests with a different gas flow rates and microwave power inputs, liquid and gaseous samples were collected to evaluate the plasma reactor's performance. The conversion efficiency ranged from 19 to 100% and it depended on the specific energy input (SEI), gas flow rate, initial tar concentration, and the nature of the tars compounds. Generally, it was shown that the conversion rate increased with the SEI and that the aliphatic, cyclic and substituted compounds were converted much easier than benzene. Moreover, applying plasma led to the production of heavier aromatics (i.e. naphthalene, indene, acenaphthylene) but the rise in their concentration was significantly smaller than the amount of converted compounds. The gas composition changes revealed in the increase of H 2 and CO concentration that was an effect of hydrocarbons and CO 2 conversion. Additionally, it was indicated that the microwave plasma reactor's performance was noticeably worse than in the case of the laboratory test with a simulated producer gas. This was mainly attributed to differences in the reactors' geometry, lower hydrogen concentration and the presence of inorganic deposit on the reactor's walls that might have inhibited microwaves transfer. In general, the microwave plasma technology seems promising in the context of cleaning and upgrading the producer gas, however, further optimization research is necessary to make it more reliable and less energy consuming. Graphic AbstractBiomass-derived producer gas treatment in the context of tar conversion is a current and important research issue. Many plasma techniques have been investigated to solve the problem of tar's presence. However, most of them considered simplified model mixtures of gas and a model tar compound. There is a negligible amount of research that applies a real producer gas obtained in the gasification process. Moreover, none of them includes microwave plasma, which has a few promising features considering producer gas valorization. Therefore, the main goal and novelty of this work were to investigate the microwave plasma treatment of the gas derived from sewage sludge gasification and to compare it with the results obtain in laboratory research using model mixtures.

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Section: Introductionmentioning

confidence: 99%

“…The most common approach is the incineration [7,12], but it involves the emission of significant amounts of pollutants such as SO 2 , NO x , and heavy metals [7,13]. Alternatively, sewage sludge could be processed via gasification resulting in the production of valuable producer gas of flexible utility [7,10,11].…”

Section: Introductionmentioning

confidence: 99%

Sewage Sludge-Derived Producer Gas Valorization with the Use of Atmospheric Microwave Plasma

Wnukowski

Kordylewski

Łuszkiewicz

et al. 2019

Waste Biomass Valor

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“…Combustion is a predominant sludge thermal utilization technology [3]. The rotary kilns, pushing screw conveyors [4,5], and combustion in fluidized bed [6] are often used to prevent sintering in sludge combustion. Combustion generates volatile pollutants that require complex cleaning systems.…”

Section: Introductionmentioning

confidence: 99%

“…In [21], the authors demonstrate that with a switch from sludge to the mixture with a wood pellet content of 30%, chemical efficiency increases from 20-30% to 30-50%. However, the high fraction of sewage sludge in the mixture apart from the deterioration in gas characteristics and fuel conversion can lead to sintering and reduction in the bed permeability [4,5]. The obtained gas contains more condensate, and therefore requires additional cleaning.…”

Section: Introductionmentioning

confidence: 99%

“…The measurements made by the authors indicate that the increase in the fraction of sludge worsens the burning gas characteristics, however it facilitates a more complete conversion of the fuel mixture. Sludge pyrogasification in rotating reactor (for elimination of sintering problems) was performed in [5], where authors report on the 67% cold gas efficiency, which is achieved owing to the external heat supply, though. In [26], the authors propose an effective method of sludge gasification in water under supercritical conditions.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study on the Efficiency of Biomass and Municipal Waste Fixed-Bed Co-Gasification

Donskoy

2019

E3S Web Conf.

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The utilization of combustible waste, such as sewage sludge, can be combined with energy production for small-scale consumers. One of the ways of such utilization can be gasification, which makes it possible to obtain a combustible gas suitable for thermal and electric energy production. The aim of this study is to estimate the efficiency of sewage sludge co-conversion with woody biomass using mathematical model that allows to investigate process characteristics under different process conditions (air stoichiometric ratio, fuel mixture composition, initial moisture of sewage sludge). Dependencies of gasification process characteristics are evaluated and compared with published experimental data. Fixed-bed downdraft process is investigated related to using of wood and sewage sludge mixtures. New results are obtained considering process efficiency dependence on input fuel composition, method is proposed to estimate acceptable fuel mixtures based on agglomeration and efficiency requirements.

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