Article

Energy from Gasification of Solid Wastes

Department of Civil Engineering (DICIV), Università degli Studi di Salerno, Fisciano, Campania, Italy
Waste Management (Impact Factor: 3.22). 02/2003; 23(1):1-15. DOI: 10.1016/S0956-053X(02)00149-6
Source: PubMed

ABSTRACT

Gasification technology is by no means new: in the 1850s, most of the city of London was illuminated by "town gas" produced from the gasification of coal. Nowadays, gasification is the main technology for biomass conversion to energy and an attractive alternative for the thermal treatment of solid waste. The number of different uses of gas shows the flexibility of gasification and therefore allows it to be integrated with several industrial processes, as well as power generation systems. The use of a waste-biomass energy production system in a rural community is very interesting too. This paper describes the current state of gasification technology, energy recovery systems, pre-treatments and prospective in syngas use with particular attention to the different process cycles and environmental impacts of solid wastes gasification.

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    • "During gasification of MSW, the chemical energy content in the carbonaceous fractions of the waste is converted, under substoichiometric conditions, to a gaseous product or syngas [4]. As a waste-to-energy technology, gasification offers remarkable opportunities for increasing overall plant efficiencies by utilization of the syngas in higher efficiency electricity-production system, such as gas turbines, reciprocating engines [5] and fuels cells [6]. "
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    ABSTRACT: In this work a comprehensive two-dimensional CFD model was used in order to assess the potential of syngas produced from gasification of Portuguese MSW (municipal solid waste) by using a semi-industrial gasification plant. An EulerianeEulerian approach within the computational fluid dynamics Fluent framework was used to describe the transport of mass, momentum and energy for both solid and gas phases. Pyrolysis was also modeled. Numerical results were validated against experimental ones. Results were in good agreement with each other. Influence of temperature, MSW admission and equivalent ratio on products of gasification and their concentrations were studied. Considering operating conditions influence on the combustible gases, it was concluded that gasification temperature had the greatest influence on syngas heating value. After analyzing syngas composition and other gasification products the best use for a particular produced syngas was investigated. For the MSW used in this work one of the most promising uses for the obtained syngas was for chemical fuel application.
    Full-text · Article · Dec 2015 · Energy
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    • "On the other hand, gasification is a thermochemical conversion process in which oxygen, in air or pure O2, is reacted with sludge at high temperature to generate a synthetic combustible gas (syngas) and ash/slag. This syngas contains mainly CO, H 2 and N 2 , with heating values of 4-7 MJ/N m 3 (Belgiorno et al. 2003). Energy can be recovered as heat and/or electricity from fluegas/syngas , usually via combined heat and power systems (Marani, Braguglia, et al. 2003). "
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    ABSTRACT: Sewage sludge is a by-product generated from municipal wastewater treatment plants (WWTP). This study examines the conversion of sludge via gasification/combustion for energy recovery for thermal treatment of dewatered sludge. The present analysis is based on a chemical equilibrium model of thermal conversion of dewatered sludge with moisture content of 60-80%. Prior to combustion/gasification, sludge is dried to a moisture content of 25-55% by two processes: (1) heat recovered from syngas/flue gas cooling, and (2) heat recovered from syngas combustion. Gas temperature, and total heat and electricity recoverable are evaluated using this model. Results show that generation of electricity from dewatered sludge with low moisture content (Y M,dew ≤70%) is feasible within a self-sufficient sludge treatment process. Optimal conditions for gasification correspond to equivalence ratios (ER) of 2.2 and dried sludge moisture content (Y M,dry) of 25%. Electricity generated from syngas combustion can total 0.09 kWh/m 3 of wastewater treated, up to 32-36% of plant energy consumption.
    Full-text · Conference Paper · Aug 2015
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    • "Direct gasifiers normally operate using air or oxygen as oxidizing agents. In this case the heat necessary for the process is produced inside the reactor (Vitasar et al., 2011), since the oxidation reactions provide the energy to maintain the high temperature of the process (Belgiorno et al., 2003). "
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    ABSTRACT: Thermal treatment is an interesting strategy to dispose of municipal solid waste: it reduces the volume and weight of the material dumped in landfills and generates alternative energy. However, the process emits pollutants, such as dioxins and furans. The present study evaluated MSW gasification-combustion integrated technologies in terms of dioxin and furan emission; and compared the obtained data with literature results on incineration, to point out which operational features differentiate the release of pollutants by these two processes. The results show that the process of integrated gasification and combustion emitted 0.28 ng N-1 m-3, expressed in TEQ (Total Equivalent Toxicity), of PCDD/F, less than the maximum limits allowed by local and international laws, whereas incineration normally affords values above these limits and requires a gas treatment system. The distinct operational conditions of the two thermal processes, especially those related to temperature and the presence of oxygen and fixed carbon, led to a lower PCDD/F emission in gasification.
    Full-text · Article · Jan 2015 · Brazilian Journal of Chemical Engineering
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