Surrogate model for improved simulations of small-scale sludge incineration plants

Žnidarčič, Anton (author), Seljak, Tine (author), Katrašnik, Tomaž (author)

Although various modelling approaches exist for the simulation of solid fuel combustion, no specific model hasbeen developed for the accurate description of gas-phase combustion in small-scale combustion devices. This isparticularly limiting in scenarios when volatile-rich, complex and incompletely described solid fuels such assewage sludge are used. To address this issue, an accurate description of combustion from the fuel bed onwardsis required as well as an improved description of emitted volatiles. This paper introduces an innovative surro-gate-based combustion model that combines data on sludge devolatilisation and measured combustion char-acteristics to offer a new surrogate composition. The composition includes heavy hydrocarbon species to ac-curately describe combustion evolution. A sensitivity analysis revealed that H2contributes significantly tocombustion evolution, while the most robust surrogate composition is obtained when ethanol is used as a leadingrepresentative of heavier hydrocarbons. The model can be used to produce suitable surrogates for the mainsludge combustion interval, offering the required improvement in fuel descriptions and accuracy of simulationsin the vicinity of the fuel bed. Hence, this model is particularly suitable for the optimisation of temperature, heatrelease rate, and concentration field in combustion chambers with limited volumes.

• Language: English
• Keywords: sewage sludge, combustion, detailed reaction kinetics, volatiles, 3D CFD numerical simulations
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Year: 2020
• Number of pages: Str. 1-15
• Numbering: Vol. 280
• PID: 20.500.12556/RUL-119391
• UDC: 519.876.5:662.581(045)
• ISSN on article: 0016-2361
• DOI: 10.1016/j.fuel.2020.118422
• COBISS.SI-ID: 25534979
• Publication date in RUL: 08.09.2020

Secondary language

• Language: Slovenian
• Keywords: odpadni mulj, zgorevanje, detajlna kemijska kinetika, volatili, 3D CFD numerične simulacije