Mathematical modelling of gasification process of sewage sludge in reactor of negative CO2 emission power plant

• Published in: Energy (Oxford) Vol. 244; p. 122601
• Main Authors: Ziółkowski, Paweł, Badur, Janusz, Pawlak- Kruczek, Halina, Stasiak, Kamil, Amiri, Milad, Niedzwiecki, Lukasz, Krochmalny, Krystian, Mularski, Jakub, Madejski, Paweł, Mikielewicz, Dariusz
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2022; Elsevier BV
• Subjects: Alternative energy sources; Biological activity; Biomass; Carbon dioxide; Carbon dioxide emissions; Carbon sequestration; CCS; Chemical equilibrium; CO2 negative power plant; Contaminants; Energy balance; equations; Gasification; Heavy metals; human health; Inorganic contaminants; Mathematical models; Nuclear fuels; Organic matter; Polycyclic aromatic hydrocarbons; Power plants; propane; Renewable energy sources; Sewage disposal; Sewage sludge; Sewer gas; Sludge; Sulfur; Sulfur dioxide; Thermodynamic equilibrium; Wastewater; CCS; Gasification; Sewage sludge; Thermodynamic equilibrium; CO2 negative power plant
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2021.122601

Sewage sludge is a residue of wastewater processing that is biologically active and consists of water, organic matter, including dead and alive pathogens, as well as organic and inorganic contaminants such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Due to the nature of sewage sludge and its possible influence on human health and wellbeing, it is a subject of various regulations. Currently, sewage sludge is considered as biomass, according to the new Polish act on renewable energy sources of February 20, 2015 and its novel version of July 19, 2019. This study presents a novel model, along with a comparison with experimental results. The model could be used for sewage sludge gasification modelling for accurate assessment of the performance of novel concepts bioenergy with carbon capture and storage (BECCS) installations, using sewage sludge as a fuel. The composition of the dry produced gas, determined experimentally, yields: XCO = 0.093, XCO2 = 0.264, XCH4 = 0.139, XCxHy = 0.035, and XH2 = 0.468. Performed modifications to the original Deringer-with-Gumz-modification gasification model allowed to obtain good agreement with the experimental results, reaching XCO = 0.071, XCO2 = 0.243, XCH4 = 0.139, XC3H8 = 0.035, and XH2 = 0.512. The main novelty in the formulas of the internal model was due to propane inclusion, which was not found in the literature before. Additionally, sulphur dioxide was applied in exchange for other sulphur components presented in the original model. Equilibrium constants were adjusted to suit the experimental model. For ease of calculation, the own code was used to iterate multiple temperatures. Included was the energy balance equation that is essential for verification. •Modified Derringer-Gumz sewage sludge gasification model is introduced.•The model gave better agreement with an experiment of steam gasification.•The main modification was an introduction of reaction creating propane.•Modified model could be aimed at being used in simulations of BECCS installations.•Steam gasification is essential for swift CO2 capture post combustion in BECCS.