Steam gasification of lime dried sewage sludge: Effects of temperature and addition of lime

Статья в журнале
Lin D. , Kai W. , Xie X. , Kozlov A. , Penzik M. , Li B.
Fuel
2024
Gasification shows great potential as an alternative method for energy utilization from sewage sludge. Lime (CaO) is a cheap and commonly used dewatering conditioner for sewage sludge. The calcium hydroxide (Ca(OH)2) generated during the drying process with lime can enhance the pH level of the sludge, thereby providing disinfection properties. This paper investigated enhancement mechanism of Ca(OH)2 on hydrogen gas generation and the effect on gas product yield during the steam gasification process of lime-dried sludge. The experiments were conducted in an electrically heated reactor at 500–800 °C. The forms of calcium present in the gasified sludge char samples were analyzed using X-ray diffraction (XRD) analysis to investigate their transformation process. Fourier transform infrared spectroscopy (FTIR) was utilized to obtain information regarding the chemical structure in the gasified sludge char samples, with the aim of exploring the mechanism behind hydrogen production from lime-dried sludge. The results indicate that the CaO generated from Ca(OH)2 dehydration acts both CO2 adsorbent and catalyst during the gasification process. The addition of Ca(OH)2 during the sewage sludge gasification process leads to a reduction in the aromatic C–H content in the organic matter, while significantly increasing the content of reactive CH3-chains. It also promotes the ring-opening and rearrangement reactions of aromatic hydrocarbons and nitrogen-containing heterocycles and steam reforming reaction of tar. The combined effects of these factors contribute to an overall increase in hydrogen gas yield. © 2024 Elsevier Ltd

Библиографическая ссылка

Lin D. , Kai W. , Xie X. , Kozlov A. , Penzik M. , Li B.  Steam gasification of lime dried sewage sludge: Effects of temperature and addition of lime // Fuel. Vol.371. ID:131932. 2024. DOI: 10.1016/j.fuel.2024.131932
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