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Experimental study on supercritical water gasification of oily sludge using a continuous two-step method.
- Source :
-
Journal of Hazardous Materials . Aug2023, Vol. 455, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
-
Abstract
- Supercritical water gasification (SCWG) technology can convert oily sludge into hydrogen-rich gas. To achieve high gasification efficiency of oily sludge with a high oil concentration under mild conditions, a two-step method involving a desorption process and a catalytic gasification process using Raney-Ni catalyst was investigated. High oil removal efficiency (99.57%) and carbon gasification efficiency (93.87%) were achieved. The lowest wastewater total organic carbon, oil content, and carbon content in the solid residues were 4.88 ppm, 0.08% and 0.88%, respectively, using a gasification temperature of 600 °C, treatment concentration of 1.11 wt%, gasification time of 70.7 s, and the optimal desorption temperature of 390 °C. The main organic carbon component in the solid residues was cellulose, which is environmentally safe. As the treatment concentration increased, the two-step method outperformed the single-step method. The mechanism for the two-step SCWG of oily sludge was revealed. In the first step, supercritical water is used in the desorption unit to achieve a high oil removal efficiency with few liquid products generated. In the second step, the Raney-Ni catalyst promotes efficient gasification of high-concentration oil at a low temperature. This research provides valuable insights into the effective SCWG of oily sludge at a low temperature. [Display omitted] • A continuous two-step method for SCWG of oily sludge was proposed. • A SCWG mechanism of two-step method for oily sludge was proposed. • The primary substance of organic carbon in solid residues is cellulose. • With increased treatment concentration, the two-step method has more significant advantages. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03043894
- Volume :
- 455
- Database :
- Academic Search Index
- Journal :
- Journal of Hazardous Materials
- Publication Type :
- Academic Journal
- Accession number :
- 163946122
- Full Text :
- https://doi.org/10.1016/j.jhazmat.2023.131619