Mechanism of highly efficient oil removal from spent hydrodesulfurization catalysts by ultrasound-assisted surfactant cleaning methods

Maolin Tian ¹, Hongtao Liu ¹, Jian Cui ¹

⁰College of New Energy and Materials, China University of Petroleum, Beijing 102249, China; State Key Laboratory of Heavy Oil, China University of Petroleum, Beijing 102249, China.

Journal of Hazardous Materials +

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May 8, 2024

View abstract on PubMed

Summary

This study introduces an effective ultrasound-assisted surfactant cleaning method to remove crude oil from spent hydrodesulfurization catalysts. The green and economical process significantly reduces oil residue and offers cost savings compared to traditional methods.

Area Of Science

Materials Science
Chemical Engineering
Environmental Science

Background

Spent hydrodesulfurization (HDS) catalysts contain valuable metals, but crude oil removal is a critical preliminary step.
Traditional roasting methods for oil removal are inefficient and have significant limitations.
Developing an efficient, environmentally friendly, and economical oil removal process is essential for catalyst recycling.

Purpose Of The Study

To develop and evaluate an ultrasound-assisted surfactant cleaning method for removing crude oil from spent HDS catalysts.
To investigate the underlying mechanism of the cleaning process through experimental and computational analysis.
To assess the techno-economic feasibility and environmental impact of the proposed method compared to traditional roasting.

Main Methods

Surfactant selection based on interfacial tension (IFT) tests, with SDBS and TX-100 identified as optimal.
Computational analysis of surfactant properties including frontier molecular orbitals, electrostatic potential, and polarity.
Application of ultrasound-assisted surfactant cleaning under optimized conditions.
Techno-economic evaluation comparing the new method with the roasting process.

Main Results

The ultrasound-assisted surfactant cleaning method effectively removed crude oil, reducing residue to 0.25% under optimal conditions.
SDBS and TX-100 surfactants exhibited high interfacial reactivity due to their electronic properties (lowest LUMO-HOMO energy gap).
The process demonstrated operational simplicity, was emission-free, and offered cost savings of $0.38 per kg of spent HDS catalyst compared to roasting.

Conclusions

Ultrasound-assisted surfactant cleaning is a highly effective, green, sustainable, and economical alternative to traditional roasting for oil removal from spent HDS catalysts.
The study provides a comprehensive understanding of the cleaning mechanism, highlighting the role of surfactant properties and ultrasonic enhancement.
This method facilitates efficient metal recovery from spent catalysts while minimizing environmental impact and operational costs.

Keywords:

Oil removal mechanism Spent HDS catalysts Surfactants Ultrasound methods

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The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.

The illustrated image represents the reaction diagrams for an endothermic chemical process progressing in the absence (red curve) and presence (blue curve) of a catalyst.