Microwave pyrolysis of oily sludge under different control modes

Area of Science:

• Environmental Science
• Chemical Engineering
• Materials Science

Background:

• Oily sludge (OS) is a problematic waste from petroleum industries.
• Pyrolysis offers a sustainable method for OS treatment and resource recovery.
• Understanding the influence of microwave pyrolysis parameters is crucial for process optimization.

Purpose of the Study:

• To investigate the effects of temperature and power on oily sludge pyrolysis.
• To analyze the product distribution and characteristics, including oil, char, and gas.
• To evaluate the environmental implications of heavy metal retention in the char.

Main Methods:

• Microwave reactor used for oily sludge pyrolysis.
• Experiments conducted under varying temperature and power control modes.
• Product analysis using techniques like X-ray photoelectron spectroscopy (XPS).
• Heavy metal analysis to assess environmental risk.

Main Results:

• Maximum oil yield of 72.55 wt% at 550°C and 71.47 wt% at 800 W.
• Sulfur content in char increased with temperature/power, indicating S retention.
• Hydrocarbon content in oil reached 14.56% at 350°C and 13.40% at 900 W.
• Higher oxygenated compounds and heterocycles in oil under temperature control.
• Increased CO yield with higher temperature/power.
• Enhanced heavy metal retention in char under temperature control, with low environmental risk.

Conclusions:

• Microwave pyrolysis effectively converts oily sludge into valuable products.
• Temperature and power are critical parameters influencing pyrolysis outcomes.
• The process demonstrates potential for safe disposal of oily sludge with resource recovery and minimal environmental risk.