Supercritical CO2 Extraction of Oily Sludge
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Solution Overview
Problem
Current methods for processing perennially and deeply polluted sludge containing oils and water, such as those found in oil mines and refineries, are inefficient due to high energy consumption and complex solvent recovery processes, which hinder the economic viability and widespread adoption of oily sludge extraction technologies.
Innovation Solution
A processing method involving a solid substance in contact with an organic liquid solvent of low boiling point and weak polarity at room temperature under pressurized conditions, followed by solid-liquid separation, gasification separation to recover the solvent, and oil-water separation to efficiently extract and recover oil while removing water, utilizing a system comprising an extraction reactor, gas-liquid separator, dryer, and solvent storage tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If liquid solvent extraction method is used to process oily sludge, then petroleum hydrocarbons can be extracted and recovered, but a large amount of extractant is consumed and high costs are incurred
Solution Approach 1:
The patent changes the physical state parameter of the extractant from liquid to supercritical fluid by adjusting temperature and pressure parameters. This transformation reduces extractant consumption because supercritical CO2 has higher density and solubility power, allowing more efficient extraction with less solvent. The CO2 is then recovered by simply reducing pressure, avoiding the need for energy-intensive distillation.
Solution Approach 2:
The patent utilizes the phase transition of CO2 between supercritical and gaseous states. By maintaining CO2 in supercritical state during extraction (high pressure), it effectively dissolves petroleum hydrocarbons. Then by reducing pressure, CO2 transitions to gaseous state, automatically separating from the extract and enabling easy recovery and recycling of both CO2 and extracted oil without additional energy consumption.
2Loss of energy
If rectification is used to separate extractant and oil, then extractant can be recovered, but a lot of energy is consumed
Solution Approach 1:
The patent replaces the rectification process with a simple pressure reduction phase transition. Instead of heating the extract to separate CO2 from oil through distillation, the system simply reduces pressure to transition CO2 from supercritical to gaseous state. This phase change occurs at low temperature and consumes minimal energy, while still achieving complete separation and recovery of CO2 for recycling.
Solution Approach 2:
The patent replaces the thermal-mechanical rectification system with a pressure-controlled phase transition system. Rather than using heat and complex distillation columns, the invention uses pressure adjustment to control the phase state of CO2, achieving separation through physical phase change instead of thermal processing. This substitution dramatically reduces energy consumption while maintaining extraction reliability.
3Manufacturing precision
If extraction method is used for oily sludge processing, then thorough processing is achieved, but processing costs are high
Solution Approach 1:
The patent changes the physical state of the extractant to supercritical, which enhances extraction efficiency and thoroughness due to the unique properties of supercritical fluids (high density, low viscosity, high diffusivity). Simultaneously, the use of CO2 as the extractant and its easy recovery through pressure reduction keeps operating costs low, making thorough extraction economically viable.
Solution Approach 2:
The patent uses CO2, which is inexpensive and readily available, as the extractant. Although CO2 needs to be continuously circulated and pressurized, its low cost and ease of recovery make it economically favorable compared to expensive organic solvents that require complex recovery systems. The system effectively uses a cheap, easily replaceable extractant that maintains high extraction efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient oil extraction from deeply contaminated sludge with simultaneous water removal and solvent recovery, reducing energy consumption and operational costs, thus enhancing the economic performance and resource utilization of oily sludge processing.
Implementation Method 1
Oily sludge is mixed with an organic solvent that is suitable for the oily sludge as an extractant, wherein water, solid particles, and carbon-containing impurities in the oily sludge cannot be dissolved in the extractant
Implementation Method 2
the mixture of extractant and oil is subjected to flash evaporation to separately recover the oil and extractant
Implementation Method 3
performing gasification separation on the solvent-oil-water mixture obtained after the solid-liquid separation to separate the organic solvent
Data Source
AI summary
A processing method for perennially and deeply polluted sludge containing oils and water, waste residues, or oil sands in natural oil mines, and a processing system thereof. In the method, a solid substance containing oils and water is in full contact with an organic liquid solvent with a low boiling point and a weak polarity or no polarity at room temperature under pressurized condition to extract oil and water from the solid substance to the liquid, the organic solvent with low boiling point and low latent heat is easily separated from oil and water in the liquid after solid-liquid separation by decompression or heating evaporation, the gas solvent is compressed and condensed for recycling, the extracted oil and water are subjected to oil-water separation, and the extracted oil may be used as fuel or used for refining.