Chinese researchers developed a new oil refining technique that could reduce energy consumption during crude oil separation by around 91% compared with conventional distillation. The researchers from the Dalian Institute of Chemical Physics say the technology could, if scaled for industrial use, lower production costs and emissions while enabling more precise separation of crude oil components and improving the value of refinery products.
Molecular Refining Targets Energy-Intensive Separation
Crude oil must first be separated into different components before refineries can convert them into fuels, plastics and other products. Traditionally, refineries use distillation, which repeatedly heats crude oil so that different components vaporise and condense according to their boiling points. However, this process requires significant energy and offers limited precision. The approach, described as “molecular refining,” instead separates crude oil components at the molecular level. It uses chemical membranes to selectively sort different molecules and direct them towards suitable production streams.
Membranes Act as Molecular Sieves
The researchers developed metal-organic framework (MOF) membranes with precisely designed pores and surface properties. These membranes act as molecular sieves and separate compounds based on their size and chemical characteristics. The process, known as cascade membrane separation, uses two stages. First, the membrane separates molecules according to size. The researchers targeted straight-chain and single-branched alkanes used to produce ethylene from other components in the mixture. Next, the remaining molecules undergo a more selective separation. A second membrane uses surface chemistry to distinguish aromatic compounds from multi-branched alkanes and cycloalkanes. Aromatics serve as important intermediates for producing plastics, resins and fibres, while the other compounds can be used in petrol production.
Researchers Test 15-Component Naphtha Mixture
To improve the membranes’ performance, the research team used a tannic acid micro-etching method to continuously adjust their pore size and surface chemistry. The researchers then tested the two membranes in sequence using a simulated light naphtha mixture containing 15 components. In laboratory tests, the membrane system separated the mixture into three groups of high-value products, achieving a recovery rate of 85–90%.
Process Could Reduce Refining Energy Consumption
The biggest potential advantage comes from eliminating the repeated heating, vaporisation and condensation required by conventional distillation. According to the study, the membrane-based process consumed approximately 91% less energy than traditional distillation under the tested conditions. Consequently, the technology could potentially reduce energy requirements, operating costs and emissions if researchers successfully scale it for industrial applications.
Potential for More Efficient Petrochemical Refining
The researchers published their findings in National Science Review, describing the graded molecular sorting approach as a potential platform for petrochemical refining. However, the reported results come from laboratory testing, and further development and scale-up would be required to determine how the technology performs under industrial refinery conditions. As reported by scmp.com, if successfully commercialised, the approach could offer refineries a more energy-efficient way to separate crude oil components while improving the recovery and utilisation of higher-value petrochemical feedstocks.
