A new approach could fractionate crude oil using much less energy than crude oil distillation

Good news! Filtering by membrane! Refining the refinery! 😊 It promises to use less crude oil to refine crude oil!

"Separating crude oil into products such as gasoline, diesel, and heating oil is an energy-intensive process that accounts for about 6 percent of the world’s CO2 emissions. Most of that energy goes into the heat needed to separate the components by their boiling point.

In an advance that could dramatically reduce the amount of energy needed for crude oil fractionation, ... engineers have developed a membrane that filters the components of crude oil by their molecular size. ...

The key innovation is that the filters we developed can separate very small molecules at an atomistic length scale ...

When the researchers used the new membrane to filter a mixture of toluene and triisopropylbenzene (TIPB) as a benchmark for evaluating separation performance, it was able to achieve a concentration of toluene 20 times greater than its concentration in the original mixture.

They also tested the membrane with an industrially relevant mixture consisting of naphtha, kerosene, and diesel, and found that it could efficiently separate the heavier and lighter compounds by their molecular size. ..."

"Many chemicals, pharmaceuticals, and petrochemicals must be isolated from a mixture of various molecules. Traditional separation processes such as distillation not only require a great deal of energy but also generate large amounts of greenhouse gases.

An attractive alternative is reverse osmosis that filters liquid solutions through a semipermeable, thin membrane by applying pressure. This method has been broadly used to separate water from salts. However, it is a challenge to create membranes that can isolate molecules from a complex hydrocarbon mixture such as crude oil. ... [researchers] report the fabrication of a reverse osmosis membrane that can separate molecules from industrially relevant organic solvents. This could potentially replace energy-intensive distillation processes in industry."

From the editor's summary and abstract:

"Editor’s summary

Membrane processes may allow for more energy-efficient approaches for the separation of complex hydrocarbon mixtures. To maximize the combination of flux and selectivity, thin polymer films, usually based on amide chemistry, are put onto porous supports.

[Researchers] use interfacial polymerization to create thin film polymers with imine linkages, where shape-persistent monomers introduce high free volume into the final film ... To avoid the need for one monomer to be stable in the water phase and the other in the organic phase, the authors used an acid-catalyzed technique with both monomers dissolved in an organic phase and polymerization occurring on contact with an aqueous phase containing an acid catalyst. The polyimine films outperformed their polyamide counterparts and were resistant to the swelling and consequent reduction in selectivity that occurs with many organic solvents. ...

Abstract

Interfacial polymerization has been an industrial standard for preparing desalination membranes. Extending the same concept to molecular separation of organic solvents would be a key enabler for the decarbonization of the chemical and petrochemical industries through energy-efficient crude or biocrude oil fractionation.

Here, we report a molecular engineering approach based on acid-catalyzed interfacial polymerization for efficient hydrocarbon separation.

The design strategies include

(i) changing the linkage from amide to imine and

(ii) subsequent introduction of shape-persistent units such as triptycene and spirobifluorene.

The prepared polyimine membranes exhibit ultrahigh microporosity and enhanced swelling and plasticization resistance compared with conventional polyamide counterparts. These membranes, which feature fast and selective transport of hydrocarbons, including multicomponent and industrially relevant mixtures, outperform commercial and state-of-the-art benchmark membranes."

A new approach could fractionate crude oil using much less energy | MIT News | Massachusetts Institute of Technology "MIT researchers’ new membrane separates different types of fuel based on their molecular size, eliminating the need for energy-intensive crude oil distillation."

A refinery in a thin film (no public access) "A thin polymer membrane can separate industrial organic solvent mixtures through reverse osmosis"

Microporous polyimine membranes for efficient separation of liquid hydrocarbon mixtures (no public access)

A membrane, pictured, that filters the components of crude oil by their molecular size