Despite efforts to turn to renewable energy sources, oil remains the backbone of modern society. It provides fuels for heating and transportation, and chemicals for everything from plastics to pharmaceuticals. But all of these uses require separating the crude oil into its various components. This separation process, which traditionally relies on heat, consumes a lot of energy and accounts for around 1% of global greenhouse gas emissions each year.
Now, chemists say a newly developed material could one day help lighten that sizable, albeit largely invisible, carbon footprint that consumes some 230 gigawatts a year, the equivalent of Nevada’s total energy consumption. Researchers report this week that a new membrane could, if scaled up, more than halve the energy needed to separate crude oil. Such membranes would not only make the use of crude oil more environmentally friendly, but also cheaper for refineries to produce, as it would save them billions of dollars a year in energy costs.
“The potential savings are quite impressive,” says Ryan Lively, a chemical engineer at the Georgia Institute of Technology who was not involved in the new work. The new membranes, he adds, still have to prove durable for months or even years at a time. He and others also warn that conventional oil refineries may be slow to adopt them because companies have already invested costs in installing conventional separation systems. However, says Lively, the new membranes could be quickly adopted in new refineries built to separate hydrocarbon mixtures created from biofuels or synthetic fuels made from renewable electricity. “It’s really ripe territory,” Lively says.
Crude oil is a mixture of tens of thousands of chemicals. The first step in oil refining is to separate this mixture through a distillation process. Crude crude oil is heated to approximately 500°C. Lighter components, such as those that make up gasoline, vaporize at lower temperatures and are captured. Heavier components, such as heating oil, vaporize at higher temperatures.
Two years ago, researchers led by Lively and Andrew Livingston, a chemical engineer at Queen Mary University of London, reported in Science that it was possible to separate these components using membranes rather than by distillation. They created membranes with embedded pores that allow small, light hydrocarbons to pass through and keep larger, heavier ones out. But light hydrocarbons passed through the membranes too slowly to make them practical for real-world use.
To get around this problem, Livingston and his colleagues turned to an industrial approach to making ultrathin water desalination membranes called interfacial polymerization. They hoped that thinner membranes would allow the desired hydrocarbons to pass more quickly. However, notes Livingston, although the membranes typically used for desalination are robust in a water-based environment, they break down quickly when subjected to hydrocarbons including industrial solvents.
So he and his colleagues reformed the polymers that make up conventional membranes. First, they made individual polymers, connecting a hydrophobic or oil-like part to a hydrophilic or water-like strand. When they added these molecules to a mixture of oil and water, they spontaneously assembled into tiny bubbles, or vesicles, with the hydrophobic part facing inward. They then used the technique of interfacial polymerization to spread these vesicles into a continuous ultrathin sheet and link all the polymer units together to form a robust membrane.
The approach worked. The vesicles’ hydrophobic cores allowed selected hydrocarbons (based on their size and other characteristics) to pass easily – about 10 times faster than in previous oil-separating membranes, Livingston and colleagues reported yesterday in Science. The researchers also showed that by tailoring the chemical composition of the polymers, they could create different membranes that selectively pass through hydrocarbons of different sizes.
According to Neel Rangnekar, a chemical engineer at Exxon and a member of the team on the new paper, switching from distillation to membrane separation could save up to 50% of the cost of heating crude oil and 75% of the cost of electricity used in refining. , amounting to at least $3.5 billion a year.
“This is a very exciting result,” says David Sholl, a separations expert at Oak Ridge National Laboratory who was not involved in the study. However, notes Sholl, the new membranes are not yet ready for industrial use. They have yet to scale from the size of a piece of stationery to hundreds of square meters and prove durable for months of continuous use. But Sholl thinks these encouraging findings will allow oil companies to continue exploring technology that could both save money and reduce carbon emissions. “All chemical companies are extremely interested in trying to do this,” he says.
Despite efforts to turn to renewable energy sources, oil remains the backbone of modern society. It provides fuels for heating and transportation, and chemicals for everything from plastics to pharmaceuticals. But all of these uses require separating the crude oil into its various components. This separation process, which traditionally relies on heat, consumes a lot of energy and accounts for around 1% of global greenhouse gas emissions each year.
Now, chemists say a newly developed material could one day help lighten that sizable, albeit largely invisible, carbon footprint that consumes some 230 gigawatts a year, the equivalent of Nevada’s total energy consumption. Researchers report this week that a new membrane could, if scaled up, more than halve the energy needed to separate crude oil. Such membranes would not only make the use of crude oil more environmentally friendly, but also cheaper for refineries to produce, as it would save them billions of dollars a year in energy costs.
“The potential savings are quite impressive,” says Ryan Lively, a chemical engineer at the Georgia Institute of Technology who was not involved in the new work. The new membranes, he adds, still have to prove durable for months or even years at a time. He and others also warn that conventional oil refineries may be slow to adopt them because companies have already invested costs in installing conventional separation systems. However, says Lively, the new membranes could be quickly adopted in new refineries built to separate hydrocarbon mixtures created from biofuels or synthetic fuels made from renewable electricity. “It’s really ripe territory,” Lively says.
Crude oil is a mixture of tens of thousands of chemicals. The first step in oil refining is to separate this mixture through a distillation process. Crude crude oil is heated to approximately 500°C. Lighter components, such as those that make up gasoline, vaporize at lower temperatures and are captured. Heavier components, such as heating oil, vaporize at higher temperatures.
Two years ago, researchers led by Lively and Andrew Livingston, a chemical engineer at Queen Mary University of London, reported in Science that it was possible to separate these components using membranes rather than by distillation. They created membranes with embedded pores that allow small, light hydrocarbons to pass through and keep larger, heavier ones out. But light hydrocarbons passed through the membranes too slowly to make them practical for real-world use.
To get around this problem, Livingston and his colleagues turned to an industrial approach to making ultrathin water desalination membranes called interfacial polymerization. They hoped that thinner membranes would allow the desired hydrocarbons to pass more quickly. However, notes Livingston, although the membranes typically used for desalination are robust in a water-based environment, they break down quickly when subjected to hydrocarbons including industrial solvents.
So he and his colleagues reformed the polymers that make up conventional membranes. First, they made individual polymers, connecting a hydrophobic or oil-like part to a hydrophilic or water-like strand. When they added these molecules to a mixture of oil and water, they spontaneously assembled into tiny bubbles, or vesicles, with the hydrophobic part facing inward. They then used the technique of interfacial polymerization to spread these vesicles into a continuous ultrathin sheet and link all the polymer units together to form a robust membrane.
The approach worked. The vesicles’ hydrophobic cores allowed selected hydrocarbons (based on their size and other characteristics) to pass easily – about 10 times faster than in previous oil-separating membranes, Livingston and colleagues reported yesterday in Science. The researchers also showed that by tailoring the chemical composition of the polymers, they could create different membranes that selectively pass through hydrocarbons of different sizes.
According to Neel Rangnekar, a chemical engineer at Exxon and a member of the team on the new paper, switching from distillation to membrane separation could save up to 50% of the cost of heating crude oil and 75% of the cost of electricity used in refining. , amounting to at least $3.5 billion a year.
“This is a very exciting result,” says David Sholl, a separations expert at Oak Ridge National Laboratory who was not involved in the study. However, notes Sholl, the new membranes are not yet ready for industrial use. They have yet to scale from the size of a piece of stationery to hundreds of square meters and prove durable for months of continuous use. But Sholl thinks these encouraging findings will allow oil companies to continue exploring technology that could both save money and reduce carbon emissions. “All chemical companies are extremely interested in trying to do this,” he says.