As pressure mounts on companies to reduce reliance on gas and oil, well-established processes, even on an industrial scale, are being questioned, presenting an opportunity for technology to step in. sepPure wants to replace the complex gas-based distillation of oils with a membrane designed at the nanometer scale, and its approach has attracted $12 million in a new round of funding.
All types of oils must be extracted and purified from their source, which can be a seed, fiber or other organic material. Sure, you can crush an olive and get a lot of oil out of it, but not all of it; to do that, the pulp is dipped in a huge amount of solvent, such as acetone or hexane, which draws out the remaining oil. The resulting mixture is then heated, usually via natural gas or oil, and the solvent and oil are separated.
This fuel-intensive process has been going on for decades, in part because the high temperatures required make it impossible to use solar or wind as a heat source.
In the water treatment room, a possible alternative appeared many years ago, which for a long time also used a distillation process to separate H2O from contaminants. Membranes can be designed to allow certain substances to pass while blocking others, allowing for example water molecules to pass but not large organic ones. This approach has been adopted by the water industry because it is cheaper, simpler and uses less energy (look for “reverse osmosis” on the label).
SepPure founder and CEO Mohammad Farahani explained that the pressures of climate change and gas prices (not to mention cost cutting) have led others to look at membranes as a possibility. For example, Divigas created a membrane that separates hydrogen from carbon dioxide, and Membrion created one to remove heavy metals from water. But water is not a particularly aggressive substance, unlike many chemical precursors to beneficial oils and other molecules.
“It took a long time to find a good solution for water, and pretty much every company making membranes was focused on water,” says Farahani. “Maybe it wasn’t until 10 years ago that research into chemical-resistant membranes began. We think we’re in the same place we were when water membranes were introduced 40 years ago – basically it will be implemented everywhere.
A computer shows a cross-section of SepPure nanofilter tubes.
SepPure makes what’s called a hollow fiber nanofilter, which is exactly what it sounds like: a hollow polymer fiber with a nanometer-scale surface designed to allow only certain molecules to pass through. Get several together and put them in a tube, pushing liquid through the tube to filter it. Although the membrane does not separate 100% of the two substances, it greatly reduces the scale of the distillation step. The concept is not new, and in fact is used all over the membrane industry, but what sets SepPure’s apart is its durability and compactness.
“Strong solvents can easily dissolve polymers – you have to make polymeric membranes using solvents, but then they have to to resist solvents. That is a challenge and a lot of research has been done to get there,” says Farahani. “The beauty of what we’ve done is create fibers that can withstand harsh chemicals, high temperatures and high pressures.”
Water and gas aren’t as demanding in those categories, so they’ve gotten most of the attention, but now there’s a version that can split oils from solvents, or other valuable molecules of a similarly difficult mixture. That has applications in every industry that still uses distillation because of the fragility of old membrane processes – and there are many. Separation processes account for a significant portion of global energy consumption and emissions.
SepPure has a competitor in the German Evonik, which makes a similar product. But Farahani said that while this earlier version of the technique is fine for high-margin products, such as pharmaceuticals, it is too slow and bulky to use in high-volume, low-margin processes, such as food oil production.
A hollow fiber nanotube is made in the lab and a small version of the final filter is shown.
Filters tend to come in a standard size: a pipe that is 4 inches in diameter by 40 inches in length. SepPure claims it can fit five times as much membrane in that space, improving efficiency and reducing costs: pushing five times as much material through the same number of pipes or filtering the same amount in much less space. And that’s without taking into account elevated pressure and other combinatorial factors.
All in all, Farahani estimates that these gains and the reduction in fuel-based heating will allow them to reduce the cost of producing (say) 100,000 tons of oil in a year from about $7.5 million to about $2.5 million. And apparently, once the filter fibers are exhausted after a few years of use, they can be reused to make flame retardants.
The $12 million A round was led by SOSV, with participation from Anji Microelectronics, Real Tech Fund, Seeds Capital, EPS Ventures and others. The company already raised $2.5 million in 2019.
The money will be used to complete the construction of the first filter manufacturing facility in Singapore.
“Once we start deploying our technology solutions to customers, we will quickly reach our maximum capacity. In anticipation of the growing demand for our modules, our team is already working on expansion plans,” said Farahadi.
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