I wrote about this idea and technology at the end of last year when I came back from the Carbon Fiber Conference put on by Composites World. This process was developed by a Japanese company by the name of Microwave Chemical Company, Ltd. The first demonstration pilot plant that was built was put on the campus of Mitsui Chemical Company in Osaka, Japan. According to Composites World, this plant made a trial run of carbon fiber in January of this year (1).
Microwave Chemical Company Process (Composites World 3/10/2023)
The lead pic in this post is a comparison done (and reported on in Composites World 3/10/2023) of the difference between conventional carbon fiber processing which typically uses natural gas or fuel oil to drive the high temperature ovens, and the microwave heating process developed by Microwave Chemical Company. The secret to success in this process is that whereas conventional processing applies high heat from the outside of the fiber to heat up the inside of the fibers to drive off everything that isn’t carbon, microwave heating heats up the fiber from the inside out. This is the same as how your microwave over your stove heats up your leftovers. It heats that lasagna from last night from the inside out.
This is because the frequency of the microwave radiation is tuned to one of the natural frequencies of the water molecules in the food, causing them to vibrate violently thereby generating heat. Since our food is largely water, this works quite well, and now nearly all kitchens have a microwave for heating up things like coffee, tea, soups and stews, and yes the left over pizza from the night before.
The same phenomenon is used in the Microwave Chemical process for carbonizing carbon fiber. Only it isn’t water that these large microwave chambers are tuned to, it is the rest of the stuff in a PAN fiber that isn’t carbon. While that eventually becomes water, what they are mostly working on is the nitrogen to start with and then getting rid of the oxygen with the remaining hydrogen. So, the frequencies are somewhat different and the microwave energy is somewhat more intense, but it is basically the same physics.
The fact that they have created a pilot line and actually had a test run of their pilot that was successful is a testament to the ingenuity of the founders of Microwave Chemical, an entrepreneur named Iwao Yoshino and a scientist named Yasunori Tsukahara. These two met in 2006 and founded their company in 2007 with a “goal to make a significant contribution to achieving carbon neutrality by innovation.” Their stated business model is to “reinvent a chemical industry that has not changed in over a century and transform the world of manufacturing.” Essentially what they intend to do, and actually have delivered on at least for carbon fiber is to make microwave processing of materials into usable products a worldwide standard. The company started with a process to produce biodiesel from waste oil at chemical and food plants. They did not get much traction for that idea from such a conservative industry, so they built their own plant with venture funding and had a successful IPO on the Tokyo Stock Exchange in 2022. That product is now on the market.
And, apparently they had been working on their microwave process for carbon fiber for some time, because in just two years after their successful IPO, they have demonstrated the pilot carbon fiber line at Mitsui Chemicals in Osaka.
Artist's Conception of Microwave Carbon Fiber Processing Line (Composites World 2/10/2023)
Other organizations have also gotten into this business albeit on a smaller scale than Microwave Chemical and have demonstrated, at least at the lab scale, the microwave carbonization of PAN to carbon fiber. They have also demonstrated plasma surface treatment of the resulting carbon fiber to use in the place of the oxidizing and sizing step commonly used with natural gas or oil fired carbonization of PAN fiber. Toho Tenax, one of the larger carbon fiber producers in Japan, started work on this in 2016. While their process is somewhat different than the direct heating process developed by Microwave Chemical Company, it still is not a natural gas or oil fired process. It is not known whether their efforts to commercialize this technology were successful because the last announcement that was made was in 2016.
And some researchers in Korea (2) in 2014 demonstrated a very similar process that they call “microwave plasma carbonization” of PAN to carbon fiber. They used a process similar to one developed in the US by Oak Ridge National Lab to create a “microwave plasma” on the surface of the PAN fiber that induced heating in the fiber sufficient to drive off the stuff that wasn’t carbon. Their end product had properties very similar to conventional carbon fiber in the T-800 to T-1000 class, with identical stiffness and comparable strength. Their fiber also had a more textured surface than some conventional fibers so resin seemed to stick to it better without the use of as much oxidation and sizing as traditional carbon fibers need.
One problem in the manufacture of carbon fiber that these processes also alleviate somewhat, besides a 50% reduction in energy expended, is that their processing lines are smaller for the same throughput and their capital expenditures are also significantly less than a traditional carbon fiber line. The traditional lines are on the order of hundreds of millions of dollars, whereas the microwave lines are more on the order of a few tens of millions of dollars for the same throughput. This is an enormous advance in the manufacture of carbon fiber, and the first companies that scale up this process, as Mitsui and Microwave Chemical are doing now, will be the overall winners in this race.
The upside for the composites industry is also enormous, especially because the demand for carbon fiber worldwide is expected to increase tenfold in the next decade or two. This is driven by an industry I write about quite a bit, the offshore wind industry. As the wind power machines and their blades get larger and larger, and more gigawatts of capacity come on line, wind power itself will drive a good bit of that demand for carbon fiber. So, the first ones to the table with a less expensive and less energy intensive, potentially carbon neutral carbon fiber that has equivalent properties to current fibers will be the winner in this very competitive industry.
That’s about it for this week. I hope everyone that reads these posts enjoys them as much as I enjoy writing them. As usual I will post this first on my website – www.nedpatton.com – as well as on LinkedIn. And if anyone wants to provide comments to this, I welcome them with open arms. Comments, criticisms, etc. are all quite welcome. I really do want to engage in a conversation with all of you about composites because we can learn so much from each other as long as we share our own perspectives.
I also wanted to remind everyone again that I am working on my second book. This one is about what I have been writing in these newsletters for the last 6 months or so – sustainability of composites and a path to the future that does not include using fossil fuels for either the raw materials or the process energy to make composites. Stay tuned to this space and I will let everyone know about my progress as I write this one. I’m about three chapters into it at this point and I know what I want to write. And now that life is settling down a little bit I have time to devote to just writing.
Finally, I still need to plug my first book, so here’s the plug. The book pretty much covers the watershed in composites, starting with a brief history of composites, then introducing the Periodic Table and why Carbon is such an important and interesting element. The book was published and made available last August, and is available both on Amazon and from McFarland Books – my publisher. However, the best place to get one is to go to my website and buy one. I will send you a signed copy for the same price you would get charged on Amazon, except that I charge $8 shipping. Anyway, here’s the link to get your signed copy: https://www.nedpatton.com/product-page/the-string-and-glue-of-our-world-signed-copy. And as usual, here’s a picture of the book.
Comentários