Looking deeper into Clariant cellulosic technology: Part 1 of 2, a visit to Straubing, Germany and an integrated pilot plant

September 16, 2018 |

When you first encounter the Clariant cellulosic ethanol technology, your nose tells you that you haven’t seen anything quite like this before. 

An ethanol plant smells like a Corn Flakes factory, you see —  warm, toasty corn scent that’s pleasant and distinctive, but cellulosic ethanol project typically had a harsher smell when you first enter the door. That’s the faint acrid  odor of the harsh chemicals which are used to pretreat the agricultural residues or wood chips — and there is the musk of corn or wheat straw instead of the toasted sweetness of grain.

But Clariant doesn’t have that acidic scent when you first enter — a sign that its pretreatment is done with steam explosion, not chemicals, and all there is at the front of the plant is the musk of the wheat straw — not unlike the grace notes of late summer hay stacked in a field. Monet would have smelled a lot of this while he was painting his haystacks.

And then, there’s this sweeter musk that you’ve never smelled anywhere near a cellulosic ethanol plant before — although its incredibly reminiscent of a Novozymes plant — and that is the scent of the enzymes in production, and the enzymes in the hydrolysis unit which is used to separate the fermentable sugars from the lignin. That’s the trick in cellulosic ethanol, after all, releasing the sugars.

Special enzymes — even more thoughtfully engineered than the high-science of enzymes used in laundry detergents to release grime from fabric and produce those whiter whites and brighter brights. These are all enzymes, and have their characteristic odor, but effective and affordable cellulase enzymes that can tease sugars out of a stalk engineered by Mother Nature to resist all pests and predators, to provide the structure and the security for all the plant’s inner workings — this is the High Temple of Enzyme design.

Only, what is this doing in a cellulosic ethanol plant? The theory of those plants is generally that you truck in the enzymes from a massive commercial-scale production facility. You use enzymes in great volumes and at great cost in a cellulosic ethanol plant, but you generally aren’t supposed to be making them there.

Which brings us to the most distinctive part of Clariant’s technology. They bite off a small fraction of the sugar stream they are creating, and feed those sugars to specially encoded yeast and they produce the enzymes as an integrated part of the technology. For plants that are in remote areas — leaving aside the costs — the improvement in the logistics of cellulosic ethanol can be remarkable.

Which is why projects in some of the most feedstock-replete but otherwise remote parts of the world — seeking to lift the value of waste agricultural residues by entering into the global energy business — Clariant has been increasingly visible as a technology partner. There are other technologies in play — as there should be — but Clariant is getting, after years of development, it’s day in the sun and for sure, you can sense it with your nose.

After enzyme production, there is the hydrolysis unit where the actual separation of lignin and sugars occur. There’s a surprising amount of sugar trapped in cellulose, as a matter of fact, almost 70% of the sugar volumes (per ton) that we see in conventional grains used on first generation ethanol production.

You see, it’s never been about the cost of the sugars — you can buy a ton of cellulose for a fraction of the cost of the grains. It has always been about releasing those sugars, sustainably and affordably. 

But then, you notice something else in a Clariant plant that’s a little different than other systems that have been advanced. There’s just the one set of identical fermentation units, where the sugars are converted into alcohols. You might find yourself looking around for one set of fermentation units that convert conventional six-carbon sugars (like glucose) to ethanol, using a basic reaction that was well known since the time of Noah and the Book of Genesis.

But then, there’s supposed to be another fermentation line where the more difficult 5-carbon sugars — the ones you might usually associate with wood which is why the most well-known of them is known as xylose — which is literary Greek for “wood sugar”. But there’s arabinose, too, and galactose — a whole set of C5 sugars known as the pentose family and they often require their own separate fermentation system. But Clariant has one pot, all the C5 and C6 fermentation is done at the one time — and that’s one of the cost-savers that makes this an attractive system even if the in-line enzyme production approach is the most unique and transformative technological breakthrough.

Technologies have been popping up over the years — each with their unique aspects. The appeal of Clariant technology for these more remote areas is of a great deal of interest, if you’ve ever driven the roads (or lack thereof) of much of the land that Brazil  has identified for sugarcane expansion in the north and west of that sprawling country.

Or, if you have traveled the back roads of Eastern Europe where agriculture reigns and residues are found in great volumes but not always as many high-grade roads that can take the constant pounding of the delivery trucks — leaving aside the transit costs and the challenges of stabilizing enzymes for delivery. The central production model will have its own brilliant set of project executions — especially where you can establish a cluster of plants. But the world could use a system that produces virtually everything it needs — power, steam, enzymes and so forth — in one place at one time.

India comes to mind of course. Praj is right there and will likely roll up a large share of the projects — they’ve been rightly focused on India all along and no company has worked harder to establish the bona fides of 2G biofuels technology there. But it would be just crazy for every single Indian project to use just the one technology — same goes for everywhere else — there’s real strength in diversification. When you think about technologies that have been robustly tested with sugarcane bagasse, and for whom the remoteness of India and the experience of working on a large set of international projects, Clariant comes to mind.

We’ll see how that works out — when you think about China and India, it’s hard to decide which one has the bigger 2G potential in the long-term — it almost depends on how big the liquid fuels market becomes. But India has some advantages in the near term because the feedstock is so organized because of the sugarcane industry.

Bagasse has its challenges, but teaching wheat farmers to collect straw is one, also. Not to mention getting baling equipment into those areas where combine harvesters are usually employed to bring in a grain harvest: these may seem like near-meaningless challenges to any group of technologists who have found a way to pick the Golden Lock of Nature’s Defenses against Cellulosic Deconstruction. But challenges these are: feedstock will need to be  sustainable, affordable, reliable and available. That’s what we call SARA, and it’s the four-letter acronym that every cellulosic project developer should chant like a mantra.

You see, we can test feedstock with great skill and for thousands of hours in our pilot-scale bioreactors — and Clariant has a lulu of a pilot operation at Straubing in southern Germany, its so complete and constantly run that it’s a shame to call it a pilot, for at 1000 tons per year it is really a fully integrated small commercial demonstration,

But Clariant calls it a pilot — they’re conservative in the way they talk up the technology, and given the fates of many other technologies that had a lot more hot wind in their marketing efforts, perhaps we all can do with a bit of understating just for now.

But all that’s in the processing. It’s hard to simulate the feedstock supply chain. The growers, their knowledge, their ability to cut the straw at the right height so that a bale is not composed, say, or 300 pounds of rock and dirt mixed into a half ton bale of straw. Or that the other detritus of the field — shoes, rakes, small animals — are not swept up in the harvest. Or that the feedstock is so well cared for that it never pre-ferments — or, god forbid, catches fire — while being stored. Biomass generates an amazing amount of heat, you’d be surprised how warm a bale of straw is to the touch. 

And then, there’s delivery, preprocessing, bundling, baling wire, and so on. No matter how affordable and available a field of straw or stover is on paper, God is in the details as Mies van den Rohe was fond of saying, and in this case God appears to sit about nine inches above the ground looking for the optimal cutting point where you maximize the organic material without dragging all the inorganics into the truck and into the plant.

All that is execution, and then you look at bagasse and smile. With bagasse, the can is already off the field, the cane sugars are extracted, and you have this leftover residue coming right out of the production process, as cleaned up as biomass ever gets, more or less. If there’s a Mr. Clean of biomass, it probably is bagasse. Nd so we always look at Brazil, and India and elsewhere where the cane is grown, and count up all the projects that might be created for cellulosics. That’s why Iogen technology is being used in Brazil by Raizen, and Praj is hard at work on their tech deployment. But there’s a place for Clariant in that mix, we think.

Which brings us to one more residue and one more scent, and that is the brownish leftover liquid stream from cane production known as vinasse. Clariant technology has this stream, too, and not just from cane processing but from wheat straw and corn stover too. It’s loaded up with nitrogen, phosphorus and potassium. And if you’ve done agriculture or even home gardening you’ll recognize NPK as the essential digits of great fertilizer. There’s a pretty good fertilizer business in vinasse if only a chemical company would step forward to optimize the NPK streams for the various crops — they all have their unique sweet spots. The world is short of phosphorus in general and wheat can usually use a pretty sizable nitrogen top-off to boost yield an the protein profile. 

SO that’s another reason for growers to look into these technologies. They say that leaving crops on the field is the best way to put the NPK back into the soil. We disagree — why not capture, liquefy, optimize? There’s value in not simply handing the residues over to whatever bacteria there might be in the field and hoping for the best.

In all, there’s much to keep on eye on as Clariant deploys. Elsewhere this week we’re covering the groundbreaking for their technology in Romania — their flagship commercial plant. But there’s more to come in Slovakia for sure and we wouldn’t be a bit surprised to see it quite a few other geographies quite soon.

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