Clariant’s demonstration cellulosic ethanol plant in Germany: The complete facility, in pictures

Source: By Jim Lane, Biofuels Digest • Posted: Monday, September 29, 2014

Our first up-close look at this cellulosic technology, now at demonstration scale.
Producing enzymes and yeasts on site, as part of the complete biomass-to-fuels manufacturing process.

About 30 miles southwest, as the crow flies, from the Czech border with the German state of Bavaria, lies the front lines of Bavaria’s investments and achievements in high biotechnology — the city of Straubing. Once the seat of the Dukes of Bavaria-Straubing — who held Amsterdam and The Hague, and a good section of Belgium and a strip of France in the Dutch-speaking section — all areas important in the bioeconomy these days and one wonders what the Dukes would think of all of it now.

In recent years — the region around Straubing turned to biotech to access the high returns in high tech for its agriculture-replete economy — and Clariant decided to build its demonstration-scale cellulosic ethanol plant here, originally under its Sud-Chemie identity.

Opened in 2012, the demo plant is rated at 100,000 gallons per year, or around 1 ton of ethanol per day from 4.5 tons of biomass per day. The plant started out testing wheat straw and has since branched into stover and sugarcane bagasse. The facility is producing ethanol and is being operated 24/7, but is not selling into the market – keeping production quantities for samples for customers and partners. At the end of the day, it’s a facility designed to validate the process and provide data towards commercial-scale deployments.


Clariant_straw handling_web

When you first enter the facility at the biomass intake, the first thing you notice is all the wheat straw — but it’s a storage area — the plant is running quite a bit of bagasse too these days. The square bales average 500 kilos — and come with the usual assortment of dirt and rocks that arrive in everyone’s pickup process — so the first mechanical section following the snipping of the plastic baling straps is a chopper unit that brings the average pieces down to 5 cm or less — and there’s a process for removing the non-fiber impurities. The dust that shakes out is collected for use — there’s fiber in there. One day, a cat on it’s 10th life came in with a bale.

The plant cost 28 million Euros and was supported by regional authorities as well as Clariant. It yields 300 liters of anhydrous ethanol per ton of biomass — so, for hydrous ethanol, add in some extra yield according to your water content target. A “small percentage” of the biomass (the exact percentage is kept under wraps) is sequestered as carbon for the growing of enzymes and yeasts for the later steps of hydrolysis and fermentation. In this way, not only are the microorganisms generated onsite as part of the process, it’s using the same carbon to grow as it will eventually attack in the bioprocessing — nice de-risking step there.


From there to steam explosion, where the chopped up biomass under heat and pressure is “exploded” to expose the cellulose and hemicellulose to the enzymes. Next, the hydrolysis, where the exploded biomass is mixed into a broth with enzymes — and, for which step, the temperature is raised. The enzymes release the C5 and C6 sugars and the lignin is separated out (and burned ultimately to provide steam, heat and power for the process.

Clariant_enzyme production_web

Thence, the broth passes over to the fermenters where the yeasts go to work fermenting the sugars into alcohol.

In both cases of enzymes and yeast, there are GMO and non-GMO strains available for customers — we heard that the GNO strains perform slightly better s could be expected — but individual customers will make decisions on production organisms according to local regulatory environments.

The demo plant has 3 hydrolysis units. It’s not clear — and Clariant is talking publicly about final designs for full-scale units for customers — whether that will remain so for the at-scale versions — but the units appear to be of roughly equal size.

From there, over to separation and distillation, where the beer is distilled down to a 99.8% pure ethanol.



The Bottom Line

Here’s the basic differentiation of the sunliquid system — it’s the onsite production of the microorganisms. So far, only Abengoa and Clariant have gone this way.

Now, every different technology has different choices on organisms, and variations on the way they engineer — but this is a very distinctive differentiation point. On the numbers — one would have to sign NDAs and run specific tests on feedstocks and look at the specific local economics of on-site vs consolidated production — no two plants are going to make the same call. But there are certain cases around the world where local conditions simply make it rough to truck in a lot of anything from far away — Brazil comes to mind. In those geographies — it is not just a case of economics, it really could come down to the feasibility of technology as a whole.

Cautionary note. There are too many good systems around in cellulosic biofuels these days for there to be a simple answer like “Technology A is the best”. It will depend on the site, the economics for biomass, infrastructure, the chosen feedstock set. A technology that lines up terribly for one site may well be the no-brainer choice for another just 200 miles away.

An important thing in doing a preliminary investigation is to ask 8 questions:

1. Has it been demonstrated? The bigger the scale, the less technology risk.
2. Has my feedstock been tested. How are the rates and yields?
3.What are my special local conditions and how does that cause me to make specific choices on enzymes, yeasts and technologies.
4. Is there a local premium for green electricity. If so, technologies that have green power options will work well?
5. How fast is performance improving — is the technology at a stand-still or are big leaps in rate, yield, temperature tolerance etc being achieved?
6. How’s the capex / opex trade off? Most of the time, choices made to reduce capex (such as eliminating harsh chemical pretreatment), can cost on yields and you have to watch opex. Or, is there so much emphasis on gross cost-per-gallon that the plant has been engineered to the point where you simply can’t afford the equity?
7. Turn around time.
8. Feedstock and product flexibility. How much is there. Could be a lifesaver some time if the economics go upside down in one of your pathways.