Clariant’s Demonstration Cellulosic Ethanol Plant in Germany: The Complete Facility, in Pictures
by Jim Lane (Biofuels Digest) … Producing enzymes and yeasts on site, as part of the complete biomass-to-fuels manufacturing process. …
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.
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.
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. READ MORE