Clariant's Cellulosic Ethanol Production Plant, Straubing, Bavaria, Germany

The Straubing demonstration

Clariant opened Germany's largest demonstration-scale cellulosic ethanol production plant in the Bavarian town of Straubing in July 2012. The plant processes agricultural residue as feedstock to produce second-generation bioethanol.

The demonstration plant is located close to the Bavarian BioCampus Straubing. Construction of the facility started in the second quarter of 2011. The project was built at an estimated cost of about €28m ($35m).

The plant was originally launched by Süd-Chemie. In June 2011, 98.6% of the stake in Süd-Chemie was acquired by Clariant for about €2bn.

The project helps in establishing a commercial scale facility for the completely integrated bioethanol production process. The commercial scale plants have production capacity of about 50,000t to 150,000t a year.

Financing the German cellulosic ethanol production plant

The estimated cost of the project construction was about €16m. Another €12m was allocated for research and development.

The project received funds of about €5m each from the Bavarian State Government and Germany's Federal Ministry of Education and Research (BMBF) in the form of subsidies towards the research related projects.

Agricultural waste feedstock used by Clariant

"The demonstration plant is located close to the Bavarian BioCampus Straubing."

The plant uses different agricultural waste feedstock to produce ethanol biofuel without any impact on the food production.

The main raw materials include wheat and cereal straws or corn stover or sugar cane bagasse. Only one feedstock is processed at a time.

Integrated bioengineered enzyme production units on site produce the necessary feedstock-specific biocatalysts and optimise them as demanded by the processes.

The plant utilises about 4,500t of wheat straw to produce about 1,000t of cellulosic ethanol per annum.

Technology incorporated into Clariant's facility

First-generation biofuels such as biodiesel and bioethanol are produced directly from starch and oil rich plant materials. The second-generation biofuels, however, utilise only the cellulosic materials of the plant, providing higher energy yields.

"The plant uses different agricultural waste feedstock to produce ethanol biofuel without any impact on the food production."

The Straubing demonstration plant uses Süd-Chemie's proprietary process technology called Sunliquid®. The company has been testing the technology in a pilot plant in Munich since early 2009.

The Süd-Chemie process increases the final yields of ethanol by about 50% due to proprietary yeast which converts C5 and C6 sugars simultaneously.

Integration of the enzyme production facility on site eliminates the dependence on enzyme suppliers. It eliminates the need for transport, storage, formulation, purification and stabilisation of the enzymes.

The integrated process also allows sharing of the production facilities and other utilities. Sunliquid technology results in the lowest enzyme costs.

The overall process consumes less energy than the conventional processes. The Sunliquid® technology received the International Sustainability & Carbon Certification (ISCC) in September 2013.

The Sunliquid® technology reduces the greenhouse gas emissions by 95%. It converts agricultural residues sustainably and efficiently into cellulosic ethanol.

Process technology at the Bavarian facility

"Bioethanol can be used as fuel blend or in pure form (E100) for motor engines."

Chopped feedstock for the plant undergoes hydrothermal treatment in a vapour pressure pot. The pre-treatment prepares the cellulose and hemicellulose sugars for further enzymatic hydrolysis and fermentation processes.

In the hydrolysis, highly optimised enzyme mixtures are used to process different feedstock varieties. The enzyme mixtures are chosen based on the specific feedstock type and the responding process conditions. These enzymes break the hemicellulose and cellulose into sugar monomers in a short reaction time.

The C5 and C6 sugars undergo fermentation simultaneously in a one pot reaction using the proprietary strain and process technology of the Sunliquid process.

Unlike the traditional distilled spirits plant routes, the cellulosic ethanol recovery process uses a proprietary downstream processing technology.

The patented purification Süd-Chemie ethanol recovery process consumes 50% less energy than conventional distillation, based on the process conditions.

The energy required for the entire process is sourced from the non-fermentable lignin fraction, making the production climate neutral. The resultant ethanol emits 95% less CO2 compared to fossil gasoline.

Bioethanol and biofuel market growth

Bioethanol can be used as fuel blend or in pure form (E100) for motor engines. Demand for climate-friendly second-generation biofuels is increasing with the support from the US and European Union legislative framework.

The EU has targeted utilisation of a minimum of ten percent renewable energy sources for the transportation sector by 2020 as per the renewable energy policy adopted in December 2008.

The US will substitute about 15% of its gasoline consumption with biofuels by 2022. About 60% of these biofuels will be produced from lignocellulosic residues.

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