Süd-Chemie Cellulosic Ethanol Demonstration Plant, Germany

Munich-based speciality chemicals company Süd-Chemie is constructing Germany's largest demonstration-scale cellulosic ethanol production plant in the Bavarian town of Straubing. The plant will process 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.

It is planned to become operational in the fourth quarter of 2011. The project is estimated to cost about €28m ($39m).

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

In June 2011, 98.6% of the stake in Süd-Chemie was acquired by Clariant for about €2bn. Clariant will continue the catalyst business of Süd-Chemie under new ownership.

Financing the cellulosic ethanol production plant

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

Süd-Chemie has 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.

Feedstock

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

The main raw materials will 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 will produce the necessary feedstock-specific biocatalysts and optimise them as demanded by the processes.

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

Technology incorporated into Süd-Chemie's plant

The 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 Straubing demonstration plant will use 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 second-generation biofuels pilot plant further developed the process technology, giving rise to demonstration size straws to bioethanol plant.

The Süd-Chemie process is expected to increase 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 will eliminate 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 is thus expected to result in the lowest enzyme costs.

The overall process is also expected to consume less energy than the conventional processes. Süd-Chemie expects to license the technology in 2012-13.

Process Technology

The 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 biofuels 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 minimum 10% 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.