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Driving on waste

St1 Biofuels Oy
St1 is steadily moving ahead with its innovative family of technologies for producing bioethanol from a variety of waste streams in small, modular plants. The first unit based on the Etanolix® process was commissioned in 2007 and has been followed by more, and work is already under way on a plant incorporating the next technology: Bionolix™.

St1 launched its decentralised ethanol production concept a couple of years ago when it commissioned a plant based on the company’s Etanolix® technology, running on bakery waste, reject, and by-products. It was the first anywhere to produce ethanol from waste for commercial use in motor fuel, and has since been followed by four other plants around Finland.

The most recent of these, commissioned in late 2009, has been built adjacent to a brewery and uses waste yeast and liquids from there, together with fermentable waste from bakeries and mills in the area. Yeast from the brewery used to go into animal feed, and dry yeast matter will continue to do so, once the ethanol has been extracted in the Etanolix® process.

The already low carbon dioxide balance of the Etanolix® process has been further enhanced at this new plant, as the CO2 produced during fermentation will be collected and refined by the brewery for re-use in its own production processes.

Continuous fermentation

The Etanolix® process is based on continuous fermentation and associated evaporation, and generates an 85% ethanol/water mixture. Depending on the raw material input, by-products can be used as animal feed or fertiliser.

Dewatering is carried out separately at a high-capacity facility, such as St1’s energyefficient ethanol rectification plant at Hamina, which is capable of processing 88 million litres of 85% ethanol annually. The resulting pure ethanol can be blended with petrol for onward distribution to service stations.

Small and modular

Initial distribution of St1’s RE85, containing 80-85% bioethanol and produced using the company’s Etanolix® technology, began in Greater Helsinki in 2009.

St1’s technology separates the production of bioethanol from dehydration of the end-product, enabling small, modular units to be located as close as possible to waste sources, making waste a commercial commodity and reducing transport costs as well.

Plant capacity can be downsized significantly and still remain competitive in terms of production costs and energy efficiency when only producing between 1,500 and 2,000 cubic metres of absolute ethanol a year. Production costs compare very favourably with conventional first-generation bioethanol plants, which can be 20 to 200 times larger.

Etanolix® has made it possible to use a completely new and cost-effective source of raw material – waste – to produce a commercially viable fuel in small volumes at costs comparable to those of large-scale production plants.

While St1’s current technology enables waste containing starch, sugars, or low concentrations of ethanol to be processed, R&D is pushing ahead to extend the range of feedstocks to include household biowaste, waste paper, municipal waste, and other manufacturing waste.

Bionolix™ and Cellunolix™

Delivering baking waste to St1’s facilityin Lappeenranta for processing into bioethanol.

The next dedicated technology to be launched by St1 will be Bionolix™, which will be able to utilise mixed waste and will usher in a completely new way of making use of biowaste collected from households and commercial kitchens. The technology will also enable thermal sludge processing units to be developed capable of generating bioelectricity in addition to ethanol.

An agreement was signed in 2009 to build the first plant of this type at a waste treatment centre in Hämeenlinna in southern Finland. This will produce both bioethanol from up to 15,000 t/a of biowaste and green electricity from landfill methane. St1 plans to build between five and 10 Bionolix™ plants in Finland over the next few years, alongside three to five Etanolix® units.

Next in line will be cellulose-based raw materials. Cellunolix™ technology, now under development, will be targeted at making use of packaging waste from sorted municipal waste streams from homes, retailing, and industry. This will be followed by Fiberix™ technology, aimed at producing ethanol from agricultural by-products, such as straw. St1’s target is to produce 300 million litres of ethanol by 2020, equivalent to around 10% of the energy content of petrol then on sale in Finland from a mixture of industrial, municipal, and agricultural waste.

High-blend bioethanol

St1 launched RE85, containing 80-85% bioethanol produced using the company’s Etanolix® technology, for use in flexi-fuel vehicles in early 2009. Capable of cutting transport-related fossil CO2 emissions by up to 80%, St1’s RE85 has been tailored to conditions in cold countries such as Finland and offers improved cold start properties, thanks to the use of carefully selected fuel components.

St1 has an extensive testing programme under way with VTT Finnish Technical Research Centre of Finland aimed at further optimising the consistency of this new high-blend ethanol. Distribution of the fuel, which is priced at least 30 euro cents lower than that of 95E petrol, currently takes place through a small number of St1 outlets in Greater Helsinki.

> Risto Savolainen
(Published in HighTech Finland 2010)