Together with Rockwell Automation, Schiefer built a wood gasification plant which – along with producing energy – has attracted a lot of attention abroad. And with 8,300 productive hours of operation per year it's hardly surprising – that's an unusually high level of availability. It's almost 95 per cent of the plant's total capacity and a performance most other wood gasification operators can only dream of. This success prompted Schiefer to think about diversifying his farming business by developing wood gasification plants for other companies.
“We developed the entire system ourselves, from the reactor down to the last filter for gas cleaning,” says Schiefer, visibly proud of a system that produces up to 200 kilowatts electrical and up to 400 kilowatts thermal energy per hour. The farmer can more or less leave the combined heat and power plant to get on with its job, thanks to the Allen-Bradley® CompactLogix™ system that manages the automation, including the heating technology, wood and maize drying and energy supply to the grid.
According to Schiefer, the key to achieving high availability in a wood gasification plant is accurate zone control within the reactor. “The reactor's ventilation is located in the oxidation zone,” he explains. “That's where CompactLogix makes sure that the zone, which is the hottest, does not rise due to variations in materials or humidity. It does that by adjusting the ventilation levels accordingly.”
He believes that as long as the ventilation is right and there's perfect coordination between the four reactor zones – drying, pyrolysis (carbonisation), oxidation and reduction – the stability issue can solve itself.