Air-supported into the furnace

e-on invested into a modern materials-handling technology for timber shred

The energy giant e-on has been operating a biomass heating and power plant in Emden since 2005. A big amount of timber shred is burned there and turned into electrical energy day by day. The company now has optimized the transport of the not really uncomplicated fuel using an air-supporting conveyor belt.

“When building the power plant we installed a 110 meter long masse conveyor between the silo and the furnace for transporting the fuel”, explains Hans Jürgen Bleeker, work-shop leader of the biomass heating and power plant Emden (BKE).”What we did not know by then-this technology wears out very fast as with the timber shred we are dealing with a complicated substance with a high degree of dust settling on all joints and producing a tremendous friction.” A basic sanitation was expected earlier than necessary.

When deciding for a new technology it was possible to refer to the company´s own references. Since the commissioning of the BKE the timber shred has been transported troublefree via a compressed air conveyor belt between the delivery and storing in the silo. It is a compressed air supporting transport system for bulk material – basicly unknown within the German power plant technology. The company Martin Engineering from Walluf took over the new technology from their American mother company. The steel work was given to IHNEN AURICH by Martin Engineering. Together the two enterprises have already exported three air conveyor belts including a customs-made steel construction to Malaysia.

The advantages of the compressed air supporting conveyor belt are short term and long term advantages. The technology has a low wear and maintenance with a reduced noise level and it uses up considerably less energy than conventional conveyors. “Basically it works like a hovercraft” describes work-shop leader Bleeker the technology.”the conveyor does not run on rollings but in a tub with holes through which the air is led in. The air pressure lifts up the conveyor and it then swims on the produced air-cushion. Friction and wear are minimized.” And it even reduces the noise level. A further positive effect for the environment:”the air compressed conveyor uses about 50 percent less energy as we do not need 240 meter long steel chains to drive the system” explains Hans-Jürgen Bleeker.

There were some difficulties to overcome in Emden. Mario Döring, installation leader of Martin Engineering:”A crucial point was the big gradient due to constructional conditions as compared to the masse conveyor a compressed air conveyor belt only makes a maximum climbing of 17 percent”. But the problem could be solved. One part of the basement ceiling was dismantled thus extending the track and minimising the gradient. Besides a kink with a belt tensioning system was integrated. This is important for reaching the right belt tension which is responsible for a steady air layer underneath the conveyor.

Sportive handling

Short term decisions and the condition to minimize the standstill of the power plant were further challenges for the participating companies. IHNEN AURICH project leader Johann Eden:”The biggest challenge for us was the time frame. That was really tight.”We only had 2 weeks available for the dismantling and the new installation. But everything worked out well and the head of the power plant praised the work: “The total handling was very sportive. The IHNEN staff worked in a very target orientated, fast and secure way.”

The new air conveyor belt plant has been in operation for three months now and everything works well. Now the e-on power plant is supposed to deliver more energy with less production interruptions due to maintenance and reconstructions and the timber shred is supposed to hover well air-supported up into the furnace.