The Ibbenbüren power plant in North Rhine-Westphalia, Germany, has lowered its energy-needs with 18%, and still relies on an optimal air flow. Key to this result are 3 ZB VSD centrifugal blowers from Atlas Copco. They are used to generate oxidation air for the flue gas desulphurization installation.
The turbo installation has not only lowered energy needs by 18%, but offers optimal reliability. The oil-free blowers hardly require maintenance due to their motor with a permanent magnet.
“Flue gas desulphurization is very complicated. Too little air is just as bad as too much. The speed-controlled ZB 130 VSD blowers a-enable us to save 18.1% in energy compared to earlier set-ups.”
The company burns anthracite which is mined right next to the power plant. In order to desulphurize any resulting flue gas in the two-circuit absorbers, RWE must add an exactly defined amount of oxidation air. "Otherwise the sulfur sticks together in the installation and cakes everywhere", Hollekamp explains. "Too little air is just as bas as too much."
That could cause the reaction to take place too early or start at the wrong location in the installation.
RWE has the process under proper control using 3 type ZB 130 VSD low-pressure centrifugal compressors. The machines are all speed-controlled with variable speed drive technology, allowing their volume flow to be adjusted precisely to need.
The system is designed with 3 ZB turbos for a volume flow of 13 680 m3/h, but no more than 12 000 m3/h is required. The pressure requirement for the air to be blown into the flue gas desulphurization installation (REA) is on average less than 1 bar according to RWE. "This depends greatly on the process," Hollekamp explained. "Today, the machines run with pressure increases of just 0.6 bar each."
The Atlas Copco compressors keep the pressure band totally stable in the process, which adds to the system’s efficiency. The pressure required is the result of the back pressure of the ducting and the static back pressure of the liquid sump in the absorbers of the REA, where the air is sprayed using spray lances.
Total control of the compressors is a typical component of numerous RWE investments. Control means flexibility and flexibility improves the profitability of the power plant on the current energy market.
“The performance of the ZB turbos were actually 8 to 9 percent higher than what Atlas Copco promised.”
A mathematician from the company came to the conclusion that the Atlas Copco machines, based on their components and design, needed less energy than the others that were being looked at. The result – 18% less power consumption in the REA – has since confirmed RWE expectations, plus a little extra: "The performance of the ZB turbos were actually 8 to 9 percent higher than what Atlas Copco promised," Uwe Jäkel says. "This is not only economical, but also good for the environment,” Manfred Hollekamp said. “At the end of the day, the power plant uses less coal per kilowatt hour produced.”
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