The challenge
The sinter-waste-gas-fan suffered from strong erosion, and voestalpine Stahl Donawitz consulted Howden to evaluate potential improvements on the wear protection.
Based on temperatures, we assumed low efficiencies, and investigated potential energy savings, while simultaneously trying to reduce the impeller speed to reduce erosion. Initial calculations revealed potential energy savings of 900 kW, making the project pay for itself in approx. 2.5 years (excl. CO2 savings).
The solution
To strengthen our argument, we performed on-site aerodynamic measurements to confirm the potential energy savings and optimise the fan selection and design, while keeping in mind a potential future capacity increase.
CFD analysis then formed the basis for stringent performance guarantees, and continuous performance measurements over several months. This confirmed that we did not need a flow control device, while collecting reliable data about the operating range over time.
The outcome
A complete turnkey retrofit, including a new fan, e-motor with frequency converter, control system, removal of the old fan, and commissioning of the new fan. We compiled a large team of experienced Howden personnel from Germany and the UK, and managed the subcontracted site work.
The job was completed on time within 10 days, and an independent party concluded that the fan over-performed at 3 duty points, and that it was "right on target" for a 4th one. This eventually lead to 1052 actual kW savings, additional CO2 savings, and reduced erosion.
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