REKUGAVO – a giant solution for giant tasks: Removing harmful nitrogen oxides and sulfur from flue gas and recovering waste heat at a SNOx plant are giant undertakings requiring gigantic heat exchange solutions. At the OMV refinery in Schwecht, one of the largest and most modern of its kind in Europe, the Kelvion REKUGAVO DeSNOX gas pre-heater has the capability to handle all three highly complex processes at the same time.
Impressive heat recovery The flue gas enters the REKUGAVO at around 211⁰C where it is heated up to 380⁰C. It then flows into a natural gas burner which heats it to approximately 404⁰C before it enters the catalyst where the nitrogen oxides and sulfur are removed. The gas is then cooled down to around 241⁰C in the REKUGAVO, which transfers heat from the hot flue gas to the cold flue gas at a performance of 61,000kw and an impressive heat recovery rate of 86%.
Custom-built for the job While the REKUGAVO model is designed to be adapted to every process engineering or space, this was the first time that Kelvion had to custom-build a unit of this size. It weighs more than 1,000 tonnes and has a heat transfer area of 95,000 sq meters – equivalent to 15 football pitches. An additional challenge was that the heat exchanger needed to be able to bear twice its weight as space constraints meant that the heat exchanger would have to sit underneath the NOx reactor and the SO2 converter, more than 2,000 tonnes in total. Also a 400 sq meter concrete slab over one meter thick had to be placed seven meters above ground to cover the plant components.The result Kelvion engineers successfully navigated through unchartered territory, in collaboration with an external structural engineer, to provide a solution that met all OMV’s expectations. The REKUGAVO is operating reliably and with a heat recovery performance that had led to energy savings for the customer.