Germany-headed combined heat and power (CHP) specialist ETW Energietechnik GmbH has delivered its first natural gas CHP units complete with selective catalytic reduction (SCR) technology. Two 999 kWe output MWM engine units each with Adblue technology from ETW were installed by the city of Duisburg's municipal utility Stadtwerke Duisburg. A third unit will be commissioned in 2019.
Two of the three ETW plants with significantly reduced nitrogen emissions have been in operation since the end of 2017 – at the Duisburg-Mitte and Duisburg-Süd sites. The third plant in Duisburg-Süd will also be commissioned at the beginning of 2019, with all three plants achieving a very good overall efficiency of 94 percent each with an intelligent heat utilisation concept based on a second installed exhaust gas heat exchanger stage (AWT) and a heat recovery from the mixed cooling circuit.
Future proofed for tougher emission standards
Compliance with the limit values from the “TA-Luft” version of 2002 is still a legal requirement in Germany. It specifies that 500 milligrams of NOx, 300 milligrams of CO and 30 milligrams of formaldehyde per standard cubic meter (Nm³) must not be exceeded. The amendment to the TA-Luft of 2017 has been initiated but has not yet been adopted.
The ETW CHPs in Duisburg is already in compliance with the new stricter emission values as these were written into the specifications by Stadtwerke Duisburg. With the fully operational, fully automatic SCR catalytic converter plant including urea injection (Adblue), the ETW plants comply with the latest state of the art and the stricter exhaust emission limits:
- NOx: < 100 mg/Nm³ (exhaust gas dry at 5 percent O2)
- CO: < 100 mg/Nm³ (exhaust gas dry at 5 percent O2)
- Formaldehyde: < 20 mg/Nm³ (dry flue gas at 5 percent O2).
According to ETW Energietechnik, it’s innovative Adblue CHP units are among the first SCR plants in Germany that are currently operating under full load on the grid. ETW managers are absolutely certain that others will follow and that Adblue will become the standard.
Usually, we only deliver the standard SCR catalytic converter housing with a single-nozzle section for Adblue with the elements for compliance with the values according to TA-Luft 2002. However, this simplifies retrofitting considerably and enables us to react immediately to customer requirements. Accordingly, we are already advising our customers to plan the SCR catalytic converter in the form of a casing, including the injection line, for all systems, said Alexander Szabo, Sales Manager at ETW.
ETW Energietechnik is confident that the limit values from the German “TA-Luft” 2017 amendment will be adopted in the foreseeable future and will become generally applicable to all CHP plants with a transition period – not just in Germany but also throughout Europe.