Duisburg municipal utility CHP plant equipped with urea injection system

ETW Energietechnik delivers the first combined heat and power plants with „SCR“ exhaust gas cleaning system

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The German CHP specialist ETW Energietechnik has delivered natural gas CHP units with selective catalytic reduction (SCR) technology for the first time. Thus, Stadtwerke Duisburg is the first user of Adblue technology from ETW. The family business from Moers comprises three plants with MWM engines of the type TCG 2020V12, each with an electrical output of 999 kilowatts.

Efficiency: 94 percent

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.

Below all current limit values

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 therefore fall below all currently required 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)

Highest environmental standards already met

From a legal point of view, 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 must not be exceeded. The amendment to the TA-Luft of 2017 has been initiated, but has not yet been adopted. The new, higher limit values, which the ETW CHPs in Duisburg already comply with, are fixed here. These stricter values were written into the specifications by Stadtwerke Duisburg. By complying with the amended 2017 directive, utilities aim to generate their energy as environmentally friendly and sustainable as possible.

Reaction to customer requirements

ETW Energietechnik‘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 currently 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“,emphasizes the sales manager at ETW, Alexander Szabo.

Be sure to plan for upgrading

„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“,adds Alexander Szabo. The specialists at ETW Energietechnik GmbH are certain that the limit values from the amendment 2017 will be adopted in the foreseeable future and will become generally applicable to all CHP plants with a transition period - certainly also throughout Europe. In Italy, even stricter limit values are required. All CHP units can be upgraded by ETW Energietechnik along the emission regulations throughout Europe.