Endesa, the Spanish energy supplier, has completed the extension to its power plant in Ceuta with the installation and commissioning of an MAN 12V48/60B engine. MAN Diesel & Turbo, Spain negotiated the contract for the new engine that includes the supply of an SCR (Selective Catalytic Reduction) system.
The 12V18/60 engine is the fourth such engine installed at Ceuta and has been Endesa’s engine of choice for many of its other power plants. The integrated SCR system significantly reduces NOx emissions at the plant and hence Endesa’s environmental impact locally.
With the installation of the engine, termed “Group 13” under its project classification, four MAN 12V48/60 models are now in operation at the power plant in Ceuta. The Ceuta engine, “Group 9”, has an “A” turbocharger configuration while the rest, “Groups 10 and 13, have “B” turbocharger configurations.
The MAN 12V48/60B engine is a four-stroke, medium-speed diesel engine with turbocharger and cooling charge air that is specially designed to run on heavy fuel oil (HFO) and diesel oil for start-up/shut-down. In comparison with other similar engines, the 12V48/60 model features a high power supply and a compact and efficient design.
The auxiliary systems that complete the scope of supply are standard for this kind of engine, with the exception of the SCR system.
Please refer to the principal engine data in the pdf-file.
SCR system description
The SCR system removes NOx from the engine’s exhaust gases. This process takes place within the catalytic converter and employs a urea solution as a reactive agent. The urea is injected into the flow of the exhaust gases by injectors with atomised air before the exhaust gases reach the catalytic convertor.
When injected into the exhaust-gas flow, urea releases ammonia (NH3) according to the following equation:
CO(NH2) 2 + 2 H2O ? 2 NH3 + CO2 + H2O
Subsequently, NH3 reacts with NOx on the surface of the catalyst which speeds up the following reactions:
2 NO2 + 4 NH3 + O2 ? 3 N2 + 6 H2O
4 NO + 4 NH3 + O2 ? 4 N2 + 6 H2O
Besides the catalytic converter, the SCR system is made up of the following components:
• A urea supply and storage system (40% urea solution) including urea storage tanks and unloading and circulation pumps
• NOx control system to control urea injection
• Urea dosification unit
• Soot blowers
• Monitoring system for released NH3 (“ammonia slip”)
Avoiding the convertor is possible thanks to by-pass valves. Due to these, the temperature remains constant in the catalyst convertor and always above 320ºC. If the temperature of the exhaust gases is lower, then the control system automatically keeps the system disconnected.
MAN Diesel & Turbo’s Power business unit in Augsburg offers a broad range of SCR systems as well as other emission-reduction systems for its entire portfolio of engines.
Endesa and Ceuta
Endesa S.A. is the largest electric utility company in Spain and a subsidiary of Enel, the Italian utility company. It has 10 million customers in Spain, with domestic annual generation of over 97,600 GWh from nuclear, fossil-fuelled, hydroelectric, and renewable resource power plants.
Ceuta is an autonomous Spanish city, located on the North African side of the Strait of Gibraltar, and separated from the Spanish mainland by the Mediterranean.
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