Ultra-low nox diesel engine generator with selective catalytic reduction engineered exhaust system and method

A power generation system, comprising:

• a diesel engine;
• an engine-mounted electronic control unit configured to govern the diesel engine;
• an electrical generator mechanically coupled to the diesel engine;
• a selective catalytic reduction (SCR) subsystem, comprising:
• an SCR reactor comprising a catalyst and an exhaust inlet, wherein the SCR reactor is configured to receive exhaust gas from the diesel engine comprising nitrogen oxides (NOx) and convert NOx to nitrogen and water in the presence of a reductant;
• an injector upstream of the SCR reactor configured to meter the reductant into the exhaust gas;
• one or more sensors comprising sensor signals of at least one of:
• upstream NOx, downstream NOx, catalyst temperature, exhaust temperature, exhaust flow, differential pressure, reductant flow, or reductant pressure;
• and
• a controller coupled to the one or more sensors and the injector, wherein the controller is configured to enable dosing of the reductant within a temperature band based on the sensor signals;
• and
• an integrated controls and switchgear assembly that coordinates with the engine-mounted electronic control unit and the SCR subsystem.

A method of controlling a selective catalytic reduction (SCR) system comprising an SCR reactor, a catalyst, and a reductant, the method comprising:

• acquiring sensor signals comprising at least one of:
• upstream NOx, downstream NOx, catalyst temperature, exhaust temperature, exhaust flow, differential pressure, reductant flow, or reductant pressure;
• receiving a load-related signal indicative of generator real-power or a kW-command from a generator supervisory controller;
• enabling reductant dosing in a temperature band conducive to NOx conversion;
• generating a dosing command for the reductant based on the sensor signals;
• metering and injecting, responsive to the dosing command, the reductant into engine exhaust upstream of the catalyst to convert NOx in the SCR reactor;
• controlling an NH3/NOx ratio toward a near-stoichiometric value to achieve NOx conversion efficiency;
• minimizing ammonia slip under steady-state and transient loading.