Selective catalytic reduction systems (SCR) (3)
Marine diesel SCR systems are mainly composed of reductant storage and supply systems, metering supply units, mixing units, SCR catalytic mufflers, catalyst carriers, soot blowing units, control systems, exhaust gas auxiliary heating systems and so on. Depending on the arrangement, there are two types of systems: high pressure and low pressure systems, with the catalyst reactor in front of the booster and the low pressure system after the booster.
The reducing agent storage and supply system mainly refers to the urea solution storage tank, urea injection pump, nozzle, urea supply pipe, etc. The urea pump pumps the urea reductant stored in the urea tank into the reductant filling and supply unit, which adjusts the urea flow into the nozzles according to the operating conditions of the diesel engine.
The urea daily cabinet includes storage cabinets and sensors, which are primarily used to store and monitor the urea solution and provide the necessary reductant for denitrification treatment.
The urea solution storage tank is used to store the urea solution and has a liquid level and temperature sensor. It is equipped with an internal icing heat exchanger, which uses the heat from the diesel engine cooling water for icing. The outlet is equipped with a coarse filter inside to prevent large particles larger than 0.1 mm from entering the injection system.
The metering supply unit is used to supply, measure, atomise and inject the reductant and consists mainly of a metering injection pump (centrifugal pump) or differential pressure metering device, urea/compressed air converter, pressure reducing valve, pressure sensor, solenoid valve, proportional valve, check valve, flow meter etc.
The metering injection pump pumps the urea solution stored in the urea storage cabinet at a certain pressure to the metering unit, which can adjust the supply rate of the urea solution by controlling the opening of the proportional valve, the supply rate is detected and displayed by the flow meter.
The urea/compressed air conversion device changes the inner tube medium according to the need, the inner tube medium is urea solution when SCR is working; the inner tube medium is compressed air when SCR is in bypass mode, so as to avoid overheating damage to the urea injector.
The SCR system for marine diesel engines consists of a reductant storage and supply system, metering supply unit, mixing unit, SCR catalytic muffler, catalyst carrier, soot blowing unit, control system, exhaust gas auxiliary heating system and so on. Depending on the arrangement, there are two types of systems: high pressure and low pressure systems, with the catalyst reactor in front of the booster and the low pressure system after the booster.
The reducing agent storage and supply system mainly refers to the urea solution storage tank, urea injection pump, nozzle, urea supply pipe, etc. The urea pump pumps the urea reductant stored in the urea tank into the reductant filling and supply unit, which adjusts the urea flow into the nozzles according to the operating conditions of the diesel engine.
The urea daily cabinet includes storage cabinets and sensors, which are primarily used to store and monitor the urea solution and provide the necessary reductant for denitrification treatment.
The urea solution storage tank is used to store the urea solution and has a liquid level and temperature sensor. It is equipped with an internal icing heat exchanger, which uses the heat from the diesel engine cooling water for icing. The outlet is equipped with a coarse filter inside to prevent large particles larger than 0.1 mm from entering the injection system.
The metering supply unit is used to supply, measure, atomise and inject the reductant and consists mainly of a metering injection pump (centrifugal pump) or differential pressure metering device, urea/compressed air converter, pressure reducing valve, pressure sensor, solenoid valve, proportional valve, check valve, flow meter etc.
The metering injection pump pumps the urea solution stored in the urea storage cabinet at a certain pressure to the metering unit, which can adjust the supply rate of the urea solution by controlling the opening of the proportional valve, the supply rate is detected and displayed by the flow meter.
The urea/compressed air conversion unit converts the inner pipe media as required, and the inner pipe is used for SCR operation.