The invention discloses a device and method for reducing
urea crystals of an SCR
system. The device comprises a temperature sensor, a
pressure sensor, a heating and pressurizing gas
nozzle, a pressurizing device, an
electric heating device, an electronic regulating valve, a pump
machine, a
waste gas temperature difference power generation device, a storage battery, a recycling
waste gas pipe and an
electronic control unit. By means of the device, aiming at the low-temperature working condition,
waste gas reduced by the SCR
system is heated, recycled and injected into the SCR
system, and therefore the
reaction temperature of
NOx and a
urea aqueous solution is increased. The
reaction temperature is increased, so that the probability of forming a liquid film is reduced, and the generation of the
urea crystals is reduced. Meanwhile, the urea
aqueous solution and the heated recycled waste gas are oppositely jetted in the SCR system, so that
airflow disturbance in a
pipe is increased, the probability of forming the liquid film is reduced, and the urea
aqueous solution and the recycled waste gas are fully mixed and fully reacted. Meanwhile, heat in waste gas is utilized to generate power by adopting a waste gas
temperature difference power generation technology, power is supplied to electric appliances in the device, and
energy conservation and emission reduction are achieved.