Diesel engine tail gas aftertreatment SCR ammonium bicarbonate injection system

Abstract

The invention discloses a diesel engine tail gas aftertreatment SCR ammonium bicarbonate injection system. The diesel engine tail gas aftertreatment SCR ammonium bicarbonate injection system is characterized in that ammonium bicarbonate replaces a traditional urea solution to serve as matter for providing an SCR reducing agent ammonia gas; the solid ammonium bicarbonate is heated with hot water ofan engine and is pyrolyzed to generate ammonia gas, carbon dioxide and water, the three kinds of matter are all gaseous, and a mixture of the ammonia gas, the carbon dioxide and the water is sprayedinto a diesel engine exhaust pipe through an SCR controller; and the ammonia gas and NOx are subjected to a reducing reaction to generate harmless nitrogen gas and water, and therefore the aim of eliminating NOx in diesel engine tail gas is achieved. The ammonium bicarbonate replaces the urea solution, the problem of urea crystallization is solved firstly, and the problem that NOx cannot be treated with urea when the exhaust temperature is lower than 160 DEG C is solved secondly; and the ammonia content of the solid ammonium bicarbonate and the ammonia content of the urea solution are fundamental equivalent, the vehicle-miles of travel is equivalent when the ammonium bicarbonate is injected once and the urea solution is injected once, and the cost of the solid ammonium bicarbonate is lower.

Description

technical field [0001] The invention is an SCR ammonium bicarbonate injection system for aftertreatment of diesel engine exhaust, which is characterized in that ammonium bicarbonate is used to replace the traditional urea solution as a supply material for SCR reducing agent ammonia, and the solid ammonium bicarbonate is supplied by the hot water of the engine Heating, ammonium bicarbonate is pyrolyzed to generate ammonia, carbon dioxide and water. The three substances are all gaseous. The mixture of ammonia, carbon dioxide and water vapor is sprayed into the exhaust pipe of the diesel engine through the SCR controller, and the ammonia and NOx are reduced. The reaction produces harmless nitrogen and water, so as to achieve the purpose of eliminating NOx in the exhaust gas of diesel engines. The urea solution is replaced by ammonium bicarbonate, which firstly solves the problem of urea crystallization, and secondly solves the problem that urea cannot To deal with the problem of ...

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Problems solved by technology

[0002] Regarding automobile emission regulations, the Euro VI standard implemented in Europe in 2014 is very strict. According to the Euro VI standard, the emission of nitrogen oxides per kilometer of diesel vehicles should not exceed 80 mg, which is 68% lower than the current standard. China The China VI standard will also be implemented in 2020. The China VI A standard can be implemented until 2023 as a transition to the China VI standard. From 2023, the China VI B standard will be fully implemented. The current SCR urea solution injection system commonly used in the automotive industry can no longer meet the requirements. According to the requirements of China VI B, another technology, canned solid ammonium (ASDS), stores ammonia gas through strontium dichloride, and then directly releases the ammonia gas into the exhaust pipe of the car through heating, so there is no low engine exhaust temperature and no NOx treatment The problem is that it can meet the requirements of the National VI B standard, but the technology is not yet mature, and the supporting facilities such as ammonia tank replacement and maintenance in the later stage are not perfect, which cannot meet the actual needs of the market. In order to meet the requirements of the National VI B emission regulations, there is an urgent need Find alternatives to SCR urea solutions and canned solid ammonium

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