Centralizing the handling and manipulating of vaporization medium to a single subsystem that supplies multiple ammonia vaporizers allows for efficient and effective production of a corresponding vaporized ammonia stream containing a controlled quantity of ammonia. These vaporized ammonia streams can then be used in conjunction with ammonia-consuming devices to reduce NOx in NOx-containing exhaust streams from multiple furnaces.

An exhaust system for a diesel engine is provided. The exhaust system includes a component body with a surface, and a surface treatment disposed on some of the surface or all of the surface. The surface treatment is disposed so as to receive Diesel Exhaust Fluid (DEF) injected into the exhaust system during operation of the diesel engine. The surface treatment facilitates increased heat transfer to the received DEF to promote water evaporation and urea thermolysis of the received DEF.

Systems and methods of continuous operation of a urea-SCR system at low temperatures (200-350° C.) in the presence of high SOx containing flue gas are described. The methods comprise introducing a solution of urea and an NO.sub.2 forming compound, preferably an alkaline earth metal nitrate, into an exhaust stream before the exhaust stream contacts an SCR catalyst.

Systems and methods of continuous operation of a urea-SCR system at low temperatures (200-350° C.) in the presence of high SOx containing flue gas are described. The methods comprise introducing a solution of urea and an NO.sub.2 forming compound, preferably an alkaline earth metal nitrate, into an exhaust stream before the exhaust stream contacts an SCR catalyst.

A reducing agent injection device includes a honeycomb structure and a urea spraying device spraying a urea water solution in mist form. In addition, the reducing agent injection device includes a carrier gas inlet that introduces carrier gas f between the urea spraying device and the honeycomb structure. The exhaust gas treatment method of the present invention supplies the urea water solution from the urea spraying device into the cells from the first end face of the honeycomb structure body to generate the ammonia, while introducing the carrier gas f from the carrier gas inlet, and injecting the ammonia to the outside to treat exhaust gas containing NO.sub.X.

A reducing agent injection device includes a honeycomb structure and a urea spraying device spraying a urea water solution in mist form. In addition, the reducing agent injection device includes a carrier gas inlet that introduces carrier gas f between the urea spraying device and the honeycomb structure. The exhaust gas treatment method of the present invention supplies the urea water solution from the urea spraying device into the cells from the first end face of the honeycomb structure body to generate the ammonia, while introducing the carrier gas f from the carrier gas inlet, and injecting the ammonia to the outside to treat exhaust gas containing NO.sub.X.

A reducing agent injection device includes a honeycomb structure and a urea spraying device spraying a urea water solution in mist form. A pair of electrode members is formed in the honeycomb structure. The honeycomb structure of the reducing agent injection device, the hydraulic diameter HD, defined as HD=4×S/C, when the area of the cross section of one of the cells in the cross section perpendicular to the cell extending direction is S, and the peripheral length of the cross section of one of the cells is C, is 0.8 to 2.0 mm. Also, the open frontal area OFA of the honeycomb structure in the cross section perpendicular to the cell extending direction is 45 to 80%.

A reducing agent injection device includes a honeycomb structure and a urea spraying device spraying a urea water solution in mist form. A pair of electrode members is formed in the honeycomb structure. The honeycomb structure of the reducing agent injection device, the hydraulic diameter HD, defined as HD=4×S/C, when the area of the cross section of one of the cells in the cross section perpendicular to the cell extending direction is S, and the peripheral length of the cross section of one of the cells is C, is 0.8 to 2.0 mm. Also, the open frontal area OFA of the honeycomb structure in the cross section perpendicular to the cell extending direction is 45 to 80%.

A reducing agent injection device includes a first honeycomb structure and a urea spraying device spraying a urea water solution in mist form. A pair of electrode members is formed in the first honeycomb structure. The ratio L/D of length L in the cell extending direction of the honeycomb structure body to diameter D of the cross section perpendicular to the cell extending direction is 0.5 to 1.2. Also, it is preferable that a urea hydrolysis catalyzer is provided in the second end face side of the honeycomb structure body, with a gap from the second end face.

A reducing agent injection device includes a first honeycomb structure and a urea spraying device spraying a urea water solution in mist form. A pair of electrode members is formed in the first honeycomb structure. The ratio L/D of length L in the cell extending direction of the honeycomb structure body to diameter D of the cross section perpendicular to the cell extending direction is 0.5 to 1.2. Also, it is preferable that a urea hydrolysis catalyzer is provided in the second end face side of the honeycomb structure body, with a gap from the second end face.