A Study on Synthetic Method and Material Characteristics of Metal Ammine Chlorides as Ammonium Transport Materials for Solid SCR
Cheon Seog (Steve) Yoon, Hannam University
Solid materials of ammonia sources with SCR have been considered for the application of lean NOx reduction in automobile industry, to overcome complex problems of liquid urea based SCR. These solid materials produce ammonia gas directly with proper heating and can be packaged by compact size, because of high volumetric ammonia density. Among various ammonium salts and metal ammine chlorides, calcium ammine chloride and magnesium ammine chloride were taken up for this study because of its ease of handling and safety.
In order to make calcium ammine chloride and magnesium ammine chloride in lab-scale, simple reactor and glove box was designed and built with ammonium gas tank, regulator, and sensors. Basic test conditions of charging ammonia gas to anhydrous calcium chloride and anhydrous magnesium chloride are chosen from equilibrium vapor pressure by Van’t Hoff plot based on thermodynamic properties of materials. Synthetic method of calcium ammine chloride and magnesium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%) from simple weight calculations which were confirmed by IC. Also, lab-made calcium ammine chloride and magnesium ammine chloride were analyzed by TGA and DSC to clarify decomposition step in the equations of chemical reaction. To understand material characteristics for lab-made calcium ammine chloride and magnesium ammine chloride, DA, XRD and FT-IR analysis were performed using the published data available in literature. From the analytical results, the water content in the lab-made calcium ammine chloride and magnesium ammine chloride can be determined. A new test procedure for water removal was proposed, by which the adsorption rate of lab-made sample was found to be approximately 100%.
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