Solid ammonia storage and delivery material

A method for selective catalytic NOx reduction in waste gases containing oxygen, using ammonia and a reduction catalyst wherein gaseous ammonia is provided by heating a solid storage medium capable of absorption/desorption of ammonia and comprising one or more ionic ammonia absorbing salts of the general formula:

• Ma(NH3)nXz,
• wherein M is one or more cations selected from alkaline earth metals, and transition metals such as Mn, Fe, Co, Ni, Cu, and/or Zn, X is one or more anions such as chloride or sulphate ions, a is the number of cations per salt molecule, z is the number of anions per salt molecule, and n is the coordination number of 2 to 12, wherein M is Mg, wherein the ammonia storage and delivery material has been saturated with ammonia and compressed to a bulk density above 70% of the skeleton density and wherein the release rate of ammonia is controlled in consideration of the content of NOx in the waste gases.

A method for selective catalatic reduction (SCR) of NOx in exhaust gases from combustion processes comprising contacting an exhaust gase with a solid ammonia storage material capable of absorption/desorption of ammonia and comprising:

• an ammonia absorbing salt, wherein the ammonia absorbing salt is an ionic salt of the general formula:
• Ma(NH3)nXz,
• wherein M is one or more cations selected from alkaline earth metals, and transition metals such as Mn, Fe, Co, Ni, Cu, and/or Zn, X is one or more anions such as chloride or sulphate ions, a is the number of cations per salt molecule, z is the number of anions per salt molecule, and n is the coordination number of 2 to 12, wherein M is Mg and wherein the ammonia storage and delivery material has been saturated with ammonia and compressed to a bulk density above 70% of the skeleton density as a source of ammonia as the reducing agent in selective catalytic reduction (SCR) of NOx in exhaust gases from combustion processes.

An ammonia delivery device comprising a container comprising

• an ammonia absorbing salt capable of absorption/desorption of ammonia, wherein the ammonia absorbing salt is an ionic salt of the general formula:
• Ma(NH3)nXz,
• wherein M is one or more cations selected from alkaline earth metals, and/or one or more transition metals, such as Mn, Fe, Co, Ni, Cu, and/or Zn, X is one or more anions, a is the number of cations per salt molecule, z is the number of anions per salt molecule, and n is the coordination number of 2 to 12, wherein M is Mg and wherein the ammonia storage and delivery material has been saturated with ammonia and compressed to a bulk density above 70% of the skeleton density, said container being provided with one or more closable outlet opening(s) connected to a pipe and further being provided with means for heating the container and the ammonia absorbing salt for release of gaseous ammonia.

A method for selective catalytic reduction (SCR) of NOx in exhaust gases from combustion processes comprising contacting an exhaust gase with an ammonia delivery device comprising a container comprising an ammonia absorbing salt capable of absorption/desorption of ammonia, wherein the ammonia absorbing salt is an ionic salt of the general formula:

• Ma(NH3)nXz,
• wherein M is one or more cations selected from alkaline earth metals, and/or one or more transition metals, such as Mn, Fe, Co, Ni, Cu, and/or Zn, X is one or more anions, a is the number of cations per salt molecule, z is the number of anions per salt molecule, and n is the coordination number of 2 to 12, wherein M is Mg and wherein the ammonia storage and delivery material has been saturated with ammonia and compressed to a bulk density above 70% of the skeleton density, said container being provided with one or more closable outlet opening(s) connected to a pipe and further being provided with means for heating the container and the ammonia absorbing salt for release of gaseous ammonia as a source for ammonia in selective catalytic reduction of NOx in exhaust gases from combustion processes.

A solid ammonia storage and delivery material capable of absorption/desorption of ammonia and comprising:

• an ammonia absorbing salt, wherein the ammonia absorbing salt is an ionic salt of the general formula:
• Ma(NH3)nXz,
• wherein M is one or more cations selected from alkali metals, alkaline earth metals, and transition metals such as Li, Na, K, Cs, Mg, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, or Zn or combinations thereof such as NaAl, KAl, K2Zn, CsCu, or K2Fe, X is one or more anions selected from fluoride, chloride, bromide, iodide, nitrate, thiocyanate, sulphate, molybdate, and phosphate ions, a is the number of cations per salt molecule, z is the number of anions per salt molecule, and n is the coordination number of 2 to 12, said storage and delivery material having been saturated with ammonia and compressed to a bulk density above 70% of the skeleton density and a density of 0.9 to 1.3 g/cm3.