High Density Storage of Ammonia

Abstract

A solid ammonia storage and delivery material comprising an ammonia absorbing/desorbing solid material, said storage and delivery material having been compacted to a density above 50% of the theoretic skeleton density provides a solid ammonia storage material which is easy to produce and handle and has a very high density of stored ammonia which is readily released under controlled conditions even though the porosity of the material is very low, and which storage material is safe for storage and transport of ammonia without special safety measures.

1 - 40 . (canceled) 
     
     
         41 . A solid ammonia storage and delivery material comprising an ammonia absorbing/desorbing solid material, said storage and delivery material having been compacted to a density above 50% of the theoretic skeleton density. 
     
     
         42 . A material according to  claim 41 , said storage and delivery material having been compacted to a density above 75% of the theoretic skeleton density. 
     
     
         43 . A material according to  claim 42 , said storage and delivery material having been compacted to a density above 85% of the theoretic skeleton density. 
     
     
         44 . A material according to  claim 41  comprising ammonia absorbed or chemically bonded or coordinated as a chemical complex in the form of a solid material that has been compressed into a block or tablet or a pellet of a desired shape. 
     
     
         45 . A material according to  claim 41 , wherein the solid material is a chemical complex in the form of an ionic salt of the general formula:
   M a (NH 3 ) n X z ,   wherein M is one or more cations selected from alkali metals, alkaline earth metals, aluminium and transition metals or combinations thereof, 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.   
     
     
         46 . A material according to  claim 45 , wherein the alkali metals are selected Li, Na, K and Cs, the alkaline earth metals are selected from Mg, Ca or Sr, and the combinations are selected from NaAl, KAl, K 2 Zn, CsCu or K 2 Fe. 
     
     
         47 . A material according to  claim 45 , wherein the solid material comprises at least one salt in the form of at least one chloride or sulphide of at least one alkaline earth metal. 
     
     
         48 . A material according to  claim 47 , wherein the solid material is MgCl 2 , CaCl 2  or SrCl 2  or mixtures thereof. 
     
     
         49 . A material according to  claim 41 , wherein the solid material is mixed with a binder. 
     
     
         50 . A method for storing ammonia in a solid material comprising steps of:
 a) providing and binding ammonia in a solid material capable of binding ammonia; and   b) compacting the ammonia-containing material into a dense, solid material having a density above 50% of the theoretic skeleton density.   
     
     
         51 . A method according to  claim 50 , wherein the solid material to be compacted consists of a granular material, a porous material, a polycrystalline material, an amorphous material or a combination thereof. 
     
     
         52 . A method according to  claim 50 , wherein the solid material is compacted and shaped in a mould using mechanical pressure. 
     
     
         53 . A method according to  claim 50 , wherein the solid material is compacted and shaped using injection moulding, extrusion or monolith preparation. 
     
     
         54 . A method according to  claim 50 , wherein the solid material binds ammonia by adsorption. 
     
     
         55 . A method according to  claim 54 , wherein the ammonia is bound in solid material in the form of a chemical complex. 
     
     
         56 . A method according to  claim 50 , wherein the solid material is saturated with ammonia. 
     
     
         57 . A method according to  claim 50 , wherein the solid material contains at least one salt of the general formula
   M a (NH 3 ) n X z ,   
       wherein M is one or more cations selected from alkali metals, alkaline earth metals, aluminium and transition metals or combinations thereof, 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. 
     
     
         58 . A method according to  claim 57 , wherein the alkali metals are selected from Li, Na, K and Cs, the alkaline earth metals are selected from Mg, Ca or Sr, the transition metals are selected from V, Cr, Mn, Fe, Co, Ni, Cu and Zn, and the combinations thereof are selected from NaAl, KAl, K 2 Zn, CsCu or K 2 Fe. 
     
     
         59 . A method of  claim 58  producing a solid ammonia storage material comprising the steps of
 1) providing the solid salt,   2) saturating the salt with ammonia forming a chemical complex, and   3) compacting the ammonia-saturated salt complex.   
     
     
         60 . A method according to  claims 57 , wherein the solid material comprises at least one salt in the form of at least one chloride or sulphide of at least one alkaline earth metal. 
     
     
         61 . A method as claimed in  claim 60 , wherein the solid material is MgCl 2 , CaCl 2 or SrCl 2  or mixtures thereof. 
     
     
         62 . A method according to  claim 50  further comprising a step mixing the solid material with a binder before compacting the solid material. 
     
     
         63 . A method as claimed in  claim 50  further comprising the step of
 c) placing the compacted ammonia-containing material in a closed chamber provided with means for conveying ammonia from the chamber to one or more ammonia consuming units and means for heating the material in the chamber, and d) heating the chamber for releasing ammonia.   
     
     
         64 . A method as claimed in  claim 63 , wherein the ammonia is conveyed by normal pressure-driven flow through connection tubes to the ammonia-consuming units and wherein the supply pressure is controlled by heating the chamber containing the compacted ammonia storage material. 
     
     
         65 . A method as claimed in  claim 63  further comprising the step
 e) providing and binding ammonia in the solid material after it has been depleted of ammonia.   
     
     
         66 . A method as claimed in  claim 65  comprising the steps of
 i) providing a container with compacted ammonia storage material,   ii) releasing the ammonia form the storage container to an ammonia consuming unit by heating the container, and   iii) re-saturating the storage container with ammonia by re-absorbing ammonia into the material by providing gaseous or liquid ammonia through a connection to the storage container.   
     
     
         67 . A system for delivery of ammonia to an ammonia consuming unit wherein the system comprises a discharge chamber for delivery of ammonia, said chamber comprising a compacted ammonia absorbing/desorbing solid material, means for heating the storage, and means for conveying the delivered ammonia from the storage chamber to one or more ammonia consuming units. 
     
     
         68 . A system according to  claim 67 , wherein the ammonia consuming unit is a system wherein ammonia is used for catalytic removal of NO x . 
     
     
         69 . A system according to  claim 68 , wherein the catalytic removal of NO x  is a selective catalytic reduction of NO x  in an oxygen-containing exhaust gas of a combustion engine or a combustion process. 
     
     
         70 . A system according to  claim 67 , wherein the ammonia consuming unit is an internal combustion engine fuelled by ammonia. 
     
     
         71 . A system according to  claim 67 , wherein the ammonia consuming unit is a fuel cell capable of using ammonia as a fuel. 
     
     
         72 . A system according to  claim 67 , wherein the ammonia consuming unit is a catalytic reactor decomposing the ammonia into hydrogen and nitrogen. 
     
     
         73 . A system according to  claim 72  further comprising means for conveying the hydrogen to one or more fuel cells using hydrogen as fuel. 
     
     
         74 . A system according to  claim 67  further comprising a feeding system for continuous feeding of solid ammonia storage and delivery material into the discharge chamber wherein ammonia is released by thermal desorption. 
     
     
         75 . A system according to  claim 67  further comprising:
 a feeding system comprising a number of compartments where each compartment comprises one or more unit(s) of compacted solid ammonia storage and delivery material, which feeding system is adapted to releasing ammonia from the units sequentially by thermal desorption.   
     
     
         76 . A system according to  claim 67  further comprising means for supplying ammonia to the storage chamber.