Abstract:
There is described a method and apparatus (100, 100′) for storing and delivering ammonia wherein at least two ammonia storage materials (1a, 2a) capable of reversibly adsorbing or absorbing ammonia having different ammonia vapor pressures are used. Ammonia storage material (2a) having a lower vapor pressure, which is only partially saturated with ammonia or void of ammonia, is brought into fluid communication with ammonia storage material (1a) having a higher ammonia vapor pressure to adsorb or absorb ammonia released from the ammonia storage material (1a) having a higher ammonia vapor pressure when the latter is higher than a pressure threshold. An automotive NOx treatment system (200) comprising such apparatus (100, 100′) is also described.
Abstract:
Disclosed is a self-supporting solid compacted composition of material comprising an ammonia storage material capable of reversibly absorbing and desorbing ammonia in its ammonia saturated state and compacted to such a density that it has of at least 70% of the single crystal density of said material in its ammonia-saturated state in admixture with one or more additive incapable of storing ammonia and having a thermal conductivity of at least five times the thermal conductivity of the ammonia storage material at a temperature of from at least −45° C. to 250° C., as well as a process for preparing it.
Abstract:
A process for saturating a material capable of binding ammonia by ad- or absorption and initially free of ammonia or partially saturated with ammonia comprises treating said material under a pressure and associated temperature located on the vapor pressure curve of ammonia with an amount of liquid ammonia sufficient to saturate said material and an additional amount of a cooling agent selected from liquid ammonia, liquid or solid CO2, hydrocarbons and hydrohalocarbons that have a higher vapour pressure than ammonia, ethyl ether, methyl formate, methyl amine and ethyl amine, such that |Qabs|≦|Qevap|+Qext, wherein Qabs is the amount of heat released from said material when it absorbs ammonia from the liquid phase thereof to the point where it is saturated with ammonia, Qevap is the amount of heat absorbed by said cooling agent when it evaporates, and Qext is the amount of heat exchanged with the surroundings and is positive, if heat is removed from the process by external cooling, and negative, if heat is added to the process from the surroundings.
Abstract:
Disclosed is a method for storing and delivering ammonia, wherein a first ammonia adsorbing/absorbing material having a higher vapor pressure at a given temperature than a second ammonia adsorbing/absorbing material is used as an ammonia source for said second ammonia adsorbing/absorbing material when said second adsorbing/absorbing material is depleted of ammonia by consumption, and a device for performing the method.
Abstract:
A method for controlling the effective heat transfer from a storage unit (1). During gas release from storage material (3) in the storage unit the storage material is heated by a heater (2). During re-saturation of the storage material (3) with gas the heater is off. Controlling of the effective heat transfer from the storage unit (1) is performed, during gas release, by ceasing convection of a convection gas and, during re-saturation, by performing or enabling convection of a convection gas to cool the storage unit (1).
Abstract:
A method for controlled dosing of a gas with fluctuating supply pressure (PSupply). Dosing of the gas through a valve (6) is performed while a valve (5) is closed, and the decrease in control-volume pressure (PCV) is recorded. The control-volume pressure (PCV) is raised by closing dosing valve (6) and opening the valve (5). The amount of the dosed gas is calculated based on the known volume (VCV) of the control volume (4) and at least one of the change in control-volume pressure (PCV) and control-volume temperature (TCV) in the period where valve (5) is closed. The amount of dosed gas is compared with a target or set-point to adjust or regulate the subsequent dosing period or dosing event.
Abstract:
A compacted block of material constructed of one or more units consisting of matter comprising an ammonia-saturated material capable of reversibly desorbing and ad- or absorbing ammonia surrounded by a gas-permeable enclosure made of a flexible material having a thermal conductivity of at least about five times the thermal conductivity of said ammonia-saturated material at −70° C.. to 250° C.. and methods for producing the same are described.
Abstract:
In a method of storing and releasing gaseous ammonia from solid storage materials a first solid storage material (14) capable of releasing ammonia by desorption in a first container (10) and a second solid storage material (24) capable of ad- or absorbing ammonia reversibly and having a higher affinity for ammonia than the first storage material (14) in a second container (20) smaller than said first container (10) are in fluid communication. The pressure in at least the first container (10) is kept below the equilibrium pressure between ammonia and the storage material contained therein by means of a pump (28). When the pressure in the first container (10) is below a pressure threshold where the first storage material (14) does not release an amount of ammonia required by an ammonia consuming device connected with the containers via the vacuum pump (28), the second storage material (24) is heated such that the ammonia pressure of the second material (24) is higher than the ammonia pressure of the first material (14). The ammonia released by the second material (24) is continuously pumped off so as to deliver sufficient ammonia to said ammonia consuming unit. A device for carrying out the method is also described.
Abstract:
A compacted block of material constructed of one or more units consisting of matter comprising an ammonia-saturated material capable of reversibly desorbing and ad- or absorbing ammonia surrounded by a gas-permeable, flexible material having a thermal conductivity of at least five times the thermal conductivity of said ammonia-saturated material at −70° C. to 250° C. and methods for producing the same are described.
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.