Patent ID: 8491842

Claim:
A system for storage and dosing of ammonia that comprises a solid ammonia storage material capable of binding and releasing ammonia reversibly by adsorption/absorption, said system being able to release ammonia gradually according to a demand that can vary over time with intermediate periods of no ammonia demand, said system comprising: a main storage unit and a start-up storage unit, the storage units holding ammonia storage material; at least one one-way valve via which the main storage unit is in communication with the start-up storage unit; heating devices arranged to heat the main storage unit and the start-up storage unit separately to generate gaseous ammonia by thermal desorption from the solid storage material; a controller configured so as to control the heating power of the main storage unit and the start-up storage unit, thereby enabling ammonia release from at least one of the start-up and the main storage unit; a dosing valve arranged to control ammonia flow from the storage units according to a demand; and a pressure sensor arranged downstream of the at least one one-way valve arranged to measure the pressure in connecting tubes between the at least one one-way valve and the dosing valve; wherein the controller, or another controller, is arranged to determine when the main storage unit is ready for ammonia release in a situation where the start-up storage unit has been used for rapid start-up while waiting for the main storage unit to be operable by determining the pressure in the main storage unit during a start-up phase in which the heating of the start-up storage unit and the main storage unit has already been started by: (a) interrupting ammonia release from the start-up storage unit, (b) relieving pressure in the system, (c) measuring the pressure which is caused to decrease by (a) and (b) with the pressure sensor downstream from the at least one one-way valve, and inferring from this measurement the pressure of the main storage unit, and wherein the controller, or another controller, is arranged such that, if the pressure inferred of the main storage unit has not yet reached a desired ammonia supply pressure for normal operation, to repeat the pressure determination according to activities (a) to (c) or, if the pressure inferred in the main storage unit has reached the desired ammonia supply pressure, to cease heating of the start-up storage unit and enable the start-up unit to begin to resaturate when the pressure in the main unit is higher than the pressure in the start-up unit.