An ammonia gas generator for producing ammonia from a solution of an ammonia precursor substance, comprising a catalyst unit that comprises a catalyst for the decomposition and/or hydrolysis of ammonia precursor substances into ammonia and a mixing chamber provided upstream of the catalyst; an injection device for injecting the solution of the ammonia precursor substance into the mixing chamber; at least one inlet for the carrier gas; and an outlet for the formed ammonia gas, said ammonia gas generator also comprising a perforated disc.

A method for reducing condensate in a subsurface formation is disclosed. The method includes introducing a reactive mixture including an aqueous solution, urea, dopamine, a silica nanoparticle precursor, a silane grafting compound, and an alcohol compound into the subsurface formation. The method also includes allowing generation of ammonia through thermal decomposition of the urea and allowing the silica nanoparticle precursor to hydrolyze, thereby forming silica nanoparticles. The method further includes allowing the silane grafting compound to graft onto the silica nanoparticles, thereby forming functionalized silica nanoparticles. The method also includes allowing polymerization of the dopamine, thereby forming polydopamine. The method also includes allowing the functionalized silica nanoparticles to attach to the subsurface formation via the polydopamine, thereby reducing condensate in the subsurface formation.

An ammonia precursor generating system includes: a storage compartment storing at least ammonia precursor granules; a tank storing an ammonia precursor solution; a dissolving compartment configured to store an ammonia precursor solution, and to dissolve ammonia precursor granules in the ammonia precursor solution; a transfer mechanism configured to transfer ammonia precursor granules from the storage compartment to the dissolving compartment; a fluid transfer device configured to transfer the ammonia precursor solution from the tank to the dissolving compartment.

Ammonia gas generator for producing ammonia from a solution of an ammonia precursor substance comprising a catalyst unit, which comprises a catalyst for the decomposition and/or hydrolysis of ammonia precursor substances into ammonia and a mixing chamber arranged upstream of the catalyst, an injection device for introducing the solution of the ammonia precursor substance into the mixing chamber, and an outlet for the ammonia gas formed, wherein the injection device comprises a nozzle which produces droplets having a Sauter mean diameter D.sub.32 of 26 to 100 m.

Methods and systems for producing a pressurized ammonia-containing gas stream from aqueous urea. The method comprising pumping an aqueous urea-containing solution to a fluid-tight enclosure at a rate to match the external demand for ammonia-gas, wherein a fluid heat transfer medium is applied to the exterior of the fluid-tight enclosure to transfer heat to the aqueous urea-containing solution sufficient to hydrolyze the solution to an ammonia gaseous product. The systems comprise means for carrying out the methods.