Process gases from the production of HDAN ammonium nitrate and ammonium nitrate based fertilisers (and explosives grade LDAN) are contaminated to differing degrees by soluble or insoluble solids and ammonia, which then require gas scrubbing or gas filtering equipment installed to prevent emission to atmosphere.
Fibre-bed technology has been used for decades and with Brownian Diffusion type designs prilled ammonium nitrate and ammonia emissions can be minimized. A key requirement for using fibre-bed candle filters is that there are no insoluble elements in the exit air, which would block the filters. Fibre-bed candle filters using P.T.F.E. media can sometimes also be used to treat the vapour from ammonium nitrate neutralisers, capturing A.N. particles and NH3.
Where there are insoluble solids present, for example C.A.N. production and emissions from granulators and dryers, then there are various designs of gas scrubbing equipment that can be implemented, to achieve legally required atmospheric emission limits, while being as maintenance-friendly as possible. To improve operational performance and to minimise down-time and cleaning, optimised packing materials for cross-flow and vertical fume scrubbers, deliver longer life and better results. Solid particles and ammonia fumes can also be handled without risk of blocking using the Begg Cousland ‘Becoflex’ rotary brush technology, which is a highly efficient and low energy package system, that requires significantly less liquid than most other wet scrubbers.