Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter77.4.11 Recycling of scrubbing and washing liquorsDescriptionThe following measures result in a considerable reduction of waste water volumes from NPKproduction:• recycling of NO x loaded scrubber liquors from treatment of exhaust gases from phosphaterock digestion• recycling of washing liquor from sand washing• avoid co-condensation of vapours from the evaporation• recycling of scrubbing liquors from scrubbing of exhaust gases from neutralisation• combined scrubbing of exhaust gases from neutralisation/evaporation and granulation units(see Section 7.4.10)• using effluents as the scrubber medium.Achieved environmental benefitsTable 7.13 shows achievable emission reductions.RecyclingwithoutwithRecycling of NO x scrubbing liquors1.2 0.6 kg N/tonne P 2 O 50.7 0.02 kg F/tonne P 2 O 5Recycling of sand washing liquor 0.4 0.02 kg P 2 O 5 /tonne P 2 O 5Table 7.13: Achievable emissions from the recycling of scrubbing/washing liquorsCross-media effectsNone believed likely.Operational dataNo specific information provided.ApplicabilityGenerally applicable. However, the degree of recycling water into the process will depend onthe water balance of the specific NPK production. For an example of a water balance, see [9,Austrian UBA, 2002].On the Kompo, Krefeld site, all wash and scrubbing waters are recycled and no waste water isgenerated [78, German UBA, 2001].On the Donauchemie site, no waste water is generated in NPK production. All scrubbing liquoris recycled into the process. Usually, rinsing and cleaning waters are collected and used asscrubbing liquid in the following production campaign if the production is carried outalternately under acidic (PK) and alkaline (NPK) conditions. Waste water is only released if thesame fertiliser type is produced within two following campaigns [9, Austrian UBA, 2002].Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers 317