nfcl, mangalore dap/npk plant feasibility study - Environmental ...

4ANNEXURE-IVPipe ReactorThe reaction between liquid ammonia and phosphoric acid takes place in thePipe Reactors, which are composed of a Mixing Head and a distribution Pipe,last one directly installed inside the granulator drum.For DAP and most of NPK grades production, both installed PRs will worksimultaneously. In some NPK grades only one PR will be enough to producethe necessary slurry.Acid fed to Pipe Reactor is constituted by the mixture of the fresh phosphoricacid fed to P.R. tank plus the mixture of phosphoric and sulphuric acids used inthe scrubbing system.Pipe Reactor is equipped with acid and ammonia flow controllers, acid beingfed by the variable speed Pipe Reactor Pumps.The use of liquid ammonia in the Pipe Reactor improves the control oftemperature in the granulator, which is very important especially in DAPproduction.Pipe Reactor residence time is only of few seconds, thus avoiding creation ofinsoluble P2O5, or formation or reaction compounds with a lot of bonded waterin their composition.An automatic and interlocked cleaning system has been also provided to flushthe Pipe Reactor with medium pressure steam in case of unexpected shutdownor scheduled flushing. In last case flushing will take less than one minute andwill be performed without stopping the rest of the plant.