At an amine recycling plant, a Börger rotary lobe pump has been introduced to add sulphuric acid to an important neutralising process. The pump has replaced a screw pump that had reoccurring problems with its sealing system.
A sodium sulphate solution (created by the reaction between caustic soda and the sulphuric acid contained in the amine sulphate) is pumped to one of two storage tanks – with sulphuric acid mixed in on the suction side until the solution reaches a pH value of 7. The unit in use is a Mobile PL200 Protect Pump in stainless steel with MIP [Maintenance In Place] and stainless steel casing liners and thermosyphon system. It is powered by a 5.5kw drive and works with 470-720rpm. With air quality control requirements of high importance, the plant specified that the rotary lobe pump be set to 8 bar. If the pressure drops below 5 bar, a pressure switch turns off the system. The medium pressure is restricted to a maximum of 3 bar by a pressure transducer, which ensures a minimum barrier pressure of 2 bar above feeding pressure.