Computer Aided Engineering (CAE) Optimization of Orifice Plate in Natural Gas Pipeline

The optimizations of the orifice plate in natural gas pipeline for 4, 5, and 6 inch orifice plates with the flow of 30, 80 and 250 MMSCF/d became necessary after frequent failure and the Fluid-structure interaction (FSI) studies show that the existing design have buckling Problems.The orifice plates were modeled with solid works and analyzed with Midas NFX under their various process conditions.The thickness is increased to 5 mm and downstream shape modification to a divergent outlet to 45 o to improve its performance.The results show higher expected service life; with increase in the differential pressure indicating that the pressures downstream partly depend on the thickness.Upon increasing the thickness from 2 mm to 5 mm the differential pressure increases by 159%, 340% and 402.85% for 4 inch (104.6 mm), 5 inch (127 mm) and 6 inch (152.4 mm) orifice plate respectively.Shape modifications had little or no positive effects on the expected life and the differential pressure designed for.There should be alternative material for orifice plate fabrication like monel other than the stainless steel commonly used Although, stainless steel rate of corrosion is slow; a lower yielding strength than monel for orifice plate fabrication.