Failure pressure of composite membrane housing for SWRO desalination plants

In this work, the failure pressure of composite membrane housing used in seawater reverse osmosis (SWRO) desalination plants has been determined using both analytical solution and finite element modeling (FEM) at two types of loading conditions namely; internal pressure neglecting the side thrust and internal pressure with associated side thrust. An experimental study of a membrane housing vessel has been presented in case of internal pressure neglecting the side thrust to verify the theoretical results. Plate samples of unidirectional E-glass/polyester material have been fabricated using hand lay-up method and tested to determine the physical and the mechanical properties. Pipe samples made of the same material with asymmetric angle-ply laminate lay-up [±66]₁₀have been fabricated using filament winding technique and tested to determine the failure pressure by hydrostatic pressure test. Experimental results showed that the failure pressure is less than that of the analytical solution with error of about 6%, while the error of maximum hoop strain is about 11%. FEM results showed that the failure pressure and the maximum hoop strain are slightly larger than that of analytical solution with error less than 1% in case of internal pressure neglecting the side thrust. While in case of internal pressure with associated side thrust, the error of failure pressure and maximum hoop and axial strains is about 3%.