Modeling and Stress Analysis of Pump Piping

Abstract

Every process piping industry uses several pumps in each process unit. Sometimes the analysis is very critical. This article explains about elaborate the method followed for stress analysis of a pump piping system. The stress system consists of typical discharge and suction lines of two pumps. Fluid from the tank is pumped to another. As per P&ID only one pump will operate at a time, other pump will be a stand by pump. This article explains about the stress analysis methodology in three parts: - a) Modeling of Pump b) Preparation of analysis Load cases and c) analyzing the output results. External loads imposed by piping on rotating equipment nozzle should be less than allowed loads. If excessive loads are imposed, misalignment may result that affects mechanical operation and could cause objectionable vibration. A close alignment between rotating and stationary parts must be maintained. The provision for expansion of the casing and maintaining close clearances requires that the forces and moments due to the piping are limited. The API 610 standard gives equation to calculate allowable forces and moments in the case of pumps for general refinery service. The criteria apply for pumps with 4 Inches discharge nozzles or smaller (suction nozzle may be larger) and situations where the pump is constructed of steel or alloy steel. The modulus of elasticity of the piping material at operating temperature (known as hot modulus) can be used to calculate actual loads. Using hot modulus will result in lower loads because the piping is more flexible at higher temperature. This paper is designed for studying a wide range of abilities and backgrounds this will cover the fundamental principles, concepts used in pipe stress analysis.