(56i) Analysing Effect of Various Parameters on Maximum Surge Pressure in a Pipeline and Deciding Governing Parameter Using Statistical Approach

Authors: 
Joshi, P., AKER SOLUTIONS
Bhende, G., PROTTON Engineering
Transporting the fluid through a long distanced pipeline is always preferred due to safety and economical reasons. Many international codes specifies requirement of Emergency Shut Down valves or Control stations to ensure safe operation of these pipelines. The quick closing and opening of manual or automated valves in the pressurized pipeline can result in Pressure Surge phenomenon. With effect of sudden closure of the valve, a pressure wave generates, travels across the pipeline, generates a sudden pressure peak known as pressure surge and finally results in the high magnitude forces which can damage the pipeline, break the supports causing catastrophic failure. Thus, considering Safety as most important aspect of Plant Engineering, Surge Analysis study comes as one of the Mandatory requirement.

Surge Analysis can be carried out in two parts: Process Calculations to evaluate Maximum Surge Pressure and Dynamic Stress Analysis to evaluate magnitude of Forces acting on a pipeline during Surge event. However, there could be conflicts when it comes to converting Surge Pressure into force. There are many critical parameters like Valve Cv, Valve Closing time, Valve closing profile which is based on type of valve, Length of Pipeline, Fluid properties, Pipeline MOC and its Mechanical properties which have considerable impact on the Surge Pressure evaluation. This paper attempts to describe and to analyze Surge Event due to sudden valve closure. Further it talks about the effect of all critical variable parameters on the Surge Pressure evaluation as a result of number of experiments carried out with the help of dynamic analytical software. At the end it tries to find out the most governing parameter affecting Surge Pressure using a unique application of ANOVA, a Statistical analysis method. The paper also explains this method with a solved example.

It also covers the differential forces acting on the pipe and tries to touch many unwritten parameters which need to be carefully considered while estimating maximum Surge Pressure in a Pipeline and their effects which could be useful for a mature Process or Piping Engineer.