Monday, April 11, 2016
Exhibit Hall E (George R. Brown )
Statistics indicate that it is in fact not uncommon to have an accidental explosion on an offshore platform, refinery or petrochemical installation. The focus for several years has been on occupied buildings and their resistance to blast loads from accidental releases of hydrocarbons. Common practice dictates that domino effects may not need to be considered given that a large catastrophic release is equivalent in consequence. However, the catastrophic events are filtered out in a risk assessment due to their unlikelihood and as a result, domino effects are not captured. For example, a small release of highly reactive fuel, can lead to a small explosion which can easily damage nearby piping and vessels which can in turn become catastrophic events. The design and assessment of piping systems and vessels against blast loads are of paramount importance and require advanced analysis capabilities. In order to have a safe, i.e. blast-resistant process piping system design, an advanced nonlinear analysis in time domain is required so that we may properly capture the dynamic response of the piping and vessels subjected to blast loading. This type of analysis, in general, should take into account (1) Blast drag load and blast overpressure; (2) Nonlinear material properties, i.e. thermal and strain-rate dependence; (3) Effects of non-structural masses and adjacent piping systems; (4) Pipe supports; (5) Failure of flanges and piping detail; (6) Effects of Operating Temperature on Material Properties; (7) Blast direction/Ignition location/Attenuation sensitivity; (8) Shielding effect, e.g. pipes behind large objects such as vessels; and (9) Effects of pipe insulation, i.e. increased pipe diameters. This paper first discusses the methodology/techniques to account for such effects in finite element analysis for a safe design. The paper then uses case studies to demonstrate the methodology we develop to show how advanced simulation techniques are applied as tools for piping blast response to minimize the risk of secondary failure due to initiating events. These case studies involve a piping system that is simulated from global to detail modeling. The goal of the paper is to discuss how to achieve a safer design for process piping systems by using advanced analysis.