Modelling an integrated impact of fire, explosion and combustion products during transitional events caused by an accidental release of LNG

In a complex processing facility, there is likelihood of occurrence of cascading scenarios, i.e. hydrocarbon release, fire, explosion and dispersion of combustion products. The consequence of such scenarios, when combined, can be more severe than their individual impact. Hence, actual impact can be only representedby integration of above mentioned events. A novel methodology is proposed to model an evolving accident scenario during an incidental release of LNG in a complex processing facility. The methodology is applied to a case study considering transitional scenarios namely spill, pool formation and evaporation of LNG, dispersion of natural gas, and the consequent fire, explosion and dispersion of combustion products using Computational Fluid Dynamics (CFD). Probit functions are employed to analyze individual impacts and a ranking method is used to combine various impacts to identify risk during the transitional events.The results confirmed that in a large and complex facility, an LNG fire can transit to a vapor cloud explosion ifthe necessary conditions are met, i.e.the flammable range, ignition source with enough energy and congestion/confinement level. Therefore, the integrated consequences are more severe than those associated with the individual ones, and need to be properly assessed. This study would provide an insight for an effective analysis of potential consequences of an LNG spill in any LNG processing facility and it can be useful for the safety measured design of process facilities

The influence of the bow design on structural response due to ice loading

The optimum bow shape for an ice-going vessel in ice conditions is different to open water conditions and research about the influence of the bow shape on the structural response due to ice loading and resistance is required. A framework is developed to study the functional relationship between the bow shape and the structural response for ice-going bows in MATLAB. The structural dimensions are optimised by an automatic link to a parametric finite element model in ANSYS Mechanical. Both the buttock angle and the average waterline angle should be as small as possible to reduce the channel ice resistance. When changing the bow shape angles along an iso-resistance curve, the design pressure is constant and thus the structural response according to the DNVGL rules. It is found that the maximum stress in plates of the bow increases by reducing the average waterline angle while keeping the structural design constant