SEISMIC EVALUATION AND STRENGTHENING OF VERTICAL AND HORIZONTAL PRESSURE VESSELS IN A REFINING COMPLEX

Pressure vessels are one of the most important equipment in the refining of the crude oil. For this reason, these equipment must resist against the loads resulting from the earthquake. Pressure vessels are found in different units of refineries and in different vertical and horizontal shapes. These equipment are located on different foundations and their seismic behavior are quite different. For seismic study of pressure vessels, at first this equipment must be screened and categorized in order to find their real behavior. The selected sample should be one that in comparison to others must have critical condition in terms of seismic vulnerabilities. According to the qualitative studies, mechanical specifications such as dimensions, temperature, weight, and the dimensions of the foundation will be determined. After analytical modeling and calculations the amount of vessel vulnerabilities will be found. All the modeling is done with the SAP2000 and SAFE2000 software. For modal and spectrum dynamic analysis shell elements and frame elements is used. After the analysis is done, the stresses and the displacement in the body of vessel and also stresses in pedestal and bolts will be determined and then it will be compared to the allowable values. At the end those elements which do not have adequate strength, will be retrofitted and all drawing and details will be presented.