Design and Analysis of Buried Liquid Petroleum Gas Storage Bullets Supported on Multiple Saddles (PVP2010-25052)

Abstract

The use of large, high pressure liquid petroleum gas (LPG) storage bullets has become a common, and often assumed safe, practice in the petrochemical industry. The Engineering Equipment and Materials Users Association (EEMUA) is an organization that has attempted to address design aspects related to mounded or buried bullets; Publication No. 190 published by the EEMUA (2000, Guide for the Design, Construction and Use of Mounded Horizontal Cylindrical Vessels for Pressurized Storage of LPG at Ambient Temperatures, EEMUA, London, England.) became a standard practice in the industry. However, the design recommended, and therefore addressed, by Publication 190 is for bullets directly supported by soil (i.e., without saddle supports). However, it has been noticed by the authors that many users are requesting these storage bullets be supported by saddles resting on foundations in order to minimize the chance of unexpected settling and any motion of the bullets underground. The large span of these bullets requires more than two saddles adding to the complexity of the design due to statically indeterminate construction, differential settlement, and uneven supports. This paper focuses on major issues related to the design of such bullets. First, the loads induced by mound weight, pressure due to mound, and the loads due to longitudinal thermal expansion and soil resistance to this expansion is analyzed. Next, a method for calculating the multiple saddle reactions and bending moments at spans and supports is provided. A simplified method for assessing the effect of differential settlement between saddles is proposed.

Design and analysis of a large horizontal vessel supported on multiple saddles according to three-moment theorem and Zick’s method

“…Therefore, a more scientific approach is needed to obtain accurate bending moment and reaction at each saddle based on possible settlements of the vessel before stress assessment. Stefanovic and Noman 12 and Popa and Sovarel 13 made progress in the calculation of multiple saddles with settlements and achieved certain results by amending three-moment equation without settlements.…”

Thermal Performance Analysis of a Mounded Liquid Ethylene Storage Tank

“…Stefanovic et al [7] designed mounded tanks with saddle support to reduce the chance of settlement and movement of the tank. Jose et al [8] conducted a finite element analysis of an mounded liquefied petroleum gas (LPG) storage tank, considering hydrostatic test loads and seismic loads, and analyzed the impact of different sand bed foundation forms on the stacked storage tank.…”

“…Stefanovic et al. 7 designed mounded tanks with saddle support to reduce the chance of settlement and movement of the tank. Jose et al.…”