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Liquefied Petroleum Gas
7.6 LPG Material Compatibility
Liquefied petroleum gas (LPG) is commonly used as an alternative fuel for
internal combustion engines of vehicles in many countries. LPG is stored
and transported based on transportation standards. In order to store LPG
in vehicles, the LPG cylinders known as LPG fuel tanks are commonly used
and approved by these regulations. The LPG tanks, low-pressure cylinders
since their service pressure (SP) is lower than 3.44 MPa (500 psi), can be commercially filled and used in the automobile industry. They are equipped
with a refillable two-way hermetic valve, are produced as LPG containers
and used in vehicles having water capacities ranging from 35 to 80 liters.
There are many studies that determine the burst pressures (BP) and the failure locations of LPG cylinders whose SP and test pressures (TP) are known
by the definitions of the standards and rules. The SP is the working (operating) pressure where the cylinders are filled and used in industrial applications. The TP is a given pressure that is applied and released after which the
permanent volume expansion of the cylinder must not exceed 10% of the
initial measured volume. Finally, the BP is the maximum pressure a cylindrical tank can withstand without bursting. In case of instability of cylindrical shells, analytical formulations are available for ideal shells with perfect
geometry and specific boundary conditions. These do not take into account
the strain distribution, and nonhomogeneous nonlinear material properties
(MPs) and geometrical imperfections including thickness variations in the
cylinder shell material. The BP of a vessel was estimated after a single application of internal pressure using mathematical and experimental models for
tensile loading.
Guidelines for the design of cylindrical shells can be found in many international codes such as BS-5500 (British Standard) and the ASME codes
(Section VIII, Division 1). These rules are restricted mostly to the load carrying capacity under internal pressure. These cylinders are equipped with
a valve system and a label welded to the shell body, as shown in Figure 7.14
(Kaptan and Kisioglu 2007).
Cylindrical LPG tanks are usually manufactured within four different
groups, which are classified by their water capacities: 35, 45, 60, and 80 liters.
Each group of cylinders has a different wall thickness ranging from 2 to
3 mm. In their study, the BP and failure locations of the most commonly used
three groups (35, 60, and 80 liters) of cylindrical LPG tanks having 2.5 mm
wall thickness are investigated. These tanks consist of three main parts: one
cylindrical shell and two torispherical end closures as shown in Figure 7.14.
The cylindrical shell is folded up and welded longitudinally and the two
torispherical drawn end closures are welded circumferentially at the ends of
the shell. Also in the figure, some design parameters are shown such as inner
diameter (ID), minimum wall thickness (t), knuckle radius (Rk), crown radius
(Rc), and length of the cylindrical shell (L). The LPG tanks are constructed
Liquefied Petroleum Gas
7.6 LPG Material Compatibility
Liquefied petroleum gas (LPG) is commonly used as an alternative fuel for
internal combustion engines of vehicles in many countries. LPG is stored
and transported based on transportation standards. In order to store LPG
in vehicles, the LPG cylinders known as LPG fuel tanks are commonly used
and approved by these regulations. The LPG tanks, low-pressure cylinders
since their service pressure (SP) is lower than 3.44 MPa (500 psi), can be commercially filled and used in the automobile industry. They are equipped
with a refillable two-way hermetic valve, are produced as LPG containers
and used in vehicles having water capacities ranging from 35 to 80 liters.
There are many studies that determine the burst pressures (BP) and the failure locations of LPG cylinders whose SP and test pressures (TP) are known
by the definitions of the standards and rules. The SP is the working (operating) pressure where the cylinders are filled and used in industrial applications. The TP is a given pressure that is applied and released after which the
permanent volume expansion of the cylinder must not exceed 10% of the
initial measured volume. Finally, the BP is the maximum pressure a cylindrical tank can withstand without bursting. In case of instability of cylindrical shells, analytical formulations are available for ideal shells with perfect
geometry and specific boundary conditions. These do not take into account
the strain distribution, and nonhomogeneous nonlinear material properties
(MPs) and geometrical imperfections including thickness variations in the
cylinder shell material. The BP of a vessel was estimated after a single application of internal pressure using mathematical and experimental models for
tensile loading.
Guidelines for the design of cylindrical shells can be found in many international codes such as BS-5500 (British Standard) and the ASME codes
(Section VIII, Division 1). These rules are restricted mostly to the load carrying capacity under internal pressure. These cylinders are equipped with
a valve system and a label welded to the shell body, as shown in Figure 7.14
(Kaptan and Kisioglu 2007).
Cylindrical LPG tanks are usually manufactured within four different
groups, which are classified by their water capacities: 35, 45, 60, and 80 liters.
Each group of cylinders has a different wall thickness ranging from 2 to
3 mm. In their study, the BP and failure locations of the most commonly used
three groups (35, 60, and 80 liters) of cylindrical LPG tanks having 2.5 mm
wall thickness are investigated. These tanks consist of three main parts: one
cylindrical shell and two torispherical end closures as shown in Figure 7.14.
The cylindrical shell is folded up and welded longitudinally and the two
torispherical drawn end closures are welded circumferentially at the ends of
the shell. Also in the figure, some design parameters are shown such as inner
diameter (ID), minimum wall thickness (t), knuckle radius (Rk), crown radius
(Rc), and length of the cylindrical shell (L). The LPG tanks are constructed