why store propane in spherical tank?

Question

commercial tank storage

Answer 1

The spherical shape is the strongest against internal or external pressure. Next comes a cylindrical shape with spherical end caps. Next comes a cylindrical shape with indented end caps sort of like the bottom of a champagne bottle.

The spherical shape also has the most volume for the surface area so less metal is needed to make the vessel.

In other words, you get the strongest vessel using the least amount of material, with a sphere.

Answer 2

Although propane is also stored in cylindrical tanks, the largest commercial tanks are often spherical because a sphere contains the most volume for a given surface area, minimizing the metal required to hold a given volume. Spherical tanks can be easily supported either in spherical concrete dishes or by supporting the sphere at its equator (Horton spheres). Because cylindrical tanks have spherical ends, there is no strength advantage to a cylindrical tank of equal thickness.

Answer 3

The differential pressure exerted on volume elements in the material are distributed in 2 dimensions. A cylindrical element for example would have all of its stress in the equatorial region and none laterally, while a spherical element has force elements in two directions, making spherical vessels twice as strong (I'm pretty sure its twice....).

EDIT:
Ok, apparently no one is saying or believes that spherical vessels are twice as strong so here is the proof:

http://physics.uwstout.edu/Statstr/Strength/Columns/cols75.htm

according to this university physics web site, the stress is thin walled pressure vessels are

stress = (PR) / (t) for a cylinder
stress = (PR) / (2t) for a sphere

Where P = internal pressure; R = radius, t = wall thickness

the sphere has a 2 in the denominator meaning half of the stress. The benifits of making them spherical because of increased volume is far out weighed by the manufacturing and storage costs associated with such a wierd shape. Why aren't oil drums spherical? natural gas and oil are pretty much the same thing.

Answer 4

propane has a boiling point of -34f. the pressure must be raised to keep it in a liquid form a spherical tank holds pressure better than a cube because the pressure of the LP trying to boil would bulge the center of the face creating enormous strain on the seams half way from the corners
and propane tanks are not made out of silver. just think of how many would be stolen. the big one are made of steal and the small ones are steal or aluminum

Answer 5

Process pressure vessels constructed offsite and transported are usually cylindrical with toroidal ends. A cylinder length to diameter ratio of approx 2.5 is the most economical. Where large volumes of a material have to be stored under pressure and onsite construction is necessary (because size prohibits transportation) the savings of metal used may make a sphere best. Really large quantities of propane (and butane and LNG) are now stored in refrigerated tanks at near atmospheric pressure and transported in refrigerated form by ship.

Answer 6

A spherical tank has (or in theory has) zero weak points. You're talking about a tremendous amount of pressure. Any weak spots will cause it to rupture. Same theory as an eggshell. It's round like that on purpose...

Answer 7

Thermal Expansion is a factor to any shaped tanks. LPG expansion and tank expansion happen as temperature rises. Sphere tank does not hide water vapour since it is rounded. A cylindrical tank has edges which can develop water vapours and also LPG is a mixture of gas and Liquid. In terms of calculation, error may occurs as vapour will occupy any sides. There are many other reasons which I guess you should know a sphere tank also called Shell Tank as Shell designed it. (I read from the web) Consultant

Answer 8

The high pressure of the propane creates stress against the container's surface.

In a square or rectangular container, excessive stress (more Pounds per square inch) are exerted against the corners of the container resulting in bulging of the container & eventually rupture due to the weakening of the container (the bulging causes the metal to stretch & become thinner).

In a cylindrical container, the stress is distributed evenly against the surface and will not result in stress fractures if the container is made to proper specifications.

Therfore, a metal *square* container will burst, whereas a *fiberglass component* cylinder (like the Lite Cylinder http://www.litecylinder.com ) will hold up to the test.

Answer 9

try putting propane in basically, a sealed box, a sealed cylinder, and a spherical container. a box is prone to leaking, so

KABOOM!!!

the cylinder's flat bottom starts to leak. someone lights a cigarette, and

KABOOM!!!

so the sphere is the only one left, and the best choice. by the way, a propane container isn't EXACTLY spherical. It's more like a franken-sphere-a-ma-linder.

Answer 10

Two reasons:
1. Angular edges are a weak point
2. A sphere of a given diameter holds more volume than a square of the same distance across and uses slightly less material.