Liquefied Gas Cylinders

All cylinders containing gases in their liquid state are filled based on theirfilling density. The filling density is defined as the maximum weight of the material allowed in the cylinder, as a percentage of that cylinder s water capacity. There is no overfill allowed with liquefied gases since temperature expansion of the liquid could result in catastrophic cylinder failure. 

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Use compatible pipe fittings. (Flammable gas cylinders have valves with left-hand threads cylinders for oxygen and nonflammable gases, except occasionally helium, have valves with right-hand threads. Certain liquefied gas cylinders have two supply lines, one for gas and one for liquid, dependent on cylinder position.)... 

Copper(II) acetylide (black or brown) is much more sensitive to impact, friction or heat than copper(I) acetylide (red-brown) which is used in electric fuses or detonators [1]. An explosion during maintenance work on a copper condenser in a methanol plant was attributed to copper acetylide deposits in the heat exchanger [2]. During internal inspection of an air-purged 15 year old 330 m3 liquefied gas cylinder, it was noticed that there was a 2—3 cm layer of mst-like deposit at the bottom. As the inspection... 

Caution If overfilled ( liquid full ), liquefied gas cylinders can rupture due to hydrostatic pressure. Never exceed the legal fill weight. 

Any of these devices will provide protection against a cylinder bursting from excessive temperature, except in the case where an intense flame impinging on the sidewall of a cylinder may weaken the metal at that point and cause a local failure before the heat or pressure cause the safety relief device to operate. Devices 3 and 4 may not provide protection in cases where a liquefied gas cylinder has been overfilled and exposed to a high temperature that is below the fusible metal s melting point. Because of this, extreme care should be used when filling liquefied gas cylinders and filling should never be attempted by the user. Never tamper or attempt to remove or block a cylinder s pressure relief devices since this could cause an extremely hazardous condition. 

Industrially, it is manufactured either by fractional distillation of air, or by electrolysis of sodium hydroxide and it is distributed as a non-liquefied gas in pressurized black cylinders at ca 2200 psig at 21°C. Since it is non-corrosive no special materials of construction are required. 

If the temperature remains constant, the pressure within any cylinder containing liquefied gas will remain constant as gas is drawn off (i.e. more liquid simply evaporates) so the quantity of gas remaining cannot be deduced from the pressure. 

Propane has a characteristic natural gas odour and is basically insoluble in water. It is a simple asphyxiant but at high concentrations has an anaesthetic effect. The TLV is 2500 ppm. It is usually shipped in low-pressure cylinders as liquefied gas under its own vapour pressure of ca 109 psig at 21°C. Its pressure/temperature profile is given in Figure 9.7. 

Ammonia is conveniently obtained from a cylinder of the liquefied gas the cylinder must be equipped with a reducing valve. The rate of flow of the gas may be determined by passage through a bubble counter containing a small volume of concentrated potassium hydroxide solution (12 g. of KOH in 12 ml. of water). A safety bottle should be inserted between the cylinder and the reaction vessel. 

Hydrogen sulfide is stable and stored as a compressed, liquefied gas in aluminum or stainless steel cylinders. 

Seamless steel pressure vessels are the most common method in use today for hydrogen transportation at short distances (<200 km) and when small quantities are involved (up to about 500 kg). The different vessel options include cylinders, manifolded cylinder pallets and tube trailers. While single cylinders or manifolded pallets are trucked to the destination and off loaded, tube trailers, which consist of several steel cylinders mounted to a protective framework, are often left in place and replaced when empty. Transporting hydrogen in liquefied form is seven times more efficient in terms of actual hydrogen weight transported than using compressed gas cylinders. 

E. C. C. Baly and H. M. Duncan studied the decomposition of ammonia by means of a hot platinum wire. Two types of ammonia may be prepared—an inactive and an active modification—which are decomposed to different extents by the same quantity of energy. The active form is obtained by the slow withdrawal of ammonia from a cylinder containing the compressed gas by warming the cone. aq. soln. and drying the gas by quicklime and by isothermal evaporation of the liquefied gas at its b.p. The inactive form is obtained by the rapid evaporation of the liquefied gas. The inactive gas slowly recovers its activity on remaining in contact with the liquefied gas. The same effect can be produced by gently warming the gas by means of a platinum wire heated at 200°. In order to observe these phenomena, the platinum wire must be activated in the same way as is customary in W. Ostwald s process for the catalytic oxidation of ammonia in air to nitric acid. Alternatively,... 

Large quantities of carbon dioxide may be obtained from a cylinder of the liquefied gas the gas should be dried by passing it through two Drechsel bottles containing concentrated sulphuric acid. A little air is present in the gas. 

During transfer of the liquefied gas from a stock steel cylinder into smaller cylinders, the effective expansion caused cooling of the stock cylinder and a fall in pressure to occur. Application of a flame to the stock cylinder of the endothermic oxide led to decomposition and explosive rupture of the cylinder [1]. The explosive decomposition of the gas at 0.05—8 bar at ambient temperature after initiation by electric discharge can be prevented by addition of 30 vol% of air, nitrogen or oxygen [2]. Oxyacetylene welding repair work on or near to a 6 t tank of liquefied oxide led to a violent explosion... 

To control the rate of flow and releasing pressure, gases are released from compressed gas cylinders by regulators (see Sec. 5.2) at a user-defined pressure. A regulator can display the amount of gas remaining in a compressed gas tank (in cubic feet of gas), but not in a liquefied gas tank. 

Nitrous oxide is contained and transported in its liquid phase in high-pressure gas cylinders or in liquid cylinders. It is transported as a liquefied compressed gas under high pressure in cylinders and at lower pressures and reduced temperatures in refrigerated cargo tanks and insulated portable tanks. Nitrous oxide is stored in a foam-insulated tank accompanied by a refrigeration unit, which is similar to the tank used for carbon dioxide. 

Chlorine is stored and transported as a liquefied gas in cylinders of 45.4-kg or 68-kg capacity that are under pressure and equipped with fusible-plug relief devices. Quantities in the range of 15 to 90 t are transported in tank cars having special angle valves on the manhole cover on top of the vessel. Tank barges of the open-hopper type having several cylindrical uninsulated pressure vessels are used for amounts ranging from 600 to 1200 t. Road tankers are used for capacities of 15 to 20 t. 

Experiments with gaseous reactants (propane and isobutane. Table III) were carried out by charging the liquefied gas from a weighed stainless-steel sampling cylinder into the sealed autoclave containing hydrochloric acid and, when used, a liquid alkane after which ethylene was charged and the autoclave was rotated and heated. 

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