Cylinder, gas

Industrial consumers of bought-in hydrogen usually store the gas in banks of vertical or horizontal cylinders at pressures in the range from 20 MPa up to a maximum of 80 MPa. Such high pressures necessitate thick-walled and heavy steel containers. In the past, failures have been experienced through hydrogen embrittlement, which induces stress fractures in the steel. Cylinder manufacture is now therefore subject to strict standards and codes of practice. This form of storage is modular with little economy of scale. 

Manual valve or electrical valve or in-tank regulator 

A novel method to improve the amount of hydrogen that can be stored in composite cylinders involves cryo-compression of the gas. This depends on the fact that gases are denser at cryogenic temperatures than at ambient temperature. Also, they adsorb more readily on to materials with high surface areas. A medium-pressure composite cylinder (20—40 MPa) is filled with activated carbon as an adsorbent and then enclosed in an insulated jacket of liquid nitrogen (77 K). Compressed hydrogen is introduced into the cylinder where it cools, densifies, and is adsorbed on the surface of the carbon. The resultant storage capacity is several times that of the same cylinder at ambient temperature. 

Of course, the cylinder must be kept at 77 K at all times, which necessitates regular topping up of the system with liquid nitrogen. Failure to do so would result in activation of a pressure release valve or, worse, explosion of the cylinder through progressive heating. 

Several factors make hydrogen pipelines more expensive to install than those for the transport of natural gas. The hydrogen molecule is smaller than the methane molecule and therefore diffuses more readily through materials, which necessitates the use of special gaskets and flanges. Since the volumetric energy 

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Specialty Gases. The specialty gases are generally more reactive than the bulk gases and usually have low volume flow requirements in their appHcations. Historically, these have been deHvered almost exclusively in standard compressed gas cylinders. However, as the need for increased quantities has arisen, bulk specialty gas supply systems utilising larger ton-sized containers and tube trailers are being developed. 

Storage and Shipment. VDF or HFC-1132a is stored and shipped in gas cylinders or high pressure tube trailers without polymerization inhibitor and is placarded as flammable compressed gas. Terpenes or quinones can be added to inhibit polymerization. Elf Atochem North America, Inc. and Ausimont USA, Inc. supply VDE in the United States other producers are in Japan and Europe. 

For distributing larger quantities of gaseous helium, argon, and occasionally neon, a number of large, horizontal, compressed gas cylinders are manifolded on tmck semitrailers (called tube trailers) or railroad cars. Like individual cylinders, these serve both as transport containers and rental storage containers. Capacities of tube trailers range from about 300 to 5,000 m (10,000—175,000 fT) of gas. 

The largest use for calcium carbide is in the production of acetylene for oxyacetylene welding and cutting. Companies producing compressed acetylene gas are located neat user plants to minimize freight costs on the gas cylinders. Some acetylene from carbide continues to compete with acetylene from petrochemical sources on a small scale. In Canada and other countries the production of calcium cyanamide from calcium carbide continues. More recentiy calcium carbide has found increased use as a desulfurizing reagent of blast-furnace metal for the production of steel and low sulfur nodular cast iron. 

Small shipments of ethylene oxide ate made in either compressed gas cylinders up to %).l (30 gal) or in lAl steel dmms (61 gal). Very large shipments... 

Hydrogen chloride [7647-01-0] M 36.5. Passed through cone H2SO4, then over activated charcoal and silica gel. Fumes in moist air. Hydrogen chloride in gas cylinder include ethylene, 1,1-dichloroethane and ethyl chloride. The latter two may be removed by fractionating the HCl through a trap cooled to -112°. Ethylene is difficult to remove. Fumes in moist air. HARMFUL VAPOURS. 

The synthesis gas cylinder should be installed with an instrument-quality forward pressure regulator, since this will control the experimental pressure of the whole unit. The nitrogen cylinder can have an ordinary regulator, because it is used only for flushing the unit. 

For example in paint shops, TCE evaporates and causes air pollution. The contaminated air has 250 ppm TCE in it and this can be fed to a moving bed reactor at 300°C that is charged with OXITOX (Chovan et al, 1997) The kinetics must be studied experimentally. The experimental setup is shown in Figure 4.5.1 and the following description explains the recommended procedure. In the experimental unit shown, the feed is contained under pressure in a gas cylinder. Two percent of the feed is saturated by TCE and diluted with the rest of the feed. The rate is calculated as ... 

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.)... 

Do not use oil, grease or joining compounds on any fittings for compressed gas cylinders. 

Precautions for handling carbon monoxide in compressed gas cylinders in addition to those given in Table 9.3 include ... 

The main hazard is that of flammability. The following precautions supplement those in Table 9.3 for the storage of methane gas cylinders ... 

Compliance with limits set for stocks of potentially hazardous chemicals Storage, segregation and handling of gas cylinders Display of appropriate warnings/notices... 

Gas storage cabinets are used to contain compressed gas cylinders containing toxic, flammable, or corrosive gases. 

Gas storage cabinets are designed to contain one to four gas cylinders. The cylinders are connected to a gas distribution system which is also contained in the cabinet. Very sophisticated systems are available from cabinet manufacturers. These may include automatic or semiautomatic change-over capabilities, fire sprinklers, purging systems, and gas detection systems which may include alarms and automatic shutoff. Point-of-use scrubbers may also be incorporated into the design, depending on the gas being used (see Fig. 10.43). 

FIGURE 10< 108 The procedure to measure the capture efficiency by the tracer gas method, aj The measurement of the reference concentration in the duct, when the tracer is released direcdy into the duct, fb) The measurement of the concentration in the duct, when the tracer is released from the source, / -= sampling point, 2 = pump, J = analyter, 4 - injection of tracer, 5 = tracer gas flow meter, 6 = tracer gas cylinder. 

The relief valve was sized on the assumption that only two gas cylinders would be used at a time, though connections were provided for four cylinders. 

It is very important that the inert gas be available from a reliable source and that the proper pressure and flow rate are always provided. A low-pressure switch and alarm are sometimes installed in the inert gas supply line to the equipment and piping. The alarm will warn the operator that a problem may be occurring with the inert gas supply. The switch is also sometimes interlocked to open up a valve in piping from a backup inert gas cylinder bank. 

The cost of N2, like that of O2, is particularly dependent on electricity costs, though plant maintenance and transport costs also obtrude. Typical prices in 1992 for No in the USA were about 32 per tonne for bulk liquid (exclusive of transportation and handling charges). Costs for small-scale users of N2 from gas cylinders are proportionately much higher. 

Flasche, /. bottle flask jar (for gas) cylinder ( Founding) casting box, flask (Afech.) block. 

Flaschen-hals, m. neck of a bottle or flask. -inhalt, m. contents of a bottle or flask or gas cylinder, -kappe, -kapsel, /. bottle cap. -kiirbis, m. bottle gourd calabash. -achild n. bottle (flask, etc.) label, -stdpsel, -ver-schluss, m. bottle (or flask) stopper or fastener, -zug, m. set of pulleys, block and tackle. 

Gas-feuerung, /. gas heating, gas firing gas furnace, -fiamme, /. gas flame, -flamm-kohle, /. = Flammkohle. -flammofen, m. gas-fired reverberatory furnace. -flasche, /. gas cylinder, gas bottle, gasfdrmig, a. gaseous, gasiform. 

Gas-kalk, m. gas linxe. -kammer, /. gaa chamber, -kampf, m. gas warfare, chemical warfare. -kampffiasche, /. a small gas cylinder for cloud gas attacks, -kampfstoff, m. war gas. -kette, /. (Elec.) gas cell. 

The Regulations relating to gas cylinders apply to suppliers, importers, fillers and owners of cylinders from 1 January 1991 if ... 

Aluminium-sprayed coatings are used successfully on gas cylinders and on ammunition boxes under a wide variety of atmospheric conditions. 

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