Helium extraction

Gas Chromatography. A Hewlett-Packard 5890 gas Chromatograph (Hewlett-Packard, Avondale, PA) with a flame ionization detector (FID), equipped with a 60 m X 0.32 mm I.d. DB-WAX column (df > 0.25 pm, bonded polyethylene glycol, J W Scientific, Folsom, CA) was employed. Helium carrier gas was used at a flow rate of 1.64 mL/min (30 C). The oven temperature was programmed from 30 C (4 min isothermaQ to 180 C at 2 C/min. A spirt ratio of 128 was used. The injector and detector were maintained at 200 C and 220 C, respectively. A 60 m X 0.32 mm i.d. DB-1 column (df - 0.25 pm, bonded dimethyl polysiloxane, J W Scientific, Folsom, CA) was used to anal e the sample prepared by vacuum steam distillation-extraction. Helium carrier gas was used a t a flow rate of 1.60 mL/min (30 C). The oven temperature was programmed from 30 C (4 min isothermal) to... 

An estimated 78 percent of the world s helium was produced in the United States in 2008. Other producers included Algeria, Qatar, Russia, and Poland. Nineteen U.S. plants extracted helium from natural gas. Those plants were located in Colorado, Kansas, New Mexico, Oklahoma, Texas, Utah, and Wyoming. According to the U.S. Geological Survey (USGS), between 2009 and 2015, about nine new helium plant projects are slated to begin work worldwide. Such plants will be located in the United States (2), Algeria, Australia, China, India, Indonesia, Qatar, and Russia. 

The composition of natural gas (Table 6.1) indicates the presence of up to 0.5—1% helium. The concentration of helium in air is much less than 0.001 %, and it is impractical to extract helium from air. Argon, another noble gas, is present at up to 1% in air, and it is obtained as a by-product in the liquefaction of air and the production of O2 and N2. Thus, since He is only available economically from natural gas, it is obvious that when natural gas is exhausted, so will be the inexpensive supply of He. Hence, it is imperative that wherever possible, He should be extracted from natural gas before it is put into pipelines, burned, or used for chemical processes. He is usually stored in abandoned mines (storage in cylinders as a compressed gas is too costly). It must be stressed that if natural gas with even 0.5% He is burned, the He is lost and will only be recoverable from air at a very great expense. 

Air contains 0.000524% He, 0.001818% Ne, and 0.934% Ar, by volume. The proportion of Kr is about 1 ppm by volume, and that of Xe, 0.05 ppm. The atmosphere is the only source of all these gases except helium. The main source of helium is certain natural gas wells in the western United States that produce natural gas containing up to 8% He by volume. It is cost-effective to extract helium from natural gas even down to levels of about 0.3%. Underground helium accumulates as a result of a-particle emission by radioactive elements in Earth s crust. Whereas the abundance of He on Earth is very limited, it is second only to hydrogen in the universe as a whole. 

Except for hydrogen, helium is the most abundant element found through out the universe. Helium is extracted from natural gas. In fact, all natural gas contains at least trace quantities of helium. 

The fusion of hydrogen into helium provides the energy of the hydrogen bomb. The helium content of the atmosphere is about 1 part in 200,000. While it is present in various radioactive minerals as a decay product, the bulk of the Free World s supply is obtained from wells in Texas, Oklahoma, and Kansas. The only known helium extraction plants, outside the United States, in 1984 were in Eastern Europe (Poland), the USSR, and a few in India. 

Use of excess sodium drives the reaction, usually done under an argon or helium blanket, to completion. After cooling, the excess sodium is leached with alcohol and the sodium and potassium fluorides are extracted with water, leaving a mass of metal powder. The metal powder is leached with hydrochloric acid to remove iron contamination from the cmcible. 

The second important component is the cooling agent or reactor coolant which extracts the heat of fission for some usefiil purpose and prevents melting of the reactor materials. The most common coolant is ordinary water at high temperature and high pressure to limit the extent of boiling. Other coolants that have been used are Hquid sodium, sodium—potassium alloy, helium, air, and carbon dioxide (qv). Surface cooling by air is limited to unreflected test reactors or experimental reactors operated at very low power. 

Helium is extracted from natural gas in the southwestern United States and moved by a 685-km, 50-mm dia pipeline to storage in a partially depleted gas field near Amarillo, Texas, as part of the U.S. government s helium conservation program. 

Extracted from TsederLerg, Popov, et al., Theimodynamic and Theimophysical Propeities of Helium, Atomizdat, Moscow, 1969, and NBS-NSF TT 50096, 1971. Copyriglit material. Reproduced hy permission. This source contains entries for many more temperatures and pressures than can he reproduced here, v = volume, mVkg h = enthalpy, kj/kg s = entropy, kJ/(kg-K). 

Carbon soot from resistive heating of a carbon rod in a partial helium atmosphere (0.3bar) under specified conditions is extracted with boiling C H or toluene, filtered and the red-brown soln evapd to give crystalline material in 14% yield which is mainly a mixture of fullerenes C q and C70. Chromatographic filtration of the crude mixture with allows no separation of components, but some separation was observed on silica gel... 

Because Raman spectroscopy requires one only to guide a laser beam to the sample and extract a scattered beam, the technique is easily adaptable to measurements as a function of temperature and pressure. High temperatures can be achieved by using a small furnace built into the sample compartment. Low temperatures, easily to 78 K (liquid nitrogen) and with some diflSculty to 4.2 K (liquid helium), can be achieved with various commercially available cryostats. Chambers suitable for Raman spectroscopy to pressures of a few hundred MPa can be constructed using sapphire windows for the laser and scattered beams. However, Raman spectroscopy is the characterizadon tool of choice in diamond-anvil high-pressure cells, which produce pressures well in excess of 100 GPa. ... 

The CNTs were prepared by the group at EPF in Lausanne [10] following the method of Ebbesen et al. [ll]. A 100 A, 20 V dc arc between a 6.5 mm diameter graphite anode and a 20 mm graphite cathode is sustained in a 6.7x10 Pa helium atmosphere for about twenty min. Nanotubes were found on the cathode, where they were encapsulated in a cylindrical 1 cm long shell. The shell was cracked and the powdery soot-like deposit extracted. The powder was then... 

Extracting an electron from helium takes less energy than expected because of electron-electron repulsion. The helium nucleus actually does pull twice as a hard as a hydrogen nucleus does, but the two electrons in helium are also repelling one another. The net effect is to make an electron in a multielectron atom easier to remove than one would expect if the other electrons were not present. 

Ion extraction. The aspirated or laser ablated sample is transported from the sample introduction system into the center of the torch by a 1 1/min flow of Ar carrier gas where it is immediately dissociated and ionized by energy transfer with the hot -6000 K temperature of the surrounding Ar plasma. Ionization efficiencies are >95% for U and Th (Jarvis et al., 1992). For laser ablation sampling, helium may be employed as the carrier... 

Now and then, projectiles from outer space cause excitement and surprises, as in January 2000, when a meteorite impacted the frozen surface of Lake Targish in Canada. It was a new type of C-chondrite with a carbon concentration of 4-5%, and probably came from a D-type asteroid (Hiroi et al., 2001). More exact analysis of the Targish meteorite showed the presence of a series of mono- and dicarboxylic acids as well as aliphatic and aromatic hydrocarbons (Pizzarello et al., 2001). Aromatic compounds and fullerenes were detected in the insoluble fraction from the extraction this contained planetary helium and argon, i.e., the 3He/36Ar ratio was... 

In 1908, Kamerling-Onnes got the liquefaction of helium (discovered by Janssen e Lockyer during the solar eclipse of 18 August 1868). Kamerlingh-Onnes obtained in Leiden 60 cc of liquid helium extracted from several tons of monazite sable imported from India. Kamerlingh-Onnes himself discovered the X-transition and the superfluidity in 4He and in 1911 the superconductivity of Hg, a particularly pure substance at that time. In the race towards lower and lower temperatures, Kamerling-Onnes, pumping on liquid 4He, obtained 0.7K in 1926. 

Nowadays, helium is no longer extracted from minerals, but from natural gas sources. 

Zsolnay and Kiel [26] have used flow calorimetry to determine total hydrocarbons in seawater. In this method the seawater (1 litre) was extracted with trichlorotrifluoroethane (10 ml) and the extract was concentrated, first in a vacuum desiccator, then with a stream of nitrogen to 10 pi A 50 pi portion of this solution was injected into a stainless steel column (5 cm x 1.8 mm) packed with silica gel (0.063-0.2 mm) deactivated with 10% of water. Elution was effected, under pressure of helium, with trichlorotrifluoroethane at 5.2 ml per hour and the eluate passed through the calorimeter. In this the solution flowed over a reference thermistor and thence over a detector thermistor. The latter was embedded in porous glass beads on which the solutes were adsorbed with evolution of heat. The difference in temperature between the two thermistors was recorded. The area of the desorption peak was proportional to the amount of solute present. 

Addison and Ackman [69] have described a direct determination of elementary yellow phosphorus in mud in which the phosphorus is extracted with benzene or isooctane. Gas chromatographic separation is achieved on a 2mx3mm column packed with 3% OV-1 or SE-30 on Chromosorb W maintained at 100 or 120°C respectively. The carrier gas was helium (80ml m 1). A flame photometric detector with a 526nm filter at 200°C was employed. Down to lpg of phosphorus could be determined. 

Lobinski et al. [72] optimized conditions for the comprehensive speciation of organotin compounds in soils and sediments. They used capillary gas chromatography coupled to helium microwave induced plasma emission spectrometry to determine mono-, di-, tri- and some tetraalkylated tin compounds. Ionic organotin compounds were extracted with pentane from the sample as the organotin-diethyldithiocarbamate complexes then converted to their pentabromo derivatives prior to gas chromatography. The absolute detection limit was 0.5pg as tin equivalent to 10-30pg kg-1. 

It had been observed already that the radioactive minerals on heating give off Helium — a gaseous element, characterised by a particular yellow line in its spectium — and it seemed not unlikely that helium might be the ultimate decomposition product of the emanation. A research to settle this point was undertaken by Sir William Ramsay and Mr. Soddy, and a preliminary experiment having confirmed the above speculation, they carried out further very careful experiments. "The maximum amount of the emanation obtained from 50 milligrams of radium bromide was conveyed by means of oxygen into a U-tube cooled in liquid air, and the latter was then extracted by the pump." The spectrum... 

Purge gas typically helium or nitrogen, used to remove analytes from the sample matrix in purge-and-trap extractions. 

Determine the power required by the compressor, power required by pumps 1 and 2, power produced by turbines 1, 2, and 3, rate of heat added by the nuclear reactor, net power produced by the Brayton gas turbine plant, net power produced by the Rankine plant, rate of heat removed by coolers 1 and 2, rate of heat exchanged in the heat exchanger, rate of heat added in the gas burner, mass rate flow of helium in the Brayton cycle, mass rate flow of steam extracted to the feed-water heater (mixing chamber), cycle efficiency of the Brayton plant, cycle efficiency of the Rankine plant, and cycle efficiency of the combined Brayton-Rankine plant. 

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