Helium Conservation

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. 

The history of helium conservation measures dates hack to 1925 when the U.S. Congress passed ihe Helium Act of 1925. Congress amended the act in 19 >o to provide for stripping natural gas of its helinni. lor purchase ci 1 the separated helium by the government, and fur its long-ierm storage. In 1971, after about 28 billion cubic feel hud been stored i in a federally owned... 

Howland, H. R. Hulm, J. K. The Economics of Helium Conservation, Final Report to Argonne National Laboratory, Contract No. 31-109-38-2820, December,1974. 

Let us do a little bookkeeping with the exact masses of these nuclei. Actually we will simplify a bit and use the exact masses of the atoms. This will make no difference. The masses of the atoms differ from the nuclear masses by the masses of the number of electrons in each atom. We have shown that electrons are conserved in nuclear changes. Exact masses of atoms (that is, exact masses of each isotopic species and not the chemical atomic weights shown on the inside back cover) are readily available. For our hydrogen-helium reaction we have... 

In chemical terms this proposal is certainly more conservative and more generally plausible to chemists, than the relocation of helium, although this is not the reason for suggesting it here. In addition, the relocation of hydrogen is supported in some respects on chemical grounds as has been argued previously by many authors (9). 

With increasing incentives because of natuial gas pricing iNalural Gas Policy Act of 1978). several firms have plans to drill and develop nearly 250 deep Wells, from which 2.8 billion cubic feet of acidic gas per day would he produced. Il private developers elect not to conserve the helium from this project (Rilev Ridge Natural Gas Project), it is estimated that about 5 billion cubic feet of He would be vented to the atmosphere each year. 

The Q value is positive (exothermic) for spontaneous a decay. The helium nucleus emerges with a substantial velocity and is fully ionized, and the atomic electrons on the daughter are disrupted by the sudden change, but the whole process conserves electrical charge. We can rewrite the equation in terms of the masses of the neutral atoms ... 

Insufficient experimental data is available to demonstrate either the occurrence or lack of selection rules. In Table 15, some of the fastest reactions do correspond to transitions allowed for both atoms. Singlet helium transfers to Ne at a rate consistent with the data in Fig. 26, whereas triplet helium transfers comparatively slowly neither of the He transitions is allowed. However, there appear to be other cases, discussed earlier, where a forbidden transition is preferred to an allowed transition. Stepp and Anderson146 have suggested that there is partial conservation of electronic angular momentum accompanying energy transfer between atoms, and interpreted experiments on mercury fluorescence by means of the steps... 

My preference today would be for a high-pressure mixing system if I had to run very complex mixtures on a routine basis because these systems give the best reproducible gradients as a rule. As a routine research instrument or a methods development system, I would prefer a low-pressure, four-solvent dynamically mixed system using a dual-headed pump. I would use the deoxygenation apparatus (Fig. 6.4) to degas my solvents with helium and run them under a helium demand valve to conserve helium. 

Since the helium atom s direction has reversed, j9ne,final = —6.64 x 10-24 kg m s-1. Conservation of momentum implies that />wail nn.ai = 1.33 x 10-23 kg m s-1 to balance Equation 7.5. The wall acquires a kinetic energy of /Cali, final/2m= 8-8 x... 

JAEA conducted an improvement of the RELAP5 MOD3 code (US NRC, 1995), the system analysis code originally developed for LWR systems, to extend its applicability to VHTR systems (Takamatsu, 2004). Also, a chemistry model for the IS process was incorporated into the code to evaluate the dynamic characteristics of process heat exchangers in the IS process (Sato, 2007). The code covers reactor power behaviour, thermal-hydraulics of helium gases, thermal-hydraulics of the two-phase steam-water mixture, chemical reactions in the process heat exchangers and control system characteristics. Field equations consist of mass continuity, momentum conservation and energy conservation with a two-fluid model and reactor power is calculated by point reactor kinetics equations. The code was validated by the experimental data obtained by the HTTR operations and mock-up test facility (Takamatsu, 2004 Ohashi, 2006). 

Small amounts of helium are extracted from the atmosphere by fractionation methods, but not commercially because of the small amount of helium in the atmosphere. A number of natural gas wells contain helium, which can be recovered by a liquefaction and stripping process. Natural gas containing at least 0.2 percent helium has been found in the American Southwest, where the natural gas fields are the major U.S. source of helium. Those helium-rich fields are within 250 miles of Amarillo, Texas other helium-bearing fields have been found in Saskatchewan, Canada, and in areas near the Black Sea. Helium cannot be synthesized so conservation and cleanup recycle systems for spent gas are important means of preserving the earth s helium resources. 

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