Pressure helium recovery

Pressure swing adsorption (PSA) processes are widely applied industrially for gas separations. Applications are numerous and include hydrogen and helium recovery and purification, air drying, the production of oxygen from air, and the separation of normal paraffins from isoparaffins. 

The load schedule performance is assessed in terms of how well temperatures on the hot side of the combined plant are maintained constant. Also of interest are the pressures on the helium side for assessment of creep under pressure load. The pressures in the HTSE plant were maintained at 5 MPa over the load schedule from the point downstream of where the reactant water is fed in up to the point where the products enter the pressure-work recovery turbine. 

If hydrogen and neon are contained in the crude gas to the helium recovery plant, the separation of these components in a pressure swing adsorber station is not possible, since they behave similar to helium. Hydrogen can then be... 

A cell model is presented for the description of the separation of two-component gas mixtures by pressure swing adsorption processes. Local equilibrium is assumed with linear, independent isotherms. The model is used to determine the light gas enrichment and recovery performance of a single-column recovery process and a two-column recovery and purification process. The results are discussed in general terms and with reference to the separation of helium and methane. 

An example of the effect of pressure on the performance of the single column process for the methane-helium separation is shown in Table 1. Using Figure 4(b) and 4(d), the cuts corresponding to 80 percent recovery of helium were determined as a function of yF and Pr L Then the enrichments and in... 

The gas flow rates were helium 2 mL/min hydrogen 3 mL/min air 50 mL/min. The column head pressure was maintained at 0.85 bar. GC peaks representing diastereomers of (+)- and (-)-etodolac eluted at 17.5 and 19.8 min, respectively. The derivatized internal standard had a retention time of 12.5 min. The calibration curves for each enantiomer were linear over the concentration range of 0.25 - 20 pg/mL. The minimum quantifiable concentration of each enantiomer was 50 ng/mL, with observed coefficients of variation being within 8%. The recoveries from plasma for (+)- and (-)-etodolac at concentrations of 2.5 pg/mL were 66.50 0.04% and 65.83 0.03%, respectively. 

The CEA decomposition loop operates at low pressures, near 5 bar. This is because the decomposition reaction is favoured at lower pressures. However, the GA flow sheet is conducted at 70 bar, near the expected operating pressure of the secondary helium loop. This is to minimise mechanical and thermal stress induced by a large pressure gradient between the helium and the chemical process at high temperatures. The GA design of the decomposition loop allows for more heat recovery, but does so with a more complex configuration. In practice, trade-offs between complexity and cost will be necessary to develop the most cost-efficient design. 

Monitoring differential pressure between the primary and secondary cooling systems would be one of the candidates for detecting the heat transfer tube rupture. Meanwhile, the pressure varies even at normal operation and therefore there is a concern of malfunction of CV isolation valves. In case of primary helium gas recovery flow rate, primary helium pressure control system only covers the rated operation since the system activates when the primary coolant pressure reaches about 3.95 MPa. On the other hand, the primary-secondary differential pressure control system covers start-up, shutdown and rated operations. The control system keeps supplying helium gas to the secondary cooling system during the scenario. Thus, monitoring the entire secondary helium gas supply would be an effective way to detect the tube rupture. 

Sood S K, Fong C, Kalyanam K M, Busigin A, Kvelton O K and Ruthven D M (1992), A new pressure swing adsorption (PSA) process for recovery of tritium from the ITER solid ceramic breeder helium purge gas . Fusion Technol, 21, 299. 

Neon and helium accumulate in the condenser of the high pressure column. They can be purged from the system from time to time and sent to a separate purification unit for recovery of neon from nitrogen and helium. The purification involves adsorption and distillation to obtain a high purity neon. The quantity of helium produced in this way is too small to be economically attractive and it is discarded. Neon is produced with a very high purity. 

FIGURE 6.24 CO conversion and H2 recovery (a), and H2 permeance and H2/CO2 reparation factor (b) versus time-on-stream for WGS reaction in the modified bilayer MFI zeolite membrane (total feed gas flow rate 100 ml/min (STP), feed side pressure 2 atm, helium sweeping 20 ml/min (STP), permeate side pressure 1 atm). (Taken from Figure 6 of H. Wcmg, X. Dong, YS. Lin, J. Membr. Sci. 450 (2014) 425.)... 

The system consists of an insulated 4100 gal tank mounted on a 50,000 lb platform-type scale. Support equipment consists of helium pressurization providing the means of transferring the fluids from the test tank to t ie recovery tank, a 4100 gal insulated recovery tank and a pump system capable of returning the recovered test fluid to the tank. The test system is shown in Figs. 1 and 2. 

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