Heat limitation

Another objective of gas processing is to lower the Btu content of the gas by extracting heavier components to meet a maximum allowable heating limit set by a gas sales contract. If the gas is too rich in heavier components, the gas will not work properly in burners that are designed for lower heating values. A common maximum limit is 1100 Btu per SCF. Thus, if the gas is rich in propane and heavier components it may have to be processed to lower the heating value, even in cases where it may not be economical to do so. 

Hawaii (40% below the national mean no heating, limited air conditioning) and Maine (almost 30% above the mean due to heating). 

The moisture uptake models we have discussed have been concerned with pure components. The deliquescing material could be a drug substance or an excipient material. In pharmaceuticals, however, mixtures of materials are also important. One possible situation involves mixing nondeliquescing and deliquescing materials that are formed into a porous tablet or powder blend. The obvious question is, Do the models for pure components apply to porous heterogeneous materials For pure components we have assumed that the mass and heat limiting transport... 

Fauske (1973) showed that drops of R-11 could be injected into warm water (—343 K) with little boiling. The drops, being more dense than water, fell to the bottom of the vessel. No explosions were noted. Also, for R-11 and (R-21), Chukanov and Skripov (1971) measured the super-heat-limit temperatures (see Table XVI). 

A number of technical and cost issues facing polymer electrolyte fuel cells at the present stage of development have been recognized by managers and researchers (6, 27, 28, 29). These issues concern the cell membrane, cathode performance, and cell heating limits. 

The high costs of using radio frequency heating limit its use to very expeusive remediation projects that require a uuique heating method (D15838X, pp. 2-9). 

The packed bed reactor is used to contact fluids with solids. It is one of the most widely used industrial reactors and may or may not be catalytic. The bed is usually a column with the actual dimensions influenced by temperature and pressure drop in addition to the reaction kinetics. Heat limitations may require a small diameter tube, in which case total through-put requirements are maintained by the use of multiple tubes. This reduces the effect of hot spots in the reactor. For catalytic packed beds, regeneration is a problem for continuous operation. If a catalyst with a short life is required, then shifting between two columns may be necessary to maintain continuous operation. 

It appears that the repository capacity for high-level wastes will be heat-limited to one kilowatt/acre. This is equivalent to one ton of fuel after storage for ten years. The spent fuel discharged by the year 2000 will require about 2700 subterranean acres. This would be reduced to 1000 acres if the uranium and the plutonium were removed, and considerably less than that if the strontium and the cesium also were removed. Although reprocessing would reduce the transuranic content by a factor of 10 to 50, this amount would be an insignificant fraction of the transuranic hazard in the waste. 

Fig. 6.10. (a) Variation of the penetration depth of atomic deuterium in the light of D1 as a function of the limiter temperature, (b) Differences of the Lt -light between cold and heated limiters... 

The length of the zone which can be heated limits the length of filament which can be produced but lengths of up to 250 mm have been announced. Processing is carried out under inert gas or vacuum. Several batches of fiber can be processed simultaneously to produce up to 150 g of filaments at a time. 

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