Bureau of Mines / Minerals yearbook: Metals and minerals 1977
Year 1977, Volume 1 (1977)
Alverson, Larry J.
Rhenium, pp. 777-783 ff. PDF (1015.1 KB)
MINERALS YEARBOOK, 1977778 low-lead gasolines, production of which placed in operation and larger ones were is enhanced by bimetallic catalytic re- being designed. A valuable byproduct of the forming.2 process is hydrogen, which is produced in Eight States have 100% bimetallic- greater amounts and at higher purity than reforming capacity; 22 States have none. was attainable before the continuous proThe remaining 20 States have bimetallic cess was developed. capacity ranging from 30% (Ohio) to 94% The remaining 20% of estimated domes(Mississippi). The trend has been to convert tic rhenium consumption was used in higholder monometallic units to bimetallic be- temperature thermocouples, X-ray tubes cause increasing demand has put a strain and targets, vacuum tube and flashbulb on existing production potential. filaments, electrical contacts, electronic deMost of the increased capacity in catalytic vices, heating elements, electromagnets, reforming took place in the smaller refin- metallic coatings, and high-temperature aleries (less than 200,000 barrels per day (bpd) loys for research and development work. of crude oil capacity). Reforming capacity in Rhenium has experienced growth in the these refineries increased 22% over that of field of rotating anodes for diagnostic X-ray 1976; similar capacity of larger refineries tubes. Many of the unique properties of (greater than 200,000 bpd) was virtually rhenium are incorporated into composite unchanged in the same period. However, anodes, composed of a molybdenum backthe total reforming capacity of the larger ing, surfaced with a tungsten-rhenium alloy refineries represented 84% of total reform- layer. The rhenium content of the layer ing capacity. averages about 10%. Wear on the focal One of the advantages of platinum- track is minimized because the tungstenrhenium catalysts is that they can tolerate rhenium alloy layer withstands the electron more carbon than monometallic catalysts bombardment better than pure tungsten. and regenerate to comparable carbon levels. Also, rhenium resists the recrystallization One of the Union Oil Co. refineries reported and grain growth typical of tungsten and 18 weight-percent carbon on a R16H imparts ductility to the target surface. The platinum-rhenium catalyst, after 115 bar- composite targets have made possible the rels of feed per pound of catalyst at about 96 development of high-speed tubes with research octane number (RON); 14 weight- decreased anode angles. This permits the1 percent on R22, a bimetallic catalyst with- development of smaller focal spots without out rhenium, after 81 barrels per pound at sacrificing X-ray intensity.4 92 to 96 RON; and 13 weight-percent on A thermocouple that utilizes rhenium in R16G platinum-rhenium catalyst, after 117 two separate sections was manfactured by a barrels per pound at 90 to 92 RON. Carbon domestic firm. The tube well is a Mo-50% deposition rates tend to be lower for bime- Re alloy, and the thermocouple itself is tallic catalysts than for monometallic ones, either W versus W-26% Re or W-5% Re allowing for operation at lower pressure, versus W-26% Re. Both thermocouples can lower hydrogen recycle ratio, and higher be used up to 4,200' F in vacuum, or in severity.' hydrogen, nitrogen, or other inert atmosThe Wynnewood refinery of Kerr-McGee pheres. The insulator used in both is berylRefining Corp., with a reforming capacity of hum oxide. Other thermocouples are avail7,500 barrels per stream-day, has used a able with tantalum or molybdenum tube bimetallic platinum-rhenium catalyst for wells and magnesium or beryllium oxide about 8 1/2 years. The charge has been insulators in combination with both types of regenerated more than seven times, tungsten-rhenium thermocouples. approaching 800 barrels per pound on the In modern mass spectrometry, rhenium material, and is still performing like fresh was used in thermionic and thermoelectric catalyst. The initial charge of bimetallic emitters. The favorable combination of platinum-rhenium catalyst was installed in properties of rhenium has resulted in sub1967 in Chevron's El Segundo No. 1 reform- stantial replacement of previously used er. The catalyst is still in service today. materials such as tungsten, tantalum, moSome has been replaced, but most has gone lybdenum, and other refractory metals. The over 700 barrels per pound, and has been main advantage of rhenium in this applicaregenerated 15 times. Tests indicate that it tion is that it provides high stability of is as good as fresh catalyst. electronic emissions in atmospheres of varUniversal Oil Products (UOP) had over 50 ious gases. This ensures higher accuracy of continuous Platforming units onstream or mass spectrometric analysis and reduces under construction. A 42,000 bpd unit was the memory effect in the instrument corn-
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