Earliest operation

Large-scale recovery of light oil was commercialized in England, Germany, and the United States toward the end of the nineteenth century (151). Industrial coal-tar production dates from the earliest operation of coal-gas faciUties. The principal bulk commodities derived from coal tar are wood-preserving oils, road tars, industrial pitches, and coke. Naphthalene is obtained from tar oils by crystallization, tar acids are derived by extraction of tar oils with caustic, and tar bases by extraction with sulfuric acid. Coal tars generally contain less than 1% benzene and toluene, and may contain up to 1% xylene. The total U.S. production of BTX from coke-oven operations is insignificant compared to petroleum product consumptions. 

The earliest operate at high pressure, between 30 and 35. 10 Pa absolute, at temperatures from 350 to 400°C, in reactors which arc ... 

These are the earliest, operating at 24. 10 Pa absolute, and around 180 to 190 in which the carbamate is decomposed at about 160 by simple flashing in two stages (1.7 and 0.2.10 Pa absolute). The ammonia and carbon dioxide recovered are sent to other units (nitric aci4 ammonium sulfate, ammonium nitrate etc.). 

Evidently periods of reactor operation at 800"C and 750 C increased catalyst activity for subsequent operation at 700 C with the level of enhancement dependent upon the frequency of operation at 750-800°C. The increase in activity induced in this manner decayed with time falling to the unactivated condition some 30-50 hours after activation. Increasing the frequency of operation at higher temperature reduced the rate of decline of activity at 700"C leading to increased activity at the lower temperature as shown in Fig. 5. However the temperature activation was not sufficient to restore the activity found in the earliest operations and it appears that the initial decline was irreversible. 

Free-electron lasers have long enabled the generation of extremely intense, sub-picosecond TFlz pulses that have been used to characterize a wide variety of materials and ultrafast processes [43]. Due to their massive size and great expense, however, only a few research groups have been able to operate them. Other approaches to the generation of sub-picosecond TFlz pulses have therefore been sought, and one of the earliest and most successfid involved semiconducting materials. In a photoconductive semiconductor, carriers (for n-type material, electrons)... 

Ma.nufa.cture. AU. manufacturers of butynediol use formaldehyde ethynylation processes. The earliest entrant was BASF, which, as successor to I. G. Farben, continued operations at Ludwigshafen, FRG, after World War II. Later BASF also set up a U.S. plant at Geismar, La. The first company to manufacture in the United States was GAF in 1956 at Calvert City, Ky., and later at Texas City, Tex., and Seadrift, Tex. The most recent U.S. manufacturer is Du Pont, which went on stream at La Porte, Tex., about 1969. Joint ventures of GAF and Hbls in Mad, Germany, and of Du Pont and Idemitsu in Chiba, Japan, are the newest producers. 

Montan Wax. Montan wax [8002-53-7] is derived by solvent extraction of lignite (qv). The earliest production on a commercial scale was in Germany during the latter half of the nineteenth century, and Germany continues to supply the majority of the world s production of montan wax. Montan wax production at Amsdorf is part of a massive coal-mining operation from a continuous vein and raw material is expected to last for decades. Montan wax is also produced in the United States. Imports of montan wax into the United States for the years 1990—1995 are Hsted in Table 1. Germany suppHes over 80% of the montan wax imported into the United States (3). 

Maximum allowable vibration limits on bearing housings in ips (peak) for operation up to earliest possible corrective shutdown... 

It is of paramount importance to make sure that the operating company has a full understanding of all analytical product and raw materials specifications w ithin the plant at the earliest study stage. Such specifications have major impact on capital and operating costs. 

Batch crystallizers are widely used in the chemical and allied industries, solar saltpans of ancient China being perhaps the earliest recorded examples. Nowadays, they still comprise relatively simple vessels, but are usually (though not always) provided with some means of agitation and often have artificial aids to heat exchange or evaporation. Batch crystallizers are generally quite labour intensive so are preferred for production rates of up to say 10 000 tonnes per year, above which continuous operation often becomes more favourable. Nevertheless, batch crystallizers are very commonly the vessel of choice or availability in such duties as the manufacture of fine chemicals, pharmaceutical components and speciality products. 

By introducing the time-ordering chronological operator8 P which rewrites a product of time labeled operators as the product of these same operators ordered according to their time label, the one with the earliest time label standing farthest to the right, we can rewrite the expansion (10-151) in the form... 

From the earliest days of steam production, it was recognized that a complementary combination of external and internal water treatment was a vital requirement of boiler operating practice. The justification for investment in external conditioning was (and continues to be) based... 

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