On-stream

The stream data in Fig. 13.6 include those associated with the reactor and those for the rest of the process. If the placement of the reactor relative to the rest of the process is to be examined, those streams associated with the reactor need to be separated from the rest of the process. Figure 13.7 shows the grand composite curves for the two parts of the process. Figure 13.7b is based on streams 1, 2, 6, and 7 from Table 13.1, and Fig. 13.7c is based on streams 3, 4, 5, 8, 9, 10, and 11. 

Earlier processes (e.g. hydroforming) used MoO,i —AI2O3 catalysis but platinum-based catalysts are now extensively used, enabling longer on-stream times before catalyst replacement. 

During this period newly drilled producers are progressively brought on stream. 

Initially new wells may still be brought on stream but the older wells start to decline. A constant production rate is maintained. This period is typically 2 to 5 years for an oil field, but longer for a gas field. 

One of the techniques capable of being used "on stream" is the novel INCOTEST technique, see figure 2, which measures wall thickness of piping and vessels through an insulation layer with a maximum thickness of 10 centimetres. This system is based on pulsed eddy currents, was first developed in the United States, and is now being commercialised and extensively validated for a number of applications. 

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. 

Ma.nufa.cture. Most butanediol is manufactured in Reppe plants via hydrogenation of butynediol. Recendy an alternative route involving acetoxyiation of butadiene has come on stream and, more recendy, a route based upon hydroformylation of allyl alcohol. Woddwide butanediol capacity has climbed steadily for many years. In 1990 it was estimated to be 428,000 metric tons (141), as compared to a Htde more than 70,000 metric tons in 1975... 

In the 1980s cost and availabiUty of acetylene have made it an unattractive raw material for acrylate manufacture as compared to propylene, which has been readily available at attractive cost (see Acetylene-DERIVED chemicals). As a consequence, essentially all commercial units based on acetylene, with the exception of BASF s plant at Ludwigshafen, have been shut down. AH new capacity recendy brought on stream or announced for constmction uses the propylene route. Rohm and Haas Co. has developed an alternative method based on aLkoxycarbonylation of ethylene, but has not commercialized it because of the more favorable economics of the propylene route. 

Ca.ta.lysts, Catalyst performance is the most important factor in the economics of an oxidation process. It is measured by activity (conversion of reactant), selectivity (conversion of reactant to desked product), rate of production (production of desked product per unit of reactor volume per unit of time), and catalyst life (effective time on-stream before significant loss of activity or selectivity). 

Ammonia from coal gasification has been used for fertilizer production at Sasol since the beginning of operations in 1955. In 1964 a dedicated coal-based ammonia synthesis plant was brought on stream. This plant has now been deactivated, and is being replaced with a new faciUty with three times the production capacity. Nitric acid is produced by oxidation and is converted with additional ammonia into ammonium nitrate fertilizers. The products are marketed either as a Hquid or in a soHd form known as Limestone Ammonium Nitrate. Also, two types of explosives are produced from ammonium nitrate. The first is a mixture of fuel oil and porous ammonium nitrate granules. The second type is produced by emulsifying small droplets of ammonium nitrate solution in oil. 

A variety of processes for synthesizing glycerol from propylene are shown in Figure 1. The first glycerol process, put on stream in 1948, followed the discovery that propylene could be chlorinated in high yields to aHyl chloride [107-05-1] (see Chlorocarbons and chlorohydrocarbons,allylchloride). 

A development in the 1960s was that of on-line elemental analysis of slurries using x-ray fluorescence. These have become the industry standard. Both in-stream probes and centralized analyzers are available. The latter is used in large-scale operations. The success of the analyzer depends on how representative the sample is and how accurate the caUbration standards are. Neutron activation analyzers are also available (45,51). These are especially suitable for light element analysis. On-stream analyzers are used extensively in base metal flotation plants as well as in coal plants for ash analysis. Although elemental analysis provides important data, it does not provide information on mineral composition which is most cmcial for all separation processes. Devices that can give mineral composition are under development. 

The UPI and MI retorts are processing 7000 t/d (7700 short tons/d) of Irati shale to produce 24,381 m /d (3870 bbl) of shale as well as 80 t (55 short tons) of LPG, 132 t (145 short tons) of clean fuel gas, and 98 t (108 short tons) of sulfur. The SIX plant has reached its design rate (Table 16) in an energy efficient manner with a high on-stream (operating) factor. 

Production Costs and Capital Requirements. The production cost for 1.5 wt % from air, assuming 100% on-stream time, varies... 

The cracked products leave as overhead materials, and coke deposits form on the inner surface of the dmm. To provide continuous operation, two dmms are used while one dmm is on-stream, the one off-stream is being cleaned, steamed, water-cooled, and decoked in the same time interval. The temperature in the coke dmm is in the range of 415—450°C with pressures in the range of 103—621 kPa (15—90 psi). Overhead products go to the fractionator, where naphtha and heating oil fractions are recovered. The nonvolatile material is combined with preheated fresh feed and returned to the furnace. The coke dmm is usually on stream for about 24 hours before becoming filled with porous coke, after which the coke is removed hydraulically. 

The catalyst is employed in bead, pellet, or microspherical form and can be used as a fixed bed, moving bed, or fluid bed. The fixed-bed process was the first process used commercially and employs a static bed of catalyst in several reactors, which allows a continuous flow of feedstock to be maintained. The cycle of operations consists of (/) the flow of feedstock through the catalyst bed (2) the discontinuance of feedstock flow and removal of coke from the catalyst by burning and (J) the insertion of the reactor back on-stream. The moving-bed process uses a reaction vessel, in which cracking takes place, and a kiln, in which the spent catalyst is regenerated and catalyst movement between the vessels is provided by various means. 

A second pressure on elemental production was the development of processes which remove impurities from phosphoric acid made by the wet process, to generate acid of equivalent purity to that obtained by the electric furnace route. Two such plants were brought on stream one at Aurora, North Carolina in 1990 by a joint venture of Albright Wilson, Texasgulf, and Olin, and another at Geismar, Louisiana, in 1991 by Rhc ne-Poulenc. These units have reported capacities of 47,600 and 31,700 t/yr elemental phosphoms equivalent, respectively (14). 

Researchers at Phillips Petroleum Company developed a commercially viable process for the synthesis of PPS involving the polymerization of /)-dich1orohenzene and a sodium sulfide source in a polar organic compound at elevated temperature and pressure. This Phillips process was patented in 1967 (18). Between 1967 and 1973, Phillips built and operated a pilot plant, estabhshed market demand, and constmcted a hiU-scale commercial plant. In 1973, the world s first PPS plant came on-stream in Phillips faciUty in Borger, Texas. 

In 1974, Monsanto brought on-stream an improved Hquid-phase AIQ. alkylation process that significantly reduced the AIQ. catalyst used by operating the reactor at a higher temperature (42—44). In this process, the separate heavy catalyst—complex phase previously mentioned was eliminated. Eliminating the catalyst—complex phase increases selectivities and overall yields in addition to lessening the problem of waste catalyst disposal. The ethylben2ene yields exceed 98%. 

In 1976 the first section of a new smelting process that requited 30% less electric power than the best Hah-HAroult cehs came on stream. In this process, alumina, carbon, and chlorine reacted to produce aluminum chloride and carbon dioxide. The aluminum chloride was electrolyzed in bipolar electrode cehs to produce aluminum and chlorine and the chlorine was recycled to make more aluminum chloride. After six years of operation, the plant... 

In the 1980s manufacturing capacity for aniline underwent some major changes. It is estimated that aniline capacity utilization was about 50% of nameplate capacity when Aristech s new 91,000 t/yr plant came on stream. That same year American Cyanamid closed its 23,000-t plant at Willow Island, W. Va., and withdrew from the aniline business. Mobay shut down its larger plant (45,000-t) at New Martinsville, W. Va. in 1983 and Du Pont idled its 77,000-tfacihtyinl984. 

These reductions in capacity, coupled with the growth in aniline demand led to shortages in aniline supply in 1987 and 1988. The shortage is expected to persist into the early 1990s until new capacity comes on stream. Mobay and BASF have aimounced plans to build new plants (113,000 and 54,000 t, respectively), which are to start in 1992. 

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