Gulf Coast

The dominant role of petroleum in the chemical industry worldwide is reflected in the landscapes of, for example, the Ruhr Valley in Germany and the U.S. Texas/Louisiana Gulf Coast, where petrochemical plants coimected by extensive and complex pipeline systems dot the countryside. Any movement to a different feedstock would require replacement not only of the chemical plants themselves, but of the expensive infrastmcture which has been built over the last half of the twentieth century. Moreover, because petroleum is a Hquid which can easily be pumped, change to any of the soHd potential feedstocks (like coal and biomass) would require drastic changes in feedstock handling systems. 

The acid content of cmde petroleum varies from 0—3%, with cmdes from California, Venezuela, Russia, and Romania having the highest content. Smaller amounts are found ia U.S. Gulf Coast cmdes, whereas Httie or no naphthenic acids are found ia Pennsylvania, Iraq, or Saudi Arabia cmdes. Typical concentrations are shown ia Table 2. Minor amounts of naphthenic acids are also found ia bituminous oil sands, but these are not economically recoverable. Identification of naphthenic acids ia water from oil-beating strata is being examined as a potential method of petroleum exploration (18). 

A. H. Bouma, Shell Dredging and Its Influence on Gulf Coast Environments, Gulf Pubhshing Co., Houston, Tex., 1976. 

The key elements of the cost of production of phenol are feedstock cost and capital cost. For phenol produced on the U.S. Gulf Coast in a 200,000 t/yr phenol plant built in 1994, the cumene feedstock cost represents 70% of the net cost of production, after allowance for acetone coproduct value. Depreciation of equipment represents 14% of the net cost and utilities approximately 7.6%. The remaining 8.4% covers all other expenses, including plant labor, maintenance, insurance, adininistration, sales, etc. 

The other refining centers in the United States are all located near one of the major pipelines that are suppHed either from the Gulf Coast oil fields or from Oklahoma, Texas, or Louisiana fields. The Pacific Northwest refineries were originally suppHed mostly by Canadian production. Currently (ca 1995), these refineries are predominantly suppHed by Alaskan North Slope cmde, which is brought in from Valdez to the refinery ports in tankers. 

Most of the petrochemical facihties that depend on a cheap and abundant supply of natural gas are also located in the Gulf Coast, where a surplus of offshore gas is available. These facihties use cracking of natural gas to produce ethylene as the starting point for the refining of their products. This... 

Reduced energy ammonia process utilizing natural gas feed at a U.S. Gulf Coast location. Daily production of 1,000 t, yearly production of 345,000 t, and... 

Ammonia and urea prices from 1968 to 1986 are shown in Figure 22 (82). The average FOB price of ammonia on the U.S. Gulf Coast in early 1991 was 105/t. 

Transportation and Distribution Cost. Although much ammonia serves as feedstock for other processes, the largest single use in the United States is as a direct appHcation fertiliser without further processing. This direct appHcation consumption is mosdy in the farm belt and ammonia produced in the Gulf Coast states is shipped to terminal faciUties and then distributed by retail outlets to the farmer. 

Propylene is usually transported in the Gulf Coast as compressed hquid at pressures in excess of 6.9 MPa (1000 psi) and ambient temperatures. Compressed hquid propylene densities for metering purposes may be found in the ALPI Technical Tata Took (13). Another method (14—17) predicts densities within 0.25% and has a maximum error on average of only 0.83%. 

Propylene has many commercial and potential uses. The actual utilisation of a particular propylene supply depends not only on the relative economics of the petrochemicals and the value of propylene in various uses, but also on the location of the supply and the form in which the propylene is available. Eor example, economics dictate that recovery of high purity propylene for polymerisation from a smaH-volume, dilute off-gas stream is not feasible, whereas polymer-grade propylene is routinely recovered from large refineries and olefins steam crackers. A synthetic fuels project located in the western United States might use propylene as fuel rather than recover it for petrochemical use a plant on the Gulf Coast would recover it (see Euels, synthetic). 

Sodium is not found ia the free state ia nature because of its high chemical reactivity. It occurs naturally as a component of many complex minerals and of such simple ones as sodium chloride, sodium carbonate, sodium sulfate, sodium borate, and sodium nitrate. Soluble sodium salts are found ia seawater, mineral spriags, and salt lakes. Principal U.S. commercial deposits of sodium salts are the Great Salt Lake Seades Lake and the rock salt beds of the Gulf Coast, Virginia, New York, and Michigan (see Chemicals frombrine). Sodium-23 is the only naturally occurring isotope. The six artificial radioisotopes (qv) are Hsted ia Table 1 (see Sodium compounds). 

It is a mature industry and the capacity in the United States is not expected to increase rapidly. The annual capacity of 5.3 x 10 t already substantially exceeds the domestic demand. Approximately 20% of U.S. production is exported. The U.S. styrene producers benefit from the huge ethylene capacity and the relatively low energy cost present in the Gulf Coast. 

Salt-Dome Sulfur Deposits. The sulfur deposits associated with salt domes in the Gulf Coast regions of the southern United States and Mexico have historically been the primary sources of U.S. sulfur. These remain an important segment of both U.S. and world sulfur supply. Although the reserves are finite, many are large and voluntary productive capacity ensures the importance of these sources for some time to come. In 1994, the output from the salt domes in the U.S. was about 2.09 million metric tons (21). 

Evaporite Basin Sulfur Deposits. Elemental sulfur occurs in another type of subsurface deposit similar to the salt-dome stmctures in that the sulfur is associated with anhydrite or gypsum. The deposits are sedimentary, however, and occur in huge evaporite basins. It is befleved that the sulfur in these deposits, like that in the Gulf Coast salt domes, was derived by hydrocarbon reduction of the sulfate material and assisted by anaerobic bacteria. The sulfur deposits in Italy (Sicily), Poland, Iraq, the CIS, and the United States (western Texas) are included in this category. 

Gulf Coast Section Committee, Text. Chem. Color. 22(3), 33 (1990). 

Disproportionation of Olefins. Disproportionation or the metathesis reaction offers an opportunity to convert surplus olefins to other desirable olefins. Phillips Petroleum and Institut Fransais du Petrc le have pioneered this technology for the dimerization of light olefins. The original metathesis reaction of Phillips Petroleum was intended to convert propylene to 2-butene and ethylene (58). The reverse reaction that converts 2-butene in the presence of excess ethylene to propylene has also been demonstrated (59). A commercial unit with a capacity of about 136,000 t/yr of propylene from ethylene via 2-butene has been in operation in the Gulf Coast since 1985 (60,61). In this process, ethylene is first dimerized to 2-butene foUowed by metathesis to yield propylene. Since this is a two-stage process, 2-butene can be produced from the first stage, if needed. In the dimerization step, about 95% purity of 2-butene is achieved at 90% ethylene conversion. 

Oligomerization of Ethylene. 1-Butene is a small by-product in the production of linear alpha-olefins by oligomerisation of ethylene. Linear alpha-olefins have one double bond at the terminal position and comprise the homologous series of compounds with carbon atoms between 4 and 19. The primary use of alpha-olefins is in the detergent industry. About 245,000 t/yr of 1-butene was produced for chemical use in the Gulf Coast of the United States in 1988 (72). 

Since the above reaction is reversible, it can be used to produce either propylene or ethylene and butenes depending on relative prices. For example, when propylene is inexpensive, ethylene and butenes are produced. When ethylene is inexpensive and there is a high demand for propylene, ethylene is dimerized to butene and then the reverse reaction is utilized. A commercial plant based on the reverse reaction has been built on the Gulf Coast. 

There are 12 producers of ethylene oxide ia the United States. Table 9 shows the plant locations, estimated capacities, and types of processes employed. The total U.S. production capacity for 1992 was ca 3.4 x 10 metric tons. The percentages of total domestic production made by the air- and oxygen-based processes are ca 20 and 80%, respectively. The largest producer is Union Carbide Corp. with approximately one-third of the United States ethylene oxide capacity. About 94% of domestic ethylene oxide capacity is located on the Gulf Coast near secure and plentiful ethylene suppHes. Plans for additional U.S. production ia the 1990s have been announced by Union Carbide (incremental expansions), Eormosa Plastics (at Pt. Comfort, Texas), and Shell (at Geismar, Louisiana) (101). 

Guthries method [K. M. Guthrie, Chem. Eng., 76, 201-216 (Apr. 14, 1969)] is mainly graphical, using average mid-1968 costs for a United States Gulf Coast location. 

A number of other chemicals suspected of having endocrine disrupting potential also occur at high levels in the tissues of marine mammals. For example, tribiityltin compounds are present in the tissues of the Steller sea lion (Eumetopias juhatus) from Hokaido, Japan, and in stranded bottlenose dolphins (Tursiops truncatus) found along the US Atlantic and Gulf coasts.Additional chemicals detected include PAHs, toxaphene and chlordane. ... 

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