Petroleum feedstocks

The petroleum industry is now the principal suppHer of ben2ene, toluene, the xylenes, and naphthalene (see BTX processing Feedstocks). Petroleum displaced coal tar as the primary source for these aromatic compounds after World War II because it was relatively cheap and abundantly available. However, the re-emergence of king coal is predicted for the twenty-first century, when oil suppHes are expected to dwindle and the cost of producing chemicals from coal (including new processes based on synthesis gas) will gradually become more competitive (3). 

If the product is essentially identical to that produced by other manufacturers, then the price is determined principally by the commodity market price. However, contract features such as guaranteed deHvery schedules can influence price. Examples of commodity pricing are petrochemicals, petroleum feedstocks, petroleum products, and primary metals. 

Feedstock petroleum as it is fed to the refinery a refinery product that is used as the raw material for another process the term is also generally applied to raw materials used in other industrial processes. 

Petroleum and Related Feedstocks. Petroleum sulfonate by-products were the first petrochemical product. Since that time. By-product petroleum sulfonates have gradually found utilization m a great many applications, including as lubricant additives for high performance engines as emulsifiers, flotation agents, and corrosion inhibitors and for enhanced oil recovery. The importance of petroleum sulfonates has grown to the point where these compounds are produced as coproducts, or even as primary petrochemicals. 

Petroleum wax is used in the manufacture of candles, polishes, ointments and for waterproofing purposes. Waxes are also used as a cracking feedstock for the production of 1-alkene.s for conversion to detergents. 

Biedermann, J.M., J.-P. Peries and J. Bousquet (1987), SOLVAHL an attractive way to provide conversion units with high quality feedstocks . National Petroleum Refiners Association (NPRA) paper No. AM-87-41, Annual meeting, San Antonio, TX. 

Although the rapid cost increases and shortages of petroleum-based feedstocks forecast a decade ago have yet to materialize, shift to natural gas or coal may become necessary in the new century. Under such conditions, it is possible that acrylate manufacture via acetylene, as described above, could again become attractive. It appears that condensation of formaldehyde with acetic acid might be preferred. A coal gasification complex readily provides all of the necessary intermediates for manufacture of acrylates (92). 

Higher aliphatic alcohols (C —C g) are produced ia a number of important industrial processes using petroleum-based raw materials. These processes are summarized in Table 1, as are the principal synthetic products and most important feedstocks (qv). Worldwide capacity for all higher alcohols was approximately 5.3 million metric tons per annum in early 1990, 90% of which was petroleum-derived. Table 2 Hsts the major higher aliphatic alcohol producers in the world in early 1990. 

The Dimersol process (Erench Petroleum Institute) produces hexenes, heptenes, and octenes from propylene and linear butylene feedstocks. This process is reported to produce olefin with less branching than the corresponding polygas olefins. BASE practices this process ia Europe. 

TURBINE fuels), are both in demand. Solvent extraction is also extensively used to meet the growing demand for the high purity aromatics such as ben2ene, toluene, and xylene (BTX) as feedstocks for the petrochemical industry (see BTX PROCESSING FEEDSTOCKS,PETROCHEMICALS). Additionally, the separation of aromatics from aUphatics is one of the largest appHcations of solvent extraction (see Petroleum, refinery processes survey). 

Anhydrous Acetic Acid. In the manufacture of acetic acid by direct oxidation of a petroleum-based feedstock, solvent extraction has been used to separate acetic acid [64-19-7] from the aqueous reaction Hquor containing significant quantities of formic and propionic acids. Isoamyl acetate [123-92-2] is used as solvent to extract nearly all the acetic acid, and some water, from the aqueous feed (236). The extract is then dehydrated by azeotropic distillation using isoamyl acetate as water entrainer (see DISTILLATION, AZEOTROPIC AND EXTRACTIVE). It is claimed that the extraction step in this process affords substantial savings in plant capital investment and operating cost (see Acetic acid and derivatives). A detailed description of various extraction processes is available (237). 

Coal is used ia industry both as a fuel and ia much lower volume as a source of chemicals. In this respect it is like petroleum and natural gas whose consumption also is heavily dominated by fuel use. Coal was once the principal feedstock for chemical production, but ia the 1950s it became more economical to obtain most industrial chemicals from petroleum and gas. Nevertheless, certain chemicals continue to be obtained from coal by traditional routes, and an interest in coal-based chemicals has been maintained in academic and industrial research laboratories. Much of the recent activity in coal conversion has been focused on production of synthetic fuels, but significant progress also has been made on use of coal as a chemical feedstock (see Coal CONVERSION processes). 

Many valuable chemicals can be recovered from the volatile fractions produced in coke ovens. Eor many years coal tar was the primary source for chemicals such as naphthalene [91-20-3] anthracene [120-12-7] and other aromatic and heterocycHc hydrocarbons. The routes to production of important coal-tar derivatives are shown in Eigure 1. Much of the production of these chemicals, especially tar bases such as the pyridines and picolines, is based on synthesis from petroleum feedstocks. Nevertheless, a number of important materials continue to be derived from coal tar. 

Production of Eastman s entire acetic anhydride requirement from coal allows a reduction of 190,000 m /yr (1.2 million barrels/yr) in the amount of petroleum used for production of Eastman chemicals. Now virtually all of Eastman s acetyl products are made in part from coal-based feedstocks. Before the technology was introduced, these chemicals had been made from petroleum-based acetaldehyde. Reduced dependence on petroleum, much of which must be obtained from foreign sources, is important to maintain a strong domestic chemical industry. 

Olefins are produced primarily by thermal cracking of a hydrocarbon feedstock which takes place at low residence time in the presence of steam in the tubes of a furnace. In the United States, natural gas Hquids derived from natural gas processing, primarily ethane [74-84-0] and propane [74-98-6] have been the dominant feedstock for olefins plants, accounting for about 50 to 70% of ethylene production. Most of the remainder has been based on cracking naphtha or gas oil hydrocarbon streams which are derived from cmde oil. Naphtha is a hydrocarbon fraction boiling between 40 and 170°C, whereas the gas oil fraction bods between about 310 and 490°C. These feedstocks, which have been used primarily by producers with refinery affiliations, account for most of the remainder of olefins production. In addition a substantial amount of propylene and a small amount of ethylene ate recovered from waste gases produced in petroleum refineries. 

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