Petroleum coke production

The major portion of sait is found in residues as these streams serve as the bases for fuels, or as feeds for asphalt and petroleum coke production, the presence of salt in these products causes fouling of burners, the alteration of asphalt emulsions, and the deterioration of coke quality. Furthermore, calcium and magnesium chlorides begin to hydrolyze at 120°C. This hydrolysis occurs rapidly as the temperature increases (Figure 8.1) according to the reaction i. ... 

During the past 25 years United States petroleum coke production has increased from less than 1,000,-000 tons per year to 3,400,000. Most of the 1,000,-000 tons were produced in externally fired shell stills and manually removed from the stills. Almost all of the 3,400,000 tons were produced in large "delayed coker" type coke drums and removed mechanically. As was true 25 years ago, the major use for petroleum coke is as a fuel, although the proportion so used is declining. Its use in aluminum production is growing rapidly and currently takes about 18% of the production. 

According to reports by the U. S. Bureau of Mines, the petroleum coke production in the United States was 980,000 tons during 1925. During 1949 it was 3,392,000 tons with an estimated 3,420,000 tons for 1950. This represents an average growth of 5.5% per year. Actually the growth was irregular, since the period includes an economic depression and a war. 

Figure 7 shows expected coke production levels in the United States by sulfur content category. Shown is Pace s current petroleum coke production forecast. Most of the additional coke production will be in the category of four percent sulfur or greater. 

Petroleum coke consumption by the utility power industry has been minor, even though another solid fuel, coal, has become the industry s major source of fuel. Domestically, only 630,000 short tons of petroleum coke was consumed by the United States utility industry in 1983, or approximately three percent of total domestic petroleum coke production. 

Marketers who fail to anticipate cyclical downturns in their premium markets can suffer severe losses when forced to sell to fuel markets instead. To compound this fragile pricing structure, the supply keeps coming since petroleum coke production is inelastic to demand. 

A slight decrease in petroleum coke production that began in June. 

Free world petroleum coke production has increased dramatically in the past decade. The United States continues to be a dominant factor in the petroleum coke industry, accounting for more than 75% of the total production. 

An expanding U.S. petroleum refinery was increasing its petroleum coke production. It has been said that the new corporate owners of this refinery had to drop their plans for a festive formal publicity announcement of the startup of the unit when a gigantic vessel... 

Petroleum Coke. Petroleum coke is an important raw material from petroleum for the chemical industry. Unlike most petroleum raw materials which go into organic synthesis, petroleum coke is important in inorganic technology. Anodes for aluminum manufacture consume 600,000 tons of petroleum coke annually—18% of U.S. petroleum coke production. About 0.7 pound of petroleum coke is consumed for every pound of aluminum produced. The next most important chemical use is in the manufacture of graphite electrodes for the steel industry, a use which consumes about 5% of current coke production. 

Petroleum coke is a carbonization product of high-boiling hydrocarbon fractions obtained in petroleum processing (heavy residues). It is the general term for all special petroleum coke products such as green, calcined and needle petroleum coke. 

Table 11, Coefficients of Thermal Expansion for Petroleum Coke Products...

Types of Petroleum Coke Products and Services Global Carbon, ConocoPhillips Houston, Texas, 2004 (http //www.conoco.com/products/global carbon/types.asp)... 

Worldwide petroleum coke production now exceeds 127,600 tcme/day (141,800 ton/day) or 46,600,000 tonne/year (51,740,(KX) ton/year) and is continuously growing [1]. Jacobs Consultancy estimates that worldwide production of petroleum coke will exceed 58 million tonnes/year by the end of 2002 [6]. Jacobs reports an annual increase in petroleum coke supply, from 1996 to 2001, of 7.3 percent and an increase in supply from 2001 to 2002 of 11.3 percent [6]. The distribution of petroleum coke production conforms to the following percentages North America, 66.5 percent Europe, 17 percent Asia-Pacific, 9.5 percent South America and the Caribbean, 4.5 percent and the Middle st and Africa, 2.5 percent [7]. 

Petroleum coke is an excellent fuel, and that is its main use, especially for the coke from fluid coking". There are some other markets that have to do with calcined coke electrodes for aluminum production or for all other electrolytic cells, carbons for electro-mechanical equipment, graphite, and pigments. 

As a whole, a given crude is generally used to make products most of which have positive added values. This is particularly the case for motor fuels and specialty products. However, some of the products could have negative added values, as in the case of unavoidable products like heavy fuels and certain petroleum cokes. 

In 1984, the Ube Ammonia Industry Co. began operating the largest Texaco coal gasification complex to date. This faciUty is located in Ube City, Japan, and has a rated gasification capacity of 1500 t/day of coal, and production capacity of 1000 t/day of ammonia. The plant has successfully gasified coals from Canada, AustraUa, South Africa, and China. At the present time the plant uses a mixture of petroleum coke and coal (43). 

Alternative Processes for Aluminum Production. In spite of its industrial dominance, the HaH-HAroult process has several inherent disadvantages. The most serious is the large capital investment requited resulting from the multiplicity of units (250 —1000 cells in a typical plant), the cost of the Bayer aluniina-puriftcation plant, and the cost of the carbon—anode plant (or paste plant for Soderberg anodes). Additionally, HaH-HAroult cells requite expensive electrical power rather than thermal energy, most producing countries must import alumina or bauxite, and petroleum coke for anodes is in limited supply. 

Thermal Cracking. Heavy petroleum fractions such as resid are thermally cracked in delayed cokers or flexicokers (44,56,57). The main products from the process are petroleum coke and off-gas which contain light olefins and butylenes. This stream also contains a considerable amount of butane. Process conditions for the flexicoker are more severe than for the delayed coker, about 550°C versus 450°C. Both are operated at low pressures, around 300—600 kPa (43—87 psi). Flexicokers produce much more linear butenes, particularly 2-butene, than delayed cokers and about half the amount of isobutylene (Table 7). This is attributed to high severity of operation for the flexicoker (43). 

Graphitization. Graphitization is an electrical heat treatment of the product to ca 3000°C. The purpose of this step is to cause the carbon atoms in the petroleum coke filler and pitch coke binder to orient into the graphite lattice configuration. This ordering process produces graphite with intermetaHic properties that make it useful in many appHcations. 

Production of one metric ton of molten aluminum requites about 500 kg of anode carbon and 7.5—10 kg of cathode blocks which is the largest industry usage of carbon materials. Aluminum smelters generally have an on-site carbon plant for anode production. Anode technology is focused on taw materials (petroleum coke and coal-tar pitch), processing techniques, and todding practices (74). 

Carbon black from oil is the main competition for the product from coal, which is used in filters. Carbon for electrodes is primarily made from petroleum coke, although pitch coke is used in Germany for this product. The pitch binder used for electrodes and other carbon products is almost always a selected coal tar pitch. 

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