Petroleum Coke Combustion

Petroleum coke (also known as pet coke) is a carbonaceous solid derived from the cracking processes of oil refineries and has been a source of relatively cheap pulverized fuel for the kiln industry. It is called green coke until it is thermally treated into crystalline or calcined pet coke used in the manufacture of electrodes for steel and aluminum extraction. Green coke comes from several sources, all from the petroleum refinery industry. Table 6.2 gives some green coke analyzed by Polak (1971) showing their sources and their elemental analyses. 

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Table 2.9. Melting and Decomposition Temperatures of Nickel and Vanadium Compounds Potentially Formed from Petroleum Coke Combustion...

Several utility-scale demonstration facilities having power outputs in the 300-MW class have been constmcted in the United States and Europe. These started accumulating operating experience in 1995 and 1996. Other IGCC plants have been constmcted, including units fueled by petroleum coke and refinery bottoms. Advanced 500-MW class IGCC plants based around the latest heavy-duty combustion turbines are expected to be priced competitively with new pulverized-coal-fined plants utilising scmbbers. 

Hower, J. C., Robertson, J. D. Roberts, J. M. 2001. Petrology and minor element chemistry of combustion by-products from the co-combustion of coal, tire-derived fuel, and petroleum coke at a western Kentucky cyclone-fired unit. Fuel Processing Technology, 74, 125-142. 

Petroleum coke calcining is a process whereby green or raw petroleum coke is thermally upgraded to remove associated moisture and volatile combustible matter (VCM) and to otherwise improve critical physical properties, e.g., electrical conductivity and real density (JL ) The calcining process is essentially a time-temperature function the most important variables to control are heating rate, VCM to air ratio and final temperature. To attain the calcined coke properties necessary for its end use by the amorphous carbon or graphite industries, the coke must be heat treated to temperatures of 1200-1350°C (2200-2500°F), or higher, to refine its crystalline structure. 

CFB (3) [Circulating Fluidized Bed] A coal combustion process for developing steam for power generation, developed by Foster Wheeler. The process is suitable for burning many fuels, including waste coal, petroleum coke, and even shredded car tires. 

Meta-4 A process for converting ethylene and 2-butene into propylene by metathesis. The process operates in the liquid phase at low temperatures in the presence of heterogeneous catalyst based on rhenium oxide on alumina. The catalyst is constantly regenerated by coke combustion. Developed by IFP and the Chinese Petroleum Corporation of Taiwan. A demonstration plant was operated from 1988 to 1990 and the process was demonstrated at Kaohsiung, Taiwan, in 1999. Now offered by Axens. 

Sahagian, J., and Engstrom, F. Combustion of Petroleum Coke in an Ahistrom Pyroflow Circulating Fluidized Bed Boiler, Proa-Refin. Dep. Am. Pet. Inst., 65, p. 585 (1987). 

In this paper the combustion reactivities of four flash pyrolysis chars are compared with the results for chars produced from low and high-rank coals under conditions simulating pulverized-coal combustion, for anthracite and semianthracite, and petroleum coke. Reactivity is expressed as the rate of combustion of carbon per unit external surface area of the particle, with due correction being made for the effect of mass transfer of oxygen to the particle. 

Skrifvars B.-J, et al. (1997) Mechanisms of bed material agglomeration in the cyclone and the return leg of a petroleum coke fired circulating fluidized bed boiler. In Proceedings in I4th International Conference on Fluidized Bed Combustion, Vancouver, Canada, 819-829. 

A single, present-day phosphorus furnace produces from 60 to 160 tonnes of phosphorus per day, almost the same as the annual production figures of the early arc furnaces, and requires a power supply of about 90,000 kW for a single, 160 tonne/day furnace. Power consumption per tonne of phosphorus produced varies with the % calcium phosphate in the rock (% BPL level) and furnace size among other factors but ranges around 12,000-14,000 kWh/ tonne (Table 10.4). Hence, power is a major cost component of electric furnace phosphorus production. This realization has prompted a reexamination of fossil-fueled (petroleum coke-based) sources of heat for rotary kiln combustion to provide the energy of the endotherm of the reaction [15]. 

Anthony EJ, Jia L, Burwell SM, Najman J, Bulewicz EM (2006) Understanding the Behavior of Calsium Compounds in Petroleum Coke Fluidized Bed Combustion (FBC) Ash. journal of Energy Resources Technology 128 290-299... 

Li F, Zhai J, Fu X, Sheng G (2006) Characterization of Fly Ashes from Circulating Fluidized Bed Combustion (CFBC) Boilers Cofiring Coal and Petroleum Coke. Energy Fuels 20 1411-1417... 

Until recently, one of the most widely used methods for determination of total sulfur content has been combustion of a sample in oxygen to convert the sulfur to sulfur dioxide, which is collected and subsequently titrated iodometricaUy or detected by nondispersive infrared (ASTM D-1552). This method is particularly applicable to heavier oil and fractions such as residua that boil above 177°C (350°F) and contain more than 0.06% w/w sulfur. In addition, the sulfur content of petroleum coke containing up to 8% w/w sulfur can be determined. 

The burning rate of chars at a pressure of 1 atm for petroleum coke and the different coal rank has been compared by Sergeant and Smith [27]. The collected experimental data show that the char burning rates expressed in (kg m- s ) is slightly lower for the same particle temperature, for petroleum coke against anthracite however the behavior of both coke residue (petroleum coke) and char (anthracite) is similar. The burning profile technique is a method for predicting the relative combustion characteristics of fuels. 

Petroleum coke (64741-79-3) presents a spontaneous combustion hazard and can form explosive concentrations of dust. 

One of the reasons that Powder River Basin (Wyoming) coals are widely used for pulverized coal combustion power plants (despite the relatively low heating value) is the low sulfur content. With the increased restrictions on sulfur dioxide emission regulations, coal combustion power plants looking to avoid expensive and efficiency-reducing flue gas desulfurization retrofits have switched to low-sulfur Powder River Basin coal. There is also the possibility that western coals can be combined with petroleum coke in order to increase the heating value and decrease the moisture content of the gasification feedstock. 

Partial oxidation, which can be applied to a wide range of hydrocarbons but also to other carbonaceous materials such as oil, petroleum coke and coal, consists of burning the hydrocarbons or powdered coal with a preheated gas mixture of steam and oxygen using a burner inside a refractory-lined combustion chamber. The role of the steam is to moderate the combustion. The overall reaction scheme for the partial oxidation of a hydrocarbon having the empirical chemical formula S is ... 

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