| OCR Text |
Show conducted at the Franklin Research Center of this PETCOM have been very encouraging and are described in this paper. 2. FUEL DESCRIPTION Cities PETCOM is comprised of No. 6 oil, or Bunker "C" fuel oil, and pulverized petroleum coke. No. 6 oil or Bunker "C" is typically a blend of the refinery residuum and No. 2 oil to achieve specification viscosities. This product is usually kept in storage tanks (bunkers) which are kept at 100 to 150°F to maintain a low viscosity so that the fuel may be easily pumped from storage. For these initial experiments the PETCOM was prepared by mixing finely ground petroleum coke and No. 6 fuel oil. The coke was first crushed to pass a 50 mesh screen (295 microns) and subsequently ground in a wet mill to a mass median diameter of about 17 microns. Figure 2-1 shows a logarithmic plot of the cumulative size distribution of this PETCOM. Settling characteristics of the solids in PETCOM are strongly affected by the particle size distribution. This particular size distribution has shown minimal sedimentation at high temperatures (180°F) for more than six months without added water or any other chemical stabilization additives. Particle size distribution must also be carefully tailored to provide PETCOM of practicable viscosity. This grind also has a fairly narrow size distribution and is 98% less than 325 mesh (44 microns) by volume or weight. Fuel-grade petroleum coke contains much of the crude's sulfur and heavy metals, i.e. nickel, vanadium, iron as well as other elements, such as sodium. Chemical characteristics of coke as well as that of the No. 6 fuel oil vary with the origin of the crude and the multitude of refining processes. Physical characteristics of the coke also depend on the coking method. A delayed coke similar to what will be produced by Cities Service in 1983 to 1984 was used in the Franklin combustion experiments. Table 2-1 summarizes chemical compositions of No. 6 oil, coke and the 45% PETCOM slurry. It shows that the vanadium level of 45 percent PETCOM is 730 ppm, iron and nickel 310 ppm, and sodium 130 ppm. 19-3 |
