Carbonaceous, generally residue

Coke Coke is the solid, cellular, infusible material remaining after the carbonization of coal, pitch, petroleum residues, and certain other carbonaceous materials. The varieties of coke generally are identified by prefixing a word to indicate the source, if other than coal, (e.g., petroleum coke) or the process by which a coke is manufactured (e.g., oven coke). 

One area of cat cracking not fully understood is the proper determination of carbon residue of the feed and how it affects the unit s coke make. Carbon residue is defined as the carbonaceous residue formed after thermal destruction of a sample. Cat crackers are generally limited in coke burn capacity, therefore, the inclusion of residue in the feed produces more coke and forces a reduction in FCC throughput. Conventional gas oil feeds generally have a carbon residue less than 0,5 wt for feeds containing resid, the number can be as high as 15 wt lf. 

Experimental data were obtained on the carbonaceous residue (char), and sulfur distribution was calculated for the solid and gaseous products from the pyrolysis of model compounds. Sharp differences were observed in the quantity of char and the sulfur distribution for the different substances studied. The quantity of volatile matter varied from 21 to 43%. The sulfur retained by the char varied from 21 to 74% of the total present in the compound pyrolyzed (see Table I). The raw data show a possible relationship between the volatile matter and sulfur retention which indicates that as volatile matter decreases, sulfur retention generally increases (Table I). Neither structural features nor the molecular size of the various model compounds appear to have a significant relationship to sulfur distribution. 

In general, all the above treatments affect the decomposition products, by heat, of the fibrous material. After treatment, the solid carbonaceous residue from combustion of fiber tends to increase and the quantity of tarry by-products to be reduced. 

For more than a decade, numerous research studies have been carried out on the flame-retardant properties conferred by nanoparticles and mainly by organo-modified layered silicates (OMLS). Earlier work at Cornell University and National Institute of Standards and Technology in the United States showed that nanocomposites containing OMLS reduced polymer flammability and enhanced the formation of carbonaceous residue (char).14 Owing to a strong increase in polymer viscosity, impairing processability, and also due to the breakdown of ultimate mechanical properties, the acceptable rate of incorporation for nanoparticles to improve flame retardancy is generally restricted to less than 10 wt %. 

Deposition of carbonaceous residues on the platinum-iridium catalyst was less than half of that on the platinum-rhenium catalyst (2.9 vs. 6.9 wt% on catalyst at the ends of the runs). In general, we observed that the rate of deposition of such residues on platinum-iridium catalysts is lower than on platinum or platinum-rhenium catalysts under conventional reforming conditions. 

Calcining polyiminoalanes usually results in the formation of aluminum nitride at comparably low temperatures. If the calcination is carried out in ammonia, carbon contamination is easier to avoid, calcining in argon usually results in the formation of black carbonaceous residues in the range of 10-20 wt% carbon. In general, crystallization is promoted by using ammonia and is prevented if argon is used. 

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