Fuel coker test

The fuel coker test suffers from precision problems and has been largely replaced by a test for the thermal oxidation stability of the fuel (ASTM D-3241, IP 323) that overcomes the disadvantages of the fuel coker test in fuel specifications. 

Thermal stability. A manual, semiautomatic or automatic CFR fuel coker shall be used. The equipment and operating procedures shall be in strict accordance with Method 3464 of Federal Test Method Standard No 791. No deviation from this method is aUowed... 

High-temperature coking resistance is checked by the panel coker test where an aluminium plate, held at temperatures ranging from 275 to 350°C, is splashed with lubricant and the deposited coke is weighed and rated. This procedure has many variations including methods to measure the effect of the oxidising effect of fuel oil contamination on lubricant stability. 

A test run is conducted to evaluate the performance of a 50,000 bpd (331 m /hr) FCC unit. The feed to the unit is gas oil from the vacuum unit. No recycle stream is processed however, the off-gas from the delayed coker is sent to the gas recovery section. Products from the unit are fuel gas, LPG, gasoline, LCO, and decanted oil (DO). Tables 5-2 and 5-3 contain stream flow rates, operating data, and laboratory analyses. The meter factors have been adjusted for actual operating conditions. 

A high carbon value for gasoline, jet fuel or 2 fuel oil is a good indication that the fuel has been contaminated with residual fuel oil. Heavy streams such as VGO, coker gas oil, and 6 fuel oil can contaminate gasoline, jet fuel and diesel fuel. These streams tend to form carbon residue when pyrolyzed and can be identified as fuel contaminants through carbon residue testing. 

Seven fuels were burned in these initial tests two petroleum fuels, one regular sulfur fuel oil (RSFO) and a low sulfur fuel oil (LSFO), and five EDS fuel oils. The EDS fuel oils were blended from components produced in the one ton per day pilot unit at the Exxon Research and Engineering site in Baytown, Texas. Products from the liquefaction of two coals, a bituminous Illinois coal from the Monterey No. 6 mine, and a sub-bituminous Wyoming coal from the Wyodak mine, were tested. Fuel oil blends were made with products from each of the coals, with and without coker liquids, to produce four of the EDS fuels. The fuel oil derived from Illinois coal containing coker liquids was blended... 

Better correlation between test results and refinery experience with anti-foulants is claimed with data from the Jet-Fuel Thermal Oxidation Tester (JFTOT) developed by a San Antonio, Texas firm. The device operates on the same principles as the Erdco coker developed in 1965 by Amoco, and according to ASTM D-1660. One of the main advantages of the JFTOT tester is that it uses only one quart of fuel. 

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