Besides being a useful fuel source, calcined petroleum coke has several other industrial applications. Testing petcoke ensures its metal, sulfur and carbon concentrations remain below standards that could affect refining equipment and the environment.
The coke is burned in rotary kilns to eliminate excess moisture, resulting in higher density coke. The resulting product is used for the manufacture of carbon and graphite electrodes.
Testing petcoke allows producers to make sure its metal, sulfur and carbon levels are at a safe level for use in refining equipment. It also helps them ensure they sell quality material to customers.
All GPC has residual volatile matter (VM), which calciners use as fuel, so they must be careful not to overheat the coke and increase its VM levels. They must also avoid high VM levels in fuel-grade coke, which can damage their equipment.
Independent or merchant calciners typically blend different quality GPCs together to produce CPC that meets anode specifications for S, V and Ni. They may also add a bit of high S, low V calcined coke from the delayed coker to improve anode smelting performance.
Many calcining facilities use SO2 scrubbing to meet strict emissions standards. In the future, more smelters are likely to require this technology, and some calciners will need to install fluidized-bed scrubbers. CII Carbon has added SO2 scrubbers at its Lake Charles and Chalmette calciners.
The petroleum coke, or petcoke, produced in the cracking process of oil refineries is a carbonaceous byproduct. A significant portion of this coke is heat treated in rotary kilns to drive off residual volatile hydrocarbons and produce calcined petroleum coke (CPC) that is used in the Hall-Heroult aluminum smelting process for its low sulfur, sulfide, and trace metal content.
The CPC produced from this coke is primarily used to make anode coke in the aluminum smelting process because of its low impurity level and ready availability. Independent or merchant calciners often blend different quality GPC from various refining companies to produce a product that meets anode coke specifications for sulfide and metal content.
X-ray powder diffraction analysis of calcined coke provides valuable structural information on the microstructure and chemical composition of these samples. The peaks obtained at the maximum on doubled Bragg diffraction angles (2nd) attribute these structures to particular elements and reveal the chemical composition of the sample.
The quality of calcined petroleum coke for aluminium production is regularly determined through proximate analyses (moisture, ash volatile matter and fixed carbon) or ultimate analyses (ash, nitrogen, oxygen, sulfur and hydrogen). Trace metal concentrations also have to be controlled in order to ensure the function of electrodes.
Using a new digestion method with optimized ICP-OES measurement it is possible to determine trace metals at low sample preparation time. This results in the same data as obtained by a conventional analysis but with less time and lower costs.
The process of calcining produces particulate and gaseous emissions which may pose human health risks. This risk characterization has been performed by measuring and modeling exposure levels of ambient air pollutants in the vicinity of the calciner facility and comparing them to standards protective of public health. The results demonstrate that the emissions from this calcining facility are below public health exposure limits. The modeled SO2, CO, and PM10 levels are below the standard to avoid adverse respiratory health effects.
A carbon fuel that resembles coal, petcoke is the byproduct of the final cracking process of crude oil refining. Refineries use this material to create electricity, heat buildings and run industrial equipment. It is also used to produce paper, brick, fertilizer and cement. It is important to test petcoke to ensure it meets contractual requirements, is safe for industrial equipment and emits few greenhouse gases.
A method for preventing agglomeration of petroleum coke during calcining. The coke is crushed to a Tyler sieve size of minus 20 and is contacted with an oxygen-containing gas stream at about 500 F. for a time of about 0.5 to 2.0 hours. The resulting calcined coke has low metal content and is useful in the production of graphite electrodes for aluminum, steel and titanium smelting processes.
In order to lower the price of their low sulfur GPC, an oil refinery switched to a higher specific gravity and API gravity shale crude blend in 2012. This increase in S level caused the company to use more of its expensive domestic light sweet crude and import high S coke.
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