Refined Petroleum Specifications
Petcoke is produced as a byproduct in many — though not a majority of oil refineries. Crude oil is first processed in an atmospheric distillation unit, followed by a vacuum distillation unit. The heavy residuum exiting the bottom of the vacuum tower (i.e., vacuum tower bottoms, or VTB) can be used to make asphalt, blended with some light products such as diesel to produce residual fuel oil (RFO), or used as coker feed.
Traditionally, cokers are installed in oil refineries to convert VTB and other heavy residual oils into higher-value light transportation products (e.g., gasoline, jet fuel, and diesel fuel). Until recently, a coker almost invariably increased refinery profitability because the yield of high-value transportation fuels is maximized and production of low-value residual fuel oil (RFO) is minimized.
There are two general applications for petcoke: as a carbon source and as a heat source. The former requires better quality (e.g., low sulphur and metals) and commands higher prices.
Green petcoke is usually upgraded by calcination (a process which removes moisture and volatile matter and improves critical physical properties) when it is used as a carbon source. Petcoke that has been calcined is referred to as calcined petcoke (CPC). The largest market for CPC is in the production of anodes for aluminium smelting; other uses for CPC are in the production of carbon electrodes for electric arc furnaces, titanium dioxide (TiO2) production, and as a recarburizer in the steel industry. About 25% of the petcoke produced is sold into these higher value-added markets for higher- quality petcoke; the remainder of the petcoke is sold into the fuel market, where it almost always competes with coal.
Types Of Coke:
Specialty Coke (aka Needle coke); Calcined Coke (aka Anode grade coke); and Fuel Coke (Shot, Sponge or a combination of both).
Needle Coke is made exclusively from highly aromatic FCC decant oil or coal tar pitch and is used to produce the electrodes used in an electric arc furnace (EAF) steel production.
Calcined Petroleum Coke (CPC):
- The process of calcining converts green coke to almost pure carbon and has the highest carbon purity
- Sulfur content differs based on the crude slate used to make the green petroleum coke.
- Sulfur range is 0.5 – 3%
- High grade petcoke which is low in sulphur and heavy metals can be used to make electrodes for the steel and aluminum industry.
- More than 85 percent of all CPC is used to produce anodes for smelting alumina into aluminum via the Hall-Héroult process.
- Calcined petcoke is also used in the production of titanium dioxide (TiO2) and as a recarburizer in the steel industry.
- Recarburizers are used to make minor adjustments to carbon content to ensure that each batch of steel meets specifications for the carbon content.
Fuel grade petcoke represents nearly 80 percent of worldwide production and has high heating value (BTUs per pound) and is a source of fuel for cement kilns and electric power plants.
In the power industry, petcoke is most efficiently burned in circulating fluidized bed (CFB) boilers. The largest market for fuel grade petcoke is the cement industry. Due to having a higher metal content, fuel grade petroleum coke is not suitable for anode grade.
The quality of the product will depend on the crude oils processed by the refinery.
Typical U.S Fuel Grade Non Calcined Petroleum Coke:
- Moisture as received, % unit., 8-12
- Total Sulphur, % unit., 4.5–7.0 max
- Ash, % unit., 0.2–0.3
- Volatile Matter, % unit, 8-11
- Fixed Carbon, % unit, min. 87.73–91.01
- Calorific Value, kcal/kg 8000 and above
- HGI 40-45
*We can source both high and mid sulfur petcoke from resellers, refiners in the USGC, Europe, M.East, Canada for destinations such as India & China