Petroleum coke, also called petcoke, is a rocklike leftover of the oil refining process. Energy can be created from petroleum coke, so it is often turned into dry cells and fuels based on the type of coke it is. There are several classifications of petroleum coke, and each one is used to create different substances.
Fuel-grade coke is spongy in texture and contains high amounts of sulfur. It can withstand high heat and contains little ash. This type of coke is primarily used in power generators that burn coal. There is such as high sulfur content that businesses using fuel-grade coke must use a sulfur capture system to reduce the amount of sulfur released into the air and meet clean-air standards.
Marketable coke is high in carbon, if it's not just pure carbon. Depending on the texture, marketable coke is either turned into fuel-grade coke or needle coke. Catalyst coke is impure and spongy, so it can be used for fuel. Needle coke is crystalline in nature and is used for dry cells and electrodes.
Calcined petroleum coke is made when petroleum coke is calcined, or roasted, just below the melting point. This coke is commonly used in the smelting industry for the creation of metals such as titanium, aluminum and steel. This is because calcined coke is used as an anode, or electrode, to produce these metals.
While petcoke is useful in the energy-creation market, it also creates high amounts of pollution when used. When burned and released into the air, petroleum coke releases mercury, lead, carbon dioxide, sulfur dioxide and general soot particles that inhibit breathing, especially in people with health conditions that leave them sensitive to the pollution. There are laws designed to reduce the amount of air pollution released and make it safer for people living in areas where petroleum coke is used.
According to the material safety data sheet (MSDS) on petroleum coke, it is a safe material. On a scale from 0 to 4, with 0 being insignificant and 4 being extreme, both health and physical safety are ranked at 0. Flammability is ranked at 1. Unless inhaled in great quantities by people with lung conditions, petcoke is not believed to cause any problems. If there is a fire produced from petcoke, a water spray, foam, dry chemical or carbon dioxide blanket will put out the fire.