Petroleum coke

Petroleum coke, abbreviated coke, pet coke or petcoke, is a final <a href="/facts/Carbon/ukrgQexo">carbon</a>-rich solid material that derives from <a href="/facts/Oil_refinery/yeaW0UMv">oil refining</a>, and is one type of the group of fuels referred to as <a href="/facts/Coke_(fuel)/vD8xjd0m">cokes</a>. Petcoke is the coke that, in particular, derives from a final <a href="/facts/Cracking_(chemistry)/EBLtwW4g">cracking</a> process—a thermo-based chemical engineering process that splits long chain hydrocarbons of petroleum into shorter chains—that takes place in units termed <a href="/facts/Coker_unit/QGQgYTTB">coker units</a>. (Other types of <a href="/facts/Coke_(fuel)/vD8xjd0m">coke</a> are derived from <a href="/facts/Coal/83kV3qxg">coal</a>.) Stated succinctly, coke is the "<a href="/facts/Carbonization/o8LenJPn">carbonization</a> product of high-boiling hydrocarbon fractions obtained in petroleum processing (heavy residues)". Petcoke is also produced in the production of <a href="/facts/Synthetic_crude/T2qSRHDR">synthetic crude</a> oil (syncrude) from <a href="/facts/Bitumen/tW6EqphW">bitumen</a> extracted from Canada's <a href="/facts/Oil_sand/ewYn43lb">oil sands</a> and from Venezuela's <a href="/facts/Orinoco_oil_sands/I23PPdcT">Orinoco oil sands</a>.
In petroleum coker units, residual <a href="/facts/Oil/fsgX2IRM">oils</a> from other <a href="/facts/Distillation/plDvUMxn">distillation</a> processes used in <a href="/facts/Petroleum_refining/yeaW0UMv">petroleum refining</a> are treated at a high temperature and pressure leaving the petcoke after driving off gases and volatiles, and separating off remaining light and heavy oils. These processes are termed "coking processes", and most typically employ <a href="/facts/Chemical_engineering/Fb64amQf">chemical engineering</a> plant operations for the specific process of <a href="/facts/Delayed_coking/MmzVbJIe">delayed coking</a>.

This coke can either be fuel grade (high in <a href="/facts/Sulfur/IK0amTfM">sulfur</a> and metals) or <a href="/facts/Anode/TjYt95zG">anode</a> grade (low in sulfur and metals). The raw coke directly out of the coker is often referred to as <a href="/facts/Green_coke/e6TnzCRr">green coke</a>. In this context, "green" means unprocessed. The further processing of green coke by <a href="/facts/Calcination/hghqlHwo">calcining</a> in a <a href="/facts/Rotary_kiln/T8Meq7T0">rotary kiln</a> removes residual volatile hydrocarbons from the coke. The calcined petroleum coke can be further processed in an anode baking oven to produce anode coke of the desired shape and physical properties. The <a href="/facts/Anode/TjYt95zG">anodes</a> are mainly used in the <a href="/facts/Aluminium/7wmR8jYE">aluminium</a> and <a href="/facts/Steel/aN6qWo4H">steel</a> industry.
Petcoke is over 80% carbon and emits 5% to 10% more <a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a> (CO2) than coal on a per-unit-of-energy basis when it is burned. As petcoke has a higher energy content, petcoke emits between 30% and 80% more CO2 than coal per unit of weight. The difference between coal and coke in CO2 production per unit of energy produced depends upon the moisture in the coal, which increases the CO2 per unit of energy – <a href="/facts/Heat_of_combustion/HdQX0mPP">heat of combustion</a> – and on the volatile hydrocarbons in coal and coke, which decrease the CO2 per unit of energy.

Petroleum coke open-in-new

Petroleum coke