Petcoke information

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Petcoke can be used in various industries; petcoke used as fuel in power plants and cement factories requires a high calorific value and good grindability； Petcoke used as raw material in aluminum plants, steel plants, or carbon factories requires control over its sulfur content and volatility, whether it is used as a raw material for anode pastes and artificial graphite electrodes or for the production of carbides. For petcoke intended as raw material for electrodes, the metal content also needs to be controlled. Petcoke is also used as fuel in CFB boilers in power plants. The current situation in China’s petcoke market is one of an excess supply of high-sulfur petcoke, which is primarily used as fuel ； Low-sulfur petroleum coke products are mainly used in metallurgy and for export ； Advanced petroleum coke products need to be imported. I. Properties of petroleum coke Petroleum coke is a black or dark gray, hard solid petroleum product with a metallic luster; it is porous and consists of carbonaceous materials in granular, columnar, or needle-shaped forms formed by tiny graphite crystals. Petcoke components are hydrocarbons, containing 90–97% carbon and 1.5–8% hydrogen, as well as nitrogen, chlorine, sulfur, and heavy metal compounds. Petcoke is a by-product produced when the feed oil in a delayed coking unit is pyrolyzed at high temperatures to produce light hydrocarbon products. The production of petroleum coke is about 25-30% of that of the crude oil. Its lower heating value is about 1.5–2 times that of coal, the ash content is no more than 0.5%, and the volatile matter content is around 11%; its quality is similar to that of anthracite. II. Quality standards for petroleum coke: Delayed petroleum coke refers to the coke produced by delayed coking units, also known as ordinary coke; at present, there are no corresponding **standards** for it. Currently, domestic manufacturers primarily produce in accordance with the industry standard SH0527－92 established by the former Sinopec Corporation (see the attached table for details). This standard classifies petroleum coke primarily based on its sulfur content; grade 1 coke is suitable for use in the steelmaking industry to produce graphite electrodes of ordinary capacity, as well as in the aluminum industry for use as carbon in aluminum production ； Coke No. 2 is used as electrode paste and electrodes in electrolyzers (furnaces) in the aluminum smelting industry, while Coke No. 3 is used to produce silicon carbide (an abrasive material) and calcium carbide (calcium carbide), as well as other carbon products. It is also used to manufacture the anode blocks for aluminum smelting electrolyzers, as well as for carbon lining bricks in blast furnaces or for constructing furnace bottoms. Table 1: Standards for Delayed Petroleum Coke SH0527–92 – Parameters and Quality Indicators
Grade: No.1, No.2, No.3; Categories: A, B
Sulfur content, %: ≤0.5, ≤0.5, ≤0.8, ≤1.0, ≤1.5, ≤2.0, ≤3.0
Volatile matter, %: ≤12, ≤10, ≤12, ≤12, ≤15, ≤16, ≤18
Ash content, %: ≤0.3, ≤0.3, ≤0.5, ≤0.5, ≤0.5; v0.8 ≤1.2
Moisture content, %: ≤3
True density (after calcination at 1300°C for 5 hours), g/cm3: 2.08–2.13 (measured)
Percentage of fine coke particles (size less than 8 mm): 25 (measured)
Silicon content, %: ≤0.08; Vanadium content, %: ≤0.015; Iron content, %: ≤0.08

III. Main Uses of Petroleum Coke
The main uses of petroleum coke include serving as pre-baked anodes and anode pastes in aluminum electrolysis, as a carbonizing agent in the carbon industry, for producing graphite electrodes, in the production of industrial silicon, and as fuel. Based on their structure and appearance, petroleum coke products can be divided into four types: needle coke, sponge coke, pellet coke, and powder coke. (1) Needle coke has a distinct needle-like structure and fibrous texture, and is primarily used as high-power and ultra-high-power graphite electrodes in steelmaking. Due to the strict quality requirements for needle coke in terms of sulfur content, ash, volatile matter, and true density, there are special demands on both the production process and the raw materials used for needle coke. (2) Sponge coke, with high chemical reactivity and low impurity content, is mainly used in the aluminum smelting industry and the carbon industry. (3) Pellet coking or spherical coke: It has a spherical shape with a diameter of 0.6–30 mm; it is generally produced from high-sulfur, high-asphaltene residue oils, and can only be used as fuel in industries such as power generation and cement production. (4) Powdered coke: Produced through a fluidized coking process, it has fine particles (diameter 0.1–0.4 mm), a high volatility content, and a high coefficient of thermal expansion; therefore, it cannot be used directly in electrode production or the carbon industry. Based on their sulfur content, they can be divided into high-sulfur coke (with a sulfur content of over 3%) and low-sulfur coke (with a sulfur content of under 3%). Low-sulfur coke can be used as anode paste and pre-baked anodes for aluminum plants, as well as graphite electrodes for steel plants. Among them, high-quality low-sulfur coke (with a sulfur content of less than 0.5%) can be used to produce graphite electrodes and carbonizers. Low-sulfur coke of general quality (with a sulfur content of less than 1.5%) is commonly used in the production of pre-baked anodes. Low-quality petroleum coke is mainly used in the production of industrial silicon and anode paste. High-sulfur coke is generally used as fuel in cement plants and power plants. In graphite electrodes used for steelmaking, or anode pastes (fused electrodes) used for aluminum and magnesium production, petroleum coke (raw coke) must be calcined to meet the required standards. The calcination temperature is generally around 1300°C, with the aim of removing as much of the volatile components in petroleum coke as possible. This reduces the hydrogen content in petroleum coke reproducts, increases the degree of graphitization of the coke, thereby enhancing the high-temperature strength and heat resistance of graphite electrodes, and improving their electrical conductivity. Calcined coke is mainly used in the production of graphite electrodes, carbon paste products, emery, in the food-grade phosphorus industry, the metallurgical industry, and calcium carbide, among which graphite electrodes are the most widely used. Raw coke can be used directly as the main ingredient for calcium carbide in the production of calcium carbide, as well as for the manufacture of silicon carbide and boron carbide used as grinding materials, without the need for calcination. It can also be used directly as coke for blast furnaces in the metallurgical industry or as carbon bricks for blast furnace linings, as well as as dense coke for casting processes.