Utilization value of petroleum coke

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Petroleum Coke

Size

According to your requirements

Package

25 kg small bags into ton bags or ton bags

Features

Low ash content and low boiler ash discharge, etc.

Application

Depending on its quality, petroleum coke can be used in industries such as graphite, smelting and chemical industry, etc

Petroleum coke, as a byproduct of petroleum, is produced in the process of petroleum processing, that is, the crude oil is distilled to separate light and heavy oil, and the heavy oil is converted into petroleum coke by hot cracking. If petroleum coke can be obtained directly from petroleum processing, then the petroleum coke is raw coke or ordinary coke. Petroleum coke has irregular shape, dark gray or black, porous structure and metallic luster.

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Petroleum coke can be used in different industries. Petroleum coke used in power plants and cement plants as fuel requires high calorific value and good abrasiveness. It is used by major factories and plays a key role. The Franli plant also produces petroleum coke with different sulphur contents and purities.

Petroleum coke is a product formed by the separation of light and heavy oil from crude oil by distillation, and then the final conversion of heavy oil by thermal cracking. During petroleum refining, the delayed coking unit is used to carry out high-temperature deep thermal cracking and polycondensation reaction of petroleum residue to produce decoking gas, so that low-cost oil products are mainly converted into high-value liquid oil products and gases. by-products of the chemical process. Various impurities in crude oil and catalysts in the refining process are finally left in the petroleum coke. The sulfur content, which is a harmful substance, is one of the important indicators of petroleum coke.

Petroleum Coke
Physical property

Petroleum coke, also known as raw coke, is mainly composed of carbon (84-97%), which is produced during the thermal decomposition of oil in the refining process. There are various forms of coke, such as needle coke, sponge coke, and pellet coke. The sulfur content and impurity content are different with different microstructures. The quality of crude oil is the key to determining which of these types of coke – coke produced from high asphaltene content feedstock contains high concentrations of sulfur and metals.

Coking is the product of delayed coking and contains a lot of hydrocarbons. It has a unique hydrocarbon odor and can contain 4% to 21% of volatile compounds, mainly residual hydrocarbons, including polycyclic aromatic hydrocarbons (PAHS), according to the heating rate of the refining process.

Calcined petroleum coke is made of raw coke and is heated (>1200) ° C) It is heated. This process almost eliminated all hydrocarbon content (i.e. < 0.1%). Fine water mist containing surfactants is usually used to suppress dust. Surfactants reduce the surface tension of water, make it more effectively wet the goods, and reduce the necessary water content. It is usually used in the form of dilution (between 100:1 and 3000:1) and is generally classified as harmless.

The exact properties of petroleum coke depend on the source of crude oil raw materials and the heating process used. However, the main components are expected to be within the range shown in. Trace metals such as nickel and vanadium may be up to one in a million. The proportion of petroleum coke to water is between 0.8-2.1. Therefore, the product specifications for each piece of goods must be consulted to determine whether it floats or sinks. Generally speaking, most petroleum coke products will sink into the seawater. Petroleum coke is stable and insoluble in water, so if discharged at sea, it is likely to form a slurry.

Influence of petroleum coke on Environment

Environmental toxicity studies have shown that in general, petroleum coke has a low potential for adverse effects on aquatic and terrestrial terminals of plants and animals. Therefore, the chemical safety technical specification (MSDS), the EU CLP regulations, and the ages amp/ehs comprehensive hazard document list (2015) all indicate that petroleum coke will not cause harm to the marine environment. No updates on petroleum coke have been added to the latest versions of IMSBC (2020) and MARPOL Annex V, indicating that the substance is considered harmless by 2021. However, recent evidence shows that petroleum coke is not as inert as originally thought, and environmental-related substances (nickel and vanadium) have been found in the filtrate of the coke; When discharged into the sea in a low dilution environment, the growth of algae may be affected.

It is worth noting that although petroleum coke is described as harmless, small particles in powder or particles have potential effects on human health as inhaled (i.e. air-borne) dust.

As mentioned earlier, hydrocarbon content in coke or petroleum coke is likely to form luster on the water surface, although this is likely to be local and nonpersistent. The most worrying concern after the release of petroleum coke (e.g. in the case of ship casualties) is the potential suffocation effect, especially in low energy or shallow water areas, where diffusion and dilution are reduced. If a large number of black solids are washed to the shore, the discharge near the coastline can also cause negative visual effects. Any increase in pH or gloss will be short-term as long as there is sufficient water depth and water exchange. As for the discharge of small amounts of petroleum coke in clean waters, it is not expected to harm the marine environment as long as the hydrocarbon content of the goods is low enough. However, this comment should be read in conjunction with the governing legislation described below.

Petroleum Coke

Factors that determine the value of petroleum coke

There are three factors affecting the value of petroleum coke, let’s illustrating one by one.

(1) Purity: the content of sulfur and ash in petroleum coke. High-sulfur coke will cause the product to swell during graphitization, resulting in cracks in the graphite product. High ash content will hinder the crystallization of the structure and affect the performance of graphite products

(2) Crystallinity: through the structure of petroleum coke and the size of mesophase spheres. The petroleum coke formed by small spheres has a porous structure such as sponge-like, and the petroleum coke formed by large spheres has a dense structure such as fibrous or needle-like, and its quality is superior to that of sponge coke. In the quality index, true density roughly represents this performance, high true density indicates good crystallinity.

(3) Thermal shock resistance: The crack resistance of petroleum coke when it is subjected to thermal shock suddenly rising to high temperature or rapidly cooling from high temperature. Petroleum coke products have good thermal shock resistance, so they have high use value. The coefficient of thermal expansion represents this property. The lower the thermal expansion coefficient, the better the thermal shock resistance.

Petroleum Coke

Application of petroleum coke

Petroleum coke is suitable for different industries, for example, graphite electrodes with lower resistivity can be fabricated from petroleum coke etc. as following:

(1) Fuel for power plant boilers: In order to cope with the processing of imported sulfur-containing crude oil and the upgrading of oil product quality, it is necessary to add or expand a number of delayed coking units in coastal and riverside enterprises. It is estimated that the output of petroleum coke can reach 360Mt. To digest these petroleum cokes with high sulfur content and low price, advanced circulating fluidized bed technology can be used, and a batch of CFB boilers using petroleum coke as raw materials can be built to provide low-cost steam, electricity and hydrogen for refineries. This can kill three birds with one stone. It not only digests the low-cost high-sulfur petroleum coke, but also meets the steam and electricity needs of the new projects of the enterprise. It can also replace some existing oil-burning boilers and save valuable heavy oil resources.

(2) Petroleum coke is used as a raw material for anode paste and graphite electrodes in smelters: petroleum coke with low sulfur content can be used as a raw material for electrodes in smelters. Carbon plants use petroleum coke, produce anode pastes for aluminum plants, and produce graphite electrodes for steel plants. The sulfur content of petroleum coke affects the use of coke and the quality of carbon products made from coke. Especially in the manufacture of graphite electrodes, the sulfur content is a relatively important indicator. Too high sulfur content will directly affect the quality of the graphite electrodes, as well as the quality of steelmaking. When petroleum coke is used as a raw material for anode paste, its sulfur content also has a significant impact on power consumption.

Today, the consumption areas of petroleum coke products are still concentrated in the fields of prebaked anodes, fuels, recarburizers, silicon (including metal silicon and silicon carbide) and graphite electrodes, among which the consumption of prebaked anodes ranks first. In recent years, the electrolytic aluminum market and the production profit of silicon products have continued to be high, and downstream enterprises have been enthusiastic about purchasing and production, which has become the main driving force for the growth of petroleum coke consumption.