The role of graphite petroleum coke in industry

The role of graphite petroleum coke in industry

1. Graphite petroleum coke is used as fuel for CFB boilers in power plants

In order to cooperate with the processing of imported sulfur-containing crude oil and the upgrading of oil quality, a number of delayed coking units need to be added or expanded in coastal and riverside enterprises. It is estimated that the output of graphite petroleum coke can reach 360Mt. To digest these high-sulfur and low-priced graphite petroleum cokes, advanced circulating fluidized bed technology can be used to build a number of CFB boilers using graphite petroleum coke as raw materials to provide low-cost steam, electricity and hydrogen for refineries. This is a three-pronged approach, which not only digests the low-priced high-sulfur graphite petroleum coke, but also meets the steam and electricity needs of the company's new projects. It can also replace some existing oil-fired boilers and save precious heavy oil resources. In 2000, Hebei Petrochemical Plant built a new 75t/h circulating bed boiler burning graphite petroleum coke. It can use limestone as bed material to achieve furnace desulfurization during the combustion process, while reducing NOx emissions. The boiler combustion efficiency can reach 90%~90%. Zhenhai Petrochemical processes a large amount of foreign sulfur-containing crude oil and produces hundreds of thousands of tons of high-sulfur graphite petroleum coke every year. Due to the high sulfur content in graphite petroleum coke, it is difficult to process and has little utilization value. In 1999, CFB (circulating fluidized bed) boiler technology was used to use high-sulfur graphite petroleum coke for power generation, with a cost of only 0.18 yuan per kilowatt-hour, while the cost of residual oil power generation was as high as 0.58 yuan. In 2000, 24Mt (24 million tons) of graphite petroleum coke was digested. Shanghai Petrochemical is expanding its thermal power plant and using CFB boilers to process 280kt of high-sulfur graphite petroleum coke every year.

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2. Graphite petroleum coke is used as a raw material for anode paste and graphite electrodes in smelters

Graphite petroleum coke with low sulfur content can be used as a raw material for making electrodes in smelters. Carbon plants use graphite petroleum coke to produce anode paste for aluminum plants and graphite electrodes for steel plants. The sulfur content of graphite petroleum coke affects the use of coke and the quality of carbon products made from coke. Especially in the manufacture of graphite electrodes, sulfur content is a relatively important indicator. Too high sulfur content will directly affect the quality of graphite electrodes and the quality of steelmaking. At high temperatures above 500°C, the sulfur in the graphite electrode will be decomposed. Excessive sulfur will cause the electrode crystal to expand, causing the electrode to shrink and crack, and in severe cases, the electrode may be scrapped. In the production of graphite electrodes, the sulfur content of graphite petroleum coke will affect the power consumption. When using graphite petroleum coke with a sulfur content of 1.0% to produce electrodes, the power consumption per ton is about 9% more than that of graphite petroleum coke with a sulfur content of 0.5%. When graphite petroleum coke is used as a raw material for anode paste, its sulfur content also has a significant impact on power consumption.