Application of new petroleum coke materials

Petroleum coke, as a petroleum by-product, is produced in the process of petroleum processing, that is, crude oil is separated from light and heavy oil after distillation, and heavy oil is transformed into petroleum coke after thermal cracking. If petroleum coke can be obtained directly from petroleum processing, the petroleum coke is raw coke or ordinary coke. Petroleum coke has an irregular shape, dark gray or black, porous structure, and metallic luster.

The carbon content of petroleum coke is very high, about 90%, mainly in the form of hydrocarbons. Other contents in petroleum coke, such as ash, moisture, or volatile matter, are relatively low. Many petroleum cokes have high sulfur content, about 2% to 5%. Petroleum coke has very high calorific value and its quality is very close to anthracite, so it can be used as fuel. Compared with other carbon raw materials, petroleum coke has a tighter structure, a higher degree of order, and higher crystallinity. It can be said that it is a partially graphitized carbon form.

Petroleum coke new material

The high specific surface area activated carbon

Activated carbon has a wide range of applications in the fields of the chemical industry, medicine, or food. When preparing activated carbon with a high specific surface area, alkaline activator and petroleum coke particles are mixed, and the size of petroleum coke must meet relevant standards. If the preparation process is appropriate, the obtained activated carbon can exceed the surface area of 3000m2 / g. The particle size of petroleum coke raw materials shall not be too small, generally between 100 ~ 200um. In order to maximize the specific surface area, the activation temperature must also be between 700 ~ 800 ℃. Moreover, the activation time should be less than 2H.

Nano carbide particles

Generally speaking, carbides have high hardness and high melting points, which are widely used in the preparation of cemented carbide. The melting point of nano carbide will decrease rapidly when its surface energy is high. If the sintering temperature is low and the holding time is short, the prepared ceramics will be very dense and have excellent properties. After sintering, the grain size of nano carbide will be very small, but its strength and hardness will become higher.

Advanced composites

The first is reaction sintered silicon carbide, which can also be referred to as RBSC. RBSC is a process of in-situ formation of SiC ceramics through liquefied silicon deep into carbon billets and relevant chemical reactions. When directly Sintering SiC ceramics, the time and temperature required are longer and higher than RBSC, and the equipment is more expensive. RBSC can not only keep SiC ceramics with good size retention but also prepare products with complex shapes. Moreover, the cost of preparing RBSC from petroleum coke can be effectively reduced. Therefore, petroleum coke can be mixed with SiC particles, and then the mixed liquid can be siliconized. In addition, the filler can be mixed into petroleum coke to adjust the density of carbon material and then infiltrate silicon.

Electrorheological smart materials

Electrorheological smart materials include piezoelectric ceramics, electrorheological, and shape memory alloys, covering a wide range. Among them, the viscosity of ER fluid of ER materials can change from low to high in an instant under the action of a certain intensity of the external electric field, and may even become a solid, which has been paid attention to and widely used. Such as clutch, shock absorber, and hydraulic valve. Petroleum coke is used in the development of ER materials. After grinding, 10 ~ 75% can be obtained μ M, the volume fraction of methyl silicone oil is between 33% ~ 35% by dispersing in methyl silicone oil with a viscosity of 50 mm2 / s. When the external field strength is 2KV / mm, if the material viscosity is 20 times larger than the zero-field viscosity, it means that the ER effect is very good. In addition, when its current density ratio is 60 μ If a / cm2 is even smaller, it means that its suspension stability is very good.

The cathode material of the lithium battery

The positive and negative electrodes of lithium-ion batteries re embedded materials with different potentials so that lithium ions are de-embedded from the positive electrode and embedded into the negative electrode when the battery is charged. When discharging, the situation is just the opposite. In order to develop lithium batteries with high performance, the first thing is to find suitable cathode materials, whose working voltage should be as low as possible, the amount of lithium intercalation should be high, and the reversibility of lithium-ion de intercalation is good. Carbon materials are the most successful cathode materials, including petroleum coke, activated carbon, graphite, and so on.

Here, several technologies developed by the clean utilization technology of high sulfur petroleum coke are described as examples.

Activated carbon technology

In foreign countries, petroleum coke has been applied to the preparation of activated carbon technology for more than 20 years, and its raw material is mainly low sulfur petroleum coke. Sulfur content greatly affects the specific surface area of activated carbon. The specific surface area of activated carbon products can be greatly improved only when the desulfurization rate of high sulfur petroleum coke reaches 98%. In China, the research on this aspect is only in the pilot stage. High sulfur petroleum coke can be used as raw material for the production of natural gas adsorbents with high performance. However, in the discharged gas, due to its high sulfur content, it does not meet the relevant requirements of environmental protection level.

The process is as follows: the crushed limestone and petroleum coke are sent to the lower part of the furnace through the feeder to heat and burn the recycled high-temperature materials. After the primary air is preheated, it is sent to the furnace from the bottom of the furnace to make its particles flow upward to form a dense-phase fluidized bed. After the secondary air is preheated, it is sent to the furnace from the coke inlet of the furnace, and the fine combustion particles are carried out of the CFB furnace and then sent to the cyclone separator. The separated materials will be sent back to the furnace by the return system for combustion again. The flue gas is heat exchanged through the economizer and the boiler, then dedusted through the dust collector, and then discharged into the chimney to discharge the ash from the slag discharge port at the bottom of the furnace.

CFB technology has been gradually improved and the availability has been improved. The concurrent projects of CFB boilers with high sulfur petroleum coke fuel as the main raw material will gradually increase. The values were 95.17% and 97.3%.

Conclusion

With the rapid development of material science, the application of new materials of Petroleum Coke will be more and more widely, and there will be more and more application fields, which will bring greater social and economic benefits to society and enterprises than traditional application methods.