Workers in coal tar industry, please come in
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I am mainly engaged in the research and development of coal tar pitch, and I hope to exchange ideas with others. Everyone is welcome to share new findings related to coal tar pitch in this post, as well as to raise questions related to production processes; I and other professionals can then discuss these issues together to find solutions.
What is the latest technology in coal tar pitch at the moment?
Today, coal tar asphalt is widely used, and the main application technologies include: asphalt delayed coking production technology, granular asphalt production technology, road construction asphalt production technology, and asphalt carbon fiber production technology, among others. Among them, the production technology of pitch carbon fibers holds great prospects for development. Its main process is as follows: (tar pitch) → heat treatment → (modified pitch) → melt spinning → (pitch fibers) → non-melting treatment → carbonization (heating under inert gas conditions) → carbon fibers. The most important steps in this process are pretreatment and non-melting treatment, which enable the raw pitch to possess sufficient spinability through modification and give the surface of the pitch fibers non-melting properties.
Is there anyone else who can take the floor?
There is currently no specialized pitch produced in China for impregnation processes; this has led to a series of problems in impregnation production. In industrially developed countries, there are strict requirements for the pitch used as an impregnating agent in the production of graphite products; specialized and dedicated pitch is employed. The Anshan Thermal Energy Research Institute in our country conducted research, and Jining Coal Chemical Company also carried out experiments, but nothing was commercialized. The main characteristics of Japanese impregnating asphalt are a high softening point, high carbon content, low viscosity, and a low QI value; as a result, it provides good impregnation effects. Japan’s impregnating asphalt is coal tar asphalt, with a QI value of 0.1%, which corresponds to the specifications for soft asphalt used in the production of coal-based needle coke. It is also a new type of impregnating asphalt that has been developed through research in recent years; the QI value of the older versions of this product was 3%. Since QI particles are difficult to graphitize, the formation of more homologous carbon during carbonization affects the degree of graphitization of the graphitized products, increasing their thermal expansion coefficient and resistivity. In addition, there are two situations that affect the permeability of the material being impregnated: when the native QI is in the form of solid particles, it can form a filter cake on the surface of the porous material, thereby increasing the permeation resistance ； Secondary QI consists of non-solid particles in a colloidal form, which present greater permeation resistance; it forms a few-millimeter-thick filter cake on the surface of the product, creating an almost impermeable interface layer. When there is no QI in the asphalt, its penetration into porous materials is influenced only by pressure, temperature, and viscosity.
What is the latest use of coal tar pitch? Can it be directly used to produce gasoline or diesel?