In the last decade, great progress has been made in unveiling the geochemistry and macromolecular structure of coal. The studies on coal geochemistry underscored the composition of high organic sulfur coal sulfide, bark coal aliphatic hydrocarbon, and coal polycyclic aromatic hydrocarbon, while the studies on coal macromolecular structure addressed the theory of bonding and embedded structure. Yet it is evident that the exigencies of promoting the development of new theories and technologies for the geochemistry and macromolecular structure of coal have been gaining soaring attention.
Coal is a complex sedimentary rock derived from plant remains that underwent peatification and subsequent coalification. Given the fact that the organic chemistry of coal has been investigated for more than one century, the geological factors in coal chemistry have been often underacknowledged, which encompass
1) Coal metamorphism. Rank is considered to be the only important parameter of coal variability, but rank is not the only the source of variance in coal properties. Other factors include constituent minerals and macromolecular functional groups in coal.
2) Coal geochemistry and thermal processing. For low-rank coal and anthracite, it is worth discussing why they do not show significant cohesiveness during liquefaction and coking. It is very difficult to explain this phenomenon of low-rank coal and anthracite based on the current theoretical knowledge of coal organic geochemistry.
3) Coal isotope. Studies on the sedimentary environment and organic geochemistry of coal facilitate how to understand the hydrocarbon generation potential of coal. However, due to the complexity of the physical and chemical process of hydrocarbon generation from coal, the introduction and development of new technologies for determination of coal isotope aims to better trace this process.
4) The chemical and physical structure of coal. Spectroscopy technologies are employed to analyze the chemical structure of coal, whereas high-resolution microscope technologies are used to observe the physical structure of coal. Yet less is known about the interlinkages between chemical structure (molecular structure) and physical structure (pore/fissure structure) of coal, especially for some special coal structures, such as broken soft coal (interbedded with primary structured coal, fractured coal, and pulverized coal). This kind of coal has the characteristics of soft crushing, high gas content, high pressure, and low permeability, which results in low gas extraction efficiency and extremely difficult gas control.
5) Coal ecology and environment. The relationship between coal organic geochemistry and the environment mainly concerns the utilization of coal, in particular the impacts of carbon emissions on the environment. How the reduction of carbon emissions during coal processing and utilization needs further investigation.
This Research Topic welcomes Original Research Articles, Reviews, and Short Communication. Key themes include, but are not limited to:
• Geochemistry of coal-bearing series
• Fine characterization of coal structure
• Coal macerals and chemical processes
• Coal isotope tracing
• Clean coal technologies
• Coal ecology and environment
In the last decade, great progress has been made in unveiling the geochemistry and macromolecular structure of coal. The studies on coal geochemistry underscored the composition of high organic sulfur coal sulfide, bark coal aliphatic hydrocarbon, and coal polycyclic aromatic hydrocarbon, while the studies on coal macromolecular structure addressed the theory of bonding and embedded structure. Yet it is evident that the exigencies of promoting the development of new theories and technologies for the geochemistry and macromolecular structure of coal have been gaining soaring attention.
Coal is a complex sedimentary rock derived from plant remains that underwent peatification and subsequent coalification. Given the fact that the organic chemistry of coal has been investigated for more than one century, the geological factors in coal chemistry have been often underacknowledged, which encompass
1) Coal metamorphism. Rank is considered to be the only important parameter of coal variability, but rank is not the only the source of variance in coal properties. Other factors include constituent minerals and macromolecular functional groups in coal.
2) Coal geochemistry and thermal processing. For low-rank coal and anthracite, it is worth discussing why they do not show significant cohesiveness during liquefaction and coking. It is very difficult to explain this phenomenon of low-rank coal and anthracite based on the current theoretical knowledge of coal organic geochemistry.
3) Coal isotope. Studies on the sedimentary environment and organic geochemistry of coal facilitate how to understand the hydrocarbon generation potential of coal. However, due to the complexity of the physical and chemical process of hydrocarbon generation from coal, the introduction and development of new technologies for determination of coal isotope aims to better trace this process.
4) The chemical and physical structure of coal. Spectroscopy technologies are employed to analyze the chemical structure of coal, whereas high-resolution microscope technologies are used to observe the physical structure of coal. Yet less is known about the interlinkages between chemical structure (molecular structure) and physical structure (pore/fissure structure) of coal, especially for some special coal structures, such as broken soft coal (interbedded with primary structured coal, fractured coal, and pulverized coal). This kind of coal has the characteristics of soft crushing, high gas content, high pressure, and low permeability, which results in low gas extraction efficiency and extremely difficult gas control.
5) Coal ecology and environment. The relationship between coal organic geochemistry and the environment mainly concerns the utilization of coal, in particular the impacts of carbon emissions on the environment. How the reduction of carbon emissions during coal processing and utilization needs further investigation.
This Research Topic welcomes Original Research Articles, Reviews, and Short Communication. Key themes include, but are not limited to:
• Geochemistry of coal-bearing series
• Fine characterization of coal structure
• Coal macerals and chemical processes
• Coal isotope tracing
• Clean coal technologies
• Coal ecology and environment
