Research On Nano-Structure Of Magmatic Contact Metamorphosed Coal （P₁） At Huainan Coalfield

In Huainan coal field, Shanxi Formation and Lower-Shihezi Formation are the main coal seams. During the Middle Yanshan period, north of the coal field underwent the impact of magmation. Thus the physical and chemical structure and the quality of the coal were complicated; especially the development of micro pores provided a convenience for the Coalbed Methane (Gas) storage, adsorption and migration. Hence, there are both theoretical and practical significances to study the physical and chemical structure of the coal impacted by magma-contact metamorphism.On the basis of sufficiently investigating and surveying literatures at home and abroad, as a research object the Lower-Permian coal in Huainan coal field, which was impacted by magma-contact metamorphism, was studied using a series of scientific methods, such as in situ X-Ray Diffraction (XRD), Fourier Transform Infrared Spectrometry and so on. Comprehensively applied interdisciplinary theory of coal geology, coal petrology, coal chemistry and so on, this article systematically revealed the internal structure of crystal nucleus and the characteristic of the surface pore structure based on the chemical structure study of solid product after different coal pyrolysis. The main achievements as the following:(1)After the analysis of the coal sample from metamorphic belt in Pansan coal mine using Micro-Raman Spectroscopy Sytem and Atomic Force Microscopy, we can find that accompanied with the increasement of the metamorphic grade, The Raman First and Second Modular reveal the arrangement tendence of the coal molecule to the graphite-like structure highly condensed of aromatic nucleus; Total quantity of surface pores are less on the highly metamorphic anthracite, anthracite and meager coals than on the normal coals, but micro pore and minor pore develop well whereas the porosity is lower of the coal closer to the intrusive body. This verifies that the stress provided by the intrusive of the magma plays a limited part.(2)After using X-Ray Diffraction and Fourier Transform Infrared Spectrometry to the coal samples near the contact-metamorphic coal belt in Zhuji coal mine, it can be found that parameters ((d002),(La) and (Lc)) of different ranks of coals vary relatively as the distance decreasing to the intrusive body, and that the stress provided by igneous intrusion plays a limited part to the evolution of the aromatic-plane diameter La. With increasing of coal rank, the degree of condensation of the aromatic nucleus increases and bridged linkage, side chain and oxygen-containing functional group decrease. Combined the in situ FTIR test of solid product after different coal pyrolysis and the highest paleogeothermal renewed by the easy Ro method, it can be confirmed that, at least300℃is the temperature of the intrusive magma during the Lower-Permian period in Huainan coal field.