In-situ variable-temperature single-point NMR imaging study of coals

To monitor the dynamical changes in coals with temperature, an in-situ method must be used, therefore, we have applied Single-Point-Imaging and have carried out the first systematic in-situ variable-temperature NMR imaging study of coals between 25 and 500°C with our newly developed high temperature imaging probe and systems. It was found that the distribution of mobile components was very heterogeneous like the distribution of macerals at room temperature. As the temperature became higher, the mobile component started increasing but remained heterogeneous above 400°C and over this the distribution of mobile components became more homogeneous. It is clear that in-situ variable-temperature NMR imaging method is very powerful to investigate and clarify the thermal change of coal.

[1]  Barbara L. Smith,et al.  Evaluating human breast ductal carcinomas with high-resolution magic-angle spinning proton magnetic resonance spectroscopy. , 1998, Journal of magnetic resonance.

[2]  D. Cory,et al.  Constant time imaging approaches to NMR microscopy , 1997, Int. J. Imaging Syst. Technol..

[3]  T. Yokono,et al.  High temperature 1H-NMR study of coal and pitch at the early stages of carbonization , 1979 .

[4]  C. Karr.  Analytical methods for coal and coal products , 1978 .

[5]  D. S. Webster,et al.  1H n.m.r. evidence to support the host/guest model of brown coals , 1988 .

[6]  R. Sakurovs,et al.  Direct observations on the interaction of coals with pitches and organic compounds during co-pyrolysis , 1993 .

[7]  J. Andresen,et al.  Quantification by in situ1H n.m.r. of the contributions from pyridine-extractables and metaplast to the generation of coal plasticity , 1997 .

[8]  T. L. Peck,et al.  Magnetic Resonance Microscopy , 1995 .

[9]  G. Cody,et al.  Imaging the microstructure of low rank coals : a study combining nuclear magnetic resonance, scanning electron and optical microscopic imaging , 1994 .

[10]  D. Cory,et al.  Sensitivity and Resolution of Constant-Time Imaging , 1994 .

[11]  D. S. Webster,et al.  The molecular basis of coal thermoplasticity , 1988 .

[12]  T W Bremner,et al.  Relaxation time mapping of short T*2 nuclei with single-point imaging (SPI) methods. , 1998, Journal of magnetic resonance.

[13]  R. Sakurovs,et al.  Oxidation studies of high fluidity coals , 1989 .

[14]  R. Kimmich.  NMR: Tomography, Diffusometry, Relaxometry , 2001 .

[15]  S. L. Dieckman,et al.  Microscopic NMR imaging of coal , 1990 .

[16]  H. Carr,et al.  The Principles of Nuclear Magnetism , 1961 .

[17]  Lon J. Mathias,et al.  Solid state NMR of polymers , 1991 .

[18]  G. Maciel,et al.  Variable-Temperature High-Resolution Proton NMR Study of Laboratory-Frame and Rotating-Frame Spin−Lattice Relaxation in Coals , 1997 .

[19]  L. J. Lynch,et al.  An NMR method for quantitative determination of the carbonaceous mesophase content of a petroleum pitch , 1991 .

[20]  David H. Scott,et al.  Developments affecting metallurgical uses of coal , 1994 .

[21]  J. Andresen,et al.  In-situ 1H NMR investigation of particle size, mild oxidation, and heating regime effects on plasticity development during coal carbonization , 1997 .

[22]  D. Grant,et al.  Carbon-13 solid-state NMR of Argonne-premium coals , 1989 .

[23]  R. Sakurovs,et al.  Molecular mobility during pyrolysis of Australian bituminous coals , 1987 .

[24]  E. Stach,et al.  Stach's Textbook of coal petrology , 1975 .