Xiaoxun Ma

Relationship between trace elements and macerals in Huanglong Jurassic coal

ABSTRACT This study is the detailed publication concerning the origins of trace elements in Huanglong Jurassic coal. Forty-two coal samples were collected from Huanglong Jurassic coalfield. Twenty-two elements, including U, B, F, Hg, Be, Cd, Cr, Cu, Mn, Mo, Ni, Pb, V, Zn, Ba, Co, Ga, Sr, As, Se, Cl, and P, were determined. The element profiles were compared with the organic petrography, and the statistical analysis was also carried out to provide preliminary information for origins of the trace elements. The following conclusions were obtained: Cd, Cr, Cl, Ni, Zn, Co, Ga, Sr, As, Se, and B show inorganic affinity. Hg, V, Be, Cu, Pb, and F show generally vitrinite affinity, suggesting that their origins are associated with parenchymatous and woody tissues of roots, stems, barks, and leaves composed of cellulose and lignin. U shows inertinite affinity, which indicated that wood and leaf tissue weakly altered by decay or by biochemical alteration are the main origins of U. P, Mn, Mo, and Ba show overall mixed affinities, indicating the complex of biological origins.

Properties and carbonization behavior of asphalt modified with the THF-soluble fraction of a coal liquefaction residue

ABSTRACT This study focuses on the effects of the tetrahydrofuran-soluble fraction of direct coal liquefaction residue as a modifier to modify asphalt with formaldehyde. The properties and carbonization behavior of matrix asphalt and the modified asphalts were studied. The results indicate that the ductility properties of modified asphalts have been effectively improved. The morphology of modified asphalts without the addition of formaldehyde is a set of uniform distribution point, and it is converted from linear distribution to clustered distribution observed in fluorescence microscope images with the increase of the adding amount of formaldehyde.

The Application of an Improved BPNN Model to Coal Pyrolysis

The pyrolysis characteristics of nine kinds of Chinese coals obtained by the thermogravimetry were modeled using artificial neural network. In order to remedy the defects of back propagation algorithm, a momentum term and an adaptive learning rate were introduced. The architecture of the improved back propagation neural network model was 3 × 5 × 3, which included three input nodes (content of volatiles and ash, C/H), five hidden nodes, and three output nodes (the weight loss percentage, the maximum weight loss velocity temperature, and the weight loss peaks). The model prediction results indicated that the modified back propagation neural network had a fast convergence speed and a high accuracy. Moreover, the maximum relative error was less than 4%. Furthermore, in model analysis the effect of each input node was quantized by the sum of absolute values of weights. And the results indicated that C/H had more remarkable influence than the other two.

Modification with formaldehyde on the thermal reactivity of >300°C distillation fraction from low-temperature coal tar

ABSTRACT A >300°C distillation fraction (300F) from low-temperature coal tar was reacted with formaldehyde. Residual oil (RO) and residual solid (RS) were collected. RO was detected by gas chromatography-mass spectroscopy (GC-MS) and shows that it mainly contains alkanes and polycyclic aromatic hydrocarbons. The degradations under a nitrogen atmosphere of 300F and RO were investigated by Fourier transform infrared spectrometer. The result shows that 300F and RO consist of two degradation stages and five stages, respectively. CO has significant absorbency in the pyrolysis process of RO, not in 300DF. Modification of formaldehyde and compounds with carboxyl, short-chain fatty, and ester group in 300F generates polymers and fixes these compounds.