Yuanyu Tian

Preparation of micro-porous monolithic activated carbon from anthracite coal using coal tar pitch as binder

Monolithic activated carbon (MAC) has been produced from steam activation of monoliths prepared by mixing coal powders with high-temperature coal tar binder for a long time. However, this process leads to poor working conditions, environmental pollution, and waste of resource. This study investigated the use of coal tar pitch as binder to prepare MAC with high surface area, micro-pore structures, and strong mechanical strength. The performances of the MACs with both coal tar and coal tar pitch as binders were compared. The product yield of MAC bonded with coal tar pitch (MACp) was 10% higher than that with coal tar (MACT). The BET surface area, micropore volume, and average pore diameter of MACP were 837.99xa0m2xa0g−1, 0.346xa0m3xa0g−1, and 1.776xa0nm, respectively, which were all superior to the corresponding values of MACT. Only the attrition resistance strength of MACP was slightly lower than that of the MACT. The SEM images showed that the cokes on the surface of both MACs distributed identically and uniformly. Furthermore, XRD results revealed that the pore-expanding reactions mainly led to the reduction of carbon crystallite along with the stacking direction rather than horizontal direction during steam activation process. This work demonstrates that cost-effective MAC can be prepared with the coal tar pitch as binder and the results of the investigation presented in this work provide new and important information necessary to the successful application of MACs in industrial field.

Facile preparation of a Ni/MgAl2O4 catalyst with high surface area: enhancement in activity and stability for CO methanation

Abstract To enhance the performance of anti-coking and anti-sintering of the Ni-based catalysts during the reaction process of CO methanation, we synthesized a group of catalysts denoted as “Ni-xMgAl2O4” via the modified co-precipitation method utilizing carbon black as hard template. The addition of carbon black could significantly improve the specific surface area of MgAl2O4 to 235.8 m2 g−1. The Ni catalysts supported on high-surface-area MgAl2O4 (Ni-0.25MA) exhibited enhanced catalytic performance and hydrothermal stability in comparison with the conventional Ni-based magnesia alumina spinel catalysts with the same NiO content. In the process of 120-h stability test, the Ni-0.25MA catalyst exhibited remarkable improvement in both anti-sintering and anti-coking. After a series of characterizations, we found that the addition of carbon black could make more pores over MgAl2O4, resulting in the supported Ni particles being anchored in the pore rather than on the outside surface of support. This structure enhanced the dispersion of nickel nanoparticles, thus strengthening the interaction between nickel species and the MgAl2O4 support, which led to the promotion in catalytic activity and stability of high-surface-area Ni/MgAl2O4.

Identification and classification of aromatic hydrocarbons from fast pyrolysis of coal for the purpose of environment-pollution evaluation

Aromatic hydrocarbons are the main composition in coal tar from industrial coal processing process, which have long been recognized as the major environment pollutant. The biological toxicity of aromatic hydrocarbons are closely related to their structural configurations. In this work, detailed composition of aromatic species during fast pyrolysis of Shandong coal were identified and classified to evaluate their toxicities based on the specific structure features. In total, 83 kinds of aromatic hydrocarbons were identified and the most abundant aromatic hydrocarbons were toluene, p-xylene, 1-ethylidene-1H-Indene, and 1,2-dehydro-as-hydrindacene. Carbon number of aromatic hydrocarbons ranged from 6 for benzene to 16 for the alkyl-substituted phenanthrene and the content of C8 aromatic hydrocarbons was largest. The ring of aromatic hydrocarbons is distributed from 1 to 4 and their contents decrease gradually with increasing of ring number.