Preparation and Performance Study on Lignite Briquette Coke
In order to promote the energy utilization efficiency and reduce the environmental pollution in the process of lignite direct utilization, lignite briquette and its coke were prepared. The effects of pyrolysis temperature and holding time on the briquette coke were investigated through the pyrolysis experiments of lignite briquette. The results showed that the changes of yield, volatile, ash, fixed carbon, elemental composition and oxygen functional groups content of briquette coke were dependent on increasing pyrolysis temperature and holding time. The mechanical properties of the briquette coke were assessed by means of their cold strength, compressive strength, thermal strength, immersion strength, falling strength, and so on. The fine quality briquette coke prepared from lignite briquette with high strength, heat stability more than 96%, low calorific value on dry basis higher than 6600Cal/g, and its volatile content could reach no more than 3%.
In-situ SAXS study of pore structure during carbonization of non-caking coal briquettes
Abstract Carbonization can enhance the utilization of coal. Pore structure is the main feature of the physical structure of coal and its carbonization products as char and coke. In this work, we performed an in-situ small angle X-ray scattering (SAXS) study on high temperature carbonization (1200 °C) of a kind of lignite and a kind of sub-bituminous coal. The variation of pore structure including pore size distribution, porosity and specific surface area of coal illustrates the different stages of the carbonization process.
Neutron Residual Stress Measurements on Rail Sections for Different Production Conditions
Rail sectioning with subsequent neutron diffraction experiments has been used to assess residual stresses in the rails. In this study we present the results of neutron stress measurements performed at the NIST Center for Neutron Research (NCNR) on rail sections from rails that were produced under various conditions. Specifically, these are air-cooled, air-cooled and roller-straightened, head-hardened and head-hardened and roller-straightened. More significantly, a head-hardened and roller-straightened rail was also studied after service to elucidate evolution of the service-induced residual stresses. In the latter case both a transverse-cut slice and the central region of a 0.53 m long piece were studied. Measurements on this piece are the first in which triaxial stresses have been determined for an intact rail. Neutron strain measurements with 3×3×3 mm3 spatial resolution were successfully employed for transversally cut slices to verify the difference in the stress state depending on the production process. Although examination of slices allows determination of only two-dimensional stresses in the plane of the slice, additional measurements on obliquely-cut slices, which were also carried out, and utilization of FEM gives the possibility of reconstructing the full triaxial stress distribution. Together, these approaches provide a better understanding of rail fabrication and the possibility of improving the durability and safety of rails in the future.Copyright © 2004 by ASME