K.-C. Xie

A Study on the Combustion Properties of Western Chinese Coals

Abstract Combustion process and influencing factors have been researched systematically by means of thermogravimetric analysis and kinetics analysis methods on three inertinite-rich Chinese coals and one middle Chinese. The results indicate that coal types, heating rate, and oxygen flow rate are the main effect factors, and yet, the sample usage and particle size have little influence on the combustion of coal. The kinetics analysis shows that unreacted shrinking core model comparatively fits for the mechanism illustration of coal combustion and the activation energy decreases with carbon content in coal increasing and heating rate stepping up.

The Development of Methanol Industry and Methanol Fuel in China

Abstract In 2007, China firmly established itself as the driver of the global methanol industry. The country became the worlds largest methanol producer and consumer. The development of the methanol industry and methanol fuel in China is reviewed in this article. China is rich in coal but is short on oil and natural gas; unfortunately, transportation development will need more and more oil to provide the fuel. Methanol is becoming a dominant alternative fuel. China is showing the rest of the world how cleaner transportation fuels can be made from coal. *The content in this review was given as the plenary report in the 6th Annual Methanol Forum in Dubai (2008) and the XVII International Symposium on Alcohol Fuels in China (2008).

Preparation of Y/MCM-41 composite materials

Abstract A composite material (denoted as Y/MCM-41) composed of a core of zeolite Y particle and a thin layer of MCM-41 have been prepared by the crystallization of the reaction mixture of MCM-41 and zeolite Y particles. The Y/MCM-41 particle size increases with the increase of the SiO 2 /Al 2 O 3 ratio of MCM-41. Introduction of hydroxymethyl fiber into the zeolite Y particle favors the significant increase of its strength, but zeolite p easily formed. The adsorption property of Y/MCM-41 is different from those of zeolite Y and MCM-41. H(Y/MCM-41) as a catalyst is highly selective to C 4 -C 5 hydrocarbons and slowly deactivated in the cracking of n-heptane compared to the mechanical mixture particles of HY and HMCM-41 (designated as H(Y+MCM-41)).

Combustion Characteristics and Kinetics of Lingwu Coal and Its Macerals

Abstract Maceral composition and mean reflectance are considered to be important parameters influencing the coal combustion characteristics. The combustion characteristics and kinetics of Lingwu coal and corresponding macerals were researched by means of the thermogravimetric analysis method. The results showed that inertinite has slightly higher combustion activity than that of raw coal and vitrinite, but it is also responsible for last carbon loss. As inertinite content increases, the combustion activity of the blending sample increases slightly, whereas the last carbon conversion reduces. The shrinking core model is used to illustrate the sample combustion mechanism. With increasing heating rate, the activation energies and pre-exponent factors decrease on sample combustion.

The Structure Characteristics and Reactivity of Lingwu Coal and Its Macerals in Western China

Abstract Structure characteristics, pyrolysis, and gasification reactivity of Lingwu coal and its macerals were studied by means of ultimate analysis, Fourier transform infra-red spectroscopy and thermogravimetric analysis techniques. The results indicate that Lingwu coal has the characteristics of a typical weak reducibility coal, which has higher atomic O/C ratio, aromaticity, ring condensation number, ring condensation index, and lower atomic H/C ratio. Lingwu coal inertinite contains more aromatic structure units than the vitrinite. The pyrolysis reactivity sequence for Lingwu coal is vitrinite > raw coal > inertinite. The gasification reactivity sequence is just the reverse: inertinite char > raw coal char > vitrinite char. The pyrolysis reactivity decreases and the gasification reactivity increases gently as the inertinite content increases in the experimental samples. In addition, Lingwu coal has lower pyrolysis reactivity and higher gasification reactivity compared to Pingshuo coal, which is considered as strong reducibility.

Low Carbon Economy and Energy Technologies for a Low Carbon Future

Abstract Mankinds behaviors in immoderate use of the energy resources and its high-speed economic development have resulted in serious problems, and in the mean time the huge quantity of greenhouse gases exhausted from the fuel consumption has led to more environmental pollution. Since 2003, the conception of low carbon economy has been put forward, suggesting that the economic development should follow the way of low energy consumption, low pollution, and low emission. In China, with the increasing development of low carbon economy, we also have encountered both opportunities and challenges. In this article, the author starts with the characteristics of the Chinese industrial structure and the energy consumption, concluding that it is imperative for China to develop the low carbon economy for the time being. Based on the features of Chinese energy supply and resources, the Chinese low carbon way may be different from that of the other developed countries.

Molybdenum loaded on HZSM-5: A catalyst for selective catalytic reduction of nitrogen oxides

A series of Mo/ZSM-5 samples were prepared by an impregnation method. The catalytic studies show that the catalytic activity of Mo/ZSM-5 for SCR of NO x is strongly influenced by the Mo content loaded on HZSM-5 zeolites. The temperatures at which maximum NO x conversion was obtained declined with increasing Mo content. Furthermore, the Si/Al ratio also has a distinct effect on catalytic performance over the Mo/ZSM-5 catalyst; the sample with the lowest Si/Al ratio of 28 is much better than silicon-richer samples at higher temperatures. XPS and NO-TPD results indicate that the catalytic activity of Mo/ZSM-5 samples may be related to the percentage of Mo on the surface of ZSM-5 since the surface Mo species can considerably change the capacity of NO adsorption on the surface of Mo/ZSM-5, which may promote the formation of some kind of active sites for catalytic reduction of NO x .

Influence of synthesis parameters on the formation and structure of bimodal mesopore silica in a controlled sol-gel process

In the present work, a series of synthesis parameters, including those that may affect the size of surfactant micelles and that may affect the relative rate of hydrolysis and condensation of tetraethyl orthosilicate (TEOS), were judiciously adjusted to study their direct influence on the formation and structure of our previously reported bimodal mesopore silica (designated as BMS). It is found that both the framework and textural mesopores of BMS silica can be tailored over a fairly wide size range, but on the whole the textural mesopore size is more sensitive to the change of the synthesis parameters than that of the framework mesopore size. The change of three synthesis parameters, such as increasing the amount of ethanol, decreasing the chain length of surfactant or increasing the alkali/silica molar ratio, would lead to the mesostructure of the silica obtained to transform from initial BMS into MCM-41.

02-P-14 - Synthesis of nanocrystal zeolite Y and its host effect

Publisher Summary This chapter describes the synthesis of well-crystallized nanometer-sized zeolite Y of particle size less than 70nm by a two-step-way. This synthesis is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric-differential thermal analysis (TG-DTA). Zeolite Y performances as host for metal complex in zeolites have also been studied. The ultraviolet-visible (UV-vis) spectra, XRD patterns, and TG-DTA curves show that [Fe(phen) 3 ] 2+ has been formed in the supercage of zeolite Y, and higher complex concentration can be obtained in the samples by using nano Y as host through the flexible-ligand method. [Fe (phen) 3 ] 2+ /nano Y exhibits higher activities for the liquid-phase oxidation of cyclohexane with aqueous hydrogen peroxide (H 2 O 2 ) than [Fe (phen) 3 ] 2+ / Y because of the higher surface area and shorter diffusion pathways.

Limitation of metal particle size to carbon chain growth in fischer-tropsch synthesis

Publisher Summary In this chapter, it is approached that the functional relationship between particle size and the maximum hydrocarbon chain length formed on it, and the functional properties of q(An) is also investigated. The results support the viewpoint that the negative deviation from ASF distribution is caused by the cut-off effect of small particle size. In recent years, a lot of negative deviations from Anderson-Schulz-Flory (ASF) distribution were observed on highly dispersed catalysts. It has been suggested that the negative deviation might be caused by external origin, such as wax deposition in transient condition. Some deviations are due to these external reasons, but many others are not, especially for the recent experimental results by Snel, who claimed that all the external effects were eliminated in his experiment and the negative deviation was only chemically induced. A number of papers suggest that the carbon number distribution is related to the size of metal crystallite, particularly, that the length of the growing chain is limited by the dimensions of the metal crystallite.