Response of inertinites from some Australian coals to non-catalytic hydrogenation in tetralin

Inertinite concentrates from three Australian bituminous coals were hydrogenated at various temperatures ranging from 350 to 475 °C in the presence of tetralin without any added catalyst. Both conversion yields and microscopic observations of the benzene-extracted hydrogenation residues have revealed that the hydrogenation of the inertinite macerals becomes significant only > 400 °C, whereas the dissolution-hydrogenation of the accompanying vitrinite macerals occurs mainly between 350 and 400 °C. The major reaction pathway for the inertinite particles in the hydrogenation process appears to be one of initial mild carbonization followed by hydrogenation. A simplified reaction scheme is proposed which describes the reaction pathway involved in the hydrogenation of inertinite.     

Influence of the oxygen content of low-rank coals on the development of porosity during carbonization

The development of porosity in the course of carbonization of a flame coal, original and pre-oxidized, was studied by means of the adsorption of benzene and carbon dioxide. The results were compared with corresponding data for cokes from a xylitic brown coal. The influence of coal oxygen content on the formation of coke porosity and its thermal dependence is discussed.     

Analytical pyrolysis as a tool for the study of plastic coals

The technique of analytical pyrolysis has been used to characterize 40 similar mid-rank western Kentucky coals of widely differing ASTM Gieseler plasticity. Certain pyrolysis/g.c. variables were shown to correlate well with both ASTM Gieseler and isothermal plasticity. Highly plastic coals were shown to exhibit certain characteristic peaks in the 450 °C pyrogram which were absent in the pyrogram of the non-plastic coals. Two coals, representing the two extremes in plasticity, were selected for further study. After extraction with solvents such as DMF the characteristic peaks were absent in the 450 °C pyrogram of the extraction residue of the highly plastic coal. These peaks were also shown to decrease with increasing severity of air oxidation of the plastic coal. This technique appears to be a useful tool for the analysis of mid-rank plastic coals and supports the view that the substances contained in the bitumen fraction of these coals are involved in the development of the plastic state.     

Studies of elemental distributions within discrete coal macerals: Use of secondary ion mass spectrometry and X-ray photoelectron spectroscopy

Secondary ion mass spectrometry has been used to measure qualitatively the distributions of many trace and minor elements within some well-characterized coal macerals: vitrinite, fusinite and exinite. Complementary information was obtained by using X-ray photoelectron spectroscopy. Within the vitrinite specimens studied, a widely-dispersed largely inorganic aluminosilicate phase was identified, which contained a number of other trace elements. By contrast, within the organic-rich phase of this macerai, titanium was detected in a very even distribution; this suggests that some titanium may be bonded in an organic complex. The fusinite was shown to contain elevated concentrations of calcium, magnesium and fluorine, dispersed over a large portion of the maceral. The high fluorine content could be identified as an organo-fluoro compound using XPS. Exinite was found to contain lower concentrations of most elements, compared to other macerals. The organic composition of this maceral was significantly different from that of surrounding macerals; this could be seen from the enhanced emission of the C₂H₂-secondary ion and images of this ion thus clearly outlined the position of such macerals.     

煤系高岭土制备裂化催化剂的探索性研究

从石嘴山煤系高岭土的分析测实,经过改性处理,实验后得出具有碱改性条件,且制备裂化催化剂后重油转化能力有明显提高,开拓了煤系高岭土在石化领域的应用。     

煤代油方式的经济性分析

对两种煤代油方式——水煤浆和煤制混合煤气进行了燃料价格、设备投资及运行费用的分析对比。结果表明，两种代油方法均有可观的经济效益，燃料费用可分别节约52．4％和45．2％。如果原燃油工业炉窑由于工艺需要已装有除尘设备而又可用产生的蒸汽做雾化剂时，则水煤浆代油更具有经济优势。     

中铝河南分公司矿山在土地复垦中的有益探索

分析了铝土矿露天开采和土地、环境之间的利害关系，并对矿山公司“土地复垦”工艺技术进行了阐述，介绍了中铝河南分公司矿山公司方面的具体作法和成功经验。     

Mining process models with non-free-choice constructs

Process mining aims at extracting information from event logs to capture the business process as it is being executed. Process mining is particularly useful in situations where events are recorded but there is no system enforcing people to work in a particular way. Consider for example a hospital where the diagnosis and treatment activities are recorded in the hospital information system, but where health-care professionals determine the “careflow.” Many process mining approaches have been proposed in recent years. However, in spite of many researchers’ persistent efforts, there are still several challenging problems to be solved. In this paper, we focus on mining non-free-choice constructs, i.e., situations where there is a mixture of choice and synchronization. Although most real-life processes exhibit non-free-choice behavior, existing algorithms are unable to adequately deal with such constructs. Using a Petri-net-based representation, we will show that there are two kinds of causal dependencies between tasks, i.e., explicit and implicit ones. We propose an algorithm that is able to deal with both kinds of dependencies. The algorithm has been implemented in the ProM framework and experimental results shows that the algorithm indeed significantly improves existing process mining techniques.     

Emission of trace toxic metals during pulverized fuel combustion of Czech coals

A study of the trace elements emission (As, Se, Cd, Co, Cr, Cu, Zn, Hg, Tl, Pb, Ni, Sn, Sb, V, Mn and Fe) from pulverized coal combustion has been made at six heating and power stations situated in the Czech Republic. The amount of chlorine in coal has considerable influence on volatilization of some elements such as Zn, Cu, Pb, Hg and Tl, which is explained by the formation of thermodynamically stable compounds of these elements with chlorine. Generally, the affinities for Cl follows the order Tl > Cu > Zn > Pb > Co > Mn > Sn > Hg. The experimental data indicates enrichment of some of the trace toxic elements in the emissions (Cu, Zn, As, Se, Cd, Sn, Sb, Hg and Pb) and good agreement was obtained by thermodynamic equilibrium calculations with a few exceptions. In the case of Fe, Mn, Co, Cr and Sn calculated values are overestimated in the bottom ash and there are zero predicted amounts of these elements in the fly ash. In comparison, the results from experiments show up to 80% of these elements retained in fly ash. This implies that there exist additional steps leading to the enrichment by Fe, Mn, Co, Cr and Sn of small particles. Such mechanisms could include the ejection during devolatilization of small inorganic particles from the coal of bottom ash particles, or disintegration of the char containing these metals to small particles of fly ash. On the other hand, there are slightly overestimated or similar values of relative enrichment factors for As, V, Cu, Cd, Sb, Tl and Pb in the fly ashes and zero predicted values for bottom ashes. Our experimental results show about 5% or less of these elements are retained in bottom ashes, so they probably remain in the bottom ash inside unburned parts of coal. Copyright © 2003 John Wiley & Sons, Ltd.     

40kg试验焦炉的研制

文章介绍了40kg试验焦炉，分析和比较了试验焦炉与生产焦炉的差异，指出它们之间的模拟条件是炭化室宽度、煤料堆密度、炼焦速度和单向传热。