Nano Composite from Coal Modified Novolac Resin

Coal-modified novolac/clay nanocomposites were synthesized using clay as reinforcing materials. It was found that coal-modified novolac resin based silica nano-composites showed improved tensile strength compared to that of neat novolac resin. The structure of the nanocomposites was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Scanning electron microscopy (SEM) studies have also been undertaken to see the morphology of the nanocomposites prepared. The results obtained are being reported.     

煤焦油改性酚醛树脂研究

引入含有多环芳烃煤焦油组分来改性酚醛树脂,在反应釜中按一定比例加入苯酚、甲醛、氢氧化钠和煤焦油.在碱性催化剂作用下反应4～7 h,真空脱水,得到了煤焦油改性热固性酚醛树脂.对改性后树脂的固含量、残炭值测定和热失重-差热分析,结果表明煤焦油加入量为苯酚质量的15%时改性树脂具有较大的固含量和残炭值,耐热性也得到了显著提高.     

粉煤灰在油田开发中的应用

在对某热电厂粉煤灰全面的性能分析的基础上,介绍了一种以粉煤灰为主剂的水井用调剖剂。经室内实验分析和现场应用的效果分析,证明FP-2型粉煤灰类调剖剂的堵水调剖效果好,为粉煤灰的综合利用找出了一条新的应用途径。     

The physical character of coal char formed during rapid pyrolysis at high pressure

Rapid pyrolysis was conducted in a drop tube reactor using seven coals under various operating conditions. In addition to dense char, porous chars (network char and cenospheric char) were formed by the rapid pyrolysis under certain conditions. Porous char was mainly composed of film-like carbon and skeleton carbon. The pyrolyzed coal char particles were characterized in detail. Morphology and bulk density of porous char were quite different from the dense char formed under the same conditions, but elemental composition and BET surface area were similar to each other. CO₂ gasification reactivity of porous char was lower than dense char in the later gasification stage, and this was ascribed to the low reactivity of skeleton carbon.     

Pressurised flash drying of Yallourn lignite

A previously developed 1D model of lignite drying for pulverised lignite feeding into a conventional pulverised fuel boiler during the coal milling process is applied to lignite in an entrained flow configuration at elevated pressure. A combustor fired with diesel and air was used to produce a flue gas at 800 °C and 10 atm to flash dry Yallourn lignite at a nominal feed rate of 725 kg/h along a 50 m duct. A coal feeder arrangement was also developed which provides a simple positive feeding device for feeding against a back pressure. The feeder takes as an input coal which is nominally <50 mm and discharges it as a finely divided product with a mean particle size of approximately 1.0-1.5 mm. The comparison between model predictions and measured temperature profiles for the flue gas and final moisture content of the dried coal product showed excellent agreement. Coal moisture was reduced from 67 wt% to between 30 and 40 wt%, depending upon on the coal feed rate and particle size. The small variation in the final outlet temperature observed between the model and experimental results is due to heat losses from the exposed duct work to the environment.     

Kinetic mechanism studies on reactions of mercury and oxidizing species in coal combustion

The emission of mercury by coal-fired power plants has become a recent concern on the part of the electric utility industry. Knowledge of mercury kinetic mechanisms is imperative for the research of predicting mercury transformation and finding its effective control methods in coal combustion flue gas. Near the end of the flue gas path, mercury exists as a combination of elemental vapor and HgCl₂ vapor. HgCl₂ is more likely to be removed from the flue gas. Thus, the degree of oxidation is considered to be a critical factor that tends to reduce emission. In the present work, the microcosmic kinetic mechanisms of reactions between mercury and oxidizing species were investigated by ab initio calculations of quantum chemistry. The geometry optimizations of reactants, transition states, intermediates and products were made by the quantum chemistry MP2 method at SDD basis function level. All molecule energies were calculated at QCISD(T)/SDD level and corrected with zero point energy. The activation energies and heat of reactions were calculated. The reaction rate constants were calculated from transition state theory (TST). The performance of the ab initio calculations of quantum chemistry was assessed through comparisons with the literature data. The comparisons showed that the ab initio calculations of quantum chemistry were in agreement with the literature data. The results showed that quantum chemistry was an effective means for investigating kinetic mechanism of mercury interaction with combustion-generated flue gas.     

Ge extraction from gasification fly ash

Water-soluble germanium species (GeS₂, GeS and hexagonal-GeO₂) are generated during coal gasification and retained in fly ash. This fact together with the high market value of this element and the relatively high contents in the fly ashes of the Puertollano Integrated Gasification in Combined Cycle (IGCC) plant directed our research towards the development of an extraction process for this element. Major objectives of this research was to find a low cost and environmentally suitable process. Several water based extraction tests were carried out using different Puertollano IGCC fly ash samples, under different temperatures, water/fly ash ratios, and extraction times. High Ge extraction yields (up to 84%) were obtained at room temperature (25 °C) but also high proportions of other trace elements (impurities) were simultaneously extracted. Increasing the extraction temperature to 50, 90 and 150 °C, Ge extraction yields were kept at similar levels, while reducing the content of impurities, the water/fly ash ratio and extraction time. The experimental data point out the influence of chloride, calcium and sulphide dissolutions on the Ge extraction.     

烟煤为主的多煤种混合喷吹技术的实验分析

实验研究了以烟煤为主的多煤种混合煤的理化性质,包括爆炸性、燃烧性、可磨性。并讨论混合煤的性质与煤的种类和配比之间的关系及其在高炉喷吹中应用的合理性。为生产中的使用提供了重要依据。     

Thermodynamics of Hydrogen Production Based on Coal Gasification Integrated with a Dual Chemical Looping Process

The performance of an innovative hydrogen production technology, which is based on a coal gasification system integrated with a dual chemical looping process, namely, chemical looping air separation (CLAS) and calcium looping CO₂ absorption (CaL), is evaluated. CLAS offers an advantage over other mature technologies in that it can reduce capital costs considerably. CaL is an efficient method for hydrogen production and CO₂ capturing. The proposed technologies are studied by Aspen Plus based on the Gibbs free energy minimization principle. The key factors in terms of reduction temperature, gasification pressure, temperature of water‐gas shift reaction, and water consumption, which proved to have a significant impact on the performance of the whole hydrogen generation process, are discussed.     

Pillar design and coal burst experience in Utah Book Cliffs longwall operations

Longwall mining has existed in Utah for more than half a century. Much of this mining occurred at depths of cover that significantly exceed those encountered by most other US longwall operations. Deep cover causes high ground stress, which can combine with geology to create a coal burst hazard. Nearly every longwall mine operating within the Utah's Book Cliffs coalfield has been affected by coal bursts. Pillar design has been a key component in the burst control strategies employed by mines in the Book Cliffs.Historically, most longwall mines employed double-use two-entry yield pillar gates. Double-use signifies that the gate system serves first as the headgate, and then later serves as the tailgate for the adjacent panel. After the 1996 burst fatality at the Aberdeen Mine, the inter-panel barrier design was introduced.In this layout, a wide barrier pillar protects each longwall panel from the previously mined panel, and each gate system is used just once. This paper documents the deep cover longwall mining conducted with each type of pillar design, together with the associated coal burst experience. Each of the six longwall mining complexes in the Book Cliffs having a coal burst history is described on a panel-by-panel basis.The analysis shows that where the mining depth exceeded 450 m, each design has been employed for about 38000 total m of longwall panel extraction. The double-use yield pillar design has been used primarily at depths less than 600 m, however, while the inter-panel barrier design has been used mainly at depths exceeding 600 m. Despite its greater depth of use, the inter-panel barrier gate design has been associated with about one-third as much face region burst activity as the double-use yield pillar design.