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.     

絮凝剂和溶剂对煤焦油净化效果的影响

研究煤焦油净化处理过程中絮凝剂和溶剂对净化效果的影响，确定一种无机絮凝剂为煤焦油净化处理最佳絮凝剂，其最佳用量为8％（絮凝剂／煤焦油），芳香族溶剂洗油的最佳用量为混合液的35wt％～45wt％，脂肪族溶剂煤油的最佳用量为混合液的20wt％～25wt％，净化澄清液QI含量在0．5％左右。     

共炭化对热缩聚及炭化工艺过程的影响

采用煤沥青闪蒸油为原料,乙烯残油为添加剂,在实验室内进行热缩聚及炭化实验。结果表明:加入添加剂后,缩聚沥青的平均分子结构得到改善,从而显著改善了针状焦的显微组织结构,同时具有良好的脱氮效果。     

Investigation of kinetics of agglomerate growth in oil agglomeration process

In this study, the kinetics of agglomerate growth in a batch oil agglomeration process has been studied using bituminous coal. The effect of operating variables such as kerosene concentration, pulp density and speed of agitation on the agglomeration process was investigated. It has been found that the second-order kinetic equation describes the growth of agglomerates adequately. The growth of the agglomerates in the oil agglomeration process shows a self-preserving growth. Using this, a characteristic curve has been developed. For the prediction of the size distribution of the agglomerates, the d₅₀ values of the agglomerates must be known. Therefore, a model has been developed by using the kinetic equation for estimation of d₅₀ values of agglomerates for this coal. It was shown that the size distribution of the agglomerates for any levels of the process variables studied can be predicted using the equation of characteristic curve and d₅₀ values. Knowledge obtained from this study will be helpful for technological advancement of this kind of study.     

Fate of the chlorine and fluorine in a sub-bituminous coal during pyrolysis and gasification

The fate of the chlorine and fluorine present in a sub-bituminous coal from Indonesia during pyrolysis and gasification has been studied with fixed and entrained bed reactors. The rate profile for HCl evolved in the temperature programmed pyrolysis exhibits the main and shoulder peaks at 480 and 600 °C, respectively. Model experiments and subsequent Cl 2p XPS measurements show that HCl reacts with metal impurities and carbon active sites at 500 °C to be retained as inorganic and organic chlorine forms, from which HCl evolves again at elevated temperatures. It is suggested that the HCl observed in the coal pyrolysis may originate from the above-mentioned chlorine functionalities formed by secondary reactions involving the nascent char. In the CO₂ gasification of the 900 °C char at 1000 °C and 2.5 MPa, any measurable amounts of HCl and HF could not be detected even at a high conversion of 75 wt% (daf), suggesting the accumulation of these halogens in the residual char. When the coal is injected into an O₂-blown, entrained bed gasifier at 1200-1400 °C under 2.6 MPa, the partial oxidation proceeds to a larger extent at a higher O₂/coal ratio, whereas the chlorine and fluorine are enriched in the remaining char, and the extent of the enrichment at the latter stage of gasification is larger with the fluorine. The XPS measurements of the chars reveal the presence of the broad F 1 s peak, which can cover a wide range of binding energies attributable to inorganic and organic fluorine. The halogen enrichment during gasification is discussed in terms of secondary reactions of HCl and HF with char.     

大浓度范围内PV型旋风分离器粒级效率的计算方法

探讨了旋风分离器入口含尘浓度对其分离性能及粒级效率的影响机理。对旋风分离器内部气固两相运动进行了相似分析,得到了包括入口含尘浓度在内的一系列影响分离性能的相似准数。通过相似试验及试验数据的多元回归分析,建立了各相似准数与粒级效率的关系,得出了能精确估计大浓度范围内PV型旋风分离器粒级效率的计算公式。     

Texaco与Shell煤气化工艺比较分析

煤气化技术对于促进煤炭的综合利用、改善当前资源紧缺状况,并减少环境污染具有重要的意义。阐述了Texaco和Shell煤气化的工艺流程,并对2种煤气化工艺进行了比较分析,找出各自的优缺点,为煤气化工艺的选择提供参考。     

DEVELOPMENT AND VALIDATION OF A PROCESS SIMULATOR FOR DRYING SUBBITUMINOUS COAL

Drying subbituminous coal has never been practiced commercially. The commercial dryers built to date have been designed for drying surface moisture in conjunction with upstream coal preparation facilities. This type of drying is mainly controlled by input energy and the basis of the design is an energy balance. In drying inherent moisture from subbituminous coal, the thermal conductivity of the coal and the diffusion of molecular water within coal particles impose limitations on the process conditions. Energy input and solids residence time in the dryer have to be controlled properly for simultaneously balancing the heat and mass transfer within the coal particles. Improper control of either parameter can cause fires and explosions during the key steps of the drying process—drying and cooling

In parallel to the Anaconda coal drying pilot plant program, a cross-flow, fluid-bed coal drying/cooling process simulator was developed for: (1) understanding the drying phenomena on an individual particle basis; (2) analyzing potential risks and safety limits, and (3) designing the Anaconda pilot plant program

The development of the process simulator was based on both first principles and laboratory data and can be divided into two phases:

1 Development of a semi-mechanistic drying model for Powder River Basin subbituminous coal employing an analytical solution of the diffusion equation

2.Formulation of a fluid-bed cross-bed cross-flow dryer/cooler simulator employing simultaneous heat and mass transfer

This model was validated against process variables data taken on a 4 tph pilot plant. An operable range, or process envelope, has been developed through the pilot plant experience and the process simulation study. Based on the model predictions, an uncertainly range was defined in the design recommendations of a pioneer coal drying plant in scale-up.     

Catalytic coal partial gasification in an atmospheric fluidized bed

The coal partial gasification catalyzed by limestone, sodium carbonate and dolomite was studied using a bench-scale atmospheric fluidized bed in the presence of air and steam at 900 °C. The effects of limestone, sodium carbonate and dolomite on composition, heating value, gas yield of product gas and carbon conversion in the catalytic coal partial gasification have been examined. The experimental results show that the catalysts can effectively improve the gas quality, the heating value and the gas yield of product gas and carbon conversion. The catalytic effect of sodium carbonate is better than that of limestone and dolomite. The increase of limestone loading can enhance the quality of product gas, such as the content of combustible gas, the high heating value and the gas yield, during coal partial gasification. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

A study of the properties of carbon foam reinforced by clay

A novel carbon foam with high strength and very low thermal conductivity was prepared by thermal treating of coal tar based mesophase pitch mixed with montmorillonite clay. SEM observation showed that less micro-cracking appeared on the cell wall of foam by adding of clay-montmorillonite. Foam mechanical properties were improved and its thermal conductivity was markedly decreased. The compressive strengths were increased by 64%, 96% and 100% when the additive amounts of clay were 2%, 5% and 10% (wt%), respectively. Due to the high thermal insulation and lamellar structure of clay, the thermal conductivity of carbon foam decreases from 2 W/m K to 0.25 W/m K.