Characterization of Thai limestone for desulphurization in a fluidized bed combustor

The objective of this study is to determine the chemical kinetics of desulphurization of Thai limestone in an atmospheric fluidized bed combustor (AFBC). The experiments, which employed the batch technique using the limestone samples from six major sources in Thailand, were performed in a laboratory‐scale AFBC. The results obtained were analysed and correlated in the form of apparent reaction rate and deactivation rate constants as a function of operating conditions of the furnace and their properties, respectively. The formulae derived from these correlations were kept as general as possible in order that they could be used as input parameters for the selected mathematical model of desulphurization in an AFBC that is suitable for practical use. The predicted results were in good agreement with the experimental data reported in the literature. Copyright © 2003 John Wiley & Sons, Ltd.     

石灰石在煤气化过程中的催化和固硫作用

基于CaO在煤气化中的催化和固硫作用,以及石灰石加热分解的性质,石灰石有可能作为煤气化过程中的催化剂和固硫剂。本文根据国内外对石灰石在煤燃烧和煤气化中作用的研究,从石灰石结构、Ca/C,Ca/S,可能的反应机理等几个方面进行了介绍和分析,并指出需进一步研究的内容。     

Chemical Reaction Engineering and Research and development of gas solid systems

A general procedure is proposed for innovative research and development of gas-solid reactor systems, with a brief explanation of the significance of each step in the procedureBased upon the contacting mode between gas and solid phases, as well as the ways of supplying thermal energy to the reacting regions, various types of gas-solid reactor systems are classified by using tables of so called “matrix” form, for thermal cracking and gasification of heavy oils, gasification of coal, gasification of solid waste, calcination of limestone, clinkering of cement and reduction of iron ore.The importance of fundamental concepts is emphasized for successful research and development by presenting several examples; namely, calcination of limestone, thermal cracking of heavy oils and gasification of solid waste materials.In connection with the direction in which fundamental research should be oriented, four primary ways of thinking are proposed, which can be applied to obtain innovative ideas for further research and development in this field.One example of the author's practical experience was selected to show the role of the fundamental research in the course of large scale development. Finally the author outlines the role of chemical reaction engineering to innovate the novel gas-solid reactor systems which may be inevitable for simultaneous solution of the three big E's; namely, Energy, Environment and Economy.     

基于表面反应和扩散迁移控制的灰岩单裂隙渗流—溶解模型及其数值模拟

针对碳酸盐类可溶岩地区水电站坝址流场、化学场以及固相介质属性等随时间发生改变,从而对工程安全运行造成不利影响等问题,研究了灰岩地区地下水运移过程中各物理场间的相互作用,分析了影响灰岩溶解速率的两个因素,即表面反应控制和扩散迁移控制。在此基础上,建立了单裂隙中的渗流—溶解耦合模型,并进行数值求解。模拟结果表明,在垂直裂隙延伸方向,其溶蚀锋面为非齐整平面,而是呈似“虫洞”状非均一变化,而沿裂隙延伸方向即自上游侧向下游方向溶蚀程度逐渐减轻;而通过裂隙的流量呈现随时间逐渐增大的趋势,但变幅不大;根据流量求得的等效水力隙宽,其增幅和增长速率均小于实际平均隙宽;同时,化学场中Ca2+浓度的分布与裂隙开度变化具有相似性,不同时刻下上游侧反应速率R均大于下游侧。就反应机制而言,在初期均受表面反应控制,而随反应进行,位于上游补给区部位转为受扩散迁移控制,但在下游位置仍受表面反应控制。     

水平切片解释方法在焦作井田构造复杂区的应用

河南焦作某矿地处焦作煤田东部,该矿东三盘区地质构造复杂,主采的2号煤层底板与L_8灰岩平均间距仅20m,与奥灰顶界面平均间距约100m,因此断层的存在极易导通奥灰水,形成较大的水患事故。故查明区内构造分布情况十分必要。本文重点介绍了用三维地震常规解释方法结合偏移及方差数据体水平切片解释方法在构造复杂区的应用情况,具有一定的推广意义。     

坝址区垂直温度场及其水文地质意义——以湖北溇水江坪河水电站为例

江坪河水电站坝址区钻孔内分层水温随埋深增大而上升,钻孔孔底水温17.16℃~19.83℃为所处河湾地块岩溶地下水代表性水温,钻孔顶面水温15.88℃~16.30℃与河水水温15.81℃相近,反映了坝址区河水位比下伏岩溶水位高,部分河水下渗补给下伏岩溶水。通过比较得出,左岸ZK17与右岸ZK19一线,河水对岩溶地下水下渗补给比下游ZK79、ZK36地段强烈。分层测温这种简单易行的研究分析方法对具有复杂水动力场的同类型岩溶峰丛峡谷建坝有一定参考意义。     

Effect of polycarboxylate-type superplasticizer on the paste fluidity based on the water film thickness of flocs

The excess water film theory and the properties of flocs are integrated to examine the effect of the polycarboxylate-type superplasticizer on the paste fluidity.The theory states that excess water can surround the flocs rather than the particles and that the cell consists of a floc and a superficial water film.Experiments on limestone powder pastes were conducted to verify the theory.The superplasticizer dosage(sp%)and the water–powder ratio by volume(Vw/Vp)were systematically varied.A sedimentation balance method was used to measure the size distribution of the flocs in the limestone powder pastes.The water film thickness(WFT)of flocs was then calculated and shown to determine the paste fluidity.Based on this WFT of flocs,the effect of the sp on the paste fluidity was determined and then compared with the effect of water.     

岩溶区排泥库工程地质勘察方法——以广西平果铝矿板下排泥库为例

排泥库为废弃泥存放和澄清场地，在岩溶区建库，有其特殊性，稍有不慎即造成环境污染，从平果铝矿板下排泥库营运中出现的环境污染（砂泥泄漏，排水通道填塞造成洪涝，矿泥渗漏等）问题的原因分析入手，提出了岩溶区排泥库勘察工作要点，报告书应重点分析和评价的内容，库区岩溶发育规律，渗漏治理措施，坝肩及排水隧道进出口破碎其岩的处理措施。     

饱水石灰岩骨架和流体弹性参数的估算

本文利用Niu等提出的基于临界孔隙度模型的组分弹性参数数值计算方法,把测试岩石样品的孔隙度、整体密度、纵波速度和横波速度作为数值计算的输入数据,运用双线性数值计算方法反演求出临界点、流体和骨架的12个弹性参数。具体做法是:基于临界孔隙度模型,给出三组线性关系,即密度—孔隙度,整体剪切模量—孔隙度,整体纵波模量—孔隙度,上述每组线性关系分别以孔隙度作为自变量和因变量得到两个线性方程,再把两个方程计算的结果进行加权平均得到相关的弹性参数估算值,并结合饱水石灰岩样品数据实现了弹性参数估算。数值计算结果表明,由数值计算得到的弹性参数与测试弹性参数的均值和方差相差甚微,特别是密度数据的偏差均值更小,说明文中的数值计算结果是可靠的。     

不同孔隙类型礁灰岩模型微观水驱渗流实验

为了更好地了解礁灰岩储层中的流体在微观渗流过程中的渗流规律和分布特征,文中以流花油田D5P1井为例,利用礁灰岩岩心制作了岩心薄片模型,采用可视化技术微观模拟水驱油过程,并选取具有代表性的4种孔隙类型进行对比分析研究。实验观察发现,裂缝方向与微观流体渗流和剩余油的分布密切相关,孔洞的存在有利于提高岩心采收率,在驱替结束时基质中普遍存在大量的剩余油。这些发现为该油田下一步进行注水开发提供了参考依据。