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CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2016年第35卷第8期·2426·化 工 进 展典型气流床煤气化炉气化过程的建模东赫1，刘金昌1,2，解强1，党钾涛1 ，王新1（1中国矿业大学(北京) 化学与环境工程学院，北京 100083；2九州大学电子和材料应用科学系，日本 福冈春日 816-8580 ）摘要：利用Aspen Plus 、基于热力学平衡模型对GSP 煤粉气化炉、GE 水煤浆气化炉及四喷嘴对置式水煤浆气化炉的气化过程建模。
根据煤颗粒热转化的历程，将煤气化过程划分为热解、挥发分燃烧、半焦裂解及气化反应4个阶段，利用David Merrick 模型计算热解过程，采用Beath 模型校正压力对热解过程的影响，选用化学计量反应器模拟挥发分燃烧反应，编制Fortran 程序计算半焦裂解产物收率，最后基于Gibbs 自由能最小化方法计算气化反应。
结果表明，采用建立的气流床气化过程模型模拟工业气化过程的结果与生产数据基本吻合，对GSP 煤粉气化炉、GE 水煤浆气化炉及四喷嘴对置式水煤浆气化炉等3种气化炉有效气成分（CO+H 2）体积分数模拟结果的误差均不超过2%，建立模型的可靠性得到验证。
关键词：气流床气化炉；热力学平衡模型；Aspen Plus中图分类号：TQ 546 文献标志码：A 文章编号：1000–6613（2016）08–2426–06 DOI ：10.16085/j.issn.1000-6613.2016.08.19Modeling of coal gasification reaction in typical entrained-flow coalgasifiersDONG He 1，LIU Jinchang 1，2，XIE Qiang 1，DANG Jiatao 1，WANG Xin 1（1School of Chemical and Environmental Engineering ，China University of Mining and Technology （Beijing ），Beijing 100083，China ；2Department of Applied Science for Electronics and Materials ，Kyushu University ，6-1 Kasuga-Koen ，Kasuga ，Fukuoka 816-8580，Japan ）Abstract ：This paper presents a modeling method for the coal gasification process proceeding in GSP pulverized coal gasification ，GE coal-water slurry gasification and Opposed Multiple-Burner gasification based on the thermodynamic equilibrium with the aid of Aspen Plus. In the light of thermal conversion procedure of fine coal particles ，the coal gasification was interpreted as consisting of four stages including pyrolysis ，volatile combustion ，char decomposition and gasification reaction. Then ，the pyrolysis stage was calculated by the David Merrick model and the effect of pressure on the coal pyrolysis was corrected by means of Beath model. The volatile combustion stage was simulated by using Rstoic reactor and the yield of char decomposition products was calculated via compiling Fortran program. And finally ，the gasification reaction stage was simulated based on the Gibbs free energy minimization. The results revealed that the simulated values from the developed simulation model of gasification processes were in good consistent with the industrial field data. The deviation of simulated results of volume fraction of the effective gas (CO+H 2) of these three typical entrained-flow gasifiers were all less than 2%，which can validate the reliability of the coal gasification model.第一作者：东赫（1991—），女，硕士研究生。
网络出版时间：2012-10-22 11:28网络出版地址：/kcms/detail/11.1759.TS.20121022.1128.006.html闪式提取法提取枣果皮中多酚的工艺研究张迪1，王勇1，王彦兵1,3，刘绣华1,2*（1.河南大学化学化工学院环境与分析科学研究所，河南开封，475004；2.河南大学化学生物学研究所，河南省天然药物与免疫工程重点实验室，河南开封，4750043.河南福森药业有限公司，河南淅川，474405）摘要：利用闪式提取法提取枣果皮中的多酚。
考察了乙醇体积分数、料液比、提取时间和提取次数对枣果皮中多酚得率的影响，根据考察结果运用正交实验方法对影响多酚得率的条件进行优化，然后进行验证实验。
结果表明，最佳提取工艺条件为：乙醇体积分数为60%，料液比1∶35（g/mL），提取时间为2min，提取3次，在此条件下，多酚得率达到13.62mg/g。
该工艺与超声波提取相比，简单，迅速，得率高，可用于枣果皮中多酚的提取。
关键词：枣果皮，多酚，闪式提取法，正交实验Study on extraction of polyphenolics from Zizyphus Jujube peel by flashextractionZHANG Di1, WANG Yong1, WANG Yan-bing1,3 , LIU Xiu-hua1,2*(1. Institute of Environmental and Analytial Science , College of Chemistry and Chemical Engineering, HenanUniversity, Kaifeng 475004, China;2. Institute of Chemical Biology of Henan University, Key Laboratory of Natural Medicine andImmuno-Engineering of Henan Province, Kaifeng 475004, China;3. Henan Fusen Pharmaceutical Co., Ltd., Xichuan 474405, China)Abstract: The flash extraction method was employed to extract polyphenolics from Zizyphus jujube peel. The effects of single factor of ethanol volume fraction, ratio of raw material to liquid, extraction time, extraction times on the extract rate of polyphenolics were investigated. The orthogonal experiment was conducted on the base of the single factor experiment, and then the verification test and comparative experiments were also conducted. The results showed that the optimum extraction conditions were as follows: volume fraction of ethanol of 60%, ratio of raw material to liquid of 1∶35 (g/mL), extracting three times, and each for 2min. Under such conditions, the yield of polyphenolics was 13.62 mg/g. Compared with the ultrasonic extraction, the proposed method is simple and fast with high extraction efficiency, which can be used to extract polyphenolics from Zizyphus jujube peel.Key words: Zizyphus jujube peel; polyphenolics; flash extraction; orthogonal experiment中图分类号：TS201.1献标识码：A 文章编号：枣(Zizyphus jujube dates)，又名大枣、华枣，是鼠李科枣属植物枣树的果实[1]，在我国已有四千多年的种植历史。
第49卷第11期 当 代 化 工 Vol.49，No.11 2020年11月 Contemporary Chemical Industry November，2020基金项目：国家重点研发计划资助项目(项目编号：2018YFB0604803)。
收稿日期：2020-07-06作者简介：黄晓凡（1983-），男，安徽省合肥市人，高级工程师，工学硕士，研究方向：现代煤化工、C 1化学和工业催化等。
E -mail：************************。
由煤炭制取芳烃技术进展黄晓凡，汤效平，崔宇，王兹尧，王彤（华电电力科学研究院有限公司，杭州 310030）摘 要： 介绍国内外煤炭低温热解、煤炭加氢液化、合成气制芳烃、煤基甲醇芳构化、甲苯甲醇烷基化等几种由煤炭转化制取芳烃的技术路线。
比较各种技术路线的原料转化、产物组成和目标产物收率等差异。
从大规模工业化的角度出发，分析各种技术存在的问题，并对未来重点研发方向提出建议。
指出煤炭制取芳烃产品，应走绿色、清洁、高效的转化路线，以高附加值化学品为终端产物，甲醇制芳烃技术具有甲醇转化率高、芳烃收率高的优点，是目前适合大型工业化的技术路线。
关 键 词：芳烃；煤制芳烃；甲醇制芳烃；合成气制芳烃；加氢液化；烷基化中图分类号：TQ536 文献标识码： A 文章编号： 1671-0460（2020）11-2615-06Advances in Coal to Aromatics TechnologyHUANG Xiao-fan , TANG Xiao-ping , CUI Yu , WANG Zi-yao , WANG Tong（Huadian Electric Power Research Institute Co., Ltd., Hangzhou Zhejiang 310030, China ）Abstract : Several domestic and foreign technical routes of coal to aromatics were introduced, such as low-temperature pyrolysis of coal, coal hydro-liquefaction, synthesis gas to aromatics, coal-based methanol aromatization, alkylation of toluene with methanol. The differences of raw material conversion, product composition and target product yield were compared. From the perspective of large-scale industrialization, the problems of these technologies were analyzed, and suggestions for the future research were put forward. It was pointed out that the conversion route of coal to aromatics should be green, clean and efficient, taking high value-added chemicals as the end product. The methanol to aromatics technology has the advantages of high conversion rate of methanol and high yield of aromatics, which is suitable for large-scale industrialization.Key words : Aromatics; Coal to aromatics; Methanol to aromatics; Syngas to aromatics; Hydro-liquefaction; Alkylation芳烃是一类含有苯环的碳氢化合物，是关系国计民生的重要有机化工原料，其中的“三苯”，即苯（B）、甲苯（T）、二甲苯（X），在医药、合成材料、印染、纺织等众多行业有着广泛应用，其生产规模仅次于乙烯和丙烯。
工程科学学报，第 43 卷，第 1 期：58−66，2021 年 1 月Chinese Journal of Engineering, Vol. 43, No. 1: 58−66, January 2021https:///10.13374/j.issn2095-9389.2020.06.29.001; 磨矿和浮选过程中黄铁矿电化学行为的研究进展龚志辉，戴惠新✉，路梦雨，武立伟，赵可可昆明理工大学国土资源工程学院，昆明 650093✉通信作者，E-mail：***************摘 要 综述了黄铁矿在选矿过程中有关的电化学行为及工作机理，重点讨论了黄铁矿结构特性、溶液中氧化、金属离子作用和抑制剂对黄铁矿电化学行为的影响；此外，还讨论了磨矿过程中电偶相互作用、研磨介质形状、介质材料和研磨气氛对研磨中黄铁矿电化学行为的影响.其中黄铁矿晶体结构的不同对黄铁矿表面的氧化具有较大影响，从而间接的影响黄铁矿的可浮性，半导体性质对黄铁矿的导电率具有显著的影响；同时适度的氧化有利于黄铁矿的无捕收剂浮选，而强烈的还原电位或氧化电位会抑制黄铁矿的浮选；电位的增加，对铜活化黄铁矿有不利影响，主要原因是电位增加导致活化Cu+的浓度降低，同时黄铁矿表面被铁氧化物覆盖阻碍了铜离子的吸附.抑制剂的加入可以直接参与捕收剂与黄铁矿之间的氧化还原反应，从而抑制黄铁矿的浮选；同时磨矿介质及气氛条件的不同也会影响黄铁矿电化学行为.关键词 选矿；黄铁矿；研磨；浮选；电化学分类号 TD952Research progress in the electrochemical behavior of pyrite during grinding and flotationGONG Zhi-hui，DAI Hui-xin✉，LU Meng-yu，WU Li-wei，ZHAO Ke-keFaculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China✉Correspondingauthor,E-mail:***************ABSTRACT Metal sulfides are highly desirable owing to their semiconductor properties promoting electrochemical reactions for sulfide flotation. As the most common sulfide mineral, pyrite is found in coal and can contain a small amount of gold. The potential of electrochemical reactions for the beneficiation of pyrite makes it necessary to study its electrochemical behavior. The present work focuses on the electrochemical behavior and working mechanisms of pyrite in mineral processing. The effects of the structural characteristics of pyrite, oxidation in solution, the presence of metal ions, and inhibitors on the electrochemical behavior of pyrite were discussed emphatically. The effects of galvanic interaction and grinding medium shape, material, and atmosphere on the electrochemistry of pyrite in grinding were also discussed. It has been shown that the different crystal structures and semiconductor properties of pyrite can greatly influence the oxidation of its surface, which indirectly affects its floatability. Moreover, moderate oxidation conditions are beneficial to the collector-free flotation of pyrite, whereas strong reduction or oxidation potentials inhibit its flotation. It has also been shown that increase in potential and iron oxide on the pyrite surface lead to the decrease in the concentration of copper (Cu+) ions, thereby adversely affecting the activation of pyrite by copper. Furthermore, inhibitors can directly participate in the redox reaction between the collector and pyrite, thus inhibiting the flotation of pyrite. Different grinding media and atmosphere conditions also affect the electrochemical behavior of pyrite.KEY WORDS mineral processing；pyrite；grinding；flotation；electrochemical收稿日期: 2020−06−29基金项目: 国家自然科学基金资助项目（51764023）黄铁矿（FeS 2）是自然界最常见的硫化矿物.通常与闪锌矿、黄铜矿、方铅矿、金和煤等有价值的矿物共伴生[1−2]. 黄铁矿的经济价值低，通常被作为脉石矿物处理，黄铁矿进入有价值的精矿中会导致精矿品位降低，同时在冶炼过程中会产生大量的硫化气体，造成环境污染[3]. 天然黄铁矿在厌氧环境中是疏水的，因此常用浮选的方法选别.然而当黄铁矿长时间暴露于大气或水性条件下时，黄铁矿表面会被氧化从而降低其疏水性[4−5].大多数金属硫化物具有半导体特性，硫化矿物浮选取决于发生的电化学反应[6]. 黄铁矿浮选过程中发生的各种现象，如氧化引起的黄铁矿表面化学变化、黄铁矿与其他组分的相互作用、捕收剂的吸附和其他金属离子在黄铁矿表面的沉淀，通常都是由电化学机制引起的[7−9]. 影响电化学反应的主要因素是矿物/溶液界面的电化学势，该电位是一种混合电位，其中发生在矿物表面的阳极反应和阴极反应的速率完全相等，该电化学反应不仅控制着矿物在浮选过程中表面物种的形成，还抑制其表面物种的形成[10−11]. 因此电化学反应机理的研究对黄铁矿的浮选研究具有重要的意义. 本文综述了黄铁矿在选矿过程中有关的电化学行为及工作机理，重点讨论了黄铁矿结构、溶液氧化、离子活化和抑制剂对黄铁矿电化学行为的影响. 此外，还讨论了磨矿过程中研磨介质形状、介质材料和研磨气氛对研磨中黄铁矿电化学行为的影响. 并对今后的研究思路和方向进行了展望.1 黄铁矿晶体性质1.1 黄铁矿晶面特性黄铁矿的晶体类型众多，对黄铁矿晶体研究表明，大多数天然黄铁矿主要有三个解离面，分别为{100}，{210}和{111}，这三个晶面的比例为224∶42.8∶1[12−14]. 一些研究表明，黄铁矿的反应活性在晶体方向上是特定的. Zhu 等[15]研究了黄铁矿晶体结构对黄铁矿表面氧化的影响. 结果表明，在潮湿的空气中，黄铁矿{111}和{210}的初始氧化速率均大于黄铁矿{100}；在干燥的空气中，黄铁矿{210}的初始氧化速率大于黄铁矿{111}的初始氧化速率；在潮湿的空气中，黄铁矿{111}的初始氧化速率最大；同时{111}是黄铁矿氧化最敏感的面. 黄铁矿氧化相关反应如图1所示. 这些研究的发现明确了黄铁矿的晶面与反应活性的关系，不仅对黄铁矿氧化机理有了新的认识，也为发生在矿物-水界面的其他界面反应提供参考.S O 42−S O 32−/S 2O 32−+H +S 22−Fe 3+Fe 2+O 2ee e+H 2OPyrite①①S 22−−e (to Fe 3+)+H 2O → S O 32−/S 2O 32−+H +S O 32−/S 2O 32−+O 2→S O 42−②②③③④④Oxidation routeFe 2+−e (to O 2) → Fe 3+H 2OFe 3++e (from S 22−) → Fe 2+H 2O 图 1 黄铁矿空气中氧化反应路线图Fig.1 Mechanisms of pyrite oxidation in airXian 等[16]对纯黄铁矿、砷取代黄铁矿、钴取代黄铁矿和晶间金黄铁矿四种类型的黄铁矿进行了浮选研究. 浮选结果表明，钴取代黄铁矿和晶间金黄铁矿的可浮性随矿浆充气时间的延长而增加，而纯黄铁矿和砷取代黄铁矿的可浮性随矿浆充气时间的延长而降低. 通过电子结构和能带结构研究发现黄铁矿的稳定性受晶格缺陷和电子结构的影响，所观察到的浮选行为差异是由于黄铁矿的稳定性和氧化强度不同所致.1.2 半导体特性黄铁矿具有高电子迁移率和高光吸收系数，是一种潜在的光伏吸收材料. 然而天然黄铁矿的半导体性质存在较大的差异，从而影响了黄铁矿的电化学反应[17]. Abratis 等[18]综合评述了黄铁矿的半导性，发现已报道的电导率相差四个数量级.根据地质条件的不同，天然黄铁矿既可以作为n 型半导体存在，也可以作为p 型半导体存在. 在较高温度下形成的黄铁矿通常具有n 型特征，而在较低温度下形成的黄铁矿通常为p 型. 使用n 型黄铁矿作为微电极在混合硫化物矿物矿浆中（不考虑动力学因素），具有较高静息电位的黄铁矿将成为阴极，而更具活性的硫化物将成为阳极.龚志辉等： 磨矿和浮选过程中黄铁矿电化学行为的研究进展· 59 ·但是，所产生的阳极硫化物优先溶解的速率将取决于由杂质或半导体类型引起的黄铁矿静止电位的变化.Savage 等[19]研究发现，杂质元素Co ，As 对黄铁矿半导性具有较大的影响. 富含Co 的黄铁矿是具有低电阻率和高载流子迁移率的n 型半导体，而砷黄铁矿倾向于p 型且具有较高的电阻率. 硫化矿物与捕收剂之间相互作用的差异是由矿物表面不同的半导体特性引起的. 与n 型半导体相比，p 型半导体对黄药的吸附更为有益.2 浮选中黄铁矿电化学行为2.1 黄铁矿在矿浆中的氧化黄铁矿在水溶液中通过电化学反应被氧化，氧化速率受溶液pH 、溶液电位值、氧化剂种类和浓度、粒径、温度、搅拌速度等多种因素的影响.由于铁硫比、晶体结构和表面形态不同，导致黄铁矿表现出不同的电化学反应活性. 黄铁矿在氧化过程中通常是不完全氧化，除亚铁离子和硫酸根离子外，还生成了单质硫. 亚铁离子进一步反应生成的氢氧化铁沉淀附着在黄铁矿表面，并抑制黄铁矿的进一步氧化[20−22].矿浆中溶解氧含量对矿浆电位变化和黄铁矿亲水性表面的生成有一定影响. Owusu 等[23]通过需氧量试验和泡沫浮选，研究了两种黄铁矿矿物的电化学反应活性及其对黄铜矿浮选的影响. 通过氧化还原电位（E h ）、溶解氧（DO ）、pH 等参数控制矿浆化学，可显著提高硫化矿物的浮选回收率、品位和选择性. 需氧量测试表明，不同黄铁矿的电化学反应活性有明显差异. 此外，矿浆的持续充气降低了黄铁矿的氧化速度. 溶液和表面分析结果表明，随着充气的进行，黄铁矿表面会形成氢氧化物表面涂层，防止或最大限度地减少黄铁矿进一步被氧化反应. 图2显示了25 ℃下黄铁矿电化学势与pH 的关系[24].S 2−2S 2−2S 2−n 硫的氧化行为的研究对于理解黄铁矿的氧化非常重要，但是在不同的溶液条件下，各种中间的硫氧化产物会使其复杂化. Chandra 和Gerson [25]研究表明在新鲜破碎的黄铁矿表面存在四种不同的硫：（体相）（4配位）、（表面）（3配位）、S 2−和S 0/（分别为缺金属硫化物和多硫化物）.这些硫在破碎的黄铁矿表面呈不均匀分布. 当O 2解离和H 2O 分子吸附到存在高密度悬挂键的表面Fe 位时，开始氧化. 同时H 2O 可能会解离产生OH 自由基. 研究表明，Fe−O 键先于Fe−OH 键SO 2−4O 2−3S 2−3形成. S 的氧化是通过Fe 位上形成的OH 自由基的相互作用进行的，而的形成是通过S 2/中间体进行的. 从而进一步证明黄铁矿的氧化过程本质上是电化学的过程.S 2−n Tu 等[26]研究了黄铁矿在pH 为2的电解液中的电化学氧化机理. 研究表明在0.50 V 的低电位下，黄铁矿表面形成并覆盖一层富硫层（S 0）使得黄铁矿表面钝化，从而造成黄铁矿电化学氧化扩散受限. 当电位增加到0.60 V 时，由于无定形单质硫转化为晶态，黄铁矿氧化的扩散限制和表面钝化停止，导致先前被覆盖的活性位重新暴露，从而造成黄铁矿继续氧化. 在较高电位（0.70 V 和0.80 V ）下，在黄铁矿表面形成并积累了较多的单质硫和多硫化物（），以及由Fe(OH)3、FeO 和Fe 2O 3组成的富铁层，这些产物导致了氧化速率降低. 表面粗糙度随氧化电位的增加而增加，黄铁矿表面的氧化是不均匀的. 这些发现进一步揭示了黄铁矿在电化学氧化过程中所经历的物理和化学变化.Tao 等[27]对表面氧化的黄铁矿进行了无捕收剂泡沫浮选试验. 在原位断裂电极上进行的计时安培分析表明，在pH 为9.2时，表面氧化的黄铁矿电位为−0.28 V （SHE ），在pH 为4.6时为0 V. 在稍高的正电势下进行初始氧化会生成疏水性富硫物质，最有可能是多硫化物或缺乏金属的硫化物，从而使黄铁矿表面具有疏水性. 无捕收剂的浮选试验结果表明，黄铁矿在表面氧化后具有较好的可浮性. 黄铁矿的无捕收剂浮选回收率取决于氧化过程中产生的多硫化物，可溶物和不溶物的相对量，这取决于溶液的pH 值和电位.2.2 不同金属离子对黄铁矿的影响2.2.1 铜离子对黄铁矿的影响活化是硫化物浮选过程中最常用的方式之一，SO 42−SO 42−Fe(OH)3Fe(OH)2Fe 2++2SFe 2++H 2SFe+H 2SFeS+H 2SFe+HS −FeS+HS −Fe FeS 2F e (O H )2+F e (O H )2+Fe 3+pH02468101214图 2 25 ℃下FeS 2–H 2O 体系E h –pH 图Fig.2 E h –pH diagram for the FeS 2–H 2O system at 25 ℃· 60 ·工程科学学报，第 43 卷，第 1 期在这个过程中金属离子沉淀或吸附在矿物表面，为捕收剂的吸附创造合适的位点. 在碱性溶液中黄铁矿可被铅离子和铜离子活化.Owusu 等[28]使用黄铜矿和黄铁矿组成的混合矿物体系，研究了黄铁矿对矿浆化学和黄铜矿回收率的影响. 浮选试验表明，随着黄铁矿含量的增加，黄铜矿的可浮性、回收率、品位和矿浆氧化电位降低，而黄铁矿回收率增加.Peng 等[29]在pH 值为9的条件下，以不同的电化学势测量了铜离子的浓度. 研究发现铜离子的浓度在很大程度上取决于电化学势. 在−185 mV 的电势下，溶液中几乎所有的铜都以亚铜离子的形式存在，而在−10 mV 的电势下，溶液的铜质量分数降低到28%；电位为+260 mV 时，溶液中亚铜离子不存在. 在−10 mV 和+260 mV 范围内，几乎所有的铜都以Cu(OH)2的形式析出；而在−185 mV 的电位下，只有少量铜以Cu(OH)2的形式析出. 因此，提高矿浆的电化学电位可以增加Cu(OH)2的生成，降低Cu +在黄铁矿表面的浓度. 由于铜离子活化黄铁矿强烈依赖于Cu(I)−硫化物的形成，因此在还原条件下更有利于黄铁矿活化.S 2−n S 2−2Chandra 等[30]用光发射电子显微镜（PEEM ）分析研究了弱酸性条件下铜离子活化黄铁矿. 研究发现Cu 以Cu +形式吸附在黄铁矿表面. 与未活化黄铁矿相比，活化黄铁矿中存在较多的和S−OH ，较少的S 2−和. 这一现象是由于O 2/H 2O 的存在和铜离子在黄铁矿表面吸附而引起的氧化，并证实了离子交换、铜离子还原和硫氧化是同时进行的.综上，电势的增加对铜离子活化黄铁矿具有不利的影响. 主要有以下三个原因：一是电势的增加加快了Cu(I)到Cu(II)的氧化速率，结果导致用于活化的Cu(I)离子浓度降低；二是在高电势下，黄铁矿被氧化形成氧化铁/氢氧化物薄膜阻碍了亚铜离子与黄铁矿的作用；三是已经作用在黄铁矿表面的亚铜离子在高电势的作用下形成了亲水性碳酸铜/铜羟基物质影响了活化效果.2.2.2 铅离子对黄铁矿的影响在方铅矿和黄铁矿的电偶中，方铅矿充当阳极，黄铁矿充当阴极，通过电流作用将硫离子从方铅矿中氧化为元素硫，并将溶解的氧还原为氢氧根离子. 在没有捕收剂仅方铅矿存在的情况下，黄铁矿可表现出较强的可浮性. Peng 等[29]对铅活化黄铁矿进行了ζ电位测量，发现铅活化黄铁矿在不同的电化学电位下表现出相似的ζ电位性质. 铅活化的黄铁矿具有类似于氢氧化铅、氧化物或碳酸盐的等电点. 另一方面，在活化过程中加入的铅离子几乎都可以用乙二胺四乙酸溶液提取. 这些发现显然表明，铅对黄铁矿的活化主要是通过形成铅表面络合物如氢氧化物来实现的.2.2.3 铁离子对黄铁矿的影响铁离子和溶解氧在黄铁矿氧化过程中起着至关重要的作用，黄铁矿氧化过程可看作是黄铁矿，铁离子与氧之间的一系列反应. Liu 等[31]研究了Fe 3+对黄铁矿电化学行为的影响. 结果表明，三价铁在黄铁矿的溶解中起重要作用，黄铁矿电极的开路电势随Fe 3+浓度的增加而增加；Tafel 极化曲线表明，Fe 3+浓度的增加引起了黄铁矿电极极化电流的增加.黄铁矿的氧化是在黄铁矿电极和电解质界面发生的，并且在氧化过程中形成了由元素硫、多硫化物组成的钝化膜. 黄铁矿电极的极化电流随着Fe 3+浓度的增加而增加.2.2.4 金对黄铁矿的影响金常与黄铁矿伴生，以细小包裹体形式赋存于黄铁矿基质中，从而导致金不能被浸出剂浸出.为了使金能够被浸出剂浸出，通常需要通过氧化剂对黄铁矿基质进行强化氧化，然后释放出金颗粒.Huai 等[32]研究了金耦合对黄铁矿被铁离子氧化后的表面性能的影响. 研究表明，金可以催化三价铁还原，金的耦合显著促进了黄铁矿的氧化，在黄铁矿表面形成更多的铁氧化物. 同时，金的耦合还使黄铁矿的比表面积变的更粗糙、更大，从而提高黄铁矿氧化溶解的电化学活性.2.3 抑制剂对黄铁矿的影响2.3.1 无机抑制剂黄铁矿的无机抑制剂种类众多，通过电化学反应影响黄铁矿可浮性的主要有氰化物、硫化物和硫氧化物. 氰化物对黄铁矿浮选的抑制可能有以下几种机制[33−35]：在非离子活化条件下，当黄药存在时，主要是形成不溶性硫氰酸盐络合物取代了双黄药吸附位；当无捕收剂时，氰化物在黄铁矿表面的吸附导致形成不溶性的铁氰化物，使黄铁矿表面亲水性；在铜离子活化条件下，主要是通过降低矿浆铜离子含量，并形成铜氰化合物抑制黄药的吸附. Janetski 等[36]使用伏安法研究了氰化物抑制黄铁矿时对黄药的影响. 结果表明在黄原酸盐浓度和pH 恒定的情况下，氰化物离子浓度的增加会导致黄原酸盐的氧化电势向更正值移动. 氰化物离子对黄药的氧化过程具有抑制作用. 同时还发现在恒定的黄原酸酯浓度下，随着氰化物离龚志辉等： 磨矿和浮选过程中黄铁矿电化学行为的研究进展· 61 ·子浓度的增加，黄原酸酯氧化电位的阳极位移随着溶液pH 的降低而逐渐降低.由于氰化物有剧毒，硫化物作为替代物被广泛应用，硫化物、亚硫酸盐和硫酸盐的抑制机理主要是消耗溶液中的氧气，降低了溶液的混合电位，从而阻止了双黄药在黄铁矿表面的吸附. Janetski 等[36]通过伏安法研究了硫化钠如何抑制黄铁矿的浮选，并发现硫化钠的存在引入了新的阳极反应.相对于黄原酸盐氧化，新的阳极反应归因于溶解的硫化物（S 2−或HS −）在阴极电位下发生氧化. 硫化钠消耗了氧气并降低了混合电位，从而阻止了双黄药的生成和黄铁矿浮选. Khmeleva 等[37]研究了亚硫酸盐对黄铁矿浮选的影响. 结果发现，在有空气的情况下，黄铁矿表面上会形成多种氧化产物，亚硫酸盐可以在溶液中与黄铁矿和捕收剂相互作用. 亚硫酸盐的存在消耗了溶液中溶解的氧气，从而导致矿浆电位下降. 2.3.2 有机抑制剂无机抑制剂虽然有效，但对环境有害，并在处理过程中会造成额外费用. 有机抑制剂具有来源丰富、可生物降解和相对便宜等优点. 黄铁矿的有机抑制剂主要有羧甲基纤维素（CMC ），木质素磺酸盐. 由于聚合物结构复杂和矿物表面的非均质性，聚合物与矿物表面之间的相互作用非常复杂. 但可以简单的解释为有机抑制剂与黄铁矿矿物表面的吸附或结合，如图3所示[35]. 一是有机抑制剂与黄铁矿表面带相反电荷，二者之间存在静电吸引；二是有机抑制剂的非极性链段与矿物表面疏水区域之间的疏水相互作用驱动抑制剂聚集在矿物表面；三是羟基或羧基与矿物表面水合金属位点之间相互作用形成氢键，特别是在碱性pH 值下；四是阴离子官能团（如羧基或磺酸基团）与矿物表面的金属阳离子之间形成化学键驱动有机聚合物与矿物表面结合[38−39].(1) Electrochemical attraction(3) Hydrogen bonding(4) Chemical interaction(2) Hydrophobic interactionHydrophobic carbon chainHydrophobic sitesPyrite surfaceH HC C OHHO H HH H H OH OH O OO OH COOHOHHOH HHOMeMeMeMeC CC C C C C O OOH++图 3 有机聚合物与黄铁矿矿表面可能的相互作用机制：静电吸附（1），疏水相互作用（2），氢键（3）和化学相互作用（4）Fig.3 Possible interaction mechanisms of organic polymers with pyrite surface: electrochemical attraction (1), hydrophobic interaction (2), hydrogen bonding (3), and chemical interaction (4)羧甲基纤维素（CMC ）是通过醚化过程产生的纤维素衍生物. 与天然多糖相比，CMC 结构中带负电荷的羧基和羟基的存在增加了CMC 的选择性. 与羟基不同的是，羧基能够与各种形式的金属物种相互作用，而羟基只能与金属羟基物种相互作用. Bicak 等[40]研究了高取代度和低取代度两种CMC 对黄铁矿的抑制效果. 研究表明，低取代度的CMC 比高取代度的CMC 抑制效果更好，主要是因为低取代度的CMC 自身负电荷较少，与黄铁矿表面的静电斥力较小，CMC 能更多的吸附在黄铁矿表面. 同时溶液中的pH 可以通过对羧基的解离、矿物表面羟基化及矿物表面电荷影响，从而影响CMC 在黄铁矿表面的吸附. 钙离子的存在可以增强CMC 在黄铁矿表面的吸附和抑制能力. 通过Zate 电位测定表明，Ca(OH)+在黄铁矿表面的吸附降低了黄铁矿表面的电负性，从而减小了CMC 与黄铁矿之间的静电排斥力. 除了静电作用外，黄铁矿表面的氢氧化物与CMC 的羟基和羧基之间形成氢键，从而抑制黄铁矿.木质素磺酸盐或磺化木质素可用作黄铁矿抑制剂. 对非活化黄铁矿浮选的电化学研究表明，生物聚合物吸附在黄铁矿表面后，使黄铁矿表面钝化，抑制了黄铁矿表面发生的电化学反应，包括黄铁矿自身的氧化还原反应和黄药在表面的氧化[35].Mu 等[41]比较了三种木质素磺酸盐聚合物（DP-1775，DP-1777和DP-1778）的抑制表现，研究表明生物· 62 ·工程科学学报，第 43 卷，第 1 期聚合物的分子量决定了其在黄铁矿表面的吸附密度，分子量越高，导致吸附能力越高，黄铁矿的抑制程度也更高.Mu等[42]通过电化学技术研究了在戊基黄原酸钾（PAX）和木质素磺酸盐类生物聚合物抑制剂（DP-1775）存在下黄铁矿表面性质的变化，对黄铁矿进行了电阻抗光谱法和循环伏安法测试.发现在不存在PAX的情况下，DP-1775不连续地分布在黄铁矿表面上并逐渐钝化黄铁矿表面；在PAX存在的情况下，预吸附的DP-1775降低了PAX的电化学氧化程度.3 研磨对黄铁矿电化学性能的影响3.1 电偶相互作用的影响磨矿对矿物/溶液界面的电化学势有很大影响，在磨矿过程中黄铁矿与磨矿介质之间存在电子相互流动，这种作用被称为电偶相互作用[29].不同电化学反应引起的电偶相互作用可以通过矿物的静息电位来预测，静息电位决定了不同硫化矿的电化学反应[43].在电偶相互作用中，黄铁矿由于具有较高的静息电位而表现出阴极的作用，从而导致其表面的氧还原和氢氧离子的产生.充当阳极的研磨介质被氧化并释放出亚铁离子.生成的亚铁离子进一步氧化成铁离子，然后与氢氧化物离子反应，以氢氧化铁的形式沉淀在黄铁矿表面，同时磨矿介质中产生的氧化铁物种对抑制黄铁矿浮选有重要作用[44]，反应如下：阳极氧化：阴极还原：水解：Huang等[45]使用低碳钢作为磨矿介质研究了黄铁矿与介质的电偶作用及对浮选的影响.研究表明，低碳钢和黄铁矿之间的电流取决于极化行为、几何关系和研磨环境.低碳钢与黄铁矿的比表面积对低碳钢的电偶电流密度影响较大，同时溶解氧在电偶电流中起着显著的作用.研磨过程中研磨介质氧化产生的可被乙二胺四酸（EDTA）提取的铁含量与低碳钢上的电流密度成线性关系.电流与铁氧化物种的数量和黄铁矿的还原速率有关.溶解O2与硫化物反应、研磨介质的腐蚀和电相互作用降低了溶解的O2浓度.由于溶解O2的减少阻碍了黄药在硫化物矿物表面的吸附，从而抑制了这些矿物的浮选.3.2 研磨介质的形状及材料在矿石粉碎过程中会涉及到许多不同变量，例如研磨介质的形状和材料可能会对所产生颗粒的性质产生重大影响.研磨介质和硫化物矿物之间的电流相互作用产生的铁氧化物质对矿物浮选具有抑制作用.研磨介质形状主要有棒介质和球介质，材料类型主要有低碳钢、锻钢、低铬钢和高铬钢.Corin等[46]使用不同类型的磨矿介质研究其对金属硫化矿浮选的影响.结果表明，棒磨和球磨对金属硫化物的浮选影响差异不大，而研磨材料对金属硫化矿的矿浆化学和浮选性能有显著影响.Mu等[47]研究了锻钢、含铬15%（质量分数）的钢和含铬30%的钢3种磨矿介质材料在一定捕收剂（戊基黄药）浓度范围内分别在pH为5.0、7.0和8.5条件下对黄铁矿浮选的影响.结果表明，在pH值为5.0时，30%铬钢研磨的黄铁矿回收率最高，其次是使用15%铬钢和锻钢，磨矿介质中的铁污染和黄药氧化对黄铁矿浮选都有一定影响.黄铁矿表面的铁污染抑制了黄铁矿的浮选，黄药氧化可降低黄铁矿表面的铁污染.pH为7.0时，黄铁矿浮选主要受黄药浓度控制.黄药浓度较低时，阳极反应以黄铁矿氧化为主，黄药不能形成双黄药，浮选效果较差.当黄药浓度较高时，双黄药的形成占优势，有利于黄铁矿的浮选.pH为8.5时，黄铁矿的氧化作用超过黄药的氧化作用，矿浆电位在黄铁矿的浮选中起主要作用，高铬钢研磨介质产生的高矿浆电位促进了黄铁矿的氧化，而黄药的氧化降低，黄铁矿的浮选性能下降；锻钢研磨介质产生的低矿浆电位可使黄药氧化形成双黄药，从而促进了黄铁矿的浮选[48].3.3 研磨环境氧气在研磨过程的电流相互作用中起关键作用.氧气的存在会增加电流相互作用，因为氧气会在接受电子时形成羟基，从而促进研磨介质的氧化并增加矿物表面上氢氧化铁的浓度.在大多数硫化物系统中，这些电化学反应消耗氧气，导致矿浆电位降低[43].Huang和Grano[45]研究了在氮气、空气和氧气的不同气氛下，磨矿过程中黄铁矿的浮选回收率随原电池电流的变化.结果表明，氮气充入产生的龚志辉等：磨矿和浮选过程中黄铁矿电化学行为的研究进展· 63 ·。
Conversion and Kinetics of the Oxidation of Coal inSupercritical WaterTao Wang*and Xiaofeng ZhuDepartment of Chemical Engineering,Tsinghua University,Beijing100084,ChinaReceived April11,2004.Revised Manuscript Received June30,2004 The oxidation of coal in supercritical water was explored by using H2O2as the oxidant source in a bench-scale semicontinuous installation.The conversion and kinetics of coal oxidation in supercritical water(SCW)medium were investigated.The reaction parameter effects on the conversion and kinetics of coal supercritical water oxidation(SCWO)were determined.Increasing temperature,H2O2concentration,or the flow rate of H2O2solution enhances the oxidation of coal in SCW.The oxidation of coal in SCW is a pseudo-first-order process.1.IntroductionSupercritical water(SCW),which is water above itscritical temperature(374.0°C)and critical pressure(22.1MPa),has unique properties and environmentallying SCW as the medium for processing ofcoal has received increasing attention in the efforts to develop techniques for the clean and effective use of coal,1-10including hydrolysis and pyrolysis of coal in SCW,liquefaction of coal in SCW,extraction of coal with SCW and SCW mixtures,and desulfurization of coal with SCW.In our previous works,11,12we firstly explored the oxidation of coal using SCW as the reaction medium for developing a clean and effective coal combustion technique.The species in the gaseous and liquid ef-fluents of the coal SCWO has been identified for investigating the transformation of the key elements in coal during the SCWO.11,12It was disclosed that the sulfur and nitrogen contained in coal could be conversed into SO42-and N2,respectively,by the oxidation in SCW with H2O2as the oxidant source under suitable reaction conditions.11,12The information on the kinetics is neces-sary for further research and development of this novel coal SCWO process.In this work,the conversion and kinetics of coal solid during SCWO was investigated. The reaction parameter effects on the conversion and kinetics of coal SCWO were experimentally determined.2.Experimental Section2.1.Materials.Coal with the particle size0.5-1.0mm and the composition given in Table1was used for this study.The oxidant hydrogen peroxide was purchased as the30.0wt% aqueous solution from Beijing Chemicals Corp.(Beijing,China) and diluted to the required concentrations with tridistilled water.2.2.Setup and Procedure.A bench-scale semicontinuous system,shown in Figure1,was used for the experiments involving SCWO of coal.H2O2aqueous solution in the reservoir(1)was continuously charged into the preheater(3)by a high-pressure pump(2) (LB-10C,Xingda Corp.,Beijing,China).In the preheaters(3 and4),H2O2decomposed and released O2to be dissolved in supercritical water.The coal sample was oxidized by O2 dissolved in supercritical water in the horizontal reactor(5), which is aΦ6×4Inconel625tube with an effective length of 230mm.The temperatures of the reactor and preheaters, which were both electrically heated,were measured with K type thermal couples and controlled with an accuracy of(1°C.The temperature of the reactor outlet was reported as the reaction temperature.The reaction pressure was controlled by a back-pressure regulator(BPR)(8)with an accuracy of (0.1MPa.After being passed through a filter(6),the super-critical water solution from the reactor was cooled in a cooler (7),depressurized to atmosphere pressure by BPR(8),and separated into gaseous and liquid effluents in the separator (9).*To whom correspondence should be addressed.Tel:+8610 62782748.Fax:+861062770304.E-mail:taowang@.(1)Aida,T.M.;Sato,T.;Sekiguchi,G.;Adschiri,T.;Arai,K. Extraction of Taiheiyao coal with supercritical water-phenol mixtures. Fuel2002,81,1453-1461.(2)Izumiya,F.;et al.Coal decomposition by supercritical water.Fuel Energy Abstr.2002,43,10-10.(3)Liu,X.;Li,B.;Miura,K.Analysis of pyrolysis and gasification reactions of hydrothermally and supercritically upgraded low-rank coal by using a new distributed activation energy model.Fuel Process. Technol.2001,69,1-12.(4)Nakagawa,H.;et al.Upgrading of low rank coals by sub/ supercritical water treatment.Fuel Energy Abstr.2002,43,12-12.(5)Matsumura,Y.;Nonaka,H.;Yokura,H.;Tsutsumi,A.;Yoshida, K.Co-liquefaction of coal and biomass in supercritical water.Fuel1999, 78,1049-1056.(6)Sasaki,A.Study of coal treatment with supercritical water.Fuel Energy Abstr.1997,38,8-8.(7)Tsutsumi,A.Liquefaction of Ishikari coal using supercritical water.Fuel Energy Abstr.1995,36,253-253.(8)Adschiri,T.;Sato,T.;Shibuichi,H.;Fang,Z.;Okazaki,S.;Arai, K.Extraction of Taiheiyo coal with supercritical water-HCOOH mixture.Fuel2000,79,243-248.(9)Li,W.;Guo,S.Supercritical desulfurization of high rank coal with alcohol/water and alcohol/KOH.Fuel Process.Technol.1996,46, 143-155.(10)Timpe,R.C.;Mann,M.D.;Pavlish,J.H.;Louie,P.K.K. Organic sulfur and hap removal from coal using hydrothermal treat-ment.Fuel Process.Technol.2001,73,127-141.(11)Zhu,X.;Wang,T.Preliminary Exploration of Coal Oxidation in Supercritical Water.Chin.J.Process Eng.2002,2,177-180.(12)Wang,T.;Zhu,X.Sulfur Transformations during Supercritical Water Oxidation of a Chinese Coal.Fuel2003,82(18),2267-2272.position of the Coal Sample moisture(wt%)ash(wt%)volatilecomponents(wt%)nitrogen(wt%)sulfur(wt%)4.07.329.20.80.31569Energy&Fuels2004,18,1569-157210.1021/ef0499123CCC:$27.50©2004American Chemical SocietyPublished on Web08/04/2004To conduct the experiment,a1.5g coal sample was packed in the clean and dry reactor.Tridistilled water was introduced into the system by the high-pressure pump during heating and pressurizing.Once the desired temperature and pressure werereached,the H2O2aqueous solution replaced tridistilled water and was continuously pumped into the system.The reaction time was set to be zero at this point.After the desired reaction time,heating and pumping were shut down,and the system was quickly depressurized.The reactor was immediately taken away from the system and quenched in water.The solid residue inside the reactor was dried and weighted.The moisture in the sample of the coal and solid residue was determined by a standard test method(ASTM D3173-00).Each experiment was repeated three or more times,and the average result is reported with a standard deviation of less than(1.5%.3.Results and Discussion3.1.The Conversion of Coal SCWO.The conver-sion of coal was defined according to the weight loss of coal by SCWO asWhere x is the conversion of the coal by SCWO,W0is the initial moisture-free weight of coal sample(g),and W is the moisture-free weight of the solid sample(g). The conversion of coal was increased as reaction time increased.Under the experimental conditions at420°C, 25.0MPa,and5.0mL/min of5.0wt%H2O2solution, the conversion of coal was respectively26.7%,68.1%, and82.1%for the reaction times of5,15,and20min, as shown in Figure2.The conversion of coal was strongly dependent on the reaction temperature.The conversion of coal at different reaction temperatures is shown in Figure3for a coal sample of1.5g oxidized at25.0MPa with5mL/min of 5.0wt%H2O2solution for17.0min.As shown in Figure 3,the conversion increased as temperature increased. When the reaction temperature was higher than380°C,it went up rapidly with the temperature increase. Figure4represents the conversion for a coal sample of1.5g oxidized at25.0MPa and400°C with5.0mL/ min of different concentrations of H2O2solutions.The conversion depended on the H2O2concentration and was enhanced by using a higher concentration of H2O2 solution.The dependence of the conversion on the flow rate of H2O2solution is illustrated in Figure5.Obvi-ously,it increased as the flow rate of H2O2solution increased.It was experimentally verified that the conversion of the coal by SCWO was enhanced with high temperature, long reaction time,high concentration,and high flow rate of H2O2solution.The reaction temperature is the most significant parameter affecting the conversion of coal SCWO.3.2.The Kinetics of Coal SCWO.The coal SCWO was assumed to be a pseudo-first-order process.So that ThenFigure1.Schematic diagram of the bench setup forSCWOof coal.Figure2.Conversion of coal vs reaction time.P)25.0MPa, T)420°C,F)5.0mL min-1,C)5.0wt%.x)W-WW×100%(1)Figure3.Conversion of coal vs reaction temperature.P)25.0MPa,t)17min,F)5.0mL min-1,C)5.0wt%.Figure4.Conversion of coal vs concentration of H2O2.T)400°C,P)25.0MPa,t)17min,F)5.0mL min-1.d W/d t)-kW(2)ln W)-kt+ln W′(3)1570Energy&Fuels,Vol.18,No.5,2004Wang and Zhu1.储双氧水罐2.泵3.4.预热器5.反应器6.过滤器7.冷却器8.背压阀9.分离罐where W 0′is the moisture-free weight of solid residue at zero reaction time when the H 2O 2aqueous solution was continuously pumped into the system to replace the tridistilled water (g),W is the moisture-free weight of the solid sample (g),t is the reaction time (min),and k is the first-order rate constant (min -1).The plotting of ln W vs t is shown in Figure 6for different reaction temperatures at 25.0MPa with 5.0mL/min of 5.0wt %H 2O 2solution.The parameters in eq 3were found by fitting the experimental data and were listed in Table 2.The data in Figures 6-8have good linearity.This disclosed that coal SCWO is a pseudo-first-order process.As shown in Figure 6,the weight of the solid sample decreased more quickly at higher temperature.The rate constant of the coal SCOW,k ,listed in Table 2increased as the reaction temperature increased.These data evidenced that the rate of the coal SCWO increased as temperature increased.As shown in Tables 2-4,the fitted parameter W 0′coincides well with the experimentally determined one,which is denoted as W 0′E .The value of W 0′E indicates the conversion of coal during heating and pressurizing,in which the hydrolysis and pyrolysis of coal take place without the oxidation.The conversion of coal during heating and pressurizing,which could be calculated with W 0′and W 0according to eq 1,declined as the reaction temperature elevated.This conversion was 22.7%at 380°C but only 2.0%at 420°C.These values disclosed that the conversion contributed by the hy-drolysis and pyrolysis of coal taking place during heating and pressuring was small at thereactionFigure 5.Conversion of coal vs flow rate of H 2O 2solution.T )400°C,P )25.0MPa,t )17min,C )5.0wt%.Figure 6.ln W vs reaction time at different reaction tem-peratures.P )25.0MPa,F )5.0mL min -1,C )5.0wt %.Table 2.Kinetic Parameters of the Coal SCWO atDifferent Reaction Temperatures T (°C)W 0′E (g)W 0′(g)k (min -1)r 380 1.16 1.180.011590.996390 1.21 1.200.017420.993400 1.30 1.310.031390.989410 1.36 1.380.047360.9904201.471.480.059770.984Figure 7.ln k vs 1/T .P )25.0MPa,F )5.0mL min -1,C )5.0wt%.Figure 8.ln W vs reaction time at different concentrations of H 2O 2.T )400°C,P )25.0MPa,F )5.0mL min -1.Table 3.Kinetic Parameters of the Coal SCWO withDifferent H 2O 2Concentration C (wt %)W 0′E (g)W 0′(g)k (min -1)r 3.0 1.27 1.280.013170.9965.0 1.30 1.310.031390.9897.01.211.220.031620.986Table 4.Kinetic Parameters of the Coal SCWO withDifferent Flow Rates of H 2O 2Solution F (mL/min)W 0′E (g)W 0′(g)k (min -1)r 5.0 1.30 1.310.031390.9897.01.301.290.041070.991Oxidation of Coal in Supercritical Water Energy &Fuels,Vol.18,No.5,20041571temperature above 420°C,although it was significant at lower temperatures.The dependence of the rate constant on the temper-ature is shown in Figure 7and could be expressed by Arrhenius’relationship,with the activation energy being 154.65kJ/mol for the data at 25.0MPa and 5.0mL/min of 5.0wt %H 2O 2solution.The kinetics was also dependent on the H 2O 2concen-tration.As shown in Figure 8and Table 3,the rate constant increased as H 2O 2concentration increased.The flow rate of H 2O 2solution also affected the kinetics of coal SCWO.As shown in Figure 9and Table 4,the rate constant depended positively on the flow rate of H 2O 2solution.4.ConclusionUnder the experimental conditions,the conversion and kinetics of coal SCWO are strongly dependent on the temperature,H 2O 2concentration,and the flow rate of H 2O 2solution.Increasing any of those enhances the oxidation of coal in SCW.The oxidation of coal in SCW is a pseudo-first-order process with an activation energy of 154.65kJ/mol at 25MPa pressure.NomenclatureC )concentration of H 2O 2aqueous solution,wt %F )flow rate of H 2O 2aqueous solution,mL/min k )first-order rate constant,min -1P )reaction pressure,MPar )linear correlation coefficient T )reaction temperature,°C t )reaction time,minx )conversion of the coal by SCWOW )moisture-free weight of the solid sample,g W 0)initial moisture-free weight of coal sample,gW 0′)moisture-free weight of the solid when t is zero,determined by data fitting,gW 0′E )experimentally determined moisture-free weight of the solid when t is zero,gEF0499123Figure 9.ln W vs reaction time at different flow rates of H 2O 2solution.T )400°C,P )25.0MPa,C )5.0wt %.1572Energy &Fuels,Vol.18,No.5,2004Wang and Zhu。
holding time on biochar propertiesBiochar is becoming an increasingly popular alternative to traditional methods for managing soil organic matter, improving soil fertility, and sequestering carbon by converting agricultural wastes into a stable and recalcitrant form of carbon. Pyrolysis, the thermal decomposition of organic matter in the absence of oxygen, is widely used to produce biochar. The pyrolysis temperature and holding time are two critical factors that influence the properties of biochar. This article aims to explore the effect of pyrolysis temperature and holding time on biochar properties and their implications for soil management.Pyrolysis temperaturePyrolysis temperature is a important factor that influences the physicochemical properties of biochar. It determines the degree of thermal degradation of the material, leading to the production of different biochar properties. The effect of pyrolysis temperature on biochar properties can be divided into three categories: chemical composition, physical characteristics, and adsorption properties.Chemical compositionPyrolysis temperature has a significant effect on the chemical composition of biochar, including carbon content, ash content, pH, and functional groups. Higher pyrolysis temperatures generally result in higher carbon content, lower ash content, and higher pH. As the temperature increases, volatile components are driven off, leaving behind a more stable and recalcitrant carbon structure. At the same time, the increase in temperature may cause some functional groups, such as carboxyl and hydroxyl groups, to be decomposed, leading to a decrease in surface functional groups and a corresponding increase in hydrophobicity of the biochar.Physical characteristicsPyrolysis temperature also affects the physical characteristics of biochar, including surface area, pore size distribution, and bulk density. High-temperature pyrolysis leads to the formation of a more open pore structure and a higher surface area. However, pore size distribution is affected by both pyrolysis temperature and the type of feedstock, with higher temperatures resulting in a shift towards smaller pore sizes. Meanwhile, an increase in pyrolysis temperature may cause a decrease in bulk density and an increase in particle size.Adsorption propertiesPyrolysis temperature affects the adsorption properties of biochar, including its ability to adsorb nutrients, heavy metals, and other pollutants. High-temperature pyrolysis generally results in biochar with a higher adsorption capacity due to its higher surface area and pore volume. At the same time, the decrease in functional groups may lead to a reduction in the biochar’s ability to adsorb certain types ofpollutants. The specific effect of pyrolysis temperature on the adsorption properties of biochar is determined by the type and concentration of the adsorbate, as well as the properties of the biochar itself.Holding timeHolding time is another important parameter in pyrolysis that affects the properties of biochar. The holding time is the duration of the pyrolysis process at a given temperature. It is an important factor that determines the final carbonization degree and the degree of thermal degradability of the feedstock. The effects of holding time on biochar properties include chemical composition, surface area, and adsorption properties.Chemical compositionIncreasing the holding time can promote the decomposition of organic matter and improve the carbonization degree of the biochar. However, excessive holding time can lead to excessive thermal degradation and a reduction in the carbon content of the final biochar. The chemical composition of biochar can be affected by the holding time either directly or indirectly. Longer holding times can result in greater efforts to remove moisture and volatile organic matter components from the feedstock, leading to higher carbon yield and lower ash content.Surface areaHolding time can also affect the specific surface area of biochar. As the holding time increases, the surface area of the biochar may increase due to an increase in the extent of decomposition and subsequent micropore formation. However, too long a holding time can also lead to a reduction in specific surface area due to excessive carbonization and vaporization of the volatile components.Adsorption propertiesHolding time can also affect the adsorption performance of biochar. An increase in holding time can result in a higher surface area and micropore volume, leading to a greater adsorption capacity for certain types of pollutants such as heavy metals. However, excessive holding times can reduce the number of surface functional groups responsible for adsorption, merely increasing the micropore density in the biochar, and reducing the potential for adsorption of some other pollutants.ConclusionIn conclusion, pyrolysis temperature and holding time are two crucial factors that influence the properties of biochar, which in turn determine its effectiveness in soil applications. High-temperature pyrolysis tends to result in biochar with higher carbon content, larger surface area, and higher adsorption capacity than low-temperature pyrolysis. Longer holding times can also modify biochar properties,although the extent depends on the conditions of the individual pyrolysis process. A well-designed pyrolysis process can thus be tailored to produce biochar with specific properties suitable for a wide range of soil applications, such as improving soil fertility, reducing greenhouse gas emissions, and remediating contaminated soils.。
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第2期·494·化工进展煤热解反应热测定方法研究进展何璐1，解强1，梁鼎成1，仝胜录2，郜丽娟2，姚金松2（1中国矿业大学(北京)化学与环境工程学院，北京 100083；2北京低碳清洁能源研究所，北京 102211）摘要：煤热解既是煤炭燃烧、气化、直接液化等工艺的初始反应和伴随过程，也是煤转化的主要工艺之一，而煤热解反应热是反应器设计、热解机理研究、建模及工艺能效评估等过程所需的重要热力学参数。
本文首先对煤及其他非均质有机物热解反应热测定方法和技术的研究现状做了综述性评介，分析比较了模型预测法（Merric 模型、Strezov模型）和实验测定法（热值法、电功率法、计算机辅助热分析法、差示扫描量热法等）方法的优势以及存在的问题，特别关注将这些方法应用于煤热解反应热测定过程中的适应性。
结果表明，在研究掌握测试参数影响煤热解反应热测定精度的规律、解决数据处理方法的前提下，基于TG-DSC同步联用法或可建立相对简单、易行、普适的煤热解反应热测定方法和技术。
关键词：煤；热解；反应热；测量中图分类号：TQ530.2 文献标志码：A 文章编号：1000–6613（2017）02–0494–08DOI：10.16085/j.issn.1000-6613.2017.02.013Measurement of reaction heat of coal pyrolysis：state-of-the-artHE Lu1，XIE Qiang1，LIANG Dingcheng1，TONG Shenglu2，GAO Lijuan2，YAO Jinsong2（1School of Chemical and Environmental Engineering，China University of Mining & Technology，Beijing 100083，China；2National Institute of Clean-and-Low-Carbon Energy，Beijing 102211，China）Abstract：In nature pyrolysis can be considered as the initial stage and/or paralleling part of coal combustion，gasification and direct liquefaction，and pyrolysis itself is also one of the fundamental technologies in coal conversion processes. Thus it is understandable that reaction heat of coal pyrolysis is of significance that it is the important thermodynamic parameter used in reactor design，mechanism study，and energy efficiency assessment. This paper presents a critical survey on the status of methods and techniques for measurement of pyrolysis reaction heat of coal and relevant heterogeneous organic matters，and a detailed analysis and comparison of these methods，such as model prediction methods （Merric model，Strezov model）and experimental measuring methods（heat value method，electricity power method，computer aided thermal analysis，and differential scanning calorimetry method）were conducted，in which especial attention was paid to the possibility of application of these methods in the measurement of pyrolysis reaction heat. Results show that an easy，but rational and considerable accurate method for measurement of coal pyrolysis heat on the basis of TG-DSC technique could be established under conditions that the effects of measuring parameters on measurement precision are thoroughly studied and elucidated，as well as the measurement data resolution process is constructed.Key words：coal；pyrolysis；reaction heat；measurement我国化石能源赋存具有“富煤、贫油、少气”的特点，石油、天然气资源的日渐短缺以及新能源技术发展的尚未完善也使得煤炭的地位和重要性收稿日期：2016-06-15；修改稿日期：2016-09-09。
山东化工SHANDONGCHEMICALINDUSTRY・126・2021年第50卷含油污泥热解残渣的性质及资源化利用研究进展冉雅郡，叶兆荣，王厚林（新中天环保工程（重庆）有限公司，重庆401147）摘要:热解技术对原油燃气回收率高、产生的污染物少，被认为是最有前景的含油污泥处理技术。
热解产生的残渣含有少量油类、重金属，有造成二次污染的风险,热解残渣的无害化处理已成为制约含油污泥热解技术推广应用的瓶颈。
本文以含油污泥热解残渣为研究对象，分析其基本性质及影响因素、资源化综合利用的研究现状，提出展望，供今后热解残渣的研究作参考°关键词:含油污泥;热解残渣;资源化利用中图分类号:X703文献标识码:A文章编号:1008-021X（2021）05-0126-02Research Process of the Characteristics and Comprehensive Utilizationof Oily Sludge5s Pyrolytic ResiCuesRan Yajun,Ye Zhaorong,Wang Houlin(Xin Zhong—an Environment Protection Engineering!Chongqing)Co.,Ltd.,Chongqing401147,China) Abstrach:Pyrolysis technology with a high recove—rate of crude oil and gas and less p—lutants produced,is considered to be the most promising oily sludge treatment technology-The residue produced by pyrolysis contains a small amount of oil and heavy metals,which may cause seconda—poVu—on.The harml—s treatment of pyrolysis residue has become a b——eneck resOic/ng the promotion and application of oily sludge pyrolysis technology-Thc paper analyzed the oily sludge pyrolysis residue's basic proper—es and in/uencing factors,and comprehensive uti/za—on—chnologies,and put for/ard prospects—r future research on py—lysis—sidues.Key words:oily sludge；py—gt—residues；comprehensive uti/za—on含油污泥是石油天然气钻井、开采、运输过程中产生的一种油、泥、砂混合物，含有重金属、氯酚类、烷桂类等有毒有害组分⑴，被列入《国家危险废物名录》HW08。
不连沟煤热解半焦燃烧特性研究薛新巧1，2，冯钰2，靳立军2，胡浩权2（1宁夏工商职业技术学院化工系，宁夏 银川750021；2大连理工大学化工学院，煤化工研究所精细化工国家重点实验室，辽宁 大连116024）摘要：煤热解产生具有高利用价值的煤气和焦油，并伴随产生大量的热解半焦，燃烧是半焦的主要利用途径之一。
本文采用非等温热重分析法研究了热解条件（热解温度和停留时间）、热解气氛和燃烧升温速率对热解半焦燃烧行为的影响，并利用Coats-Redfern 积分法对半焦燃烧过程进行动力学计算。
结果表明：热解温度对甲烷二氧化碳重整与煤热解耦合过程半焦的燃烧反应特性有重要影响。
随热解温度升高，半焦燃烧反应性呈下降趋势，反应活化能逐渐增加，这与半焦中较低的挥发分成正相关。
热解停留时间和热解气氛对半焦燃烧影响较小。
与在氮气中热解半焦相比，加氢热解和耦合热解半焦表现出几乎相同的燃烧特征和反应活化能。
燃烧升温速率显著影响半焦的燃烧特性，提高燃烧升温速率促使半焦燃烧反应在更高温度下进行。
关键词：半焦；燃烧特性；甲烷二氧化碳重整与煤热解；热重分析；动力学分析中图分类号：TQ536.1 文献标志码：A 文章编号：1000–6613（2017）09–3287–06 DOI ：10.16085/j.issn.1000-6613.2017-0375Combustion characteristics of pyrolysis char of Buliangou coalXUE Xingqiao 1，2，FENG Yu 2，JIN Lijun 2，HU Haoquan 2（1 Department of Chemical Industry ，Ningxia V ocational Technical Collage of Industry and Commerce ，Yinchuan 750021，Ningxia ，China ；2Institute of Coal Chemical Engineering ，Department of Chemical Engineering ，DalianUniversity of Technology ，Dalian 116023，Liaoning ，China ）Abstract ：Coal pyrolysis is an effective and efficient method to produce coal gas ，tar and clean char. The char ，as the main product ，is always used for combustion. To investigate the combustion performances of pyrolysis char ，the non-isothermal thermal-gravity analysis was taken to study the effect of pyrolysis temperature ，holding time and atmosphere on combustion of the resultant pyrolysis char of Buliangou coal in this paper. And Coats-Redfern integrate method was used to kinetic analysis of char combustion. The results showed that the pyrolysis temperature obviously influenced the combustion of char prepared by the integrated process of CO 2 reforming of CH 4 with coal pyrolysis. The combustion performance of char decreased and activation energy gradually increased with increasing pyrolysis temperature ，which was positively related with low volatile in the char. Pyrolysis holding time and atmosphere had slight effect on char combustion. The char from hydropyrolysis and integrated process showed the similar combustion behaviors and activation energy as those obtained under N 2 atmosphere. The heating rate of combustion affected the char combustion characteristics. High heating rate resulted in combustion at high temperature.Key words ：coal char ；combustion characteristics ；integrated process of CO 2 reforming of CH 4 with coal pyrolysis ；thermogravimetric analysis ；kinetics analysis甲烷催化转化制氢等研究工作。
