整体型催化剂甲烷自热氧化制合成气的研究

研究表明，在氧化物改性的整体型催化剂上仍能进行甲烷自热催化氧化反应，氧化物改性显著提高了甲烷自热催化氧化反应整体型催化剂的稳定性，使用整体型催化剂，可以使反应在自热条件下进行，而且空速大，效率高，同时不需要反应炉。

易燃煤层自热氧化特性的理论分析

对易燃煤层自然发火过程中煤氧化学反应的特性及其热效应进行了理论分析 。

煤体自热氧化气体生成量与煤温的耦合变化规律研究

为了分析采空区遗煤在自然过程中释放有害气体生成成分、浓度与煤温的耦合变化规律,选取大宁煤矿205工作面煤样进行绝热氧化试验,测定了氧化过程产生的不同气体浓度和煤温,建立了有害气体生成量与煤温的定量关系函数。试验结果表明,煤自热氧化时,O^(2)浓度与煤温呈线性下降关系,CO、CO^(2)、烷烃、烯烃气体生成量与煤温呈二次函数增加关系,煤体处于缓慢氧化阶段;当煤温小于103.6℃时,O^(2)消耗率与气体生成量较缓慢,煤温大于103.6℃时,O^(2)消耗率与气体生成量急剧增加,煤体处于加速氧化阶段。为采空区有害气体治理和防止自然发火提供理论依据。

采空区遗煤氧化自热隐患治理技术

某煤矿工作面末采期间采空区断层附近遗煤量大,工作面停采时间长,推采速度慢,导致采空区遗煤氧化自热,CO快速升高。通过树立“安全第一、快速高效”指导思想,确定“堵漏风、降氧气、消高温、防反复”的总体技术思路,采用“注惰防爆、分区防治、注胶降温、控氧抑温”为主的技术措施,从而有效消除采空区遗煤氧化自热高温隐患,使煤矿工作面能够安全开采,为工作面回撤工作提供安全保障。

硫化矿尘层氧化自热初始温度试验研究

为研究硫化矿尘氧化自热的影响因素,以硫化矿尘层氧化自热温度和产生二氧化硫时的内部温度为指标,以硫化矿尘的含硫量、矿尘层厚度和矿尘粒径为自变量,进行3因素3水平正交试验获得硫化矿尘层开始氧化自热时的初始温度和产生二氧化硫时的内部温度,利用灰色系统理论分别计算影响因素对单目标函数的关联系数和多目标函数的关联度,将多目标转换为以关联度为目标的单目标进一步计算各影响因素的平均关联度,从而得出硫化矿尘最易发生氧化自热的条件,为高硫矿山安全生产提供依据。

基于GRNN模型的硫化矿石堆氧化自热温度预测

为得到硫化矿石堆氧化自热温度的变化规律,自主设计硫化矿石堆氧化自热模拟试验装置,以含硫量、矿石块度、升温梯度作为试验影响因素,将硫化矿石堆氧化自热温升速率作为试验判定指标,采用L9(34)正交表构造三因素三水平回归正交试验。运用MATLAB建立硫化矿石堆氧化自热温度的GRNN神经网络模型,通过K-折交叉验证优选得到GRNN神经网络的最佳光滑因子σe,并与RBF神经网络模型、灰色神经网络模型预测效果进行对比。结果表明:GRNN神经网络在小样本预测模型中网络逼近能力、收敛速度、算法稳定性等方面具有优势,对硫化矿石堆氧化自热温度的预测精度高,预测误差为3.51%。

硫化矿氧化自热性质测试的新方法

介绍一种新的测试硫化矿样氧化自热性质的方法。该套实验装置由程序控温箱、金属网篮、热电偶以及温度自动记录仪等构成。通过设置不同的恒温条件,运用该套实验系统首次测试3种不同硫化矿样的氧化自热性质,得出各矿样在不同恒温条件下的自热规律;利用交叉点温度法解算出3种矿样(硫铁精矿、高硫精矿、原矿)的表观活化能分别为13.7366、21.3817、36.2350kJ/mol,比较3种矿样的自燃倾向性。结果表明:随着恒温温度的升高,矿样的自热幅度变大,温度交叉的速度变快;硫铁精矿的表观活化能最小,原矿的表观活化能最大,这与硫精矿更容易发生自燃的现象一致。与传统的研究硫化矿石氧化自热性质的实验方法相比,该方法的测试成本低、操作简便、可重复性强,用于判定硫化矿石的自燃倾向性有一定的适用性。

基于等转化率法的煤氧化自热动力学参数测试方法

准确获得煤氧化自热过程中的反应动力学参数是研究煤自燃及其特性的基础。针对现有方法尚无法获得煤自燃不同反应温度对应的动力学参数这一问题,开展了煤氧化自热动力学参数测试方法的研究。基于热分析动力学理论推导得到了以转化率为纽带的煤氧化自热动力学参数计算模型,提出了多升温速率实验和恒温实验相结合的测试方法。为确定测试方法的最优参数,引入了煤氧化自热反应时间作为对比参量。采用绝热氧化测试装置和同步热分析仪开展了3种不同变质程度的干燥煤样在纯氧条件下的绝热氧化实验、多升温速率实验以及恒温实验。根据多升温速率实验结果,分析了升温速率对煤氧不同反应阶段整体质量变化量的影响,确定了煤氧化自热动力学参数测试的最大升温速率。在此升温速率范围内,依据推导的计算模型,对比分析了不同升温速率组合和转化率计算步长对动力学参数计算结果的影响,发现转化率计算步长主要影响动力学参数计算结果的疏密程度,而升温速率组合对动力学参数计算结果的影响不大。根据绝热氧化实验结果,综合考虑测试时间成本,确定了获得煤氧化自热动力学参数的最优实验和计算参数,并对其准确性和适用性进行了验证。结果表明:当升温速率组合为0.2,0.5,1.0,2.0℃/min,转化率计算步长为0.03时测试得到的煤氧化自热动力学参数与实际最为贴近。

空气流量对储罐硫腐蚀产物氧化自热过程的影响

通过搭建硫化氧化试验系统,通入由硫化氢与氮气充分混合的硫化气体（VH2s∶VN2=2∶3）,模拟含硫油品储罐硫腐蚀产物的生成,探究硫腐蚀产物在与汽油储罐、柴油储罐和原油储罐环境相似的试验条件下不同空气流量对其氧化自热的影响.结果表明：空气流量对硫腐蚀产物的氧化自热过程影响较大,随着空气流量的增加,硫腐蚀产物氧化自热过程中最高温度值Tmax、最大温升速率均先增大后减小,氧化自热倾向性最大的空气流量区间为400～450 mL/min.对于汽油储罐、柴油储罐,在空气流量400 mL/min时,储罐硫腐蚀产物自燃的风险最高;而对于原油储罐,在空气流量为500 mL/min时,硫腐蚀产物氧化反应温升幅度最高,储罐自燃的风险最高.

超临界水氧化处理鲁奇炉气化废水的研究

采用240 L/d的连续式超临界水氧化(SCWO)装置对鲁奇炉气化废水进行试验研究,通过实验室设计的高压连续加氧系统和在线温度测量装置,系统研究了废水的反应温度、停留时间、质量浓度等对废水COD、NH3-N和挥发酚去除率的影响,并对氧化自热过程进行了初步探索。结果表明:升高温度和延长反应时间均可促进废水中有机物的分解;随着废水质量浓度的升高,COD去除率增加而挥发酚和NH3-N的去除率有所下降;当温度超过500℃、压力23 MPa、停留时间为68 s时,经处理的废水COD、NH3-N和挥发酚去除率均超过了99.8%。通过高质量浓度鲁奇废水的氧化试验,证明在现有的试验装置上实现过程自热操作是可行的,为过程开发和放大提供基础数据。

煤低温氧化动力学参数测试方法对比研究

针对现有研究缺乏对不同煤低温氧化动力学参数测试方法的对比分析,采用Coats-Redfern法、q/m法及Starink等转化率法3种测试方法分别计算煤低温氧化动力学参数,并以煤氧化自热反应时间和自燃临界堆积厚度作为对比参量比较3种方法的准确性。通过绝热氧化装置和同步热分析仪进行了煤样在纯氧和贫氧条件下的绝热氧化实验、多升温速率实验和恒温实验。根据热分析实验结果,分别采用3种方法计算煤低温氧化动力学参数。依据获得的动力学参数计算煤氧化自热反应时间和自燃临界堆积厚度。将计算结果与实测的煤氧化自热反应时间和采空区实际遗煤厚度进行对比,评价3种方法的准确性。实验结果表明:①通过绝热氧化实验实测的煤氧化自热温度变化率随时间的推移均逐渐增大;采用Coats-Redfern法计算得到的温度在0~8 h(q/m法为0~10 h)内几乎不发生变化,超过这一时间段后温度迅速升高;采用Starink等转化率法获得的温度变化趋势与绝热氧化实验实测结果类似。②采空区实际遗煤厚度大于Coats-Redfern法计算得到的临界堆积厚度;采用q/m法获得的临界堆积厚度超过了该工作面所在煤层厚度,与实际明显不符;采用Starink等转化率法获得的计算结果与实际较为接近。③采用Starink等转化率法获得的预测结果与实测结果更为接近,表明Starink等转化率法得到的煤低温氧化动力学参数较其他2种测试方法更为准确。

采场环境中硫化矿石氧化自热的影响因素

堆积在采场环境中的硫化矿石容易发生氧化自热,从而造成环境污染、导致矿石结块,甚至引发矿山内因火灾事故。系统阐述了硫化矿物的晶体结构、痕量元素的含量、环境温度、铁离子、氧气浓度、空气湿度、矿石含水率、矿样的粒度分布、环境的pH值、微生物等主要因素对采场中硫化矿石氧化自热的影响。结果表明,硫化矿石在低温环境中的反应模式非常复杂,其氧化自热受诸多因素共同影响;较高的环境温度和氧气浓度有利于矿石氧化,矿样粒度越小越容易自热,铁离子与细菌对硫化矿石的氧化具有催化作用,水对矿石的氧化自热具有催化和阻化两重作用,而晶体结构、痕量元素含量的影响均表现出不确定性。

煤火燃烧阶段的划分及其特征分析

煤火已成为一个世界性的问题,结合前人研究成果及野外煤火实地观察,将煤火燃烧阶段分为氧化自热期、煤层燃烧期、熄灭期3个阶段,从产物特征、地质特征、生物特征及地球物理特征等方面分析煤火各阶段所具有的特征,为识别煤火燃烧阶段提供依据。

含硫矿体中的爆炸危险

最近美国几个含硫金矿在用铵油炸药爆破时发生了数次意外爆炸，其主要原因是矿石与炸药发生化学反应放出大量热，引爆孔内的雷管和炸药。本文介绍含硫矿山应采取的一些安全措施．

Maximum Hydrogen Production by Autothermal Steam Reforming of Bio-oil With NiCuZnAI Catalyst

Autothermal steam reforming （ATR） of bio-oil, which couples the endothermic steam reform- ing reaction with the exothermic partial oxidation, offers many advantages from a technical and economic point of view. Effective production of hydrogen through ATR of bio-oil was performed at lower temperature with NiCuZnAl catalyst. The highest hydrogen yield from bio-oil reached 64.3% with a nearly complete bio-oil conversion at 600℃, the ratio of steam to carbon fed （S/C） of 3 and the oxygen to carbon ratio （O/C） of 0.34. The reaction conditions in ATR including temperature, O/C, S/C and weight hourly space velocity can be used to control both hydrogen yield and products distribution. The comparison between the ATR and common steam reforming of bio-oil was studied. The mechanism of the ATR of bio-oil was also discussed.

冬瓜山铜矿二步骤回采采场热源调查与分析

冬瓜山铜矿二步骤回采存在高温热害问题,不仅制约掘进和采矿效率,而且影响职工身心健康,威胁矿山生产安全。通过现场对比调查、测定和分析,得出导致冬瓜山二步骤采场高温的因素有:堑沟内爆堆矿石氧化放出的热量、一步骤采场胶结充填体水泥的水化热和采场本身岩温的影响三个方面,并在此基础上提出了降低高温危害的措施。

Biodegradation Kinetics for Pre-treatment of Klebsiella pneumoniae Waste with Autothermal Thermophilic Aerobic Digestion

Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneu-moniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermo-philic aerobic digestion(ATAD) . Based on an Arrhenius-type equation,an empirical model was developed to corre-late the removal of total suspended solid(TSS) with the initial TSS concentration,influent reaction temperature,aeration rate and stirring rate. The reaction temperatures of the ATAD system could be raised from the ambient temperatures of 25 °C to a maximum temperature of 65 °C. The exponentials for the initial TSS concentration,aeration rate and stirring rate were 1.579,-0.8175 and-0.6549,respectively,and the apparent activation energy was 6.8774 kJ·mol-1. The correlation coefficient for the pre-exponential factor was 0.9223. The TSS removal effi-ciency predicted by the model was validated with an actual test,showing a maximum relative deviation of 10.79%. The new model has a good practicability.

Hierarchically skeletal multi-layered Pt-Ni nanocrystals for highly efficient oxygen reduction and methanol oxidation reactions

Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their morphologies to expose more active sites is a fundamental objective for the practical application of fuel cells.Herein,we report a new class of hierarchically skeletal Pt-Ni nanocrystals(HSNs)with a multi-layered structure,prepared by an inorganic acid-induced solvothermal method.The addition of H_(2)SO_(4)to the synthetic protocol provides a critical trigger for the successful growth of Pt-Ni nanocrystals with the desired structure.The Pt-Ni HSNs synthesized by this method exhibit enhanced mass activity of 1.25 A mgpt−1 at 0.9 V(versus the reversible hydrogen electrode)towards ORR in 0.1-M HClO_(4),which is superior to that of Pt-Ni multi-branched nanocrystals obtained by the same method in the absence of inorganic acid;it is additionally 8.9-fold higher than that of the commercial Pt/C catalyst.Meanwhile,it displays enhanced stability,with only 21.6%mass activity loss after 10,000 cycles(0.6–1.0 V)for ORR.Furthermore,the Pt-Ni HSNs show enhanced activity and anti-toxic ability in CO for MOR.The superb activity of the Pt-Ni HSNs for ORR and MOR is fully attributed to an extensively exposed electrochemical surface area and high intrinsic activity,induced by strain effects,provided by the unique hierarchically skeletal alloy structure.The novel open and hierarchical structure of Pt-Ni alloy provides a promising approach for significant improvements of the activity of Pt based alloy electrocatalysts.

Effects of pyrite on the spontaneous combustion of coal

Abstract Pyrite has a significant effect on the spontaneous combustion of coal. The presence of pyrite can change the propensity of coal towards spontaneous combustion. The influences of various pyrite contents on the parameters of spontaneous combustion, such as index gases, temperature and released heat etc., were investigated in this study, Coal samples with different pyrite contents （0 %, 3 %, 5 %, 7 % and 9 %） were made by mixing coal and pyrite. The oxidation experiments under temperature-programmed condition were carried out to test the release rate of gaseous oxidation products at different temperatures. Differential scanning calorimeter （DSC） was employed to measure the intensity of heat release during coal oxidation for various pyrite contents. The results indicate that pyrite can nonlinearly accelerate the process of spontaneous combustion. The coal sample with a pyrite content of 5 % has the largest CO release rate and oxygen adsorption as well. However, the coal sample with a pyrite content of ？ % has the largest rate of heat flow according to the results from the DSC tests. Pyrite contents of 5 %-7 % in coal has the most significant effects on spontaneous combustion within the range of this study. The conclusions are conducive to the evaluation and control for the spontaneous combustion of coal.

The shortest period of coal spontaneous combustion on the basis of oxidative heat release intensity

It’s necessary to forecast the shortest spontaneous combustion period for preventing and controlling the coal spontaneous combustion.During the experimental process,a calculating model of the SSCP is established on the basis of the oxidative heat release intensity and thermal capacity at different temperatures.According to the basic parameters of spontaneous combustion,heat of water evaporation and gas desorption,the SSCPs of different coals are further predicted.Finally,this study analyzed the relationships of the SSCP and the judging indexes of the self-ignite tendency.The result shows that the SSCP non-linearly increases with the decrease of dynamic oxygen adsorption and increase of activation energy.Compared with the practical fire situation of mine,this reliable method can meet the actual requirement of mine production.