页岩层理对井壁稳定性影响分析

为了分析页岩的层理和水化损伤对钻井过程中井壁稳定性的影响,开展室内岩石三轴力学试验测试页岩原始状态和钻井液作用不同时间的力学特性;然后基于孔隙弹性理论和岩石弱面强度理论,综合考虑层理产状和水化损伤对页岩强度的影响,建立页岩地层井壁稳定性分析模型。结果表明:层理产状和水化损伤对井壁稳定性有显著的影响,都会导致坍塌压力升高,加剧井壁的不稳定性。综合考虑页岩的层理和水化损伤两个因素分析地层井壁稳定性,对优化不同时段钻井液性能,调整钻井液密度,保证钻井安全有重要意义。     

页岩水化特征及其井壁稳定分析

为深入研究页岩的水化特征及水化对井壁稳定的影响,以鄂尔多斯盆地石盒子组页岩为研究对象,开展了钻井液浸泡前后岩样的超声波透射实验、层理面直剪实验、三轴压缩实验,探讨了页岩水化的声学性质变化与岩石力学特征,分析了页岩水化对坍塌压力的影响。结果表明:弹性模量、泊松比等参数的变化难以准确评价页岩的水化特征,声波时差、衰减系数、时域曲线、频域曲线等超声波信号可作为研究页岩水化特征的有效手段;页岩水化直接导致其岩石力学性质发生变化,水化是坍塌压力上升的主要原因之一,对井壁稳定造成潜在的威胁;井壁稳定设计时应充分认识页岩的水化特征,避免井壁坍塌,确保钻井施工安全进行。     

Significant enhancement in catalytic ozonation efficacy: From granular to super-fine powdered activated carbon

In this study, super-fine powdered activated carbon (SPAC) has been proposed and investigated as a novel catalyst for the catalytic ozonation of oxalate for the first time. SPAC was prepared from commercial granular activated carbon (GAC) by ball milling. SPAC exhibited high external surface area with a far greater member of meso- and macropores (563% increase in volume). The catalytic performances of activated carbons (ACs) of 8 sizes were compared and the rate constant for pseudo first-order total organic carbon removal increased from 0.012 min^–1 to 0.568 min^–1 (47-fold increase) with the decrease in size of AC from 20 to 40 mesh (863 mm) to SPAC (~1.0 mm). Furthermore, the diffusion resistance of SPAC decreased 17-fold compared with GAC. The ratio of oxalate degradation by surface reaction increased by 57%. The rate of transformation of ozone to radicals by SPAC was 330 times that of GAC. The results suggest that a series of changes stimulated by ball milling, including a larger ratio of external surface area, less diffusion resistance, significant surface reaction and potential oxidized surface all contributed to enhancing catalytic ozonation performance. This study demonstrated that SPAC is a simple and effective catalyst for enhancing catalytic ozonation efficacy.

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PM-support interfacial effect and oxygen mobility in Pt,Pd or Rh-loaded (Ce,Zr,La)O2 catalysts

• Pt/CZL exhibits the optimum catalytic performance for HC and NO_x elimination. • The strong PM-Ce interaction favors the oxygen mobility and DOSC. • Pd/CZL shows higher catalytic activity for CO conversion due to more O_latt species. • Great oxygen mobility at high temperature broadens the dynamic operation window. • The relationship between DOSC and catalytic performance is revealed. The physicochemical properties of Pt-, Pd- and Rh- loaded (Ce,Zr,La)O₂ (shorted for CZL) catalysts before/after aging treatment were systematically characterized by various techniques to illustrate the relationship of the dynamic oxygen storage/release capacity and redox ability with their catalytic performances for HC, NO_x and CO conversions. Pt/CZL catalyst exhibits the optimum catalytic performance for HC and NO_x elimination, which mainly contribute to its excellent redox ability and dynamic oxygen storage/release capacity (DOSC) at lower temperature due to the stronger PM (precious metals)-support interaction. However, the worse stability of Pt-O-Ce species and volatile Pt oxides easily result in the dramatical decline in catalytic activity after aging. Pd/CZL shows higher catalytic activity for CO conversion by reason of more O_latt species as the active oxygen for CO oxidation reaction. Rh/CZL catalyst displays the widest dynamic operation window for NO_x elimination as a result of greater oxygen mobility at high temperature, and the ability to retain more Rh-O-Ce species after calcined at 1100°C effectively restrains sintering of active RhO_x species, improving the thermal stability of Rh/CZL catalyst.     

Development of a catalytic cracking process for converting waste plastics to petrochemicals

The catalytic degradation of polyolefin using H-gallosilicates was examined using a bench-scale reactor (0.8kg/h) with semicontinuous feeding and the following plastics: (1) low-density polyethylene (LDPE) pellets; (2) linear low-density polyethylene (L-LDPE) pellets; (3) high-density polyethylene (HDPE) pellets; (4) polypropylene (PP) pellets; (5) polyolefin obtained from pulverized industrial waste plastics. The yields of liquid compounds from these materials, which were aromatics in most cases, ranged from 55wt% to 68wt%. With an increase in the ratio of total reactant to catalyst, the liquid yield remained the same. Yields of benzene, toluene, and xylenes (BTXs) decreased rapidly to below 50wt% at a ratio of more than 30. Differences in this ratio for BTXs were always small and were independent of the material. Only about half of the gas product was propane with a fresh catalyst. When the experiments were repeated, propylene, isobutane, and isobutene were found to increase.     

SCR反应器短直进口段混氨技术研究

摘要：OI^2-SCR技术根据流场适应型设计理论设计了喷氨装置；以“主动利用不均”代替传统的“单—尺度的平均化”理念进行喷氨操作，在SCR反应器短直进口段内实现了良好的NH3／NOx混合效果，进而解决了改造工程中常见的空间制约问题。同时，充分发挥了有限体积的催化剂的效能，在较低氨逃逸率的前提下，实现了较高的脱硝效率。     

催化湿法氧化处理垃圾渗滤液的经济性初步分析

根据催化湿法氧化处理垃圾渗滤液的小试工艺条件以及实验参数，初步估算了该工艺的投资费用和运行费用，并与其它处理工艺进行了比较，结果显示，催化湿法氧化工艺处理垃圾渗滤液具有良好的应用价值。     

车用柴油机选择性催化还原技术研究进展

选择性催化还原技术(SCR)是目前唯一可以同时改善柴油机排放和燃油经济性的氮氧化物(NOX)净化技术,而以NH3作为还原剂的SCR技术(NH3-SCR)又是目前最成熟,最具推广前景的SCR技术。文章详细阐述了用于车用柴油机的NH3-SCR技术的反应机理,介绍了温度对SCR反应的影响;列举了典型SCR系统的主要部件并介绍了各部分的功能,以及法规中对车用尿素水溶液(AdBlue)主要指标的规定;总结了目前应用较多的开环、闭环两种控制策略的工作流程及特点,并且分析了各自的优缺点;在柴油机后处理系统集成的角度对SCR与颗粒捕集器(DPF)的两种整合方案进行了分析,对比了两种方案的优缺点;最后分析了SCR技术目前存在的几个问题。     

稠油废水处理工艺研究

介绍了稠油废水的来源与性质,提出3种处理技术,即"水解酸化-接触氧化-臭氧催化氧化",出水CODCr为48.6 mg/L,去除率达到86.55%,处理成本为6.03元/m3;"活性焦预吸附-厌氧-固定化微生物BAF-活性焦后吸附",出水CODCr为40.2 mg/L,去除率达到88.97%,处理成本为5.45元/m3;"强化絮凝-活性污泥MBR",出水CODCr为36.8 mg/L,去除率达到82.64%,处理成本为5.76元/m3。第2种工艺处理效率与处理成本略优。     

Enhanced catalytic complete oxidation of 1,2-dichloroethane over mesoporous transition metal-doped γ-Al2O3

High-surface-area mesoprous powders of γ-Al₂O₃ doped with Cu²⁺, Cr³⁺, and V³⁺ ions were prepared via a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al₂O₃ and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane (DCE) was studied in the temperature range of 250-400℃. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu²⁺- and Cr³⁺-containing catalysts showed 100% conversion at 300℃ and 350℃, V³⁺-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride (C₂H₃Cl) and hydrogen chloride (HCl) at all temperatures, Cu- and Cr-doped catalysts showed significantly stronger capability for deep oxidation to CO₂.