Effect of the effective stress coefficient and sorption-induced strain on the evolution of coal permeability: Experimental observations

Permeability is one of the most important parameters for CO₂ injection in coal to enhance coalbed methane recovery. Laboratory characterization of coal permeability provides useful information for in situ permeability behavior of coal seams when adsorbing gases such as CO₂ are injected. In this study, a series of experiments have been conducted for coal samples using both non-adsorbing and adsorbing gases at various confining stresses and pore pressures. Our observations have showed that even under controlled stress conditions, coal permeability decreases with respect to pore pressure during the injection of adsorbing gases. In order to find out the causes of permeability decrease for adsorbing gases, a non-adsorbing gas (helium) is used to determine the effective stress coefficient. In these experiments using helium, the impact of gas sorption can be neglected and any permeability reduction is considered as due to the variation in the effective stress, which is controlled by the effective stress coefficient. The results show that the effective stress coefficient is pore pressure dependent and less than unity for the coal samples studied. The permeability reduction from helium experiments is then used to calibrate the subsequent flow-through experiments using adsorbing gases, CH₄ and CO₂. Through this calibration, the sole effect of sorption-induced strain on permeability change is obtained for these adsorbing gas flow-through experiments. In this paper, experimental results and analyses are reported including how the impact of effective stress coefficient is separated from that of the sorption-induced strain on the evolution of coal permeability.     

油库突发安全事故的环境风险及应急措施

文章分析了油库安全事故发生的原因、类型、特点及后果,重点阐述了事故可能引发的次生环境风险影响以及应急处置措施,提出了应对突发性环境污染事故的对策与建议,对突发事故、降低环境影响的范围和程度具有一定的指导作用。     

太阳能热泵系统中的蓄热技术

开发新能源和节能是寻找能源出路的两大途径,太阳能热泵系统以其显著的节能性和环保性具有广阔的发展前景.论述了太阳能热泵系统中的蓄热原理和蓄热材料,介绍了实际蓄热工程,进行理论分析,指明了今后的研究与发展方向.太阳能蓄热装置的开发与应用对太阳能热泵系统的发展具有深远意义.     

白城地区近50年土壤有机碳动态变化研究

基于白城地区第一次、第二次全国土壤普查和野外现场采样共217个土壤剖面数据,利用＂土类-土地利用类型＂权重方法,估算白城地区11个土类从20世纪50年代至2009年近50年的土壤有机碳密度（SOD）和碳储量（SOC）,分析SOD变化规律,探讨其时空演化特征,结果表明,①近50年来,除水稻土和栗钙土SOD随时间增加外,其余各土类SOD随时间持续降低;但不同时期泥炭土SOD均最高,盐碱土均为最低。②近50年来,白城地区的SOD从92.22±21.13 t.hm-2减少至68.01±10.76 t.hm-2;表现为自北向南、自西向东降低的空间分布规律。③近50年来,白城地区SOC减少了6.2×107 t,各县市SOC呈逐年降低态。     

“双碳”目标下新疆能源系统绿色转型路径

新疆是我国最重要的资源宝库和能源基地之一。如何在“双碳”目标引领下,实现能源系统的绿色转型,事关国家能源安全。在系统总结新疆主要能源的储量及分布的基础上,梳理现阶段能源生产与消费现状,分析能源转型面临的主要问题,提出了能源绿色转型路径及相关对策和建议。结果表明：（1）新疆能源系统中化石能源占比超过85%,碳减排任务异常艰巨;（2）新疆“弃风、弃光”问题严峻,弃电率高于全国平均水平;（3）要实现新疆能源系统的绿色转型,须控制煤炭消费增长,加快水—风—光—储一体化清洁能源基地建设,扩大电力对外输送通道,推进“电气化新疆”进程,发展CCUS与大规模储能新技术等。研究结果可为新疆实现“双碳”目标提供参考。     

冬季猪粪固体堆放过程中NH3、N2O和NO排放特征研究

针对农村猪粪典型处理方式中的固体堆放管理,研究猪粪在冬季(2012年11月~2013年2月)固体堆放过程中NH3、N2O和NO排放特征.实验共设两个处理——无覆盖(non-covered,NC)和水稻秸秆覆盖(covered,C),堆放时间为73 d,期间进行了3次翻堆操作.实验观测了3种含氮气体(NH3、N2O和NO)的排放通量和堆体剖面N2O浓度变化.结果表明,猪粪固体堆放过程中NH3、N2O和NO排放累积量(以N计)分别占初始TN的比例为2.1%~2.6%、0.02%和~0.000 25%.两个处理的含氮气体排放通量变化趋势基本一致,且有覆盖堆体的含氮气体的排放量略低于无覆盖堆体.在堆放初期,NH3排放量最先出现峰值,之后N2O和NO排放开始增加.NH3和NO在固体堆放的中前期呈现互为消长的变化趋势;到堆放后期,N2O开始出现比前期高出两倍的排放高峰,而NH3和NO出现小幅增长.翻堆前后,NH3的排放无明显变化,而N2O排放在翻堆后均出现降低的变化,NO排放却出现升高的变化.     

Determining short chain fatty acids in sewage sludge hydrolysate：A comparison of three analytical methods and investigation of sample storage effects

In anaerobic digestion, the production of short-chain fatty acids （SCFAs） can be beneficial or harmful to the overall process, depending on the concentration of accumulated acids. Therefore, the accurate determination of the SCFA concentration in both fresh and stored sludge hydrolysates is important. To select a suitable method for monitoring SCFAs during the anaerobic digestion of sewage sludge, the accuracy of three available analytical methods, including 5 pH point acid titration （TITRA5）, gas chromatography （GC）, and spectrophotometry, were compared in the present study. The results revealed that TITRA5 and GC displayed better agreement in the achieved measurements and higher precision and accuracy than the spectrophotometric assay, as supported by the application of different statistical models. TITRA5 excelled in titrating unfiltered hydrolysate while simultaneously measuring the alkalinity, whereas the GC method provided detailed information on the contribution of different fatty acids to the total acidity. In contrast, the spectrophotometric assay suffered from many forms of interference, depending on the sample＇s matrix. SCFA production followed the pattern of enzymatic reactions and fitted the Michaelis-Menten model. In addition to promoting TITRA5 as an accurate and robust analytical tool for routine SCFA analyses, this comparative study also demonstrated the possibility of storing hydrolysate samples at different temperatures and durations without altering the SCFA measurements.     

面向导弹贮存延寿的PHM技术研究与工程应用

目的通过应用故障预测和健康管理(PHM)技术,实现导弹武器的可靠寿命预测和健康管理。方法在分析国内外现状的基础上,对某型导弹贮存延寿的系统架构进行设计,并对工程应用中的数据采集、寿命退化分析、预测方法,以及使用和贮存寿命预测等主要过程的技术途径和研究方法进行论述。结果工程应用证明了PHM技术在导弹贮存延寿中的可行性,相关关键技术也存在有效的解决方法。结论面向导弹贮存延寿的PHM技术体系在实现导弹武器全寿命周期管理和寿命科学评价的同时,能够有效降低装备的延寿升级经济成本。     

基于ANSYS Workbench的某弹药储运方舱支撑件力学分析

目的研究某弹药储运方舱支撑件的力学特性。方法采用SolidWorks软件建立三维模型,利用ANSYS Workbench软件进行静力学和动力学的仿真分析。结果仿真结果显示,该支撑件在静力学中所受的最大应力值为2633.7 Pa,最大变形量为5.6847×10-5m,动力学中振动形式有弯曲振动和扭曲振动,前6阶的固有频率在117.5~286.7 Hz之间。结论研究表明,该支撑件满足结构的刚强度要求,并为下一步进行瞬态动力学分析、随机振动分析奠定了基础。     

高氯原油对管道储运设施的腐蚀危害及防护措施

阐述了高氯原油对金属的腐蚀机理,对引起的管道储运设施氯腐蚀进行分析,重点对管道、加热炉和储罐的氯腐蚀危害进行识别,提供以预防、监测和控制为主的腐蚀防护措施,并对未来管道的安全保护提出建议。