Pore throat structure heterogeneity and its effect on gas-phase seepage capacity in tight sandstone reservoirs:A case study from the Triassic Yanchang Formation,Ordos Basin

The microscopic heterogeneity of pore-throat structures in tight sandstone is a crucial parameter for understanding the transport mechanism of fluid flow.In this work,we firstly developed the new procedure to characterize the pore size distribution(PSD)and throat size distribution(TSD)by combining the nuclear magnetic resonance(NMR),cast thin section(CTS),and constant-rate mercury injection(CRMI)tests,and used the permeability estimated model to verify the full-scale PSD and TSD.Then,we respectively analyzed the fractal feature of the pore and throat,and characterized the heterogeneity of pores and throats.Finally,we elaborated the effect of the pore and throat heterogeneity on the gas-phase seepage capacity base on the analysis of the simple capillary tube model and gas-flooding experiment.The results showed that(1)The PSD and TSD of the tight sandstone sample ranged from 0.01 to 10 mm and from 0.1 to 57 mm,respectively,mainly contributed by the micropores and mesopores.Meanwhile,the permeability estimated by the PSD and TSD was consistent with the experimental permeability,and relative error was lower than 8%.(2)The PSD and TSD exhibited multifractal characteristics,and singularity strength range,Δα,could be used as the indicator for characterizing the heterogeneity of pore and throat.Furthermore,the throat of the sample showed stronger heterogeneity than that the pore.(3)The throats played an important role for the fluid transport in the tight sandstone,and the effect of the throat heterogeneity on the gas-phase seepage capacity was different under the lower and higher injection pressure.The macropores and micropores maybe respectively become the preferential migration pathways at the lower and higher injection pressure.In the end,the identification plate was established in our paper,and could be described the relationship among the throat heterogeneity,injection pressure,permeability and flow path of the gas phase in the tight sandstone.

Gas-phase electrocatalytic reduction of carbon dioxide using electrolytic cell based on phosphoric acid-doped polybenzimidazole membrane

Carbon dioxide transformation to fuels or chemicals provides an attractive approach for its utilization as feedstock and its emission reduction. Herein, we report a gas-phase electrocatalytic reduction of CO2 in an electrolytic cell, constructed using phosphoric acid-doped polybenz- imidazole （PBI） membrane, which allowed operation at 170 ℃ Pt/C and PtMo/C with variable ratio of Pt/Mo were studied as the cathode catalysts. The results showed that PtMo/C catalysts significantly enhanced CO formation and inhibited CH4 formation compared with Pt/C catalyst. Characterization by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy revealed that most Mo species existed as MoO3 in PtMo/C catalysts and the interaction between Pt and MoOx was likely responsible for the enhanced CO formation rate although these bicomponent catalysts in general had a larger particle size than Pt/C catalyst.

Synthesis of dimethyl carbonate by gas-phase oxidative carbonylation of methanol in the presence of solid catalyst I. Catalyst preparation and catalytic Properties

The gas-phase synthesis of dimethyl carbonate (DMC) from methanol, carbon monoxide and oXygen has here Studied in a flow system at atomspheric Pressure. A series of Catalyst used in this reaCtion have been prepared and evaluated. The influence of trivared carbon supporters, alkaline metal Promoters and operation conditions on DMC opthesis reaction has been discussed. Under the conditions of 130℃, CO/O2=1 .96, SV=3340h-1, the space-time yield (STY) of DMC over PdCl2-CuCl2-CH3COOK/ac. catalyst is 217g/l-cat h,which is higher than what is published in the literatUre so far.

Gas-phase dehydrochlorination of 1, 1, 2, 2-tetrachloroethane over the non-metal supported ionic liquid catalyst

Developing of non-metallic catalyst to replace metal catalyst is a meaningful and challenging direction.In this work,the non-metallic catalyst was synthetized successfully by loading ionic liquid onto the silica surface,which was applied for the gas-phase dehydrochlorination of 1,1,2,2-tetrachloroethane.The 12%TPPC/SiO2(wt%)showed the best results with the conversion of 1,1,2,2-tetrachloroethane reaching 100%.The selectivity of 1,1,2-trichloroethylene was 100%,and no deactivation was found during the evaluation period.The catalytic mechanism was investigated and possible reaction route was given,which was a reference for fabricating and design of solid base catalyst.

Influence of heat treatment on microstructure and electrochemical behaviors of Mg-Zn binary alloys prepared by gas-phase alloying technique

Mg-Zn binary alloys fabricated by the gas-phase alloying technique under vacuum condition were investigated in the state of initial state and after heat treatment for the microstructure and electrochemical behaviors.Different from the traditional Mg-Zn alloys preparation methods,alloys prepared by gas-phase alloying have a large number of intermetallic compounds,such as MgZn,Mg7Zn3 and MgZn2.After solution treatment,the boundary of the eutectic disappeared and the size ofα-Mg increased from 100μm to 150μm.At the same time,the value of the resistance of charge transfer increased,which indicates that the resistance of the charge transfer and the corrosion resistance of the alloys increased.After artificial aging treatment,the distribution ofα-Mg was more uniform and its size was reduced to about 50μm,and there was new eutectic structure formed.The newly formed eutectic structure forms galvanic cells with the alloy matrix,which makes the corrosion resistance of the alloy weaken.

Anaerobic digestion of kitchen wastes in a single-phased anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO_2

The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO 2. The ASBR was operated at four chemical oxygen demand(COD) loading rates, 2.8, 5.1, 6.2 and 8.4 g/(L·d) respectively. The COD loading rate was increased with the TS concentration and HRT changing. At maximum COD loading rate of 8.4 g/(L·d), the COD, total solid(TS) removal rate and methane gas yield were 69%, 68% and 2.5 L/(L·d) respectively. The operation of the reactor with gas-phased absorb of CO 2 was stable in spite of the low pH(2.6—3.9) and high concentration of TS(142 g/L) of input mixture. The output volatile fatty acid(VFA) concentration was between 2.7—4.7 g/L and had no inhibition on the methanogenic microorganism. The reactor without gas-phased absorb of CO 2 became acidified when the total COD loading rate was increased to 5.1 g/(L·d). Stoichiometry of the methanogenesis for kitchen wastes showed a considerable amount of alkaline will be required to keep pH in the appropriate range for the methanogenic microorganism based on theoretical calculation. Gas-phased absorb of CO 2 effectively reduced the alkaline consumption, hence avoided excessive cation into the reactor.

Industrial Preparation and Acid Resistance of Ultra-stable Y Zeolite with Small Cell Size Produced by Gas-phase Method

Small-cell HSY-S zeolite prepared by the gas-phase ultra-stable method had been researched and developed,and industrial preparation tests of HSY-S have been successfully carried out for the first time.The acid resistance of industrially prepared HSY-S was investigated by acid solutions with different pH values.The structures and properties of HSY-S and its acid-treated samples were characterized by XRD,XRF,BET,and IR.Results show that the HSY-S samples have the characteristics of high crystallinity,good stability,large specific surface area,and good acid resistance.

Gas-phase CO_(2)activation with single electrons,metal atoms,clusters,and molecules

In this review,the history and outlook of gas-phase CO_(2)activation using single electrons,metal atoms,clusters(mainly metal hydride clusters),and molecules are discussed on both of the experimental and theoretical fronts.Although the development of bulk solid-state materials for the activation and conversion of CO_(2)into value-added products have enjoyed great success in the past several decades,this review focuses only on gas-phase studies,because isolated,well-defined gas-phase systems are ideally suited for high-resolution experiments using state-of-the-art spectrometric and spectroscopic techniques,and for simulations employing modern quantum theoretical methods.The unmatched high complementarity and comparability of experiment and theory in the case of gas-phase investigations bear an enormous potential in providing insights in the reactions of CO_(2)activation at the atomic level.In all of these examples,the reduction and bending of the inert neutral CO_(2)molecule is the critical step determined by the frontier orbitals of reaction participants.Based on the results and outlook summarized in this review,we anticipate that studies of gas-phase CO_(2)activations will be an avenue rich with opportunities for the rational design of novel catalysts based on the knowledge obtained on the atomic level.

The structure optimization of gas-phase surface discharge and its application for dye degradation

A gas-phase surface discharge（GSD）was employed to optimize the discharge reactor structure and investigate the dye degradation.A dye mixture of methylene blue,acid orange and methyl orange was used as a model pollutant.The results indicated that the reactor structure of the GSD system with the ratio of tube inner surface area and volume of 2.48,screw pitch between a high-voltage electrode of 9.7 mm,high-voltage electrode wire diameter of 0.8 mm,dielectric tube thickness of2.0 mm and tube inner diameter of 16.13 mm presented a better ozone（O_3）generation efficiency.Furthermore,a larger screw pitch and smaller wire diameter enhanced the O_3generation.After the dye mixture degradation by the optimized GSD system,73.21%and 50.74%of the chemical oxygen demand（COD）and total organic carbon removal rate were achieved within 20 min,respectively,and the biochemical oxygen demand（BOD）and biodegradability（BOD/COD）improved.

A Condensed Gas-Phase Chemical Model and Its Application

Using the 'lumped mechanism' and 'counting species' methods, we developed a condensed gas-phase chemical model based on a simplified one. The modified quasi-steady-state approximation (QSSA) scheme and the error redistribution mass conservation technique are adopted to solve the atmospheric chemistry kinetic equations. Results show that the condensed model can well simulate concentration variations of gas species such as SO2, NOX, O-3, H2O2 and conversion rates of SO2 and NOX transformation to H2SO4 and HNO3. These results are in good agreement with those from the simplified model. The conversion rates of SO2 and NOX under different initial concentrations and meteorological conditions are computed, and the results can be directly applied to regional acid deposition model.

NOX -Catalyzed Gas-Phase Activation of Methane: the Formation of Hydrogen

NO_x-catalyzed oxidation of methane without a solid catalyst wasinvestigated, and a hydrogen selectivity of 27% was obtained with an overall methane conversion of34% and a free O_2 concentration of 1.7% at 700℃.

AB INITIO STUDY ON GAS-PHASE FACTION OF Ca WITH HN_3

The reaction of Ca with HN3 has been investigated theoretically by an ah initio MO methodwith electron correlation being taken into account by second-order MLLER-PLESSET(MP2)perturbation theory Two possible product channels. CaN3+H. CaNH+N2, on the potential energysurfaces(PESs) have been examined and the reaction mechanism discussed. Values of tile HN-NZ,HN3, Ca-N3 and Ca-AH bond dissociation energy are also calculated, which are in good agreement withexperiment

2-42 Gas-phase Chemistry Study of Ruthenium and Rhodium Carbonyls

In this work, gas-phase chemistry of ruthenium and rhodium was studied using online isothermal chromatographyapparatus at low temperature coupled to the 252Cf SF source[1] at IMP (Fig. 1). Apart from the interferenceof precursor effect[2], 109?110Ru and 111?112Rh were chosen as the representative isotopes for the two elementsrespectively. An improved Monte Carlo molecular simulation program was compiled according to the gas-phasechemistry model[3], and was used in the optimization of the experimental condition. The adsorption enthalpies ofpentacarbonyl ruthenium and tetracarbonyl rhodium on the FEP surface were obtained.

GAS-PHASE ION-MOLECULE REACTIONS OF BUCKMINSTERFULLERENE(C_(60))WITH Si(CH_3)_n CL_(4-n)(n=2,3)IN MASS SPECTROMETER

Reactions of C60 with Si(CH_3)_nCl_(4-n) (n=2,3)in the ion source of the mass spectrometer have been studied.The corresponding adduct ions[C60Si(CH_3)_mCl3_(-m)]^+(m=1,2,3),[C60SiCl]^+ and[C60CH_3]^+ were observed and their possible structures were discussed.The results indicated that C60 is very reactive to electrophiles in the gas phase.

Gas-Phase Conversion of the U(VI), Sr, Mo, and Zr Oxides in Nitrating Atmosphere

The gas-phase conversion of U3O8, MoO3, SrO, and their mechanical mixtures, and also of ZrO2 into water-soluble compounds in the atmosphere of (NOx + vapor H2O) or HNO3 (vapor) was studied. In the course of gas-phase conversion, U3O8 and SrO transform into water-soluble compounds (nitrates, hydroxonitrates), whereas MoO3 and ZrO2 undergo no changes. The principal possibility of separating U from Mo and Zr by gas-phase conversion of the oxides in the atmosphere of (NOx + vapor H2O) or HNO3 (vapor) was demonstrated.

Optimization of a Method for the Simultaneous Determination of Phloroglucinol and Trimethylphloroglucinol by High Performance Liquid Chromatography in Routine Use in a Pharmaceutical Industry in Abidjan

In order to provide the population with safe, effective and good quality medicines, the pharmaceutical industries, before releasing batches of their products into the pharmaceutical circuit, put in place internal dosage methods to control the quality of these products. The present study consisted in optimizing a method for the simultaneous determination of Phloroglucinol (PHG) and Trimethylphloroglucinol (TPH) by high performance liquid chromatography (HPLC) routinely used in a pharmaceutical industry located in a township in Abidjan (Ivory Coast). The basic chromatographic conditions were those routinely used for the determination of these two molecules: mobile phase: acetonitrile/water (60/40), stationary phase (C18 BDS Hypersil 250 mm * 4.6 mm - 5 μm), detection wavelength (265 nm), flow rate, injection volume and run time configured at the equipment level were respectively 1 mL/min, 10 μL and 8 min. The method of preparation of the analytes (PHG and TPHG) was also applied by the pharmaceutical industry. The application of these different parameters at the equipment level made it possible to determine a chromatogram which highlights three chromatographic peaks with respective retention times (RT) of 0.773 min (unidentified compound), 2.275 min (PHG) and 7.269 min for an analysis time of 8 min with a better resolution of the peaks and baseline. The progressive optimization of different parameters such as the stationary phase (C18 YMC 150 mm * 4.6 mm - 3 μm), the proportion of the mobile phase: acetonitrile/water (80/20), the flow rate impelled by the pump (0.8 mL/min) and the modification of the analyte preparation mode (same amount of PHG and TPHG in a 50 mL volumetric flask) resulted in a final chromatogram that highlighted two chromatographic peaks at the respective RT of 2.391 min (PHG) and 3.735 min (TPHG) at a run time of 6 min. The chromatographic conditions that led to the final chromatogram can be used routinely by the pharmaceutical industry for the determination of several PHG and TPHG drug matrices after prior validation of the determination method.

离子色谱指纹图谱分析在烟用香精香料品质评价中的应用

为保证烟用香精香料品质的一致性,采用离子色谱法对烟用香精香料样品中的9种有机酸及7种无机阴离子进行分析。1.0 g样品中加入10 mL去离子水,振荡萃取30 min后,水相溶液用0.45μm微孔滤膜过滤,滤液进一步采用RP前处理柱除去基质,经离子色谱仪分离测定。采用Dionex IonPac AS11-HC阴离子交换柱及淋洗液梯度洗脱,9种有机酸和7种常规无机阴离子标准工作溶液的保留时间和峰面积日内精密度(RSD)分别为0.01%~0.69%和1.34%~2.98%,日间RSD分别为0.03%~0.68%和3.54%~5.16%。同时对烟用香精香料标准样品A~D(各5个批次)中有机酸和无机酸的保留时间和峰面积RSD进行考察,得到的保留时间和峰面积日内RSD分别为0.01%~0.71%和2.39%~3.22%,日间RSD分别0.05%~0.81%和3.61%~6.02%。建立了4种烟用香精香料(各5个批次)的指纹谱图库,并采用系统聚类分析和相似度分析法对其他生产厂家样品进行品质评价。结果表明,聚类分析法能有效地从不同生产厂家的产品中筛选出与标准样品质量最相近的样品;实际样品AY3、BY2、CY2及DY1与香精香料标准品性质最接近,品质较好。相似度分析可以对不同生产厂家的产品质量进行更加具体、量化的评价,实际样品AY3、BY2、CY2及DY1与香精香料标准品的化学成分相似度值均大于97.7%,符合相似度评价要求。相较于超声辅助液液萃取-气相色谱法,对于个别特殊样品,离子色谱法能更有效地区分香精香料样品间的品质差异。

基于代谢组学对“英红9号”及其黄化突变种“黄玉”的红茶生产适制性比较分析

目的 探究“英红9号”黄化突变种“黄玉”的生产适制性。方法 通过广泛靶向的代谢组学和气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)分析了“英红9号”和“黄玉”鲜叶和发酵叶中主要代谢产物的差异,并测定二者间表观物质生化含量如叶绿素类胡萝卜素等,综合代谢物含量进行统计分析。结果 “黄玉”鲜叶中总叶绿素与类胡萝卜素的差值小于“英红9号”。“英红9号”中山奈酚-3-糖苷的含量更高,而“黄玉”中山奈酚-3-葡萄糖苷与山奈酚-3-O-半乳糖苷的比值更高。与“英红9号”鲜叶相比,“黄玉”中作为β-胡萝卜素必要前体物质的玉米黄质和棕榈酸玉米黄质的含量显著较高。“黄玉”发酵叶中由于类胡萝卜素降解能够产生花果风味的物质如:α-法内烯、β-环柠檬醛、橙花叔醇和反式香叶基丙酮的含量均高于“英红9号”。结论 “黄玉”鲜叶中β-葡萄糖苷酶和类胡萝卜素裂解双加氧酶的活性较高。这些代谢特征说明“黄玉”适合生产绿茶、白茶等发酵程度较低的茶。其高活性的酶有助于绿茶的香气和口感形成。相比之下,“英红9号”中的代谢物使其在发酵过程中产生更多的香气成分,如橙油醇和香叶酰丙酮的增加,表明它适合生产红茶。

胶黏剂产品中VOCs含量与类别的检测方法

可靠、高效的检测方法,能够准确测定胶黏剂产品中挥发性有机化合物(VOCs)的含量及类别,进而为胶黏剂产品生产提供参考,不断提升胶黏剂产品的环保安全性。一般采用气相色谱法、气相色谱-检测器联用法、气相色谱-质谱法,通过优化顶空条件、色谱柱选择和质谱参数,实现对目标VOCs的高灵敏度、高选择性检测。这些方法能够有效分离和定量分析胶黏剂产品中的多种VOCs,包括烷烃、烯烃、芳香烃、醛类、酮类等,获得了VOCs含量和类别分布的详细数据,为胶黏剂产品中VOCs含量和类别的检测提供了一种可靠、高效的解决方案,可用于评估胶黏剂产品的环境友好性,并为制定相关标准和法规提供技术支持。

纳米晶纤维素组装的手性介孔材料及其对手性药物的分离

纤维素纳米晶体(CNC)是由硫酸催化的纤维素水解制备的,根据纤维素的来源和水解条件,纳米晶体的直径约为5~15 nm,长度约为100~300 nm。CNC在水中可以形成具有手性向列型结构的液晶相。当干燥成固体薄膜时,CNC保持螺旋手性向列顺序并组装成层状结构。在CNC自组装过程中,可以添加溶胶-凝胶前体,如Si(OMe)_(4)。随着溶剂的蒸发,这些前体会发生水解和缩合,从而形成手性向列相二氧化硅/CNC复合材料。复合材料在空气中煅烧破坏纤维素模板,留下高表面积手性向列结构的介孔二氧化硅膜。此外,有机二氧化硅或二氧化钛薄膜也采用类似的方法得到。这些薄膜可用作滤光片、反射器和薄膜。最重要的是,合成的手性介孔二氧化硅可用作手性色谱固定相材料分离手性药物。结果显示,手性分离的效果显著,为CNC开发手性新材料提供了新方法。