Temperature Sensitive Nanocapsule of Complex Structural Form for Methane Storage

The processes of methane adsorption, storage and desorption by the nanocapsule are investigated with molecular-dynamic modeling method. The specific nanocapsule shape defines its functioning uniqueness: methane is adsorbed under 40 MPa and at normal temperature with further blocking of methane molecules the K@C60¹⁺ endohedral complex in the nanocapsule by external electric field, the storage is performed under normal external conditions, and methane desorption is performed at 350 K. The methane content in the nanocapsule during storage reaches 11.09 mass%. The nanocapsule consists of tree parts: storage chamber, junction and blocking chamber. The storage chamber comprises the nanotube (20,20). The blocking chamber is a short nanotube (20,20) with three holes. The junction consists of the nanotube (10,10) and nanotube (8,8); moreover, the nanotube (8,8) is connected with the storage chamber and nanotube (10,10) with the blocking chamber. The blocking chamber is opened and closed by the transfer of the K@C₆₀ ¹⁺ endohedral complex under electrostatic field action.     

Methane hydrate formation and dissociation behaviors in montmorillonite

The methane hydrate formation and the methane hydrate dissociation behaviors in montmorillonite are experimentally studied. Through the analyses of the microstructure characteristic, the study obtains the porous characteristic of montmorillonite. It is indicated that methane hydrate in montmorillonite forms the structure I(sI) crystal.Meanwhile, molecular dynamics simulation is carried out to study the processes of the methane hydrate formation and the methane hydrate dissociation in montmorillonite. The microstructure and microscopic properties are analyzed. The methane hydrate formation and methane hydrate dissociation mechanisms in the montmorillonite nanopore and on the montmorillonite surface are expounded. Combining the experimental and simulating analyses,the results indicate the methane hydrate formation and methane hydrate dissociation processes have little influence upon the crystal structure of porous media from either micro-or macro-analysis. It is beneficial to the fundamental researches on the exploitation and security control technologies of natural gas hydrate in deep-sea sediments.     

Methane Oxidation in Pig and Cattle Slurry Storages, and Effects of Surface Crust Moisture and Methane Availability

Storages with liquid manure (slurry) may develop a surface crust of particulate organic matter, or an artificial crust can be established. Slurry storages are net sources of atmospheric methane (CH₄), but a potential for bacterial oxidation of CH₄ in surface crusts was recently suggested in a study of experimental storages. The present study was conducted to investigate methanotrophic activity under practical storage conditions. Surface crusts from slurry storages at two pig farms and four dairy farms were sampled in late autumn. Mixed samples (0–4 cm depth) were used to determine changes in CH₄, O₂ and CO₂ during incubation, while intact subsamples were used to characterize CH₄ oxidation as a function of CH₄ availability and moisture content. Methane oxidation was observed in all materials except for an expanded clay product (Leca) sampled from a pig slurry storage. Despite significant variation between replicate subsamples, there was a significant increase in methanotrophic activity when CH₄ concentrations increased from 500 to 50,000 ppmv. Maximum fluxes ranged from −1 to −4.5 g CH₄ m⁻² d⁻¹. Surface crust samples were partly dried and then re-wetted in four steps to the original moisture content, each time followed by determination of CH₄ fluxes. Only one surface crust material showed a relationship between CH₄ fluxes and moisture content that would implicate gas diffusivity in the regulation of CH₄ oxidation. The occurrence of inducible CH₄ oxidation activity in slurry storage surface crusts indicates that there is a potential for stimulating the process by manipulation of gas phase composition above the stored slurry.     

苯乙烯安全储存方法的分析与研究

通过介绍苯乙烯的性质,分析影响苯乙烯品质的各种指标和因素,并结合工程实际数据,总结了苯乙烯储存过程中可能发生的各种问题并提出了切实可行的解决措施和方案,在实际工程和项目中具有一定的指导和借鉴意义。     

液化石油气球罐储存安全设计

以液化石油气球罐为例,从相关规范的要求着手,考虑设计参数的选择,仪表设计、阀门设计等方面的问题,采取相应的安全措施,从而达到液化石油气球罐储存安全的目的。     

硝酸酯火药安全贮存寿命的预估方法和结果

介绍了热加速老化试验预估火药安全贮存寿命的方法原理。对硝酸酯火药进行不同温度（95,90,85,75和65℃）的热加速老化。以有效安定剂消耗一半所需时间（τ）作为安全贮存寿命的临界点,对不同温度（t）下的τ值,用线性最小二乘法按Bethelot方程进行线性回归,预测了硝酸酯火药在常温（30℃）下的安全贮存寿命。收集了80余种硝酸酯火药安全贮存寿命的预估结果。结果发现,一般单基、双基、三基发射药和双基推进剂的安全贮存寿命在40a以上,而加入AP、TEGN等成分改性的双基发射药和推进剂安全贮存寿命大多低于40a。比较了4个温度点与5个温度点回归处理结果的差异。提出取消90℃试验,必要时增加55℃试验的建议。根据硝酸酯火药老化分解速率的温度系数和低温试验统计结果,提出单温度（65℃）短周期预测硝酸酯火药安全贮存寿命的简便方法。     

基于凝胶干水的水合物储甲烷实验研究

利用搅拌器通过高速剪切的方法制备了疏水性气相二氧化硅(HB-630):结冷胶:水的质量比为1:2:17的凝胶干水,用显微镜观察了其微观形貌,并用高压水合物反应装置对其进行了储甲烷实验研究。显微观察发现,凝胶干水粒径范围为10～150(?)m。储甲烷实验表明,在压力为7.98 MPa、温度为0.8℃左右甲烷能在6 min内与凝胶干水作用快速生成水合物,并且2 h内储甲烷量达到100(V/V),大大提高了水合物储甲烷速率和短时间内的储气量。通过5次循环储甲烷实验发现,凝胶干水储甲烷量随着循环次数的增加而降低。     

长效家庭粮食储藏剂

本文提出一种家庭用防治储粮害虫的复配型杀虫剂。该药剂能放出Ｈ３Ｐ和ＣＨ３Ｂｒ混合气体，持效６个月。杀虫、杀菌、驱鼠效果明显，对人畜无害，且粮垛不需密封，取粮方便。     

煤层气水合物技术在储运中的应用

对煤层气和水在一定条件下生成结晶状物质（NGH）从而使得煤层气以固态方式储运进行了研究。结果表明：NGH制备和储存条件温和，分解技术难度不大。与传统储运技术相比，应用NGH技术储运煤层气密度高、费用低，而且安全可靠，在煤层气储运和矿井瓦斯处理等方面都具有很高的应用价值。     

冷库维护结构绝热层厚度的计算

介绍冷库维护结构传热系统K的确定及维护结构绝热层厚度的计算方法。     

次氯酸钙对水合物中甲烷储气量的影响

1 INTRODUCTION At present,natural gas accounts for 3% of the total energy consumption in China.It will go up to 5% in 2005 and 8% in 2010. Natural gas storage is a subject of great interest to many industries and particularly to transportation.Compressed natural gas,liquefied natural gas and adsorbed natural gas are techniques widely used.The possibility of developing a convenient storage system based on hydrate has been explored for about ten years around the world[1-5].Gudmundsson[1] has focused on the storage and transportation of gas as hydrate at atmospheric pressure since 1990.Khokhar[2] used 1,3-dimethylcyclohexane and polyvinyl-pyrrolidone as additives to lower hydrate formation pressure. Saito[3] surveyed the effects of tetrahydrofuran and acetone.Rogers[3] used sodium dodecyl sulfate as accelerator to natural gas hydrate formation. In this work,the effects of calcium hypochlorite on hydrate formation are investigated.The data show that it can lower the degree of supercooling and enhance the relative cage occupancy.     

一种评估库存发射药安全贮存寿命的方法

为了科学评估库存发射药的安全贮存寿命,通过对库存弹药(发射药)长期贮存试验研究,得到了在库存环境下贮存30多年部分发射药的DPA含量试验数据,建立了相应的数据处理数学模型和安全贮存寿命预测方法。依据试验结果和该数据处理方法,计算出该发射药在置信水平为90％的条件下,安全贮存寿命不低于56年。经试验验证,该评估结果与实际情况基本相符,表明提出的估算库存发射药安全寿命的方法是可以接受的。     

Numerical Analysis of the Catalytic Combustion of Premixed Methane/Air Mixtures in Microtubes

The combustion characteristics and extinction limits for the catalytic combustion of a methane/air mixture in a microtube are investigated computationally using the commercial CFD code FLUENT coupled to an external subroutine DETCHEM. The effects of the microtube dimensions, conductivities of wall materials, external heat losses and flow velocity on the combustion stability, are also studied. The numerical model is set as either adiabatic or non‐adiabatic with a fixed exterior heat transfer coefficient. Numerical results indicate that thermal conductivity and wall thickness are vital to preheat the methane/air mixture through the conducting wall. Two types of extinction occur, i.e., thermal quenching and blow out. These extinction limits are characterized by wall surface temperature in the microtube and the ratio of Pt(s)/O(s).     

Modified Lanthanum Catalysts for Oxidative Chlorination of Methane

Mixtures of LaOCl and LaCl₃ are promising catalysts for oxidative chlorination of methane to methyl chloride. The influence of metal dopants such as Co, Ni and Ce, which form stable chlorides under anticipated reaction conditions, on physicochemical and catalytic properties was explored. The presence of markedly redox-active dopants such as cobalt and cerium lead to a higher rate of methane conversion. However, the formed methyl chloride is strongly adsorbed and directly oxidized to CO leading to low methyl chloride selectivity. Doping with nickel weakens, in contrast, the interaction with methyl chloride leading to high methyl chloride selectivity. Angeliki A. Lemonidou is on leave from the Department of Chemical Engineering, Aristotle University Thessaloniki.     

Methane desorption from a coal-bed

We study the desorption of methane from a coal-bed. A model taking into account both methane diffusion in coal - blocks and its filtration through the system of open pores and cracks is developed. Methane pressure in the coal-bed is found for an arbitrary instant of time. Dependency of the rate of methane release upon the block size, open and closed porosity, viscosity, solubility, bed pressure and temperature is established. We derive the effective coefficient of diffusion of methane in blocks containing closed pores filled with gaseous methane. It is shown that at a hindered diffusion methane is distinctly divided into the “quick” and the “slow” one.     

非等温甲烷蒸汽转化反应催化剂的效率因子

本文将环柱状甲烷蒸汽转化催化剂简化为周边封闭的薄片状催化剂,建立了非等温效率因子的计算模型并用正交配置法求解。计算结果合理,计算速度快。     

Methane Oxyforming for Synthesis Gas Production

This article is concerned with the reforming of methane to synthesis gas; a review of the steam reforming Rxn is presented, and the dry reforming and partial oxidation Rxns introduced. Collectively, these processes are known as “oxyforming.” A background to oxyforming, industrial practice, and some of the most important latest developments will be presented, along with a section on the uses of synthesis gas. The current understanding of the Rxn mechanisms for the three processes and the problem of deactivation by carbon deposition will be discussed in detail. Finally, the economics of synfuel production will be addressed and compared with the production of other fuels, and the future directions and outlook for oxyforming will be forwarded. This article should allow the reader to make comparisons between these three important industrial reactions.     

Methane to higher hydrocarbons via halogenation

Activation of methane with a halogen followed by the metathesis of methyl halide is a novel route from methane to higher hydrocarbons or oxygenates. Thermodynamic analysis revealed that bromine is the most suitable halogen for this goal. Analysis of the published data on the reaction kinetics in a CSTR enabled us to judge on the effects of temperature, reactor residence time and the feed concentrations of bromine and methane to the conversion of methane and the selectivity towards mono or dibromomethane. The analysis indicated that high dibromomethane selectivity is attainable (over 90%) accompanied by high methane conversions. The metathesis of dibromomethane can provide an alternative route to the conversion of methane (natural gas) economically with smaller installations than the current syn-gas route.     

Methane Oxyforming for Synthesis Gas Production

This article is concerned with the reforming of methane to synthesis gas; a review of the steam reforming Rxn is presented, and the dry reforming and partial oxidation Rxns introduced. Collectively, these processes are known as “oxyforming.” A background to oxyforming, industrial practice, and some of the most important latest developments will be presented, along with a section on the uses of synthesis gas. The current understanding of the Rxn mechanisms for the three processes and the problem of deactivation by carbon deposition will be discussed in detail. Finally, the economics of synfuel production will be addressed and compared with the production of other fuels, and the future directions and outlook for oxyforming will be forwarded. This article should allow the reader to make comparisons between these three important industrial reactions.     

用于甲烷选择性氧化反应制甲醇的膜催化技术

研究了将甲烷选择性地一次氧化制取甲醇的膜催化技术。采用ZrO2－Y2O3陶瓷膜，在较温和的反应条件下（常压，460℃左右），可以将甲烷选择性地一次氧化成为甲醇。