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本文用四个并联的蒸气相裂解器在气相色谱—裂解气相色谱联用装置,四个裂解器的温度为406.554,658及768℃,解决了实用的气相色谱—裂解气相色谱联用分析要求有普遍适用的裂解温度的问题,同时得到较多较大的裂解色谱峰,使定性更加准确。 相似文献
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设计了一种裂解气相色谱--裂解毛细柱气相色谱联用仪。在第一级裂解气相色谱仪把聚合物裂解并分离裂解产物,分离了的产物用六通气体进样阀选取并逐个在第二级裂解气相色谱仪裂解,得到聚合物裂解产物的裂解气相色谱图。与低分子化合物的标准指纹图比较,这些裂解产物就得到确认,这样,就可以充分肯定地推断复杂聚合物的组成。 相似文献
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Natural gas hydrate occurrences contain predominantly methane; however, there are increasing reports of complex mixed gas hydrates and coexisting hydrate phases. Changes in the feed gas composition due to the preferred incorporation of certain components into the hydrate phase and an inadequate gas supply is often assumed to be the cause of coexisting hydrate phases. This could also be the case for the gas hydrate system in Qilian Mountain permafrost (QMP), which is mainly controlled by pores and fractures with complex gas compositions. This study is dedicated to the experimental investigations on the formation process of mixed gas hydrates based on the reservoir conditions in QMP. Hydrates were synthesized from water and a gas mixture under different gas supply conditions to study the effects on the hydrate formation process. In situ Raman spectroscopic measurements and microscopic observations were applied to record changes in both gas and hydrate phase over the whole formation process. The results demonstrated the effects of gas flow on the composition of the resulting hydrate phase, indicating a competitive enclathration of guest molecules into the hydrate lattice depending on their properties. Another observation was that despite significant changes in the gas composition, no coexisting hydrate phases were formed. 相似文献
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炼厂气是炼油工艺产生的各种气体的混合物,采用四阀六柱将炼厂气分离分解为3部分,以双TCD+FID检测器3通道气相色谱法快速分析炼厂气.FID通道用于分析烃类,一个TCD通道分析永久性气体和硫化物,另一个TCD通道分析氢气,采用面积归一化法定量计算分析结果.用该法测定了3种标准气体,测定值与标准值基本一致,测定结果的相对标准偏差小于8%.该法适用于测定包括液化气、烟气、裂解气等组分相近的样品组成. 相似文献
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Bajpai Rakesh Thompson James E. Davison Brian H. 《Applied biochemistry and biotechnology》1990,(1):485-496
A number of studies in the published literature deal with gas holdup in three-phase reactors. However, very few address the
cases in which the solid density approaches that of the liquid phases and in which low gas velocities are involved. These
conditions are commonly encountered in immobilized-cell bubble columns and in fluidized-bed bioreactors. This paper reports
the effect of gas and liquid velocity upon gas holdup and bed expansion in fluidized-bed bioreactors.
For liquid-fluidization of low-density alginate beads in the absence of gas, the terminal sedimentation velocity (vT) of the
particles is a constant, and expansion of the bed follows Richardson and Zaki’s correlation. In the presence of gas, however,
the apparent terminal sedimentation velocity value is affected by the velocity of the gas and liquid phases. For gas velocities
above a minimum value, the calculated value of vT depends on liquid velocity only, and a constant bed expansion was observed
for a range of gas and liquid flow rates. For the gas-liquid interactions, a modified drift-flux model was found to be valid.
For superficial gas velocities between 5 and 17 cm/min, the modified drift-flux velocity was observed to be a function of
gas velocity, suggesting the prevalence of a coalescence regime. 相似文献
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建立毛细管柱气相色谱法测定液化石油气中二甲醚含量的分析方法。采用静止进样法直接进样,用PLOT–Q毛细管色谱柱进行分离,以FID检测器进行检测,外标法进行定量分析。液化石油气中二甲醚的含量(体积分数)在0%~20.0%范围内与其色谱峰面积呈良好线性关系,线性相关系数r=0.999 9,方法检出限为0.05%(体积分数),测定结果的相对标准偏差小于5%(n=6),回收率在98.2%~102.9%之间。该方法与校正面积归一法测定结果相一致。该方法准确、快速、简便,适用于液化石油气中二甲醚含量的检测。 相似文献
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Measured forces between apolar surfaces in water have often been found to be sensitive to exposure to atmospheric gases despite low gas solubilities in bulk water. This raises questions as to how significant gas adsorption is in hydrophobic confinement, whether it is conducive to water depletion at such surfaces, and ultimately if it can facilitate the liquid-to-gas phase transition in the confinement. Open Ensemble molecular simulations have been used here to determine saturated concentrations of atmospheric gases in water-filled apolar confinements as a function of pore width at varied gas fugacities. For paraffin-like confinements of widths barely exceeding the mechanical instability threshold (spinodal) of the liquid-to-vapor transition of confined water (aqueous film thickness between three and four molecular diameters), mean gas concentrations in the pore were found to exceed the bulk values by a factor of approximately 30 or approximately 15 in cases of N2 and CO2, respectively. At ambient conditions, this does not result in visible changes in the water density profile next to the surfaces. Whereas the barrier to capillary evaporation has been found to decrease in the presence of dissolved gas (Leung, K.; Luzar, A.; and Bratko, D. Phys. Rev. Lett. 2003, 90, 065502), gas concentrations much higher than those observed at normal atmospheric conditions would be needed to produce noticeable changes in the kinetics of capillary evaporation. In simulations, dissolved gas concentrations corresponding to fugacities above approximately 40 bar for N2, or approximately 2 bar for CO2, were required to trigger expulsion of water from a hydrocarbon slit as narrow as 1.4 nm. For nanosized pore widths corresponding to the mechanical instability threshold or above, no significant coupling between adsorption layers at opposing confinement walls was observed. This finding explains the approximately linear increase in gas solubility with inverse confinement width and the apparent validity of Henry's law in the pores over a broad fugacity range. 相似文献
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Gas/solid reactions of acetone vapor with neutral organic compounds, salts, or host crystals with strict exclusion of solvents are reported. This gas/solid technique largely avoids waste formation and saves resources. Starting hydrochlorides or hydrobromides are also synthesized by gas/solid techniques. Dihydrohalides of o-phenylenediamines give 1,5-benzodiazepines 3 , aromatic and aliphatic 1,2-aminothiols (o-aminothiophenol, penicillamines, cysteine) yield five-membered thiazolines and thiazolidines 7, 9, 11, 13. Virtually all carbonyl reagents of the primary amino type 14 give quantitatively the imino derivatives 15 and water. Salt formation may be helpful for increasing melting points and sometimes reactivity as in 8, 10 , and 12 if surface passivation has to be overcome. In the case of solid 14 the free bases react equally well. Acetone ( 2 ) may be quantitatively removed from exhaust gases by using hydroxylaminium phosphate with formation of free acetone oxime at high flow rates. Inclusion of acetone into various hosts ( 17-20 , but not 16 ) is more efficient by imbibition from the gas phase than by crystallization from acetone as the solvent. This advantage may be utilized for gas separations. Some further gases (vapors) coexist in imbibed clathrates whereas others do not. The mechanisms of the gas/solid reactions are elucidated using atomic force microscopy (AFM). Phase rebuildings involve anisotropic movements of molecules over large distances and the formation of characteristic features. In some cases surface hydrates catalyze the gas/solid reaction. Solid-state mechanisms for imbibition from the gas phase into host crystals with formation of clathrates are similar in nature to those of the covalent reactions. These results are correlated with known X-ray crystal structures where available. 相似文献