Mass Transfer Characteristics in an Agitated Slurry Reactor Operating Under Fischer-Tropsch Conditions
Mass Transfer Characteristics in an Agitated Slurry Reactor Operating Under Fischer-Tropsch Conditions
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费托条件下运行的搅拌浆料反应器的传质特性
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
J. Soriano
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文献类型：
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作者：
J. Soriano
在这项研究中，平衡溶解度，C*，和体积传质系数，kLa，测量4种不同的气体（He，CO，N2和H2）在两种不同的液体（聚α-烯烃，PAO-8和C70沙索蜡）在1升搅拌反应器中操作的气体诱导模式下的典型条件下的费托合成。操作变量的影响，包括压力（0.7 - 3.5 MPa）、温度（423 - 523 K）、混合速度（13.3 - 20 Hz）和氧化铝粉末（用作钴催化剂的载体）浓度（0 - 50 wt.%）使用中心复合统计设计和分析技术对kLa和C* 值进行统计学研究。数据是在覆盖费托合成工业范围的宽范围操作条件下测量的。采用瞬态物理气体吸收技术测定了在所用操作条件下的kLa。在所用的两种液体中，四种气体的C* 值似乎在恒定温度下随着压力的增加而线性增加，即，在所研究的压力范围内遵守亨利定律。发现C* 值随温度的升高先减小后增大，温度对C* 的影响可用Arkenius型方程描述，其中吸附的表观活化能是温度的函数。四种气体在两种液体中的溶解度大小为：C*CO>C*N2>C*H2>C*He，在Sasol蜡中的溶解度略高于在PAO-8中的溶解度。四种气体在两种液体中的kLa值随压力、温度和混合速度的增加而增加。然而，kLa值在固体浓度小于30重量%时略微降低（20%），然后随着固体浓度从30重量%增加到50重量%而急剧降低（80%）。在类似的操作条件下，四种气体的kLa值被发现在沙索蜡中比在PAO-8中更高。这种行为与沙索蜡中产生的更大的气-液界面面积有关，因为与PAO-8相比，沙索蜡具有更低的表面张力和发泡性。开发了统计相关性来预测两种液体中四种气体的kLa值，回归系数（R2）大于97%。此外，经验关联使用无量纲数，提出了预测kLa值在气体感应浆料搅拌反应器的回归系数（R2）大于94%。
In this study, the equilibrium solubility, C*, and the volumetric mass transfer coefficient, kLa, were measured for 4 different gases (He, CO, N2 and H2) in two different liquids (Poly-Alpha-Olefins, PAO-8 and C70 Sasol Wax) in a 1-liter agitated reactor operating in a Gas Inducing mode under the typical conditions of Fischer-Tropsch synthesis. The effect of operating variables, including pressure (0.7 - 3.5 MPa), temperature (423 - 523 K), mixing speed (13.3 - 20 Hz), and alumina powder (used as a support for cobalt catalyst) concentration (0 - 50 wt.%) on kLa and C* values were statistically investigated using the Central Composite Statistical design and analysis technique. The data were measured within wide ranges of operating condition covering the industrial range of this Fischer-Tropsch synthesis. The transient physical gas absorption technique was used to determine kLa under the operating conditions used.The C* values for the four gases in the two liquids used appeared to increase linearly with increasing pressure at constant temperature, i.e., obey Henry's Law over the pressure ranges studied. The C* values were found to decrease and then increase with increasing temperature and the effect of temperature on C* was described by an Arrhenius-type equation, where the apparent activation energy of absorption was a function of temperature. The solubility values for the four gases in the two liquids used followed the trend: C*CO>C*N2>C*H2>C*He and the values in Sasol wax were slightly higher than obtained those in PAO-8.The kLa values for the four gases in the two liquids were found to increase with increasing pressure, temperature and mixing speed. The kLa values, however, slightly decreased (20%) at solid concentrations less than 30 wt% and then dramatically decreased (80%) with increasing solid concentrations from 30 to 50 wt%. Under similar operating conditions, kLa values for the four gases were found to be higher in Sasol wax than in PAO-8. This behavior was related to the greater gas-liquid interfacial area created in the Sasol wax due to its lower surface tension and foamability when compared with those of the PAO-8. Statistical correlations were developed to predict the kLa values for the four gases in the two liquids with a regression coefficient (R2) greater than 97%. Also, an empirical correlation using dimensionless numbers was proposed to predict kLa values in gas induction slurry agitated reactors with a regression coefficient (R2) greater than 94%.