A Compilation of Rate Parameters of Water-Mineral Interaction Kinetics for Application to Geochemical Modeling
A Compilation of Rate Parameters of Water-Mineral Interaction Kinetics for Application to Geochemical Modeling
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DOI：
10.3133/ofr20041068
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发表时间：
2004-03
期刊：
影响因子：
--
通讯作者：
J. Palandri;Y. Kharaka
中科院分区：
文献类型：
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作者：
J. Palandri;Y. Kharaka
摘要：地球化学反应路径模拟对于快速评估自然系统和工业过程中水-水-气相互作用的程度是有用的。一些系统的建模，如那些在低温与相对较高的水文流量，或那些扰动地下注入工业废物，如CO2或H2S，必须考虑相对缓慢的动力学矿物-气体-水的相互作用。因此，我们编制了参数符合一般的Arkenius型速率方程，超过70种矿物，包括所有主要类别的硅酸盐，大多数碳酸盐，和许多其他非硅酸盐相。这些数据已被添加到一个计算机代码，模拟一个无限搅拌间歇反应器，允许计算的传质作为时间的函数。实际的平衡速率预计会比所选计算机代码预测的速率慢得多，这主要是因为实际的地球化学过程通常涉及通过多孔或裂缝介质的流动，其中在矿物表面附近的水相中形成浓度梯度，这导致绝对化学亲和力降低和反应速率减慢。由于超出大多数地球化学模拟器范围的变量，如粒度变化、含水层异质性、首选流体流动路径、原生和次生矿物涂层以及可能导致孔隙度降低和孔喉堵塞的次生矿物，可能会出现观察到的反应速率和计算出的反应速率之间的进一步差异。
Abstract : Geochemical reaction path modeling is useful for rapidly assessing the extent of water-aqueous-gas interactions both in natural systems and in industrial processes. Modeling of some systems, such as those at low temperature with relatively high hydrologic flow rates, or those perturbed by the subsurface injection of industrial waste such as CO2 or H2S, must account for the relatively slow kinetics of mineral-gas-water interactions. We have therefore compiled parameters conforming to a general Arrhenius-type rate equation, for over 70 minerals, including phases from all the major classes of silicates, most carbonates, and many other non-silicates. These data have been added to a computer code that simulates an infinitely well-stirred batch reactor, allowing computation of mass transfer as a function of time. Actual equilibration rates are expected to be much slower than those predicted by the selected computer code, primarily because actual geochemical processes commonly involve flow through porous or fractured media, wherein the development of concentration gradients in the aqueous phase near mineral surfaces, which results in decreased absolute chemical affinity and slower reaction rates. Further differences between observed and computed reaction rates may occur because of variables beyond the scope of most geochemical simulators, such as variation in grain size, aquifer heterogeneity, preferred fluid flow paths, primary and secondary mineral coatings, and secondary minerals that may lead to decreased porosity and clogged pore throats.