论文标题
流体系统的热力学模型H2O-CO2-NACL-CACL2在中层和下地壳的P-T参数下
Thermodynamic model of the fluid system H2O-CO2-NaCl-CaCl2 at P-T parameters of the middle and lower crust
论文作者
论文摘要
基于三元系统H2O-CO2-CACL2和H2O-CO2-NACL的较早获得的状态方程，四组分流体系统H2O-CO2-NACL-CACL2的状态方程是根据Gibbs多余的自由能得出的。建立了相应的数值热力学模型。模型的数值参数的主要部分与三元系统的相应参数一致。 NaCl-CACL2相互作用参数是从盐混合物的实验液体中获得的。类似于H2O-CO2-CACL2和H2O-CO2-NACL的热力学模型，该模型的适用性范围是压力为1-20 kbar，温度从500C到1400c。该模型可以预测大多数深质石化过程中涉及的流体的物理化学特性：系统的相位状态（均匀或多相流体，存在或不存在固体盐），组件的化学活性，流体相位的密度，以及在现有相的组分的浓度。该模型用于详细研究，当将比率从1到0更改XNACL/（XNACL+XCACL2）时，水对H2O-CO2-SALT切片的活性。获得了二氧化碳不同摩尔级分的部分H2O-NACL-CACL2部分上的一组相图。对于系统的几种盐组成，获得了共存不合混合流体阶段的水最大活性的压力依赖性。由于取消了由三元系统中较少数量的成分产生的限制，因此具有盐混合组成的系统的热力学行为与单个盐分成分的人的行为有显着差异。
Based on the earlier obtained equations of state for the ternary systems H2O-CO2-CaCl2 and H2O-CO2-NaCl, an equation of state for the four-component fluid system H2O-CO2-NaCl-CaCl2 is derived in terms of the Gibbs excess free energy. A corresponding numerical thermodynamic model is build. The main part of the numerical parameters of the model coincides with the corresponding parameters of the ternary systems. The NaCl-CaCl2 interaction parameter was obtained from the experimental liquidus of the salt mixture. Similar to the thermodynamic models for H2O-CO2-CaCl2 and H2O-CO2-NaCl, the range of applicability of the model is pressure 1-20 kbar and temperature from 500C to 1400C. The model makes it possible to predict the physicochemical properties of the fluid involved in most processes of deep petrogenesis: the phase state of the system (homogeneous or multiphase fluid, presence or absence of solid salts), chemical activities of the components, densities of the fluid phases, and concentrations of the components in the coexisting phases. The model was used for a detailed study of the phase state and activity of water on the H2O-CO2-salt sections when changing the ratio xNaCl/(xNaCl+xCaCl2) from 1 to 0. Changes in the composition and density of coexisting fluid phases at a constant activity of water and changes in the total composition of the system are studied. A set of phase diagrams on sections H2O-NaCl-CaCl2 for different mole fractions of CO2 is obtained. Pressure dependencies of the maximal activity of water in the field of coexisting unmixable fluid phases are obtained for several salt compositions of the system. Due to removal of restrictions resulting from a smaller number of components in ternary systems, the thermodynamic behavior of systems with a mixed composition of the salt is significantly differ from the behavior of those with a single salt component.
