Department of Physical and Colloid Chemistry, Gubkin University, 65, Leninsky Prospekt, Building 1, 119991 Moscow, Russia.
Department of Petroleum Engineering, Kazan Federal University, Kremlevskaya Str. 18, 420008 Kazan, Russia.
Int J Mol Sci. 2023 May 26;24(11):9321. doi: 10.3390/ijms24119321.
Precise data on the non-variant equilibrium of the four phases (vapor-aqueous solution-ice-gas hydrate) in - coordinates are highly desired for developing accurate thermodynamic models and can be used as reference points (similar to the triple point of water). Using the two-component hydrate-forming system CO-HO, we have proposed and validated a new express procedure for determining the temperature and pressure of the lower quadruple point Q. The essence of the method is the direct measurement of these parameters after the successive formation of the gas hydrate and ice phases in the initial two-phase gas-water solution system under intense agitation of the fluids. After relaxation, the system occurs in the same equilibrium state ( = 271.60 K, = 1.044 MPa), regardless of the initial parameters and the order of crystallization of the CO hydrate and ice phases. Considering the combined standard uncertainties (±0.023 K, ±0.021 MPa), the determined and values agree with the results of other authors obtained by a more sophisticated indirect method. Validating the developed approach for systems with other hydrate-forming gases is of great interest.
非常需要精确的数据来描述在-坐标下的四个相（气相-水相溶液-冰-气体水合物）的非变体平衡，这对于开发准确的热力学模型非常重要，并且可以用作参考点（类似于水的三相点）。使用 CO-HO 双组分水合物形成系统，我们提出并验证了一种新的确定下四重点 Q 的温度和压力的快速程序。该方法的本质是在强烈搅拌下使初始两相气-水溶液系统中连续形成气体水合物和冰相后直接测量这些参数。在松弛后，无论初始参数和 CO 水合物和冰相的结晶顺序如何，系统都处于相同的平衡状态（=271.60 K，=1.044 MPa）。考虑到综合标准不确定度（±0.023 K，±0.021 MPa），确定的和值与其他作者通过更复杂的间接方法获得的结果一致。验证该方法对于具有其他水合物形成气体的系统具有重要意义。
