HI_(x)溶液的密度计算模型

The Density Model of HI_(x) Solution

氢是最佳能源载体之一,硫–碘(S-I)循环作为极具潜力的热化学循环制氢技术而被广泛关注。HI-H_(2)O-I_(2)(HI_(x))溶液是S-I循环核心环节Bunsen反应中的主要流体形态。不同温度组分下HIx溶液的密度数据对Bunsen反应器设计、液相分离过程分析等具有重要意义。本文综合分析了已发表的HIx溶液密度数据,基于比体积与活度系数关系,分别采用ELECNRTL模型和Wilson模型建立了理论密度模型。此外,基于热膨胀率建立了半经验密度模型。结果表明,采用ELECNRTL模型建立的理论密度模型的平均相对偏差(ARD)为6.95%,在模型中未考虑短程作用带来的影响,说明在HI_(x)溶液中短程作用不可忽略;采用Wilson模型建立的理论密度模型的ARD为1.21%,在低HI和低I_(2)浓度条件下具有较高的预测精度;采用基于热膨胀率拟合密度的半经验密度模型具有最高的计算精度,在假设热膨胀率与比体积具有二次关系时,ARD为0.93%。

Hydrogen is considered one of the most optimum energy carriers,and the sulfur-iodine(S-I)cycle is widely regarded as a promising thermochemical approach for producing hydrogen.HI-H_(2)O-I_(2)(HI_(x))solution is the major fluid medium in the Bunsen reaction,which is the core and essential part of the S-I cycle.For the design of Bunsen reactor and analysis of the liquid-liquid separation,HI_(x) solution density data in different temperature and composition is significant.This work comprehensively analyzed the published density data of HI_(x) solution.The ELECNRTL and Wilson models were used to develop the theoretical density model by considering the relationship between specific volume and activity coefficient.Additionally,the semi-empirical density model was developed based on the thermal expansion rate.The results showed that the average relative deviation(ARD)of the theoretical density model derived from ELECNRTL model is 6.95%,and this density model did not account for short-range interactions,suggesting that these interactions in the HIx solution are significant and should not be overlooked.The ARD of the theoretical density model derived from the Wilson model is 1.21%,showing high prediction accuracy at low HI and I_(2) concentrations.The semi-empirical density model,which assumed a quadratic relationship between thermal expansion rate and specific volume,achieved the highest calculation accuracy with an ARD of 0.93%.