【作者】 罗祎青；

【导师】 袁希钢；

【作者基本信息】 天津大学 ， 化学工程， 2003， 博士

【摘要】 核能是目前公认的能最大规模替代矿物燃料的能源。受控聚变的研究已给人类展示出取得更加安全、清洁，而且是无限丰富的能源的美好前景。在廉价制取聚变燃料氘以及提高核能原料利用率的方法中，低温精馏被认为是最经济可行的分离氢同位素的方法。然而，由于氢同位素物系的一些特殊性，使氢溶液的汽液平衡数据很难测得，到目前为止，还没有一个可以准确描述氢溶液的热力学模型。本研究的主要目的就是建立一个可以准确描述氢溶液汽液两相平衡关系以及热力学性质的严格热力学模型，并对实际氢同位素低温精馏过程进行准确的模拟计算。通过对精馏过程稳态和动态过程的模拟，研究实际工业精馏过程中各相物料的组成、温度和流量在塔内的分布状况，以及影响这些分布的因素。1、 将Soave改进的BWR方程（1999年）应用于饱和氢流体，通过实验数据对方程的参数进行了选择和优化。此方程可用于饱和氢溶液气液两相p-V-T关系、热力学性质以及气液平衡关系的预测。可作为低温精馏分离氢同位素的一个严格的热力学模型。2、 应用严格的热力学模型研究了带有侧线循环及平衡反应装置的氢同位素低温精馏塔的稳态分离特性。塔的一侧线流股经过一个平衡反应器完成平衡反应后，作为内部进料流股与原外部进料混合后重新进入精馏塔内进行分离操作。通过对带有侧线返回进料的塔的计算模拟，阐明了这一侧线流股对塔分离特性的影响。3、 分析了浓度极稀物系动态精馏模型的特点，建立了此类物系动态模型的求解策略，通过对模型中状态变量的转换，使原本刚性较强的微分方程组转化为一非刚性的常微分方程组。使用一般通用的积分方法，如Runge-kutta法即可得到精确的积分结果，并且积分时间大为减小。4、 阐述了使用MATLAB实现动态模拟过程的方法。建立了使用界面良好的氢同位素低温精馏动态模拟模型。5、 应用严格的热力学模型研究了氢同位素低温精馏塔在不同进料扰动、回流比扰动以及馏出量扰动情况下的动态响应情况。分析了不同开工策略对开工时间的影响。讨论了带有侧线返回进料的氢同位素低温精馏塔的动态过程特点。6、 针对氢同位素低温精馏物系的特点，提出了一种新的操作方法——准间歇精馏操作。对准间歇精馏过程进行了分离特性的研究和讨论。更多还原

【Abstract】 Researches into the nuclear fusion reactions has created a need for handling the deuterium tritium fuel employed, and cryogenic fractional distillation was selected as one of the best process for making the required separations due to relatively large separation factors, low power consumption, high throughputs, relatively short start-up times, and flexibility of design. However, only limited data have been available for hydrogen isotope system, so there is not a rigorous thermodynamics model which can accurately predict thermodynamic properties and phase equilibrium of hydrogen fluid by now. In this thesis a rigorous thermodynamics model which can accurately predicate thermodynamic properties and phase equilibrium of hydrogen fluid is established through the method based on equation of state. Using this thermodynamics model we have studied steady state as well as dynamic behavior by founding a fundamentally sound model that is capable of accurately describing the separation process.1. The BWR equation of state modified by Soave in 1999 is applied to the saturated hydrogen solutions. The parameters needed in the equation of state have been modified and optimized through fitting experiment date. p-T-V condition of the saturated hydrogen can be accurately predicted as well as thermodynamic properties and phase equilibrium of hydrogen fluid through this equation. A rigorous thermodynamic model which can be used in simulation of hydrogen isotope-separation by cryogenic distillation is then obtained.2. The rigorous thermodynamic model has been applied to study the characteristics of cryogenic distillation column having feedback stream with hydrogen isotope system in steady state. A side stream is recycled to the external feed stream of the column through an equilibrator as an internal feed stream. The simulation results indicate effects on the characteristics of cryogenic distillation column.Consideration is given to the behavior and characteristics of the set of ordinary differential equations. The numerical integration algorithm which can provide better stability, accuracy and efficiency in computing time has been investigated to solve complex cryogenic distillation dynamic<WP=5>3. problems. By dealing with the logarithmically transformed variables, the equation systems resulting from a dynamic simulation model of distillation processes become more well conditioned, and can be solved using a general integration method.4. The approach coded in MATLAB for dynamic simulation of a distillation column as well as the dynamic model window is described in the thesis. 5. The study of different processes and operations in dynamic behavior of a column has been done in detail using a rigorous thermodynamic model. The dynamic behavior of distillation column during start-up operations have been studied and analyzed. Similarly, the dynamic characteristics of a column having feedback stream with hydrogen system have been studied as well.6. A new kind of operation policy-Quasi-batch distillation is proposed for specific conditions in hydrogen cryogenic distillation. The dynamic behavior of a column in quasi-batch distillation is analyzed in some cases.更多还原