合成氨脱碳系统的模拟与研究

【作者】 李波；

【导师】 匡国柱；

【作者基本信息】 大连理工大学 ， 化学工程， 2001， 硕士

【摘要】 合成氨过程的脱碳系统一个高能耗的化工单元操作。它是影响合成氨生产能力的重要单元，并往往成为合成氨系统的瓶颈。其操作状况影响着整个系统的运行好坏，以及净化气、酸性气等输出流股能否达标。在凯洛格原流程中，系统废水排放造成了环境污染。随着能源和原材料价格的大幅度上涨、环境污染的加剧，有关脱碳系统节能与环保的问题越来越为化工界所关注。本文运用化工系统工程的相关理论，结合合成氨装置脱碳系统的实例，对其进行了模拟与优化。主要进行了四方面的工作： 1．基于脱碳系统的物性特点，选择了适当的热力学物性估算方法（ELECNRTL）和亨利组分模型（HOTDEA），用ASPEN PLUS化工系统模拟软件对脱碳系统进行模拟计算，发现以Kellogg原流程为背景的模拟结果与设计值符合良好，即模型的可靠性及可信性良好，说明所选择的热力学物性估算方法与亨利组分模型正确。 2．为实现脱碳系统的废水“零排放”的目标，采用了ASPEN PLUS中的灵敏度分析和优化函数对对脱碳系统进行了参数优化，从而获得了该系统的详尽的过程参数与设计生产的基础数据。在此基础上获得了一套该系统的改进流程，与Kellogg原流程及改良流程相比，该改进流程在节能和环保方面有较大优势。 3．对现场运行工况进行了全面分析，通过在水洗塔顶部增设热泵，回收了塔顶余热，使脱碳系统的能耗降低，用能更趋合理。 4．通过回收吸收塔底部富液的热量，并将其应用于再生塔中部，提高了再生塔的分离效率，实现了能量的合理利用。更多还原

【Abstract】 Carbon dioxide removal system of ammonia synthesis process is a high energy consumption unit operation. It’s one of the most important units and the bottlenecks influencing the production capacity of the ammonia synthesis plant. Its’ operation condition influences the system’s running state and the quality of output streams . In Kellogg original scheme, the letting of the polluted water of the system make the environment contaminative. With the rapid increase of the cost of energy resources and the pollution of environment, the problem of saving energy and environment protection of carbon dioxide removal system are concerned by more and more chemical industries. To solve the problems, we use the theories of process systems engineering in the simulation and optimization of carbon dioxide removal system in this paper. The four aspects were studied in details.1 .According to the physical properties of the carbon dioxide removal system, the proper thermodynamic property calculation method( ELECNRTL ) and the Henry components( HOTDEA ) are chosen to the system simulation and calculation on the steady state process simulation software ASPEN PLUS. It’s found that the results of the simulation, based on the KELLOGG original flow, are in good agreements with the design values. So the thermodynamic property calculation method and the Henry components are suitable for the system.2.To achieve the targets of zero let of the carbon dioxide removal system, the sensitivity analysis and optimization function in the ASPEN PLUS software have been used to determine the optimizing parameters of the carbon dioxide removal system. The detailed process parameters of this system, the fundamental for the design and the production, are get hold of. A new sort of optimization scheme of this system has been obtained. Compared with the KELLOGG original flowsheet and the KELLOGG improved flowsheet, the optimization scheme has make a big progress in saving energy and environment protection.3.The paper analyzes the disagreement of the existing and the retrofitting cases. The research show that setting up a heat pump at the top of desorption tower , the waste heat is recovered , the energy consumption of the system is decreased and the energy is utilized reasonably.4.By recovering the heat of the rich liquid at the bottom of the absorption tower and using it at the middle stage of the desorption tower, the separation efficiency of the desorption tower is increased and the energy of the system is used soundly.更多还原