大型脱硫系统的建模与优化控制方法的研究与应用

发布时间：2018-06-23 17:45

本文选题：湿法烟气脱硫 + 建模　；参考：《华北电力大学》2015年硕士论文

【摘要】：近些年,我国一直致力于通过控制大气污染物的排放来减轻环境恶化。为了加强SO2的排放管理,早在2010年相关环保部门就要求在建电厂不设旁路烟道,对取消旁路烟道的项目也实行优先审批的鼓励措施。无旁路脱硫系统的稳定运行与否将直接影响机组运行的安全性,对脱硫集控运行人员的专业素质有了更高的要求,其中最直接有效的方法是建立模拟本机组现场运行环境的仿真机来对运行人员进行岗前培训和定期考核。本文以国内某350MW热电机组的石灰石/石膏湿法烟气脱硫工程为研究对象,通过对系统结构和反应机理的详细分析推导建立了系统主要参数和设备的数学模型。通过编程将建立的数学模型进行模块化封装处理,并以基于虚拟DCS的激励式LN仿真支撑系统为平台实现了整个脱硫工艺的全图形化建模。然后根据电厂运行规程和现场运行经验对模型参数进行调试,最后采用专家经验法进行验模,证明了模型的准确性和精度是可以满足工程要求的。控制系统的优化不仅能提高系统运行的安全可靠性,还能大大降低运行的投资成本。在脱硫工艺的DCS系统中,最复杂难控的对象是吸收塔浆液p H值,这归咎于其自身具有的非线性、大延迟及大惯性特性。本文以所建的脱硫仿真机为试验平台实现控制系统的优化研究。首先采集仿真机运行数据,并基于粒子群算法对pH值的对象特性进行辨识。针对现场原有p H值单回路控制系统和现行脱硫工程中普遍采用的复合控制系统存在的缺陷,提出并设计了串级—定摩尔差控制方案。采用粒子群算法对新策略的控制器参数进行寻优,最后将优化后的控制策略在仿真机上实现,得到了比较理想的控制效果,验证了优化控制系统的可行性和优越性,为现场控制优化提供了可行的参考方案。
[Abstract]:In recent years, China has been committed to reducing environmental degradation by controlling emissions of atmospheric pollutants. In order to strengthen the emission management of so _ 2, as early as 2010, the relevant environmental protection departments required that no bypass flue should be set up in the power plant under construction, and that priority should be given to the project of eliminating the bypass flue. The stable operation of the desulfurization system without bypass will directly affect the safety of the unit operation, and it has higher requirements for the professional quality of the desulphurization centralized operation personnel. The most direct and effective method is to set up a simulator to simulate the field operation environment of the unit to train the operators before the job and to check them regularly. In this paper, the limestone / gypsum wet flue gas desulfurization project of a 350 MW thermoelectric unit in China is taken as the research object. The main parameters and the mathematical model of the equipment are established through the detailed analysis of the system structure and reaction mechanism. Through programming, the mathematical model is processed by modular encapsulation, and the full graphical modeling of the whole desulfurization process is realized on the platform of excitation LN simulation support system based on virtual DCS. Then the model parameters are debugged according to the operation rules and field operation experience of the power plant. Finally, the expert experience method is used to verify the model, which proves that the accuracy and accuracy of the model can meet the requirements of the project. The optimization of the control system can not only improve the safety and reliability of the system, but also greatly reduce the investment cost. In the DCS system of desulphurization process, the most complex and difficult object is the pH value of absorber slurry, which is attributed to its own nonlinear, large delay and large inertia characteristics. In this paper, the desulfurization simulator is used as the test platform to realize the optimization of the control system. Firstly, the running data of the simulation machine are collected, and the object characteristics of pH value are identified based on particle swarm optimization (PSO). Aiming at the defects of the original single-loop control system with pH value and the compound control system commonly used in the current desulfurization project, a cascade and constant molar difference control scheme is proposed and designed. The particle swarm optimization algorithm is used to optimize the controller parameters of the new strategy. Finally, the optimized control strategy is realized on the simulation machine, and the ideal control effect is obtained, which verifies the feasibility and superiority of the optimal control system. It provides a feasible reference scheme for field control optimization.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X773

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