【作者】 孙博；

【导师】 苏明； 刘永文；

【作者基本信息】 上海交通大学 ， 动力机械及工程， 2012， 博士

【摘要】 整体煤气化湿空气透平循环(IGHAT)结合了先进煤气化技术(IGCC)和高效的湿空气透平循环(HAT)的优点,是一种高效率、低污染和低比投资的煤炭利用节能发电系统,但同时也应注意到,其特点是系统复杂,相互影响多,耦合程度大,控制复杂,因此,IGHAT循环的研究目前还处于理论研究阶段,为了使这一高效节能清洁的发电技术尽快进入工程试验阶段,则有必要对其稳态和动态性能进行研究。由于IGHAT系统中,蒸汽轮机、余热锅炉、压气机、燃烧室和燃气透平等已经在近年的研究中形成了比较完善的通用模型,在这一背景下,本文的主要目的是利用模块化建模方法对IGHAT关键部件——气化炉和饱和器进行理论建模及稳态和动态仿真研究,搭建饱和器实验系统,通过实验研究讨论其传热传质及气液流动性能,并对本文建立的模型进行实验验证。为实现上述研究目的,本文工作从以下几个方面展开:针对Shell炉的工艺特点,分析讨论了气化炉中煤气化反应、气侧与渣层间的传热、渣的相变以及液态渣层的流动特性,以质量守恒、动量守恒和能量守恒为基础,建立了气化炉煤气化模型,可用于描述气化温度、气化煤气组分、固态渣层厚度、液态渣层厚度以及炉底排渣流量的稳态和动态特性行为。结合Demkolec IGCC示范工程中气化炉相关参数,围绕哥伦比亚煤El Cerrejon,德雷顿煤Drayton,石油焦petroleum Coke和大同煤四种燃料展开了相关稳态和动态仿真研究。其中,稳态仿真研究不仅分析了入炉氧煤比和水蒸汽/煤比对煤气成分、气化温度及冷煤气效率的影响规律,还得到了不同灰渣比热容及灰渣沉积流量下,气化温度和渣层厚度的变化规律。动态仿真得到了气化炉各参数在入炉氧煤比和水蒸气/煤比上发生阶跃扰动时的响应规律,发现各参数均存在较长的惯性响应时间,其中,气侧参数响应时间较短,渣侧参数响应时间相对较长。另外,还横向分析比较了不同煤种及不同灰渣参数下,渣侧参数及气化温度的动态响应规律。发现,灰渣的比热容对气化炉各参数的稳态值影响较大,而灰渣的沉积流量则对各参数的动态响应时间影响较大。针对填料式饱和器,分析讨论了饱和器中气侧、水侧以及填料侧的传热传质特性及填料通道中的气水流动特性,根据质量守恒、动量守恒和能量守恒原理,建立了水侧、气侧和填料侧的控制方程。将饱和器沿气相工质流动方向分段并分别进行建模,在Simulink平台上采用显式Runge-Kutta法完成模型的搭建,连接及求解。模型可用于描述饱和器出口以及沿气相工质流动方向工质状态参数、填料段压降以及填料持液量的分布以及稳态和动态特性行为。对饱和器模型进行了收敛性及分段数目合理性的分析,并结合瑞典示范机组设计工况,在高参数工况下对饱和器模型展开稳态和动态仿真研究。其中,稳态仿真研究得到了饱和器内部工质状态参数、传热传质通量的轴向分布,结果表明,沿气相工质流动方向,各段控制体内气水传热传质通量是逐渐增大的。同样,也详细分析讨论了不同进口参数对运行参数的影响规律。动态仿真研究得到了饱和器出口工质参数、填料段压降及填料持液量对进口参数上扰动的响应规律。设计仿真工况下,对于进口参数上的阶跃扰动,饱和器各参数需要一定的惯性时间才能达到新的稳定状态,出口工质温度的响应时间最长,在50s左右,压降和持液量所需时间较短。设计搭建了填料式饱和器实验系统,实现了对工质温度、湿度、流量及压力的在线测量与采集,并初次提出利用称重和液位测量的间接计算手段得到实验进行过程中饱和器填料持液量数据。对填充了250Y型不锈钢波纹板规整填料的饱和器在实验室条件下进行了相关稳态和动态实验研究。稳态工况的实验结果得到了不同进口参数下,饱和器的传热传质及气液流动参数的变化规律。指出水气比不能作为唯一衡量饱和器传热传质性能的准则,还应综合考虑进口流量的大小,即水气负荷的大小。根据实验得到的干填料及不同进水流量下的压降数据,提出了针对250Y不锈钢波纹板规整填料的压降关联式。动态工况的实验结果得到了饱和器出口工质参数对进口工质参数上发生扰动的响应曲线,在相同工况条件下,将本文建立的饱和器模型计算结果与动态实验结果进行了对比,结果表明二者具有较好的一致性。更多还原

【Abstract】 The Integrated Gasification Humid Air Turbine Cycle (IGHAT) combines the advantages of advanced coal gasification technology Integrated Coal Gasification Combined Cycle (IGCC) and high performance Humid Air Turbine (HAT) Cycle, which is a high-efficiency, low-consumption and low -specific investment coal-cleaning utilization energy-saving power generation system. Note that the system of IGHAT is complex and difficult to be controlled, therefore, the research of IGHAT is still at theoretical stage. In order to push this high-efficiency clean power generation technology into the engineering test stage, the steady-state and dynamic performance is necessary to be studied. There have been fairly perfect models for steam turbine system, compressor, gas turbine and combustion chamber etc. for IGHAT system. With this background, the purpose of this thesis is to establish theoretical models and carrying out the steady-state and dynamic simulation study on the key components of IGHAT, gasifier and saturator, design and build the saturator experimental system, discuss and analyze the heat transfer and mass transfer performance and gas-liquid flow characteristic, and validating the saturator model with experimental data.In order to achieve the research objective mentioned above, the work is expanded from three aspects:According to the processing feature of Shell gasifier, the coal gasification reactions, heat-transfer between gas side and slag side, phase change of slag and flow behavior of fluid slag layer was analyzed and discussed. A coal gasification model was built based on mass conservation, momentum conservation and energy conservation, which can describe the steady-state and dynamic behavior of the outlet variables of gasifier including the gasification temperature, coal gas component contents, thickness of solid slag layer and fluid slag layer.Based on the related parameters of the gasifier in Demkolec IGCC demonstration project, the steady-state and dynamic simulation research of El Cerrejon Coal, Drayton Coal, petroleum Coke and Datong Coal was carried out. In steady-state simulation, not only the influence of the oxygen-to-coal ratio and steam-to-coal ratio into furnace on the coal gas component contents, gasification temperature and thickness of slag layer was analyzed, but also the variation characteristics of gasification and slag layer thickness under different slag specific heat and slag deposit flux was obtained. The dynamic response rules of key outlet variables were obtained when the inlet oxygen-to-coal ratio and stem-to-coal ratio undergoes a fundamental step change. It is found that all the outlet variables have long-time inertial elements, in which, the response time of gas side variables are shorter than that of slag side variables. Otherwise the dynamic response rules of gas side variables and gasification temperature under different coals and physical properties of slag were compared, and it is found that the slag specific heat showed obvious influence on steady-state value of the outlet variables, and the slag deposit flux showed obvious influence on dynamic response time.According to packed saturator, the heat-transfer and mass-transfer characteristic of air side, water side and packing side and the gas-liquid flow characteristic in packing channels. Based on mass conservation, momentum conservation and energy conservation, the governing equations of air, water and packing are built. The saturator was subdivided into several cells in the air flow direction, and each cell was modeled individually. The model was built, connected and solved on Simulink environment by using Runge-Kutta method, which can describe the steady-state and dynamic behavior of the outlet variables of each cell of saturator including the state-variables of air and liquid fluid, packing pressure drop and packing liquid holdup.The model convergence and the rationality of cells number were analyzed, and the steady-state and dynamic simulation study was carried out based on the design condition of Swedish demonstration unit. In steady-state simulation, the distribution of the state-variables of air and liquid fluid, heat-transfer and mass-transfer flow in the axial direction was presented, the results show that the heat-transfer and mass-transfer flow in each cell increases in air flow direction. Also the influence rules on outlet variables under different inlet variables were analyzed and discussed in detail. The dynamic response rules of outlet variables of packed saturator caused by the disturbance on inlet variables were obtained in the dynamic simulation study. Under the design condition, when there is a step change on inlet variables, the outlet variables show different inertia time. Find that the outlet temperature takes 50s to stabilize at a new value, which is longer than pressure drop and liquid holdup.An experimental system of packed saturator was designed and built, which completed the online measuring and collecting of temperature, humidity, flow and pressure of air and water, and presented an indirect calculating method to get the packing liquid holdup during the condition process by using the weight and liquid level data. The related steady-state and dynamic experiment study of the saturator packed with 250Y metal mellaple packing was carried out under laboratory environment. The steady-state experimental results present the variation rules of heat-transfer, mass-transfer and air-liquid flow variables, which indicate that the water-to-air ratio couldn’t be used as the only criterion on judging the performance of saturator, and the inlet flow should be considered together, viz. the air-liquid load. Based on the pressure drop data of dry packing and with different water inlet flow, a pressure drop correlating equation according to 250Y metal mellaple packing was presented. The dynamic experimental results obtain the response curves of outlet variables of saturator when there is a disturbance on inlet variables, which agree with the simulation result under the same condition well.更多还原