火电机组热力系统全工况优化与能耗控制策略研究

The thermal power generation industry consumes about half of the primary energy in China, so the effective and clean operation of thermal power unit is of great significance to energy saving and emissions reduction. Most of the thermal power units in China operate under the condition of frequent peak regulation, variable fuel characteristics and large difference of environment temperature, and also the deficiencies of design, manufacture and operating are accompanied with the operation. According to above status quo of thermal power unit, the thermal system of coal-fired, combined cycle and cogeneration unit will be studied with theoretical, experimental and numerical methods. Firstly, the mathematical model will be developed based on the unit process, with which the characteristics of the thermal equipment in the thermal power unit will be obtained under conditions of extensiveness peak regulation and transient process. Secondly, the energy consumption characteristics of thermal power units will be studied under the conditions with coupled multi-factors, especially in typical transient process of rapid up-rating and down-rating. Finally, considering the time varying characteristics of external factors(load, fuel and environment temperature), the system optimizations and energy saving strategies for thermal power units under full operation conditions will be put forward in aspects of design, operation and waste heat recovery. The theory of energy transformation and transport will be improved, and theoretical basis for further energy saving of thermal power unit will be provided through this project research. The energy consumption of thermal power unit can be reduced by promoting the project research achievements, which is of great significance for the energy conservation and emissions reduction, and sustainable development of thermal power generation industry in China.

我国火力发电行业消耗了近一半的一次能源，火电机组的高效清洁运行对节能减排具有重要意义。本项目针对我国火电机组调峰频繁、燃料多变和环境温度差异大的现状，以及普遍存在的设计、制造和运行等方面的缺陷展开研究，采用理论分析、实验研究以及数值模拟等方法，建立基于单元过程的火电机组热力设备计算模型，获得深度调峰工况及瞬态过程热力设备的性能，查清燃煤机组、燃气联合循环机组及供热机组热力系统多因素耦合工况及机组快速升、降负荷等典型瞬态过程的能耗特性，综合考虑负荷、燃料和环境等外部因素的时变特性，从设计、运行及余热深度回收利用等三个方面建立火电机组热力系统全工况优化与能耗控制策略。通过本项目的研究，可完善火电机组热力系统能量转换及传输理论，为我国火电机组深层次节能降耗提供理论依据。通过推广本项目研究成果，可降低火电机组能耗，对我国火电行业的节能减排与可持续发展具有重要意义。

火力发电在我国电力供应中的角色由主体向基础能源转变，为消纳风能、太阳能发电，火电机组长期频繁深度变负荷运行，还需面临燃料与环境多变的运行挑战。因此，开展火电机组全工况节能的基础理论与关键技术研究，对我国“节能优先”的能源战略至关重要。本项目从热力设备的全工况性能研究出发，研究获得了热力系统稳态变工况和瞬态过程的能耗特性，从设计、运行及节能改造等三个方面提出了火电机组全工况优化与能耗控制策略。.（1）通过热力设备动态响应时间的尺度分析，发现传热设备是制约火电机组热力系统瞬态过程持续时间及能源转化的关键，进而建立了换热设备非稳态过程的熵产分析模型，发现了换热设备瞬态过程中存在附加熵产的特殊现象，从而实现了热力设备稳态变工况及瞬态过程性能的精细表征；.（2）建立了火电机组模型，验证了模型的可靠性，研究获得了内外因素耦合作用下热力系统能耗特性，研究获得了热电联产机组耦合热电解耦措施运行域的扩展规律及运行域内复杂能耗特性，将瞬态过程附加能耗分为“可避免”、“不可避免”两个部分，研究获得了火电机组瞬态过程能耗特性的变化规律。.（3）研究获得了火电机组内外因素耦合变工况及瞬态过程的能耗控制策略。通过气液固三相凝并吸收抑制低温腐蚀机理的研究，提出了将低温省煤器布置在除尘器前的余热回收新方案，实现了余热回收系统全工况高效运行；揭示了通过瞬态过程流量/温度调控降低瞬态过程熵产的机理，提出通过蓄热及蓄热分布修正的优化控制策略，可实现瞬态过程节能，将热力系统节能由稳态工况拓展至瞬态过程。.基于以上研究，发表SCI论文42篇（2篇入选ESI）、国内期刊论文18篇，申请专利17件，已授权5件，培养博士研究生3名、硕士研究生15名，主办国际、国内学术会议各1个，受邀在国际会议做主旨报告6个，获国家科技进步二等奖2项，省部级一等奖3项。研究成果在烟气余热高效回收、高参数二次再热机组设计及运行优化、热电联产机组热电解耦与运行节能等得到应用。