储能和碳捕集的燃气蒸汽混合工质循环的基础研究

Combustion gas and steam mixture power cycle (GSMC) is an integrating scheme of high efficiency power generation, peak shaving, energy storage, NOx free and CO2 capture. During off-peak hours the liquefied oxygen is produced in an air separation unit and stored in cryogenic tanks. During peak hour operation, the cryogenic liquids of both NG and oxygen are pumped to high pressure and preheated before entering the combustion chambers with combustion product heats and mixes with the feed water to form supercritical H2O/CO2 vapor mixture for power generation in a turbine unit. The water steam is condensed in the condenser and a certain part of the condensate corresponding to the water fraction of the combustion product is drained out from the system, while the majority part of the condensate water is again injected to the combustion chambers via feed water heaters and pumps. The gaseous CO2 separated from the condenser is liquefied and captured by the cryogenic liquids of both NG and oxygen through a set of heat exchangers and two stage compressors. Aiming to the performance optimization of the GSMC system, the project will focus on the impacts on the system performances and the process of CO2 capture with main parameters, the dynamic feature of the system with power regulation by combustion control etc. Investigations will be also conducted with numerical simulation and experiment on the enhanced heat transfer with the special conditions of multi-fluids, supercritical parameter, presence of non-condensable gas and cryogenic fluids in the heat exchangers such as condenser and CO2 precooler and liquefier as well as the feed water heaters and NG and O2 heaters of the GSMC, to provide theoretic basis for the demonstration project and application of the novel power cycle.

燃气蒸汽混合工质循环(GSMC)是一种集高效发电、调峰、规模储能、零NOx和碳捕集于一体的新型动力循环。在谷电时段制备液氧并储存；在峰电时段机组运行时，LNG/液氧被泵升压并经预热后进入燃烧室，燃烧产物与预热雾化的给水混合后产生超临界H2O/CO2蒸汽，在透平中膨胀作功发电。乏汽在冷凝器中凝结分离水分，冷凝器出口凝结水部分作为给水经回热系统再次进入燃烧室的火焰管和外壳之间的环形通道吸热，部分排出系统。气体CO2经2级压缩机和多个换热器，利用LNG/液氧的冷能液化捕集。本课题针对系统的主要参数对GSMC系统性能和CO2液化捕集过程的影响、以燃烧调节功率的系统动态性能等进行优化分析研究；对冷凝器、CO2预冷器和液化器、给水加热器和NG/O2加热器等换热器中的多流程、超高压、含不凝性气体和低温运行等特征的强化传热过程进行模拟和实验研究。为新型动力循环的优化设计及工程示范及应用提供依据。

燃气蒸汽混合工质循环(GSMC)是一种集高效发电、调峰储能、零NOx和碳捕集于一体的新型动力循环。燃料/液氧燃烧产物与给水混合后产生超临界H2O/CO2蒸汽，在透平中膨胀作功发电。冷凝器出口凝结水部分作为给水经回热系统再次进入燃烧室的火焰管和外壳之间的环形通道吸热，部分排出系统；气相流体则经冷却压缩后分离水分和气体CO2，后者利用液氧和其他冷媒的冷能被液化捕集。本课题针对系统的主要参数对GSMC系统性能和CO2液化捕集过程的影响进行了优化分析；提出了对于既有电厂系统增加前置透平来提高循环参数的方案，以弥补因碳捕集对效率的负面影响；对GSMC系统的CO2液化捕集流程以及运行参数进行了优化；在CO2全捕集和在1000℃ /40MPa条件下采用LNG燃料和710℃ /40MPa条件下采用超临界水氧化煤气化燃料的循环等效净效率可分别达到0.533和0.433；选择水作为循环工质易于应用于既有电厂的碳捕集升级改造，但其系统因采用透平多级抽汽回热的流程而比较复杂。根据燃料/液氧的燃烧产物主要是CO2和H2O的特点，还研究了在LNG燃料和超临界水氧化煤气化燃料下以燃烧产物和二氧化碳做循环工质的发电方案。对Allam循环的流程作了改进，将透平背压设置为临界压力附近，依靠透平的排气对循环CO2以及燃料和氧化剂加热，不仅其透平的压比小，级数少，而且可满足系统回热器材料要求并省去了多个压缩机，系统比较简单，适合于新建的电厂发电系统。同时还对冷凝器、CO2预冷器和液化器、给水加热器和NG/O2加热器等换热器中的多流程、超高压、低温运行和含不凝性气体等特征的强化传热过程进行模拟和实验研究。尤其是对半圆柱形空间提出了梯式螺旋折流板换热器的创新结构，对其和异形孔板换热器进行了数值模拟和实验研究。对功/冷联供卡林纳循环提出并研究了可以对发电与制冷量单独调节的改进流程。还研究了新型压缩空气储能方案。