三压再热汽水系统IGCC的变工况性能

本文以三压再热式汽水系统ＩＧＣＣ为研究对象,组成了整体空分ＩＧＣＣ系统方案,建立了气化炉、净化系统、燃气轮机、空分装置、余热锅炉、汽轮机各组成部件的数学模型,对ＩＧＣＣ系统的变工况特性进行计算,分析了燃气轮机采用不同调节规律和汽轮机采用不同运行方式时对系统变工况性能的影响,并提出了合理的运行方式,为我国今后建立ＩＧＣＣ示范电站做了理论上的准备工作。     

空分系统集成度对IGCC系统性能的影响

在设计工况下,计算和研究由独立空分至完全整体空分之间的整体空分ＩＧＣＣ系统中,空分装置集成度的变化对整个ＩＧＣＣ系统的功率,效率等特性的影响,从而确定设计工况时空分装置集成的最佳数值,使整个ＩＧＣＣ系统具有最大的功率和最高的效率。     

IGCC蒸汽侧合理的运行方式

通过对两种ＩＧＣＣ系统的变工况分析,比较了蒸汽侧滑压运行与定压运行时的性能,指出以选用滑压运行为佳,这时不仅ＩＧＣＣ的效率高些,且汽轮机的排汽干度较高,有利于汽轮机的安全运行。     

1000MW直接空冷机组汽机变工况与风机的节能运行

以汽轮机变工况为基础,综合考虑多种因素,结合1000MW空冷机组热力系统运行参数,应用弗留格尔公式计算了不同机组负荷下汽轮机排汽量的变化情况以及机组的背压对汽轮机功率的影响特性。根据空冷凝汽器的变工况分析,确定了不同环境温度时汽轮机排汽背压与空冷风机所消耗功率的对应关系。通过优化分析,计算了机组运行的最佳背压。编程开发了计算机应用软件,并进一步根据风机的运行原理实现了机组的不同运行状态下通过采集当时的运行参数给出最经济风机运行转速的功能,实现了对机组运行人员的在线指导。该软件在宁夏灵武发电厂4号机得到实际应用,结果表明该系统应用效果良好,具有重要的实际意义。     

空冷汽轮机低压末级变工况设计

采用CFD技术对空冷汽轮机低压末级进行全三维变工况设计，掌握了空冷机组末级动叶的变工况运行时的流动情况，对因高背压产生压力面流动分离进而引发颤振的机理有了一定了解。分析结果表明，采用专用强化叶型、控制反动度、控制攻角等方法可以有效保证空冷机组变工况安全高效运行。     

空冷汽轮机末两级变工况三维流动的数值模拟

采用三维粘性数值模拟方法对变工况下空冷汽轮机末两级流动进行了模拟,研究了效率和脱流高度等重要参数的变化规律,着重分析了设计点和小容积流量工况时的三维流场。通过分析了解了机组在变工况运行时末级流动的特点,为空冷汽轮机末级叫片的设计和优化提供了依据。图8参5     

IGCC系统中燃气轮机的工况点选择与用“当量温度”进行特性计算

论述了以天然气为燃料设计的燃气轮机用于ＩＧＣＣ系统运行时，压气机透平联合运行工况点的可能范围、选定原则。提出了“透平前当量燃气温度”的概念，并说明用当量温度进行ＩＧＣＣ系统燃气轮机特性计算的方法。     

船用核动力汽轮机组耦合变工况特性及其影响因素研究

船用核动力汽轮机组变工况运行特性的好坏直接影响其机动性、可靠性、经济性等重要指标。为此,首先给出汽轮机调节级逆顺序变工况算法和压力级组变工况算法,并提出一种能够全面考虑汽轮机喷嘴+节流+滑参数调节方式、多参数变化的多级汽轮机组变工况分析模型;然后基于动态模型的冷凝器变工况分析方法,建立一种通用型模块化的汽轮机和冷凝器耦合变工况分析模型;随后,将该耦合变工况模型应用于某船用核动力汽轮机组的变工况特性研究,分析不同外界因素对机组变工况特性的影响。结果表明,建立的汽轮机组变工况模型能够真实地反映各设备之间的强耦合关系,有效地实现了船用核动力汽轮机组全工况范围的变工况分析,并指明运行参数对汽轮机组变工况的影响机理和程度,为船用核动力汽轮机组的优化设计、高机动可靠运行提供了强有力的支撑。     

夏季工况直接空冷系统最佳真空特性的研究

以某660MW超临界直接空冷机组为研究对象,基于机组夏季工况下实际运行数据,建立了汽轮机变工况模型与空冷系统变工况模型,并分别利用电厂空冷系统常干时性能曲线以及电厂原热力特性计算说明书验证了这2个模型的计算准确性.分析了不同边界条件下(包括空气温度、凝汽器的换热环境、负荷、风机转速等)凝汽器最佳真空的选取.结果表明:夏季工况下,当负荷较高时,风机应始终保持在超频运行,以维持空冷系统的背压,保证运行安全性;当负荷较低时,在固定凝汽器蒸汽质量流量下,随着冷却空气量的增加,机组出力增加量与风机耗功增加量的差值有最大值.运行时应首先考虑如何合理设置运行参数以得到较高经济性.     

空冷系统计算工况的选择

目前空冷火力发电厂的空冷系统的设计计算,系采用典型年的气象条件,以全年不满发200小时的气温,作为汽轮机额定工况的背压计算基准条件加以确定。本文将对此方法进行讨论,对选择空冷系统设计计算的汽轮机工况提出建议,并为空冷发电厂夏季运行提供参考意见。     

Exergy analysis of two cryogenic air separation processes

Two process designs of a cryogenic ASU (air separation unit) have been evaluated using exergy analysis. The ASU is part of an IGCC (integrated gasification combined cycle); it is supplying oxygen and nitrogen to the gasifier and nitrogen to the gas turbine. The two process designs separate the same feed into products with the same specifications. They differ in the number of distillation columns that are used; either two or three. Addition of the third column reduced the exergy destruction in the distillation section with 31%. Overall, the three-column design destroyed 12% less exergy than the two-column design. The rational exergy efficiency is defined as the desired exergy change divided by the total exergy change; it is 38% for the three-column design and 35% for the two-column design. Almost half of the exergy destruction is located in compressor after-coolers. Using this heat of compression elsewhere in the IGCC can be an important way to increase the IGCC efficiency. It is proposed to use it for the pre-heating of ASU products or for the production of steam, which can be used as part of the steam turbine cycle.     

Performance analysis of a syngas-fed gas turbine considering the operating limitations of its components

As the need for clean coal technology grows, research and development efforts for integrated gasification combined cycle (IGCC) plants have increased worldwide. An IGCC plant couples a gas turbine with a gasification block. Various technical issues exist in designing the entire system. Among these issues, the matching between the gas turbine and the air separation unit is especially important. In particular, the operating condition of a gas turbine in an IGCC plant may be very different from that of its original design. In this study, we analyzed the impact of the use of syngas on operating conditions of the gas turbine in an IGCC plant. We evaluated the performance of a gas turbine under operating limitations in terms of compressor surge and turbine metal temperature. Although a lower degree of integration may theoretically allow higher gas turbine power output and efficiency, it causes a reduction in compressor surge margin and overheating of the turbine metal. The turbine overheating problem may be solved using several methods, such as a reduction in the firing temperature or an increase in the turbine cooling air. The latter yields a much smaller performance penalty. To achieve an acceptable margin for the compressor surge, either further reduction in the firing temperature or further increase in the coolant is required. Ventilation of some of the nitrogen generated by the air separation unit, i.e., a reduction of the nitrogen supply to the combustor, is another option. Coolant modulation yields the lowest performance penalty. Reduction of the nitrogen supply provides much greater system power output than control of the firing temperature. For nitrogen flow and firing temperature controls, there are optimal levels of integration degrees in terms of net system power output and efficiency.     

Effect of supplementary firing options on cycle performance and CO2 emissions of an IGCC power generation system

Supplementary firing is adopted in combined‐cycle power plants to reheat low‐temperature gas turbine exhaust before entering into the heat recovery steam generator. In an effort to identify suitable supplementary firing options in an integrated gasification combined‐cycle (IGCC) power plant configuration, so as to use coal effectively, the performance is compared for three different supplementary firing options. The comparison identifies the better of the supplementary firing options based on higher efficiency and work output per unit mass of coal and lower CO₂ emissions. The three supplementary firing options with the corresponding fuel used for the supplementary firing are: (i) partial gasification with char, (ii) full gasification with coal and (iii) full gasification with syngas. The performance of the IGCC system with these three options is compared with an option of the IGCC system without supplementary firing. Each supplementary firing option also involves pre‐heating of the air entering the gas turbine combustion chamber in the gas cycle and reheating of the low‐pressure steam in the steam cycle. The effects on coal consumption and CO₂ emissions are analysed by varying the operating conditions such as pressure ratio, gas turbine inlet temperature, air pre‐heat and supplementary firing temperature. The results indicate that more work output is produced per unit mass of coal when there is no supplementary firing. Among the supplementary firing options, the full gasification with syngas option produces the highest work output per unit mass of coal, and the partial gasification with char option emits the lowest amount of CO₂ per unit mass of coal. Based on the analysis, the most advantageous option for low specific coal consumption and CO₂ emissions is the supplementary firing case having full gasification with syngas as the fuel. Copyright © 2008 John Wiley & Sons, Ltd.     

Influence of system integration options on the performance of an integrated gasification combined cycle power plant

An IGCC (integrated gasification combined cycle) plant consists of a power block and a gasifier block, and a smooth integration of these two parts is important. This work has analyzed the influences of the major design options on the performance of an IGCC plant. These options include the method of integrating a gas turbine with an air separation unit and the degree of nitrogen supply from the ASU to the gas turbine combustor. Research focus was given to the effect of each option on the gas turbine operating condition along with plant performance. Initially, an analysis adopting an existing gas turbine without any modifications of its components was performed to examine the influence of two design options on the operability of the gas turbine and performance of the entire IGCC plant. It is shown that a high integration degree, where much of the air required at the air separation unit is supplied by the gas turbine compressor, can be a better option considering both the system performance and operation limitation of the gas turbine. The nitrogen supply enhances system performance, but a high supply ratio can only be acceptable in high integration degree designs. Secondly, the modifications of gas turbine components to resume the operating surge margin, such as increasing the maximum compressor pressure ratio by adding a couple of stages and increasing turbine swallowing capacity, were simulated and their effects on system performance were examined. Modification can be a good option when a low integration degree is to be adopted, as it provides a considerable power increase.     

整体煤气化联合循环系统中燃气轮机的变工况特性

采用ThermoFlex软件建立了200 MW级整体煤气化联合循环(IGCC)系统模型,从系统的角度研究了200 MW级IGCC系统中燃气轮机的变工况特性.详细讨论了在3种调节方式下,燃气轮机负荷、整体空分系数(Xas)、氮气回注系数(Xgn)和大气环境条件对系统性能的影响.结果表明:随着燃气轮机负荷的降低,在压气机进口可转导叶(IGV)不调时,燃气透平初温(T3)和燃气透平排气温度(T4)均呈下降趋势;在等T3调节时,T4先升高后降低,转折,最在80%负荷时;而在等T4调节时,T3先缓慢降低,而后快速降低,转折点在70%负荷时.在等T3调节时IGV可关闭的角度比等T4调节时的小.当Xas和Xgn增大时,系统发电效率降低.IGV可调的变工况性能比IGV不调时好.随着大气温度的升高,燃气轮机功率和系统功率均下降.当Xas=0.3时,燃气轮机功率和系统功率均随Xgn的增大而增加.     

燃气轮机调节方式对IGCC系统变工况性能的影响

为选择合理的燃气轮机调节方式,采用Thermoflex软件建立了200 MW级IGCC系统模型,从系统的角度出发比较研究了燃气轮机的调节方式对燃气顶循环系统、蒸汽底循环系统和整个IGCC系统变工况性能的影响.研究表明:与压气机可转导叶(IGV)不调相比,IGV可调时更有利于提高系统的变工况性能.等燃气透平初温(T3)调...     

IGCC系统中燃机岛特性研究

IGCC系统由气化岛、燃机岛、常规岛及其辅助系统组成,其中燃机岛对IGCC系统性能有较大的影响。本文利用ThermoFlex软件建立200MW级IGCC系统模型,从系统角度出发,研究IGCC系统中的燃机岛特性,分析燃机岛关键参数变化对IGCC系统的影响。研究结果表明：燃气轮机出力和系统发电量随着大气温度的升高而下降,随着大气压力升高而升高;系统的发电量和系统效率随燃气轮机负荷的下降而下降;燃气轮机出力和系统发电量随压气机进口空气量的减小而减少,随着通流面积的增加而增加。本系统最佳的氮气回注系数为60％及整体空分系数为20％。     

Coal to electricity: Integrated gasification combined cycle

An advanced energy conversion system—the integrated gasification combined cycle (IGCC)—has been identified as an efficient and economical means of converting coal to electricity for utility application. Several demonstration projects on a near-commercial scale are approaching the construction stage. A coal conversion facility has been constructed to simulate the operational features of an IGCC. This process evaluation facility (PEF-scale) performs a dual function: (1) acquiring and processing data on the performance of the individual components—coal gasifier, gas clean up, and turbine simulator—that comprise the IGCC concept and (2) simulating the total system in an operational control mode that permits evaluation of system response to imposed load variations characteristic of utility operation. The results to date indicate that an efficient, economical IGCC can be designed so that the gasification/gas clean up plant and the power generation system operate compatibly to meet utility requirements in an environmentally acceptable manner.     

整体煤气化联合循环_IGCC_系统变工况特性

作者分析了影响IGCC系统变工况的因素,基于通用性模块化建模思想,建立了IGCC系统变工况特性模型和开发出相应程序软件,通过大量的计算,得出三种调节方式下系统随负荷与大气温度变化时的变工况特性曲线簇,揭示了系统特性随主要变量变化关系。     

新型IGCC系统的开拓与集成技术

本文基于大量相关研究,全面总结分析了新型IGCC系统的开拓及其集成技术开发与进展。首先分析了IGCC固有的效率高、环保性能优以及最具发展潜力等特点,以揭示其具有的发展前景和受到重视的原因;然后总结介绍了正在发展的燃料电池一IGCC联合循环、IGCC多联产、C02零排放的IGCC以及燃料多样化的IGCC等新型系统,并扼要论述这些新系统整合机理和特性。还归纳介绍了先进的燃气轮机技术、离子膜制氧技术等集成技术开发与进展。