Energy Efficiency of a Simulated Synthetic Natural Gas Combined Cycle (SNGCC)

The objective of this investigation is to analyze the impact of the flue gas recirculation (FGR) ratio on the different energy inputs and outputs of a SNGCC power plant as well as its overall efficiency. Simulation results indicate that increasing flue gas recirculation increases the energy consumed by the recirculation compressor and the energy produced by the gas turbine. On the other hand, it decreases the production of energy of the steam turbine and the energy consumed by the pump of the steam cycle. The overall energy efficiency of the SNGCC power plant is highest (41.09%) at a value of 0.20 of the flue gas recirculation. However, the flue gas composition with a FGR ratio of 0.37 is more suitable for effective absorption of carbon dioxide by amine solutions. Based on the low heating value (LHV) of hydrogen, the corresponding overall efficiency of the power plant is 39.18% and the net power output of the plant is 1273 kW for consumption of 97.5 kg/hr. of hydrogen.

Simulation and performance analysis of organic Rankine cycle combined heat and power system

To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state. In the system,R245 fa was selected as the working fluid. A scroll expander was modeled with empirical isentropic expansion efficiency.Plate heat exchangers were selected as the evaporator and the condenser, and detailed heat transfer models were programmed for both one-phase and two-phase regions. Simulations were carried out at seven different heat source temperatures（ 80,90, 100, 110, 120, 130, 140 ℃） in combination with eight different heat sink temperatures（ 20, 25, 30, 35, 40, 45, 50,55 ℃）. Results showthat in the ORC without an internal heat exchanger（ IHE）, the optimum cycle efficiencies are in the range of 7. 0% to 7. 3% when the temperature differences between the heat source and heat sink are in the range of 70 to90 ℃. Simulations on CHP reveal that domestic hot water can be produced when the heat sink inlet temperature is higher than40 ℃, and the corresponding exergy efficiency and overall thermal efficiency are 29% to 56% and 87% to 90% higher than those in the non-CHP ORC, respectively. It is found that the IHE has little effect on the improvement of work output and efficiencies for the CHP ORC.

Improved Design of a 25 MW Gas Turbine Plant Using Combined Cycle Application

This paper presents the improved design of a 25 MW gas turbine power plant at Omoku in the Niger Delta area of Nigeria, using combined cycle application. It entails retrofitting a steam bottoming plant to the existing 25 MW gas turbine plant by incorporating a heat recovery steam generator. The focus is to improve performance as well as reduction in total emission to the environment. Direct data collection was performed from the HMI monitoring screen, log books and manufacturer’s manual. Employing the application of MATLAB, the thermodynamics equations were modeled and appropriate parameters of the various components of the steam turbine power plant were determined. The results show that the combined cycle system had a total power output of 37.9 MW, made up of 25.0 MW from the gas turbine power plant and 12.9 MW (an increase of about 51%) from the steam turbine plant, having an HRSG, condenser and feed pump capacities of 42.46 MW, 29.61 MW and 1.76 MW respectively. The condenser cooling water parameters include a mass flow of 1180.42 kg/s, inlet and outlet temperatures of 29.8°C and 35.8°C respectively. The cycle efficiency of the dry mode gas turbine was 26.6% whereas, after modification, the combined cycle power plant overall efficiency is 48.8% (about 84% increases). Hence, SIEMENS steam turbine product of MODEL: SST-150 was recommended as the steam bottoming plant. Also the work reveals that a heat flow of about 42.46 MW which was otherwise being wasted in the exhaust gas of the 25 MW gas turbine power plant could be converted to 12.9 MW of electric power, thus reducing the total emission to the environment.

Application of Supercritical CO2 Gas Turbine for the Fossil Fired Thermal Plant

A supercritical CO2 gas turbine cycle can produce power at high efficiency and the gas turbine is compact compared with the steam turbine. Therefore, it is very advantageous power cycle for the medium temperature range less than 650 ℃. The purpose of this paper is to show how it can be effectively applied not only to the nuclear power but also to the fossil fired power plant. A design of 300 MWe plant has been carried out, where thermal energy of flue gas leaving a CO2 heater is utilized effectively by means of economizer and a high cycle thermal efficiency of 43.4 % has been achieved. Since the temperature and the pressure difference of the CO2 heater are very high, the structural design becomes very difficult. It is revealed that this problem can be effectively solved by introducing a double expansion turbine cycle. The component designs of the CO2 heater, the economizer, supercritical CO2 turbines, compressors and the recuperators are given and it is shown that these components have good performances and compact sizes.

Influence of quantum degeneracy on the performance of a gas Stirling engine cycle

Based on the state equation of an ideal quantum gas, the regenerative loss of a Stirling engine cycle working with an ideal quantum gas is calculated. Thermal efficiency of the cycle is derived. Furthermore, under the condition of quantum degeneracy, several special thermal efficiencies are discussed. Ratios of thermal efficiencies versus the temperature ratio and volume ratio of the cycle are made. It is found that the thermal efficiency of the cycle not only depends on high and low temperatures but also on maximum and minimum volumes. In a classical gas state the thermal efficiency of the cycle is equal to that of the Carnot cycle. In an ideal quantum gas state the thermal efficiency of the cycle is smaller than that of the Carnot cycle. This will be significant for deeper understanding of the gas Stirling engine cycle.

单轴燃气-蒸汽联合循环机组FCB控制策略研究与应用

为强化本地支撑电源建设,提高应对突发因素造成的大面积停电事故,广东电网对联合循环机组孤网运行能力及“黑启动”功能提出了明确要求。依托某燃机电厂二期基建调试项目,开展了两套AE94.3A型燃气-蒸汽联合循环“一拖一”单轴式机组快速甩负荷(fast cut back,简称FCB)试验。试验模拟了电网外送回路故障,机组通过快切线路断路器,最终实现了汽机跳闸,燃机快速切负荷、输出功率降至带厂用电的“孤网运行”目的,试验过程各参数变化平稳,主辅机设备均为安全停运,试验取得了较好的效果。通过对汽机旁路系统、锅炉过热/再热减温水系统、汽包液位系统、凝结水及真空系统、轴封系统等的控制策略进行针对性的优化与完善,使得机组具备了完整可靠的FCB功能,显著增强了电源侧供电可靠性。相关经验可供后续同类机组参考。

耦合溴化锂制冷机组的燃气-蒸汽联合循环性能分析

燃气-蒸汽联合循环机组的运行性能容易受到环境温度的影响,使得机组在电力负荷需求高峰期面临出力不足的问题.为了解决这一问题,基于EBSILON软件,对耦合溴化锂制冷机组的SGT5-4000F型燃气-蒸汽联合循环进行仿真建模,并将冷却装置加装到压气机入口处,模拟分析进气温度对联合循环输出功率和循环效率的影响规律.研究表明:通过改变压气机进气温度可知降低进气温度可使得联合循环发电功率提高4.73%-6.10%.在温度较高的夏季工况,在燃气轮机的压气机进气口处加装进气冷却装置可以提高机组的性能,并且温度越高,联合循环输出功率提高的效果更好.

燃气-蒸汽联合循环机组性能状态评估及优化技术研究

该文主要探究燃气-蒸汽联合循环机组的性能状态评估方法和优化技术。以某燃气电厂机组作为研究对象,分别选取燃气透平内效率、蒸汽轮机内效率与循环热效率、余热锅炉余热利用率等指标,对燃气轮机、蒸汽轮机、余热锅炉的性能进行评估。结果表明,燃气轮机与蒸汽轮机性能稳定,余热锅炉性能下降明显。进一步分析余热锅炉的烟气数据和水汽数据,认为蒸发器性能下降是导致余热锅炉性能下降的主要原因,在此基础上提出加装烟气过滤装置、优化过渡烟道结构等优化策略,从而使该机组性能恢复良好。

基于DE-INSGA-Ⅱ的联合循环系统性能及参数优化研究

为了研究联合循环系统长期运行后循环效率最优的热力参数匹配,提出了一种改进优化算法,该算法融合了非线性优化思想,并利用DE(differential evolution algorithm)算法思想改善种群初始分布,同时改进快速非支配排序遗传算法NSGA-Ⅱ(non-dominated sorting genetic algorithm)交叉算子。以底循环效率最大为目标函数结合约束条件,对系统的热力参数匹配进行多目标优化。仿真结果表明:所提的DE-INSGA-Ⅱ算法具有良好分布性和收敛性,搜索能力更强。在底循环效率优化问题上,较传统NSGA-Ⅱ算法提高0.44%,余热锅炉效率提高了0.86%,汽轮机效率提升了0.15%。该研究为联合循环机组运行的热力参数匹配提供了新的参考。

LNG冷能与中深层地热能驱动的发电系统性能分析与优化

结合LNG冷能和中深层地热能特点,根据梯级用能理论,构建LNG冷能与中深层地热能驱动的联合循环发电系统,系统主要由LNG直接膨胀部分、地热单级闪蒸循环及回热式有机朗肯循环三部分组成。基于Peng-Robinson状态方程,选用模拟软件HYSYS,对发电系统进行模拟计算,研究关键参数对系统热效率、?效率和平均能源成本的影响。结果表明,随着地热水蒸发压力的增大,循环热效率提升13.99%,?效率提升7.58%,平均能源成本减小2.81%;LNG气化压力的增大使得循环热效率提升9.39%,?效率提升3.13%,平均能源成本减小8.01%;天然气外输压力的增大使得热效率降低20.93%,?效率提升38.44%,平均能源成本增加25.21%。利用遗传算法对系统进行单目标优化,结果显示系统最大热效率为37.37%,最大?效率为53.92%,最低总成本率为0.782百万美元/a。

垃圾焚烧锅炉最佳适用主蒸汽参数的探讨

提高生活垃圾焚烧锅炉的主蒸汽参数可提高热力系统循环效率。本文基于朗肯循环、理论循环热效率讨论循环热效率与主蒸汽参数的关系,并探讨我国锅炉主蒸汽参数系列的确定,分析提高蒸汽压等级对锅炉运行管理的影响。循环热效率随蒸汽初压增大而提高,实际运行过程中,应充分考虑提高蒸汽压等级对汽水循环倍率、循环系统类型、汽包蓄热能力、锅炉压力部件材质、汽水质量等运行管理过程造成的影响。

典型F级燃气-蒸汽联合循环机组进气加热变工况性能分析

以通用电气(GE)公司的9FA和三菱公司的M701F这2种典型F级燃气 蒸汽联合循环机组为研究对象,搭建配置进气加热设计的燃气 蒸汽联合循环热力模型,开展机组热力性能仿真计算。对环境温度、加热温升、机组负荷对机组性能的影响进行单一变量分析,并且对2种机型在不同运行工况下的进气加热效果提升开展对比分析,给出了不同负荷下的最佳进气参数。结果表明:在相同的进气加热工况下,9FA机组的进气加热效果提升幅度高于M701F机组,机组联合循环效率随加热温升的提高而提高;在相同的加热温升下,9FA机组的最佳进气环境温度高于M701F机组。研究结果对进气加热技术在F级燃气 蒸汽联合循环机组上的应用具有重要参考意义。

Performance Improvement of Combined Cycle Power Plant Based on the Optimization of the Bottom Cycle and Heat Recuperation

Many F class gas turbine combined cycle （GTCC） power plants are built in China at present because of less emission and high efficiency. It is of great interest to investigate the efficiency improvement of GTCC plant. A combined cycle with three-pressure reheat heat recovery steam generator （HRSG） is selected for study in this paper. In order to maximize the GTCC efficiency, the optimization of the HRSG operating parameters is performed. The operating parameters are determined by means of a thermodynamic analysis, i.e. the minimization of exergy losses. The influence of HRSG inlet gas temperature on the steam bottoming cycle efficiency is discussed. The result shows that increasing the HRSG inlet temperature has less improvement to steam cycle efficiency when it is over 590℃. Partial gas to gas recuperation in the topping cycle is studied. Joining HRSG optimization with the use of gas to gas heat recuperation, the combined plant efficiency can rise up to 59.05% at base load. In addition, the part load performance of the GTCC power plant gets much better. The efficiency is increased by 2.11% at 75% load and by 4.17% at 50% load.

Relations among Main Operating Parameters of Gasifier in IGCC

Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit with coal water slurry gasifier was simulated and calculated using THERMOFLEX software, and the relations of oxygen coal ratio (Roc), water coal ratio (Rsc), gasification pressure, gasification temperature and cold gas efficiency were mostly researched. The results show that Roc and Rsc have effect of mutual restriction on gasification temperature, cold gas efficiency and syngas composition. Gasification pressure mainly determines the capacity of the gasifier, little effects on syngas composition.

燃气蒸汽联合循环机组高温阀门开裂原因分析

采用宏观观察、金相分析、硬度试验、断口扫描电镜分析和能谱分析,对某燃气-蒸汽联合循环机组余热锅炉高压旁路阀门开裂原因进行分析。结果表明:高压旁路阀门阀壳内壁开裂类型为腐蚀性热疲劳+应力腐蚀。机组启停频繁、负荷变化大,造成高压旁路阀门减温水的频繁投入,导致阀壳内壁表面存在较大的交变热应力,在交变热应力及腐蚀性环境的作用下,阀壳内壁处发生腐蚀性热疲劳开裂,在扩展过程中伴随应力腐蚀开裂。

高参数燃气轮机与超临界二氧化碳联合循环系统热力性能分析

构建高参数燃气轮机与超临界二氧化碳(S-CO_(2))联合循环模型,并开展热力性能分析。顶循环采用燃烧室排气温度为1800℃的高参数燃气轮机,底循环采用S-CO_(2)朗肯双透平循环,同时采用三级烟气加热和两级透平排气回热;通过惩罚函数法,得到优化后的联合循环工况下的参数和热力性能,分析了高参数燃气轮机顶循环和S-CO_(2)朗肯底循环主要参数对联合循环性能的影响规律。结果表明:在燃气轮机压比为35.5,燃烧室出口温度为1800℃时,联合循环热效率可达68.61%,燃气轮机与S-CO_(2)朗肯循环效率比燃气-蒸汽联合循环提高2.3百分点。

某联合循环系统热力性能研究

基于某联合循环系统,分析了蒸汽参数选择对余热锅炉设计及三压再热联合循环整体性能的影响,通过热力计算,结合工程实际,确定主蒸汽压力12.64 MPa,再热蒸汽压力3.33 MPa,低压蒸汽压力0.66 MPa。在燃气轮机运行工况变化时,对已设计的余热锅炉进行变工况计算,结果表明,主蒸汽压力对联合循环的影响与燃气轮机负荷正相关,而再热蒸汽压力正好相反,低压蒸汽压力的影响十分有限。

集成SOFC、GTCC以及双效溴化锂制冷的新型CCHP系统4E性能分析

为减少系统中的余热损失,满足“能量梯级利用”原则,本文创新提出一个集成冷、热、电三联产的系统。该系统充分利用高温固体氧化物燃料电池的余热,利用固体氧化物燃料电池的高温尾气作为补燃气体,输入燃气蒸汽联合循环系统的三压再热余热锅炉中,在保证系统热量匹配的条件下,最大程度提高系统的做功能力。本文利用Aspen Plus软件搭建仿真模型,基于热力学定律对系统进行能量分析、[火用]分析、经济分析以及环境分析,结果表明新系统的能量效率为63.35%,[火用]效率为63.65%,平准化发电成本为0.33元/kW·h,CO_(2)排放率为420.68 g/kW·h。

钙基吸收剂法与单乙醇胺吸附法在碳减排中的应用对比

为进一步缓解电力行业发电环节中机组所产生的二氧化碳导致加剧全球温室效应的问题,在对燃气-蒸汽联合循环发电机组简单概述的基础上,基于Aspen Plus软件分别建立了单乙醇胺吸附法和碳基吸收剂与NGCC机组的耦合模型,对其在设计工况和75%负荷工况下的热力性能和成本进行对比分析,为今后碳减排方式的优选应用及优化改进方向奠定了扎实的理论基础。

燃气蒸汽联合循环机组大数据应用增效研究

大数据在传统电厂中主要应用于设备的数字化管理方面,如设备安全运行的监视和控制,其经济价值没有得到更好的发挥。针对燃气发电生产的特点,引入智能化的计算方法和分析方法,通过生产大数据建立天然气发电供电成本监测平台和机组启动消耗成本监测平台。通过对比发电供电成本和每次启动消耗的成本数据,优化运行方式和启动操作,达到经济调度、降本增效的目的。