燃料电池_燃气轮机混合动力系统中催化燃烧室特性分析

对熔融碳酸盐燃料电池/微型燃气轮机(MCFC/MGT)混合动力系统中的催化燃烧室进行了实验和理论分析,确定了燃烧室入口温度、燃料浓度对燃料转化率的影响,在非设计工况下运行时催化燃烧室入口条件会发生变化,应用数学模型分析了各主要因素对催化燃烧室运行特性的影响。结果表明,计算结果与实验结果的最大误差在4%以内。在混合动力系统的运行范围内催化燃烧室入口温度高于770K时燃料转化率达99%以上,而入口流速和燃料浓度的变化对转化率的影响不明显。     

基于生物质气的固体氧化物燃料电池-燃气轮机混合动力系统的性能分析

以生物质气为燃料,建立了固体氧化物燃料电池-燃气轮机混合动力系统的仿真模型.利用所建立的模型进行仿真,根据燃料电池特性参数和压气机、透平特性曲线,分析了燃料质量流量、空气质量流量等参数对混合动力系统性能的影响.结果表明:基于生物质气的固体氧化物燃料电池-燃气轮机混合动力系统的发电效率最高可达61.55%,但在这种情况下系统的寿命和可靠性急剧下降;在设计点工况下,系统的发电效率可达55.31%.燃料质量流量不变,空气质量流量可以在0.084 0~0.179 9kg/s内调节,系统效率变化范围为61.55%~51.43%;空气质量流量不变,为防止压气机发生喘振,燃料质量流量变化范围为0.062 3~0.084 6kg/s,功率变化范围为124.9~187.3kW.     

基于IGV控制的先进燃气轮机联合循环运行优化

为了达到高效的先进燃气轮机联合循环优化运行,提高循环的能源利用率,以先进燃气轮机联合循环技术为研究对象,通过以有机物为工质的朗肯循环回收燃气轮机的余热,进行燃气轮机联合循环变工况仿真模拟来研究联合循环运行特性,分析了环境温度和压气机进口导叶(IGV)调节对联合循环运行特性的影响,制定了IGV角度的优化控制策略。结果表明:在变负荷工况和不同环境温度下,调节燃气轮机的空燃比,可以优化该燃气轮机联合循环的运行特性,提升联合循环效率。     

9E级燃气轮机部分负荷进气加热提效技术研究与工程应用

本文在介绍燃气轮机设备运行特性和我国当前燃气轮机发电行业现状的基础上,对燃气轮机部分负荷运行情况进行了仿真计算研究和运行数据分析研究。根据实际运行数据分析,我国燃气电厂机组普遍存在实际运行负荷长期低于设计负荷、燃气轮机部分负荷运行效率衰减、高品位能源浪费巨大的问题。针对燃气电厂机组运行现状,本文通过对PG9171E型燃气轮机机组采用实际运行数据分析和仿真建模计算的方法,重点研究了燃气轮机入口空气温度调整对联合循环机组部分负荷工况性能的影响。根据研究结果,提出了一种利用燃气联合循环系统低品位余热作为热源的燃气轮机联合循环进气加热部分负荷提效技术,并对该技术在我国不同型号燃气轮机机组上的技术应用进行了分析。研究结论和实践结果表明,本文所述的燃气轮机部分负荷进气加热技术系统简洁,系统改造附加进气压损较小,能够适用于我国大部分在运燃气联合循环机组,并且能够显著提高联合循环部分负荷工况的运行效率。     

考虑冷气掺混的重型燃气轮机变工况运行的精细建模及特性分析

为了研究全工况下燃气轮机内部运行参数及其所具有的特性规律,以PG9351FA燃机为分析对象,建立具有冷气掺混的重型燃气轮机变工况运行精细模型。该模型采用半经验公式对燃机冷却空气掺混量进行估算,充分考虑了冷气掺混对透平性能的影响,以及马赫数、攻角对透平变工况运行时造成的气流参数变化及速度损失的修正。结果显示:所建模型的精度有所提高,利用其计算所得结果与厂家提供数据相比,数据误差可控制在±0.4%以内,可用于预估燃机在部分负荷工况下的运行特性。应用模型分析了透平背压变动对透平膨胀比分配、排气温度及输出功率(出功)的影响,得到了透平内部气体流动参数和性能参数以及分级特性规律,其结果更真实地反映了机组在特定运行策略是的全工况特性规律。     

基于混合模型的燃气轮机负荷与排气温度关系的研究

由于缺少关键数据和资料,从理论上研究燃气轮机负荷与排气温度关系难度较大。由燃气轮机主要设备特性分析入手,通过运用浙江大唐江山天然气热电联产机组实际运行数据和设计数据对燃气轮机进行混合建模,更全面地了解燃气轮机变工况运行过程中各参量的相互影响关系,从而发掘出基于一般规律的燃气轮机负荷对排气温度的影响,这对了解燃气轮机的整体性能、优化电厂生产具有重要意义。     

基于燃气轮机变工况的IGCC系统特性研究

燃气轮机是IGCC系统中的关键部件,其性能变化直接影响到整个IGCC系统。本文利用Thermoflex软件建立200MW级IGCC系统模型,主要分析燃气轮机在40％～100％负荷下的IGCC系统变工况特性。通过燃气轮机初温及其压气机进口可转导叶IGV变化,分析了燃气轮机实现降负荷调节方式,并从系统角度出发,研究了基于燃气轮机变工况的IGCC系统主要性能参数的变化。本文的研究结果对未来IGCC电站的设计和运行具有一定的参考价值。     

某渔业资源调查船柴电混合动力系统设计及应用

基于船舶动力系统设计平台,根据某渔业资源调查船运行工况,从柴电混合动力系统运行模式分析、设备选型分析、推进轴系回转振动分析等方面着手,开展柴电混合动力系统设计.设计的柴电混合动力系统与传统柴油机动力系统相比,装机功率降低了 17.9％,油耗降低了 6.5％.经实船应用,各项性能指标均满足技术要求.     

掺氢比例对氢混天然气燃气轮机运行特性影响的研究

采用模块化的建模方法建立燃气轮机的变工况特性预估模型,对氢气掺混比为0~100%时燃气轮机在不同负荷下的运行参数、部件运行特性及机组能耗进行了计算分析。结果表明：氢气掺混比的提升将使压气机进气量下降,喘振裕度减小;但由于压比的提升,透平有效比焓降提高,机组功率增大,且在高氢气掺混比下燃气轮机的发电效率得到提升,相比于纯天然气工况,10%,20%,40%,100%氢气掺混比下燃气轮机满负荷的发电效率可分别提高0.03%,0.06%,0.14%和0.86%。     

环境温度对微型燃气轮机运行特性的影响研究

为了研究环境温度对微型燃气轮机关键部件与系统全工况运行特性的影响规律,针对100 kW级微型燃气轮机,通过模块化的建模方法建立了全工况计算模型,在环境温度-30~40 ℃、转速在75%~100%工况下,对机组与关键部件的运行特性进行了计算和分析。结果表明：随环境温度下降压气机压比与流量显著升高;燃气初温降低,回热器换热性能与压损均降低,机组功率、回热度与发电效率得到提升;当环境温度降低使机组功率高于设计功率时,随功率增加发电效率下降。     

Performance analysis of a pressurized molten carbonate fuel cell/micro-gas turbine hybrid system

This paper presents the work on the design and part-load operations of a hybrid power system composed of a pressurized molten carbonate fuel cell (MCFC) and a micro-gas turbine (MGT). The gas turbine is an existing one and the MCFC is assumed to be newly designed for the hybrid system. Firstly, the MCFC power and total system power are determined based on the existing micro-gas turbine according to the appropriate MCFC operating temperature. The characteristics of hybrid system on design point are shown. And then different control methods are applied to the hybrid system for the part-load operation. The effect of different control methods is analyzed and compared in order to find the optimal control strategy for the system. The results show that the performance of hybrid system during part-load operation varies significantly with different control methods. The system has the best efficiency when using variable rotational speed control for the part-load operation. At this time both the turbine inlet temperature and cell operating temperature are close to the design value, but the compressor would cross the surge line when the shaft speed is less than 70% of the design shaft speed. For the gas turbine it is difficult to obtain the original power due to the higher pressure loss between compressor and turbine.     

Performance characteristics of a solid oxide fuel cell/gas turbine hybrid system with various part-load control modes

The purpose of this study is to compare the part-load performance of a solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system in three different control modes: fuel-only control, rotational speed control, and variable inlet guide vane (VIGV) control. While the first mode maintains a constant air supply and reduces the supplied fuel to achieve part-load operation, the other modes are distinguished by the simultaneous controls of the air and fuel supplied to the system. After the performance analysis of a SOFC/GT hybrid system under part-load operating conditions, it was concluded that the rotational speed control mode provided the best performance characteristics for part-load operations. In spite of worse performance than the rotational speed control mode, the VIGV control mode can be a good candidate for part-load operation in a large-scale hybrid system in which the rotational speed control is not applicable. It was also found that, in spite of a relatively small contribution to the total system power generation, the gas turbine plays an important role in part-load operation of a SOFC/GT hybrid system.     

Performance characteristics of part-load operations of a solid oxide fuel cell/gas turbine hybrid system using air-bypass valves

In spite of the high-performance characteristics of a solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system, it is difficult to maintain high-level performance under real application conditions, which generally require part-load operations. The efficiency loss of the SOFC/GT hybrid system under such conditions is closely related to that of the gas turbine. The power generated by the gas turbine in a hybrid system is much less than that generated by the SOFC, but its contribution to the efficiency of the system is important, especially under part-load conditions. Over the entire operating load profile of a hybrid system, the efficiency of the hybrid system can be maximized by increasing the contribution of power coming from the high efficiency component, namely the fuel cell. In this study, part-load control strategies using air-bypass valves are proposed, and their impact on the performance of an SOFC/GT hybrid system is discussed. It is found that air-bypass modes with control of the fuel supply help to overcome the limits of the part-load operation characteristics in air/fuel control modes, such as variable rotational speed control and variable inlet guide vane control.     

Part-load performance characteristics of a lean burn catalytic combustion gas turbine system

The purpose of this study is to compare the part-load performance of a lean burn catalytic combustion gas turbine (LBCCGT) system in three different control modes: varying fuel, bleeding off the fuel mixture flow after the compressor and varying rotational speed. The conversions of methane species for chemical process are considered. A 1D heterogeneous plug flow model was utilized to analyze the system performance. The actual turbomachinery components were designed and predicted performance maps were applied to system performance research. The part-load characteristics under three control strategies were numerically investigated. The main results show that: the combustor inlet temperature is a significant factor that can significantly affect the part-load characteristics of the LBCCGT system; the rotational speed control mode can provide the best performance characteristics for part-load operations; the operation range of the bleed off mode is narrower than that of the speed control mode and wider than that of the fuel only mode; with reduced power, methane does not achieve full conversion over the reactor at the fuel only control mode, which will not warrant stable operation of the turbine system; the thermal efficiency of the LBCCGT system at fuel only control strategy is higher than that at bleed off control strategy within the operation range.     

Performance characteristics of a MW-class SOFC/GT hybrid system based on a commercially available gas turbine

The ultimate purpose of a SOFC/GT hybrid system is for distributed power generation applications. Therefore, this study investigates the possible extension of a SOFC/GT hybrid system to multi-MW power cases. Because of the matured technology of gas turbines and their commercial availability, it was reasonable to construct a hybrid system with an off-the-shelf gas turbine. Based on a commercially available gas turbine, performance analysis was conducted to find the total appropriate power for the hybrid system with consideration of the maximum allowable cell temperature. In order to maintain high performance characteristics of the hybrid system during part-load operations, it was necessary to find the optimal control strategy for the system according to the change in power required. The results of the performance analysis for part-load conditions showed that supplied fuel and air must be changed simultaneously. Furthermore, in order to prevent performance degradation, it was found that both cell temperature and turbine inlet temperature must be maintained as close as possible to design-point conditions.     

SOFC-MGT混合发电系统的半实物仿真方案研究

提出了一种固体氧化物燃料电池(SOFC)-微型燃气轮机(MGT)混合发电系统的半实物仿真和预集成方案.该方案以基于模型的燃烧器和涡轮增压器分别作为SOFC模拟器和MGT模拟器,克服了现有的试验系统均只适用于单一工作方式和传统的慢速迭代控制算法的缺点,可以兼容增压型和常压型两种工作模式,适用于正常运行、启动、部分负荷和瞬态等多种工况的模拟.通过对比传统的慢速迭代控制算法开发模式,探讨了基于Matlab/xPC Target和PowerPC5xx的快速控制原型的V型控制器开发模式.     

Catalytic combustion and system performance assessment of MCFC-MGT hybrid system

The catalytic combustor is applied as an off-gas and startup combustor for a molten carbonate fuel cell-micro-gas turbine (MCFC-MGT) hybrid system (HS) so as to utilize the waste energy of fuel cell off-gas. Three types of catalysts are prepared over a cordieritic honeycomb support. One is Pt catalyst which is not cost effective and less high temperature stability. CeZrO₂ and LaMnO₃ have been selected as an additive for another two Pt catalysts to improve the performance. Tests have been completed in realistic conditions and reaction feed close to the MCFC-MGT hybrid system. Simulations are carried out with a fluid mechanical code that incorporates detailed transport and heat loss mechanisms. The simulation results are compared with the Pt catalyst test results. The agreement confirms the accuracy of simulation. The model can be used to develop an MCFC-MGT hybrid system with an off-the-shelf gas turbine and assess the performances during part-load operation. From the experimental results, the reaction starts at 620 K for 1 vol.% CH₄ using Pt catalyst, while the temperature is above 800 K for the addition of additive. For the 50% CH₄ conversion, the preheated temperature of the three catalysts is 713 K, 870 K and 950 K respectively. While all of the catalysts exhibit good performance when using the MCFC off-gas as fuel. The results of performance analysis for part-load conditions show that the cell operation temperature and turbine inlet temperature (TIT) should be maintained as close as possible to the design value to prevent the performance degradation.     

Operation window and part-load performance study of a syngas fired gas turbine

Integrated coal gasification combined cycle (IGCC) provides a great opportunity for clean utilization of coal while maintaining the advantage of high energy efficiency brought by gas turbines. A challenging problem arising from the integration of an existing gas turbine to an IGCC system is the performance change of the gas turbine due to the shift of fuel from natural gas to synthesis gas, or syngas, mainly consisting of carbon monoxide and hydrogen. Besides the change of base-load performance, which has been extensively studied, the change of part-load performance is also of great significance for the operation of a gas turbine and an IGCC plant.In this paper, a detailed mathematical model of a syngas fired gas turbine is developed to study its part-load performance. A baseline is firstly established using the part-load performance of a natural gas fired gas turbine, then the part-load performance of the gas turbine running with different compositions of syngas is investigated and compared with the baseline. Particularly, the impacts of the variable inlet guide vane, the degree of fuel dilution, and the degree of air bleed are investigated. Results indicate that insufficient cooling of turbine blades and a reduced compressor surge margin are the major factors that constrain the part-load performance of a syngas fired gas turbine. Results also show that air bleed from the compressor can greatly improve the working condition of a syngas fired gas turbine, especially for those fired with low lower heating value syngas. The regulating strategy of a syngas fired gas turbine should also be adjusted in accordance to the changes of part-load performance, and a reduced scope of constant TAT (turbine exhaust temperature) control mode is required.     

Performance analysis for the part-load operation of a solid oxide fuel cell–micro gas turbine hybrid system

In this paper, the performance evaluation of a solid oxide fuel cell (SOFC)–micro gas turbine (MGT) hybrid power generation system under the part-load operation was studied numerically. The present analysis code includes distributed parameters model of the cell stack module. The conversions of chemical species for electrochemical process and fuel reformation process are considered. Besides the temperature distributions of the working fluids and each solid part of cell module by accounting heat generation and heat transfers, are taken into calculation. Including all of them, comprehensive energy balance in the cell stack module is calculated. The variable MGT rotational speed operation scheme is adopted for the part-load operation. It will be made evident that the power generation efficiency of the hybrid system decreases together with the power output. The major reason for the performance degradation is the operating temperature reduction in the SOFC module, which is caused by decreasing the fuel supply and the heat generation in the cells. This reduction is also connected to the air flow rate supplement. The variable MGT rotational speed control requires flexible air flow regulations to maintain the SOFC operating temperature. It will lead to high efficient operation of the hybrid system.     

Design and partial load exergy analysis of hybrid SOFC–GT power plant

This paper presents a full and partial load exergy analysis of a hybrid SOFC–GT power plant. The plant basically consists of: an air compressor, a fuel compressor, several heat exchangers, a radial gas turbine, mixers, a catalytic burner, an internal reforming tubular solid oxide fuel cell stack, bypass valves, an electrical generator and an inverter. The model is accurately described. Special attention is paid at the calculation of SOFC overpotentials. Maps are introduced, and properly scaled, in order to evaluate the partial load performance of turbomachineries. The plant is simulated at full-load and part-load operation, showing energy and exergy flows trough all its components and thermodynamic properties at each key-point. At full-load operation a maximum value of 65.4% of electrical efficiency is achieved. Three different part-load strategies are introduced. The off-design operation is achieved handling the following parameters: air mass flow rate, fuel mass flow rate, combustor bypass, gas turbine bypass, avoiding the use of a variable speed control system. Results showed that the most efficient part-load strategy corresponded to a constant value of the fuel to air ratio. On the other hand, a lower value of net electrical power (34% of nominal load) could be achieved reducing fuel flow rate, at constant air flow rate. This strategy produces an electrical efficiency drop that becomes 45%.