固体氧化物燃料电池与燃汽轮机混合系统技术现状

固体氧化物燃料电池具有高能量密度、适用多种不同燃料、结构简单等优点,与燃气轮机结合后能达到近80%的能量利用效率,具有良好的市场前景.本文介绍了固体氧化物燃料电池与燃汽轮机混合系统的结构,应用现状,给出了未来发展的一些方向,并提出了固体氧化物燃料电池与燃气轮机混合系统发展需要解决的一些问题.     

独立风光混合系统的控制与仿真

设计了独立风光混合系统的控制策略,利用时域仿真对其控制策略进行仿真验证。仿真系统由2台直驱永磁风力机、光伏、储能和相关变流器构成。建立了系统的数学模型以及相应的控制策略,包括直驱永磁发电机、光伏变流器、储能充放电以及网侧逆变器的控制策略。通过时域仿真法对系统的相关控制策略进行动态仿真。结果表明:本文所设计的控制策略是正确、可行的。     

MCFC-并联TTEG混合系统的性能优化

为有效回收熔融碳酸盐燃料电池产生的余热,提出一种由熔融碳酸盐燃料电池(MCFC)、两级并联温差发电器(TTEG)和回热器组合而成的混合系统模型.考虑MCFC电化学反应中的过电势损失和混合系统中的不可逆损失,通过数值分析得出混合系统的输出功率和效率的数学表达式,获得混合系统的一般性能特征,讨论MCFC电流密度与温差发电器...     

基于生态学准则对MCFC/AR混合系统的优化分析

基于生态学准则对稳定状态下运行的熔融碳酸盐燃料电池(MCFC)与吸收式制冷机(AR)组成的混合系统进行优化,考虑系统存在的电化学和热力学不可逆性,导出混合系统等效输出功率、效率以及生态学性能系数(ECOP)的表达式。应用数值模拟分析混合系统性能,得到功率密度、效率以及ECOP分别与电流密度的基本关系,从而确定工作参数的优化区间。结果表明:混合系统运行时的输出功率和效率相比于燃料电池单独运行时有所提升,并且通过生态学优化能得到更为精确的优化工作区间。最后分析燃料电池的工作温度、工作压力以及制冷机内部不可逆性对混合系统生态学性能的影响。     

支撑形式及多孔电极结构参数对SOFC性能的影响

研究不同结构设计条件下，活化极化、欧姆极化、浓差极化对SOFC性能的影响。在分析浓差极化时，综合考虑了普通扩散和Knudsen扩散，使模型更接近实际。采用灵敏度分析方法，分析了5个结构参数对SOFC性能的影响。结果表明，在该文的分析条件下，阳极支撑的设计具有较好的输出特性。     

管式SOFC热电特性的三维数值研究

1前言固体氧化物燃料电池(SOFC)作为一种高效、低排放的先进发电方式,日益受到了人们的关注。其几何结构主要有板式、管式和单一整体形式。管式SOFC具体结构紧凑、能承受较高的工作压力等特点,目前,美国西屋公司开发的管式SOFC已经有了示范性工程。SOFC的平均工作温度一般在800     

基于AspenPlus的兆瓦级燃料电池分布式发电系统建模及仿真分析

目的   燃料电池分布式发电技术是适应未来能源低碳化、清洁化、高效化发展趋势的重要应用方向。国内燃料电池电站项目较少,缺乏实际项目经验积累。为了推进燃料电池分布式电站技术的应用,文章概述了国内外应用现状,总结了高温燃料电池的优势与不足,调研了国内燃料电池建设应用案例,并建立了固体氧化物燃料电池与熔融碳酸盐燃料电池发电系统流程。 方法   经过文献调研与实地调研,确定了两种适合建设大型电站的燃料电池分布式发电技术,并利用AspenPlus化工模拟软件建立燃料电池系统流程模型、电化学模型和能量分析模型,并开展系统的性能仿真分析。 结果   分析结果与实际运行结果相吻合,分析预测的系统性能趋势与已有研究相一致。 结论   该仿真方法可用于兆瓦级高温燃料电池分布式发电系统的研究,可为扩大燃料电池应用规模提供数据支持。     

感应加热过程的计算机仿真

系统地介绍了用于感应加热过程的计算机仿真的各种方法，包括三维变步长有限元法，电磁场和温度场耦合计算，场路结合分析，耦合电路法等，并对各种方法进行了比较。     

SOFC热电联供系统的设计方法研究

介绍了固体氧化物燃料电池建筑热电联供系统的各种结构流程,提出SOFC系统的设计路线,通过对SOFC系统的建模和模拟,开发出一种用于BCHP中燃料电池系统的设计方法,并利用该方法进行实例设计,结果表明:该方法可以针对用户的能源需求计算所需的燃料电池电堆的容量及系统辅助设备的容量,为电堆规模的确定、系统配套辅助设备的选型提供重要的参考依据,为SOFC在BCHP中的应用提供一个有力的系统设计工具.     

变电站的计算机培训仿真系统

介绍了一种新型、投资少、见效快、应用面广的微机变电站培训仿真系统，较详细地介绍了该计算机培训仿真系统的组成和设计实现及其特点。充分说明了运用计算机创建培训仿真系统的优越性，其发展前景是无比广阔的，为电力系统输变电运行人员的技术培训探索一条新路。     

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.     

Single-level optimization of a hybrid SOFC–GT power plant

The detailed synthesis/design optimization of a hybrid solid oxide fuel cell–gas turbine (SOFC–GT) power plant is presented in this paper. In the first part of the paper, the bulk-flow model used to simulate the plant is discussed. The performance of the centrifugal compressors and radial turbine is determined using maps, properly scaled in order to match the values required for mass flow rate and pressure ratio. Compact heat exchangers are simulated using Colburn and friction factor correlations. For the SOFC, the cell voltage versus current density curves (i.e. polarization curves) are generated on the basis of the Nernst potential and overvoltages. Validation of the SOFC polarization curves is accomplished with data available from Siemens Westinghouse. Both the steam–methane pre-reforming and internal reforming processes are modeled assuming the water–gas shift reaction to be equilibrium-controlled and the demethanization reactions to be kinetically controlled. Finally, a thermoeconomic model is developed by introducing capital cost functions for each plant component. The whole plant is first simulated for a fixed configuration. Then, a synthesis/design optimization of the plant is carried out using a traditional single-level approach. The results of the optimization are presented and discussed.     

Full load synthesis/design optimization of a hybrid SOFC–GT power plant

In this paper, the optimization of a hybrid solid oxide fuel cell–gas turbine (SOFC–GT) power plant is presented. The plant layout is based on an internal reforming SOFC stack; it also consists of a radial gas turbine, centrifugal compressors and plate-fin heat exchangers. In the first part of the paper, the bulk-flow model used to simulate the plant is presented. In the second part, a thermoeconomic model is developed by introducing capital cost functions. The whole plant is first simulated for a fixed configuration of the most important synthesis/design (S/D) parameters in order to establish a reference design configuration. Next a S/D optimization of the plant is carried out using a traditional single-level approach, based on a genetic algorithm. The optimization determined a set of S/D decision variable values with a capital cost significantly lower than that of the reference design, even though the net electrical efficiency for the optimal configuration was very close to that of the initial one. Furthermore, the optimization procedure dramatically reduced the SOFC active area and the compact heat exchanger areas.     

Enhanced coal gasification heated by unmixed combustion integrated with an hybrid system of SOFC/GT

For clean utilization of coal, enhanced gasification by in situ CO₂ capture has the advantage that hydrogen production efficiency is increased while no energy is required for CO₂ separation. The unmixed fuel process uses a sorbent material as CO₂ carrier and consists of three coupled reactors: a coal gasifier where CO₂ is captured generating a H₂-rich gas that can be utilized in fuel cells, a sorbent regenerator where CO₂ is released by sorbent calcination and it is ready for capture and a reactor to oxidize the oxygen transfer material which produces a high temperature/pressure vitiated air. This technology has the potential to eliminate the need for the air separation unit using an oxygen transfer material. Reactors' temperatures range from 750 °C to 1550 °C and the process operates at pressure around 7.0 bar. This paper presents a global thermodynamic model of the fuel processing concept for hydrogen production and CO₂ capture combined with fuel and residual heat usage. Hydrogen is directly fed to a solid oxide fuel cell and exhaust streams are used in a gas turbine expander and in a heat recovery steam generator. This paper analyzes the influence of steam to carbon ratio in gasifier and regeneration reactor, pressure of the system, temperature for oxygen transfer material oxidation, purge percentage in calciner, average sorbent activity and oxidant utilization in fuel cell. Electrical efficiency up to 73% is reached under optimal conditions and CO₂ capture efficiencies near 96% ensure a good performance for GHG's climate change mitigation targets.     

Part load operation of SOFC/GT hybrid systems: Stationary analysis

In a global energetic context characterized by the increasing demand of oil and gas, the depletion of fossil resources and the global warming, more efficient energy systems and, consequently, innovative energy conversion processes are urgently required. A possible solution can be found in the fuel cells technology coupled with classical thermodynamic cycle technologies in order to make hybrid systems able to achieve high energy/power efficiency with low environmental impact. Moreover, due to the synergistic effect of using a high temperature fuel cell such as solid oxide fuel cell (SOFC) and a recuperative gas turbine (GT), the integrated system efficiency can be significantly improved. In this paper a steady zero dimensional model of a SOFC/GT hybrid system is presented. The core of the work consists of a performance analysis focused on the influence of the GT part load functioning on the overall system efficiency maintaining the SOFC power set to the nominal one. Also the proper design and management of the heat recovery section is object of the present study, with target a global electric efficiency almost constant in part load functioning respect to nominal operation. The results of this study have been used as basis to the development of a dynamic model, presented in the following part of the study focused on the plant dynamic analysis.     

Design and eco-technoeconomic analyses of SOFC/GT hybrid systems accounting for long-term degradation effects

This study compares two SOFC/GT (solid oxide fuel cell with gas turbine) hybrid systems to that of two standalone SOFC systems via eco-technoeconomic analyses that account for long-term degradation effects. Four cases were examined: 1) standalone SOFC plant without a steam bottoming cycle; 2) standalone SOFC plant with a steam bottoming cycle; 3) SOFC/GT hybrid plant without a steam bottoming cycle; and 4) SOFC/GT with a steam bottoming cycle. This study employed a real-time 1D SOFC model with an empirical degradation calculation integrated with steady-state balance-of-plant models. Simulations used Matlab Simulink R2017a, Aspen Plus V10, and Python 3.7.4 with a pseudo steady-state approach. The results showed that, with some trade-offs, the SOFC/GT hybrid plant with the steam bottoming cycle is the best option, with an overall efficiency of 44.6% _LHV, an LCOE (levelized cost of electricity) of $US 77/MWh, and a CCA (cost of CO₂ avoided) of -$US 49.3/tonneCO₂e. The sensitivity analysis also indicated that SOFC/GT hybrid plants were less sensitive to SOFC price compared to standalone SOFC plants. The sensitivity analysis indicated that using a larger gas turbine and replacing the SOFC stack less frequently was the better design choice for the SOFC/GT hybrid plant.     

Proposal of a hybrid CHP system: SOFC/microturbine/absorption chiller

Distributed generation is becoming an attractive option for industrial and commercial scale customers. The main advantage of this on‐site power generation is that it offers a more efficient, reliable and cost‐effective power supply. In addition, waste heat can be used for local heating or cooling. This is known as cogeneration or combined heat and power (CHP). In the present work, a hybrid‐CHP system for a 230 kWe demand building is proposed and analyzed. The system considers the coupling of:

• A Solid Oxide Fuel Cell stack with an output of 200 kWe
• A Microturbine with an output of 30 kWe
• A single effect Absorption cooling system providing 55 kWt for air conditioning using water chillers

This plant would use natural gas as the primary fuel. The SOFC module is fed with the gas fuel and the whole stack generates the main power while acting as a combustor. The product gases exit the anode at a temperature of 900°C and are directly injected to the Micro Gas Turbine unit to produce additional power. Finally, the waste heat available at the turbine's exhaust fires a single effect Absorption Water‐Chiller to provide cooling for air conditioning in the building. This proposed system would generate up to 230 kWe and 55 kWt with high thermal efficiencies of around 70–75%. Currently, Hybrid SOFC/GT and Microturbine/CHP systems are being considered or tested at several facilities. However, a combination of both, which would yield to trigeneration, has not been considered yet. Here we present a conceptual model based on specific proposals and investigations done by other researchers. A theoretical analysis on the proposed model is conducted to evaluate the potential and possibilities of such Hybrid CHP system and further discussions based on the economical considerations is also presented. Copyright © 2009 John Wiley & Sons, Ltd.     

An analysis of SOFC/GT CHP system based on exergetic performance criteria

In this study, we first consider developing a thermodynamic model of solid oxide fuel cell/gas turbine combined heat and power (SOFC/GT CHP) system under steady-state operation using zero-dimensional approach. Additionally, energetic performance results of the developed model are compared with the literature concerning SOFC/GT hybrid systems for its reliability. Moreover, exergy analysis is carried out based on the developed model to obtain a more efficient system by the determination of irreversibilities. For exergetic performance evaluation, exergy efficiency, exergy output and exergy loss rate of the system are considered as classical criteria. Alternatively, exergetic performance coefficient (EPC) as a new criterion is investigated with regard to main design parameters such as fuel utilization, current density, recuperator effectiveness, compressor pressure ratio and pinch point temperature, aiming at achieving higher exergy output with lower exergy loss in the system. The simulation results of the SOFC/GT CHP system investigated, working at maximum EPC conditions, show that a design based on EPC criterion has considerable advantage in terms of entropy-generation rate.     

Performance analysis of an SOFC/HCCI engine hybrid system: System simulation and thermo-economic comparison

A novel SOFC hybrid system is proposed and evaluated relative to its thermodynamic efficiency and economy. The proposed system combines an SOFC stack with an HCCI-type internal combustion engine; the HCCI engine replaces a conventional combustor, simultaneously burns the anode off-gas, and produces additional power. To calculate the efficiency of the suggested system, each component and the overall system have been thermodynamically modeled. The levelized cost of electricity (LCOE) has been calculated and economically assessed. For quantitative comparison and evaluation, a simple SOFC system and an SOFC/GT hybrid system are designed. Consequently, the proposed hybrid system shows the efficiency 59.5%, which is 7.8% and 0.9% higher efficiency than those of the SOFC simple system and the SOFC/GT hybrid system, respectively. And the system exhibits the LCOE $0.23/kWh, that is 12.9% and 7.6% reduced LCOE compared with the other two reference cases.     

Off-design analysis of SOFC hybrid system

This paper sets out the results of mathematical modeling and numerical simulations of the off-design (part-load) operation of the solid oxide fuel cell hybrid system (SOFC-HS).