应用甲烷重整技术的燃气轮机新循环热力学分析

提出了应用甲烷重整技术的新型燃气轮机循环,建立新型燃气轮机循环系统的工作流程,并通过平衡常数的计算来分析燃烧室的反应平衡,研究了燃气轮机循环热效率的变化.结果表明：甲烷发生吸热的重整反应对甲烷燃烧的消耗量有影响;在相同燃料量的条件下,新循环与简单循环相比,热效率得到大幅提高;由于重整反应生成的混合气体组分中多了CO和H2气体,使得混合气体平均比定压热容增大;随着燃烧室出口温度T3的升高,新循环甲烷平衡的转化率逐渐增大,随着压比的增大,转化率逐渐降低.     

甲烷自热重整的燃气轮机新循环热力学分析

提出了甲烷自热重整的新型燃气轮机循环.首先建立数学模型,通过平衡常数的计算来分析燃烧室反应平衡;并据此研究了燃气轮机循环性能指标的变化.结果显示:在相同燃料量的条件下,新循环与简单循环相比,热效率得到大幅提高,循环比功也增大.原因主要是新循环消耗的空气量较少,因此压气机耗功小;同时由于重整反应生成的混合气体组分中多了C...     

燃气初温对燃气轮机[火用]损失的影响分析

基于热力学第二定律,对燃气轮机实际简单循环推导出了燃气轮机各部件[火用]损失的计算公式。通过对某型燃气轮机的定量计算,得出了燃气轮机在不同燃气初温下的[火用]损失。结果表明,燃气初温对燃气轮机的[火用]损失有较大的影响。     

应用天然气重整技术的新型动力系统开拓研究

总结概述应用天然气重整反应技术的新型动力系统开拓研究，包括燃料电池及联合循环系统、化学回热燃气轮机循环、太阳能一天然气互补动力系统以及天然气／煤双燃料综合动力系统等。分析归纳天然气蒸汽重整在动力系统应用的新方式，侧重论述天然气蒸汽重整在相关新系统集成中新应用的功能与机理，还分析揭示新系统的特性与性能。     

复杂循环燃气轮机功热并供热力学分析

对复杂循环燃气轮机功热并供的多种高效用能装置,按当量(火用)效率最高为准则进行了基本计算与分析比较,考察了燃气轮机压比、温比及高低压透平间膨胀比分配、高低压压气机间压比分配等对装置效率特性的影响,给出了它们的热力学最佳取值范围.     

燃气轮机与混合装置的(火用)性能比较

燃气轮机中的燃烧反应是一种高度不可逆的过程,因此效率较低。燃气轮机-燃料电池混合装置则由于绝大部分燃料通过电化学反应来释放能量,只有未完全利用的燃料参加燃烧反应。用热力学第一定律和热力学第二定律对燃气轮机和它与燃料电池构成的混合装置进行了比较分析,研究了循环的效率和各部件的性能对整个系统的影响,给出了混合装置中对提高系统性能具有重要影响的部件。图4表2参8。     

燃气轮机与混合装置的[火用]性能比较

燃气轮机中的燃烧反应是一种高度不可逆的过程，因此焖效率较低。燃气轮机-燃料电池混合装置则由于绝大部分燃料通过电化学反应来释放能量，只有未完全利用的燃料参加燃烧反应。用热力学第一定律和热力学第二定律对燃气轮机和它与燃料电池构成的混合装置进行了比较分析，研究了循环的炯效率和各部件的性能对整个系统的影响，给出了混合装置中对提高系统性能具有重要影响的部件。图4表2参8：     

燃气轮机与混合装置的Yong性能比较

燃气轮机中的燃烧反应是一种高度不可逆的过程，因此Yong效率较低。燃气轮机一燃料电池混合装置则由于绝大部分燃料通过电化学反应来释放能量，只有未完全利用的燃料参加燃烧反应。用热力学第一定律和热力学第二定律对燃气轮机和它与燃料电池构成的混合装置进行了比较分析，研究了循环的Yong效率和各部件的性能对整个系统的影响，给出了混合装置中对提高系统性能具有重要影响的部件。     

非平衡等离子体重整甲烷的动力学机理

采用数值模拟和实验研究相结合的方法研究了非平衡等离子体重整甲烷的动力学过程,结合实验数据,建立了低温下非平衡等离子体重整甲烷的详细反应动力学机理.与实验结果相比,该动力学机理可准确预测甲烷重整反应中甲烷转化率及各产物选择性的变化趋势.通过模拟研究了甲烷的放电特性,根据建立的机理研究获得反应路径并对积碳进行了深入分析,为等离子体与催化剂协同甲烷重整反应的机理研究奠定基础.     

跨临界CO2制冷循环火用分析

基于热力学第二定律,对跨临界CO2制冷循环过程的损失及火用效率进行理论分析,发现节流过程火用损失最大,循环火用效率为25%。提高蒸发温度和降低冷却终了温度是提高循环火用效率的有效途径;升高冷却压力,可以降低节流过程火用损失,但是对循环火用效率影响不大。     

A novel combined cycle with synthetic utilization of coal and natural gas

 In this paper, a novel combined cycle with synthetic utilization of coal and natural gas is proposed, in which the burning of coal provides thermal energy to the methane/steam reforming reaction. The syngas fuel, generated by the reforming reaction, is directly provided to the gas turbine as fuel. The reforming process with coal firing has been investigated based on the concept of energy level, and the equations has been derived to disclosing the mechanism of the cascade utilization of chemical energy of natural gas and coal in the reforming process with coal firing. Through the synthetic utilization of natural gas and coal, the exergy destruction of the combustion of syngas is decreased obviously compared with the direct combustion of natural gas and coal. As a result, the overall thermal efficiency of the new cycle reaches 52.9%, as energy supply by methane is about twice as much as these of coal. With the same consumption of natural gas and coal the new cycle can generate about 6% more power than the reference cycles (the combined cycle and the steam power plant). The promising results obtained here provide a new way to utilize natural gas and coal more efficiently and economically by synthetic utilization.     

Integrated solar combined cycle system with steam methane reforming: Thermodynamic analysis

The present paper considers an integrated solar combined cycle system (ISCCS) with an utilization of solar energy for steam methane reforming. The overall efficiency was compared with the efficiency of an integrated solar combined cycle system with the utilization of solar energy for steam generation for a steam turbine cycle. Utilization of solar energy for steam methane reforming gives the increase in an overall efficiency up to 3.5%. If water that used for steam methane reforming will be condensed from the exhaust gases, the overall efficiency of ISCCS with steam methane reforming will increase up to 6.2% and 8.9% for β = 1.0 and β = 2.0, respectively, in comparison with ISCCS where solar energy is utilized for generation of steam in steam turbine cycle. The Sankey diagrams were compiled based on the energy balance. Utilization of solar energy for steam methane reforming increases the share of power of a gas turbine cycle: two-thirds are in a gas turbine cycle, and one-third is in a steam turbine cycle. In parallel, if solar energy is used for steam generation for a steam turbine cycle, than the shares of power from a gas and steam turbine are almost equal.     

Thermodynamic analysis of an integrated power generation system driven by solid oxide fuel cell

A new integrated power generation system driven by the solid oxide fuel cell (SOFC) is proposed to improve the conversion efficiency of conventional energy by using a Kalina cycle to recover the waste heat of exhaust from the SOFC-GT. The system using methane as main fuel consists an internal reforming SOFC, an after-burner, a gas turbine, preheaters, compressors and a Kalina cycle. The proposed system is simulated based on the developed mathematical models, and the overall system performance has been evaluated by the first and second law of thermodynamics. Exergy analysis is conducted to indicate the thermodynamic losses in each components. A parametric analysis is also carried out to examine the effects of some key thermodynamic parameters on the system performance. Results indicate that as compressor pressure ratio increases, SOFC electrical efficiency increases and there is an optimal compressor pressure ratio to reach the maximum overall electrical efficiency and exergy efficiency. It is also found that SOFC electrical efficiency, overall electrical efficiency and exergy efficiency can be improved by increasing air flow rate. Also, the largest exergy destruction occurs in the SOFC followed by the after-burner, the waste heat boiler, the gas turbine. The compressor pressure ratio and air flow rate have significant effects on the exergy destruction in some main components of system.     

High efficiency chemical energy conversion system based on a methane catalytic decomposition reaction and two fuel cells. Part II. Exergy analysis

A methane catalytic decomposition reactor-direct carbon fuel cell-internal reforming solid oxide fuel cell (MCDR-DCFC-IRSOFC) energy system is highly efficient for converting the chemical energy of methane into electrical energy. A gas turbine cycle is also used to output more power from the thermal energy generated in the IRSOFC. In part I of this work, models of the fuel cells and the system are proposed and validated. In this part, exergy conservation analysis is carried out based on the developed electrochemical and thermodynamic models. The ratio of the exergy destruction of each unit is examined. The results show that the electrical exergy efficiency of 68.24% is achieved with the system. The possibility of further recovery of the waste heat is discussed and the combined power-heat exergy efficiency is over 80%.     

Thermodynamic performance comparison of SOFC-MGT-CCHP systems coupled with two different solar methane steam reforming processes

Multi-energy complementary distributed energy system integrated with renewable energy is at the forefront of energy sustainable development and is an important way to achieve energy conservation and emission reduction. A comparative analysis of solid oxide fuel cell (SOFC)-micro gas turbine (MGT)-combined cooling, heating and power (CCHP) systems coupled with two solar methane steam reforming processes is presented in terms of energy, exergy, environmental and economic performances in this paper. The first is to couple with the traditional solar methane steam reforming process. Then the produced hydrogen-rich syngas is directly sent into the SOFC anode to produce electricity. The second is to couple with the medium-temperature solar methane membrane separation and reforming process. The produced pure hydrogen enters the SOFC anode to generate electricity, and the remaining small amount of fuel gas enters the afterburner to increase the exhaust gas enthalpy. Both systems transfer the low-grade solar energy to high-grade hydrogen, and then orderly release energy in the systems. The research results show that the solar thermochemical efficiency, energy efficiency and exergy efficiency of the second system reach 52.20%, 77.97% and 57.29%, respectively, 19.05%, 7.51% and 3.63% higher than those of the first system, respectively. Exergy analysis results indicate that both the solar heat collection process and the SOFC electrochemical process have larger exergy destruction. The levelized cost of products of the first system is about 0.0735$/h that is lower than that of the second system. And these two new systems have less environmental impact, with specific CO₂ emissions of 236.98 g/kWh and 249.89 g/kWh, respectively.     

Energetic and exergetic performance analyses of a combined heat and power plant with absorption inlet cooling and evaporative aftercooling

In this paper, exergy method is applied to analyze the gas turbine cycle cogeneration with inlet air cooling and evaporative aftercooling of the compressor discharge. The exergy destruction rate in each component of cogeneration is evaluated in detail. The effects of some main parameters on the exergy destruction and exergy efficiency of the cycle are investigated. The most significant exergy destruction rates in the cycle are in combustion chamber, heat recovery steam generator and regenerative heat exchanger. The overall pressure ratio and turbine inlet temperature have significant effect on exergy destruction in most of the components of cogeneration. The results obtained from the analysis show that inlet air cooling along with evaporative aftercooling has an obvious increase in the energy and exergy efficiency compared to the basic gas turbine cycle cogeneration. It is further shown that the first-law efficiency, power to heat ratio and exergy efficiency of the cogeneration cycle significantly vary with the change in overall pressure ratio and turbine inlet temperature but the change in process heat pressure shows small variation in these parameters.     

Two novel oxy-fuel power cycles integrated with natural gas reforming and CO2 capture

Two novel system configurations were proposed for oxy-fuel natural gas turbine systems with integrated steam reforming and CO₂ capture and separation. The steam reforming heat is obtained from the available turbine exhaust heat, and the produced syngas is used as fuel with oxygen as the oxidizer. Internal combustion is used, which allows a very high heat input temperature. Moreover, the turbine working fluid can expand down to a vacuum, producing an overall high-pressure ratio. Particular attention was focused on the integration of the turbine exhaust heat recovery with both reforming and steam generation processes, in ways that reduce the heat transfer-related exergy destruction. The systems were thermodynamically simulated, predicting a net energy efficiency of 50–52% (with consideration of the energy needed for oxygen separation), which is higher than the Graz cycle energy efficiency by more than 2 percentage points. The improvement is attributed primarily to a decrease of the exergy change in the combustion and steam generation processes that these novel systems offer. The systems can attain a nearly 100% CO₂ capture.     

中冷再热STIG循环的火用分析

对中冷再热注蒸汽燃气轮机（ＳＴＩＧ）循环火用分析结果表明：中冷再热ＳＴＩＧ循环比简单ＳＴＩＧ循环的火用效率显著提高。同时，分析了设备性能和各循环参数对火用效率的影响，分析了各种不可逆损失产生的部位，得出了与热平衡本质不同的结论     

Exergy analysis,parametric analysis and optimization for a novel combined power and ejector refrigeration cycle

A new combined power and refrigeration cycle is proposed, which combines the Rankine cycle and the ejector refrigeration cycle. This combined cycle produces both power output and refrigeration output simultaneously. It can be driven by the flue gas of gas turbine or engine, solar energy, geothermal energy and industrial waste heats. An exergy analysis is performed to guide the thermodynamic improvement for this cycle. And a parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the performance of the combined cycle. In addition, a parameter optimization is achieved by means of genetic algorithm to reach the maximum exergy efficiency. The results show that the biggest exergy loss due to the irreversibility occurs in heat addition processes, and the ejector causes the next largest exergy loss. It is also shown that the turbine inlet pressure, the turbine back pressure, the condenser temperature and the evaporator temperature have significant effects on the turbine power output, refrigeration output and exergy efficiency of the combined cycle. The optimized exergy efficiency is 27.10% under the given condition.