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.     

应用甲烷自热重整技术的燃气轮机循环火用分析

提出了一种应用甲烷重整技术的燃气轮机新循环。首先,根据系统的工作过程,应用热力学平衡方法分析燃烧室反应的热平衡;其次依据热力学第二定律,研究了燃气轮机新循环火用效率的变化趋势。结果显示:新循环燃烧消耗的甲烷量小于供给量,与CO2和H2O重整消耗的甲烷量的变化趋势与反应平衡常数的大小有关。在相同燃料量的条件下,与简单循环相比,新循环的火用效率得到大幅提高,涨幅为5.05%-15.57%。     

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。     

考虑透平冷却的再热燃气轮机联合循环热力性能参数影响

燃气轮机再热被认为可以提高效率和比功。本文基于准一维透平连续膨胀冷却模型和底循环简明估算模型对再热燃气轮机联合循环进行热力性能研究,以GT-26燃气轮机为基准分析了循环总压比、燃烧室出口温度、再热压力等关键参数对联合循环热力性能的影响特性,并与无再热燃气轮机的联合循环性能进行了比较。研究表明：不同燃烧室出口温度下的再热燃气轮机联合循环效率最大值对应的循环总压比相差不大;不同燃烧室出口温度和循环总压比下,联合循环效率对应的最佳高压透平膨胀比不同。当燃烧室出口温度为1 683 K时,在各自的效率最佳压比下,再热燃气轮机联合循环比无再热燃气轮机的联合循环效率提高了1.34个百分点,同时比功提高了33.2%。     

基于固体氧化物燃料电池的有机工质余热发电联合系统特性的理论研究

针对有机朗肯循环对低温余热回收的显著优势,提出了一种基于固体氧化物燃料电池(SOFC)的有机工质余热发电联合系统.该系统包含内重整SOFC、后燃室、燃气轮机、压气机、预热器和有机朗肯循环,实现了能量的梯级利用,有效地提高了系统的总发电效率.在稳态数学模型的基础上,建立了基于SOFC的有机工质余热发电联合系统的热力仿真分析平台,研究了关键参数对系统性能的影响.结果表明:在设计工况下,系统的总发电效率可达65%以上;随着燃料摩尔流量的增加,系统的净输出功增加,但系统的总发电效率有所下降;在一定范围内,增大压气机压比可以提高系统净输出功和总发电效率;随着蒸汽与碳物质的量比的增大,系统的净输出功减小,总发电效率下降.     

燃气轮机的湿空气循环性能分析与试验

对燃气轮机湿空气循环的性能进行了分析,建立了湿化工质的热物性计算模型,并对基于微型分轴燃气轮机湿空气循环装置的性能进行了初步试验.试验结果表明,空气加湿后燃气轮机系统的运行性能有明显改善,与简单循环系统相比,比功和效率都有很大的提高.根据试验条件进行的模拟计算结果与试验结果能很好地吻合.     

MF—111燃气轮机功热并供在日本石化企业中得到广泛应用

采用高效率燃气轮机功热并供技术来提高能源利用率,是个值得重视的发展动向.日本石化企业在这方面的进展,特别引人注目.去年底,我们有幸访日考察,参观日本主要的燃气轮机制造厂家、研究所以及燃气轮机功热并供和联合循环电站等,收获不少,得到了许多有益启示.尤其对许多石化公司广泛采用三菱重工的MF—111高温燃气轮机功热并供装置,且运用效果良好,印象深刻.现就所了解的情况进行分析研究,整理成文.本文着重介绍该装置应用情况和主要特点.     

整体煤气化湿化燃气轮机循环热力性能分析

本文以降低NOX排放和有效利用低品位热量为出发点,将燃料或空气湿化应用到整体煤气化燃气轮机循环中。基于水煤浆激冷或废锅流程气化炉,构建了多种整体煤气化湿化燃气轮机循环并分析了其热力性能。研究表明：燃料湿化循环系统效率较高;空气湿化循环燃气轮机比功较大;无论采用何种湿化方式,废锅流程循环系统效率都要高于激冷流程;蒸汽底循环保留的空气湿化循环系统具有利用系统外部中低品位热量、大幅提高系统效率的潜力。     

美国GE公司发展燃气轮机新技术的情况

本文根据南京汽轮电机厂设计培训小组1986年在美国GE公司培训时R·George的讲授内容,并参阅GE公司有关论文和国外燃气轮机期刊编写而成.GE公司发展燃气轮机新技术要实现的主要目标为:改进燃气轮机的可靠性;增加机组出力和提高性能;燃烧系统的发展;发展先进的工业型燃气轮机.简单循环热效率目标为33.6%,联合循环为51%.本文还简单介绍了该公司新推出的MS7001型燃气轮机的概况.     

燃气轮机与汽轮机功热联产基本参数的分析研究

本文在文献[1]的基础上探讨了:(1)简单循环燃气轮机利用余热功热联产或汽轮机动热联产的评价准则及主要参数的影响;(2)燃用不同燃料“以热定功”功热联产时最佳功热比与经济拥系数的关系.以此可大致定量地分析各设计参数的优化匹配.     

Utilization of the cryogenic exergy of LNG by a mirror gas-turbine

In the course of worldwide efforts to suppress global warming, the saving of energy becomes more important. Recently, LNG (liquefied natural gas) terminals in our country have received more than 50 million tons of LNG per year. Therefore, the utilization of the cryogenic exergy in connection with the regasification of LNG gains more and more importance. The aim of this paper is the recovery of the energy consumed in liquefaction using the MGT (mirror gas-turbine), which is a new kind of combined cycle of a conventional gas-turbine worked as a topping cycle and TG (inverted Brayton cycle) as a bottoming cycle. The optimum characteristics have been calculated and it is shown that this cycle is superior to the current-use gasification systems in employing seawater heat in terms of thermal efficiency and specific output. In the present cycle, the cold LNG is used to cool the exhaust gas from a turbine of a TG, and then the exergy of the liquefied natural gas is transformed, with a very high efficiency, to electric energy. The main feature of this new concept is the removal of an evaporation system using seawater.     

Regenerative steam-injection gas-turbine systems

There is a demand for developments of the distributed energy system using a small-scale gas turbine. The steam injection configuration can improve the thermal efficiency of simple and regenerative gas-turbine cycles. In this paper, the performance characteristics of two types of regenerative steam-injection gas-turbine (RSTIG) systems are analyzed and they are compared with the performances of the simple, regenerative, water injection and steam injected gas-turbine (STIG) cycles. The thermal efficiencies of the RSTIG systems are higher than those of the regenerative, water injection and STIG systems and the specific power is larger than that of the regenerative cycle. The optimum pressure-ratio for maximum efficiency of the RSTIG systems is relatively low. Furthermore, the steam-injection configuration can be applied in the flexible heat-and-power cogeneration system and the total efficiency of the RSTIG cogeneration system reaches more than 70% (HHV).     

Finite-time heat-transfer analysis and ecological optimization of an endoreversible and regenerative gas-turbine power-cycle

This paper deals with the application of finite-time heat-transfer theory to optimize ecologically the power output of an endoreversible and regenerative gas-turbine power-cycle for infinite thermal-capacitance rates to and from the reservoirs. The expressions for power, thermal efficiency, and exergetic efficiency corresponding to the maximum ecological function for the gas-turbine cycle are presented. The effects of regeneration and hot–cold temperature ratio on power, entropy-generation rate, thermal efficiency and exergetic efficiency, all at the maximum ecological function, are determined. It is shown that both the power output and entropy-generation rate are increased significantly by the use of regenerators, and increase monotonically with an increase with hot/cold temperature ratio. The results further indicate that the thermal efficiency and exergetic efficiency are decreased by the use of regenerators and rise with an increase in the temperature ratio. By the introduction of the ecological function, the improvements in exergetic efficiency and thermal efficiency are evident.     

Reciprocating Joule-cycle engine for domestic CHP systems

The reciprocating Joule-cycle engine operates on a recuperated gas-turbine cycle and is intended to provide high thermal efficiency in small sizes (1–10 kW). It is designed to achieve a higher efficiency than a comparable gas-turbine by using a reciprocating compressor and expander to provide very high compression and expansion efficiencies. Possible power plants for small combined heat-and-power systems currently include Stirling engines, internal-combustion engines, gas-turbines and fuel cells. The reciprocating Joule-cycle engine appears to have considerable advantages compared with other prime movers in terms of efficiency, emissions and multi-fuel capability. The present study estimates the performance of such an engine and is the first stage in a larger project that will in due course produce a demonstration engine.     

Life-cycle emission of oxidic gases from power-generation systems

Life-cycle emissions of nitric oxide and sulphurous oxides from various types of electric-power generation systems have been estimated. Emissions from the process of building energy systems, as well as from the mining and transportation of the fuel were accounted for as well as the emissions from power stations. Two types of thermoelectric systems, namely a LNG-fuelled gas-turbine combined cycle and an integrated coal-gasification combined cycle, and four types of renewable energy systems — photovoltaic, hydropower, wind power and ocean thermal energy conversion — were evaluated. The estimated amounts of nitric oxide emitted per generated unit of electricity range from 0.06 to 0.3 g/kWh, while the amounts of suphur oxides range from 0.3 to 0.53 g/kWh. There is a tendency for renewable-energy systems to emit lower amounts of nitric oxide.     

FREQUENCY DEPENDENCE OF THE MAGNITUDE OF THERMAL STRESSES IN A FLAT PLATE SUBJECTED TO RAPID THERMAL CYCLING BY CONVECTIVE HEATING AND COOLING

Abstract

A study was conducted of the effect of the thermal stresses in a plate subjected to thermal cycling by changes in ambient temperature involving convective heat transfer, at frequencies sufficiently high that thermal equilibrium (;i.e., temperature uniformity) is not achieved within each cycle. The results obtained indicate that at any specific value of the Biot number the magnitude of maximum thermal stress within any cycle decreases with increasing frequency. Furthermore, at any given frequency the magnitude of the peak stress exhibits its maximum value during the first cycle and decreases to a constant value from cycle to cycle with increasing number of cycles     

太阳能驱动闭式简单燃气轮机循环热力学优化

研究太阳能通过换热器的闭式简单燃气轮机循环有限时间热力学性能，导出内可逆循环的最佳功率与效率间的关系，并得到最大功率输出及其相应的效率界限。用压气机和涡轮内效率表征循环内不可逆性，可得实际不可逆循环的最优性能。所得结果对闭式简单燃气轮机装置热力参数的选择有定指导意义。     

Development of efficiency-enhanced cogeneration system utilizing high-temperature exhaust-gas from a regenerative thermal oxidizer for waste volatile-organic-compound gases

We have developed a gas-turbine cogeneration system that makes effective use of the calorific value of the volatile organic compound (VOC) gases exhausted during production processes at a manufacturing plant. The system utilizes the high-temperature exhaust-gas from the regenerative thermal oxidizer (RTO) which is used for incinerating VOC gases. The high-temperature exhaust gas is employed to resuperheat the steam injected into the gasturbine. The steam-injection temperature raised in this way increases the heat input, resulting in the improved efficiency of the gas-turbine. Based on the actual operation of the system, we obtained the following results:     

Economic feasibility of waste heat to power conversion

With a high back-work ratio and a high exhaust-temperature, the simple cycle gas-turbine generation system usually has a low generation-efficiency especially when the ambient weather is hot. Among many technologies to improve the efficiency of a simple-cycle gas-turbine, inlet-air cooling, and steam reinjection are considered the best ways to modify an existing simple cycle unit without major destruction to its original integrity. To evaluate the individual effects after system modifications, a computer code for the simulation of the power-generation system was developed and validated in this study, and the ABSIM code developed by Oak Ridge National Laboratory was adopted to simulate the absorption refrigeration system. Based on the calculated improvement and the associated benefits, the estimated cost of refurbishment and other operational costs, economic analyses were performed under the current fuel and cost structures. Results indicate that the system with the steam reinjection feature has the highest generation-efficiency and thus the most potential profit on investment, while the system with both inlet-air cooling and steam reinjection features can generate the highest power-output and release the least exergy via the flue gases.     

Desiccant Cooling Cycle Tuning for Variable Environmental Conditions

The performance of desiccant cooling systems has been increasingly addressed, with applications spanning from thermal comfort to gas-turbine air cooling. Desiccant systems are particularly suitable regarding the environmental impact, due to the absence of refrigerants with ozone-depleting properties. Moreover, the use of low-grade waste heat as the primary energy source also characterizes a low global warming potential, when compared to vapor compression systems. Under this scenario, this study demonstrates how desiccant ventilation cycles can be tuned for environmental conditions while maintaining the conditioned space within acceptable thermal comfort conditions. The analysis is based on a simple numerical procedure for desiccant cooling simulation in which the overall system operation is calculated from individual cycle components’ characteristics. With the employed methodology, the conditioned space state is calculated for different environmental conditions and compared to a standard, previously set, comfort zone. The results show that, in addition to desiccant wheel performance, the effectiveness of evaporative coolers and the regenerator is of prime importance for achieving acceptable thermal comfort conditions.