Analysis of a gas turbine and steam turbine combined cycle with liquefied hydrogen as fuel

The performances of a combined cycle driven by the liquid hydrogen are discussed. The cycle consists of a gas turbine with a pre-cooler system and a steam turbine heated by the exhaust energy of gas turbine. The liquid hydrogen has not only chemical but cryogenic exergy. The latter is about 10% of the total exergy and is converted to the useful work through the pre-cooling system and an auxiliary hydrogen turbine. The specific output and thermal efficiency of the combined cycle are much higher than those of a simple cycle gas turbine, but in order to operate the combined cycle successfully, it is necessary to check the pinch point which may take place in the boiling process which is heated by the exhaust energy of the gas turbine.     

Off-design point characteristics of the precooled gas turbine cycle with liquefied hydrogen as fuel

The off-design point performance of a precooled gas turbine cycle fueled with liquid hydrogen is analyzed. The gas turbine equips the precooler and hydrogen turbine in order that the cryogenic exergy (available energy) can be effectively converted to useful work. The design point is determined by using an estimating function, F. The thermodynamic analysis reveals that even at the off-design point working conditions the thermal efficiency of this cycle is also relatively high compared to that of conventional gas turbine cycle and the load factor decreases in keeping with the decrease in the temperature of the working fluid at the inlet of the gas turbine.     

燃气轮机中冷循环功率和功率密度优化比较

计入高低温侧换热器和中冷器的热阻损失、压气机和涡轮机中的不可逆压缩和膨胀损失及管路中压力损失,用有限时间热力学方法导出了变温热源条件下不可逆闭式燃气轮机中冷循环功率和功率密度（功率与循环中最大比容之比）的解析式;分别以功率和功率密度为目标,优化了中间压比、高低温侧换热器及中冷器热导率分配,并对结果进行了比较.     

Numerical simulation of a hydrogen fuelled gas turbine combustor

The interest for hydrogen-fuelled combustors is recently growing thanks to the development of gas turbines fed by high content hydrogen syngas. The diffusion flame combustion is a well-known and consolidated technology in the field of industrial gas turbine applications. However, few CFD analyses on commercial medium size heavy duty gas turbine fuelled with pure hydrogen are available in the literature. This paper presents a CFD simulation of the air-hydrogen reacting flow inside a diffusion flame combustor of a single shaft gas turbine. The 3D geometrical model extends from the compressor discharge to the gas turbine inlet (both liner and air plenum are included). A coarse grid and a very simplified reaction scheme are adopted to evaluate the capability of a rather basic model to predict the temperature field inside the combustor. The interest is focused on the liner wall temperatures and the turbine inlet temperature profile since they could affect the reliability of components designed for natural gas operation. Data of a full-scale experimental test are employed to validate the numerical results. The calculated thermal field is useful to explain the non-uniform distribution of the temperature measured at the turbine inlet.     

A novel gas turbine cycle with hydrogen-fueled chemical-looping combustion

In this paper we have proposed a novel gas turbine cycle with hydrogen-fueled chemical-looping combustion, and the system study on two hydrogen-fueled power plants, the new gas turbine cycle and an advanced gas turbine cycle with H₂/O₂ combustion, has been investigated with the aid of exergy principle (EUD methodology). The hydrogen fueled chemical-looping combustion in the new gas turbine cycle consists of two successive reactions: hydrogen fuel is reacted with metal oxide (reduction of metal oxide), and then instead of air or pure oxygen, the reduced metal is successively oxidized by the saturated air. As a result, the new hydrogen-fueled gas turbine cycle has a breakthrough performance, with at least about 12 percentage-point higher efficiency compared to the gas turbine cycle with H₂/O₂ combustion, and will be environmentally superior due to complete elimination of NO_x formation. The promising results obtained here indicated that this novel gas turbine cycle with hydrogen-fueled chemical looping combustion could make a breakthrough in efficient use of hydrogen energy in power plants.     

Water and steam injection in micro gas turbine supplied by hydrogen enriched fuels: Numerical investigation and performance analysis

This paper investigates the energetic and environmental performance of micro gas turbine plant with two proposed concurrent improvements: the methane-based fuel enriched by hydrogen and the humidification of the plant cycle. The energetic and environmental benefits of both features are well-know, and the aim of this work is the analysis of their combined impact on the micro gas turbine operation. Despite enhancing fuel with H₂ involves significant advantages like greenhouse emission reduction and a better combustion in case of low LHV fuels, most of commercial micro gas turbine combustors are not able to burn fuels with high hydrogen content unless structurally modified. On the contrary, has been demonstrated that humidified gas turbines (i.e., gas turbines with water injection, humid air turbine (HAT) and steam injection gas turbine (STIG) cycles) improve the combustion stability as well as electric power delivered and plant efficiency. Hence, in order to investigate the feasibility of the concurrent two features, the first step of this work was the thermodynamic analysis of a micro gas turbine supplied by methane-based fuels enriched with H₂ up to 20%_vol, considering both dry and humidified cycles. Since a combustion anomaly was detected, i.e., flashback, in the CFD study on the combustion chamber, a steam injection in the combustor has been added in the plant layout with the aim of overcoming the anomaly, and its effect on the combustion process has been analyzed also raising the hydrogen content up to 30%_vol. The main outcome of this paper is the assessment of the feasibility of supplying the combustor of the proposed HGT-STIG micro gas turbine with a hydrogen enrichment up to 30%_vol, achieving a safe and regular combustion mainly owing to a steam injection mass flow equal up to 125% of fuel flow.     

考虑实际气体性质的三轴燃气轮机中冷循环性能优化

考虑实际气体的热力性质,建立了三轴燃气轮机中冷循环的热力模型,以循环功率和效率为优化目标,对中间压比(或低压压气机压比)的分配进行了优化,同时分析了低压压气机进口气流温度、中冷度和总压比对循环性能的影响。研究发现,与不考虑实际气体热力性质的研究结论相比,循环功率或效率最大时的中间压比并不等于高压压气机压比。     

Simulation of the operation of a gas turbine installation of a thermal power plant with a hydrogen fuel production system

The growth in demand for the production of heat and electricity requires an increase in fuel consumption by power equipment. At the moment, the most demanded thermal equipment for construction and modernization is gas turbine units. Gas turbines can burn a variety of fuels (natural gas, synthesis gas, methane), but the main fuel is natural gas of various compositions. The use of alternative fuels makes it possible to reduce CO₂ and NO_x emissions during the operation of a gas turbine. Under conditions of operation of thermal power plants at the wholesale power market, it becomes probable that combined cycle power units, designed to carry base load, will start to operate in variable modes. Variable operation modes lead to a decrease in the efficiency of power equipment. One way to minimize or eliminate equipment unloading is to install an electrolysis unit to produce hydrogen.In this article the technology of “Power to gas” production with the necessary pressure at the outlet of 30 kgf/cm² (this pressure is necessary for stable operation of the fuel preparation system of the gas turbine) is considered. High cost of hydrogen fuel during production affects the final cost of heat and electric energy, therefore it is necessary to burn hydrogen in mixture with natural gas. Burning a mixture of 5% hydrogen fuel and 95% natural gas requires minimal changes in the design of the gas turbine, it is necessary to supplement the fuel preparation system (install a cleaning system, compression for hydrogen fuel). In addition, the produced hydrogen can be stored, transported to the consumer. For the possibility of combustion of a mixture of natural gas and hydrogen fuel in a gas turbine the methodology of calculation of thermodynamic properties of working bodies developed by a team of authors under the guidance of Academician RAS (the Russian Academy of Sciences) V.E. Alemasov has been adapted, resulting in a program that allows to obtain an adequate mathematical model of the gas turbine. The permissible range of the working body temperature is limited to 3000 K. This paper presents the developed all-mode mathematical model of a gas turbine.On the basis of mathematical modeling of a gas turbine, a change in the main energy and environmental characteristics is shown depending on the composition of the fuel gas. Adding 5% hydrogen to natural gas has little effect on the gas turbine air treatment system, the flow rate remains virtually unchanged. CO₂ emissions decrease, but there is an increase in the amount of H₂O in the turbine exhaust gases.     

Thermodynamic analysis of the effects of atmospheric conditions on the performance of a precooled gas turbine fueled with liquid hydrogen

The effects of varying atmospheric conditions such as temperature, humidity and pressure on the performance of a precooled gas turbine cycle fueled with liquid hydrogen are analyzed. Since the hydrogen temperature at the precooler inlet is very low, the condensation and freezing of water vapor contained in suction air is supposed to occur within the precooler. Due to the condensation of water vapor, the precooling process requires more cryogenic hydrogen. Therefore, the temperature-drop ratio of suction air ? within the precooler decreases. Thermodynamic analysis has revealed that the thermal efficiency and specific output per unit mass flow rate considerably decrease with the increase of humidity ψ, the performance degradation of gas turbine due to atmospheric temperature rise is augmented with the increase of humidity. The humidity ratio between precooler inlet and outlet is also made clear.     

Dynamics of hydrogen powered CAES based gas turbine plant using sodium alanate storage system

Typical compressed air energy storage (CAES) based gas turbine plant operates on natural gas or fuel oils as fuel for its operation. However, the use of hydro-carbon fuels will contribute to carbon emissions leading to pollution of the environment. On the other hand, the use of hydrogen as fuel for the gas turbine will eliminate the carbon emissions leading to a cleaner environment. Hydrogen can be produced using renewable energy sources like wind, solar etc. Storage of hydrogen is a bottleneck for such a system. A high capacity sodium alanate metal hydride bed is used in this study to store the hydrogen. The dynamics of the CAES based gas turbine plant operating with hydrogen fuel is presented along with discharge dynamics of the metal hydride bed. The heat required for desorbing the hydrogen from the metal hydride bed is provided partly by the hot flue gas exiting from the low pressure turbine and partly by external heating. Thus some of the heat from the flue gas is extracted. A novel multiple bed strategy is employed for efficient desorption. Each bed consists of a shell and tube, with alanate in the shell and heating fluid flowing through the helical coiled tube. Hydrogen combustor is modeled using a simplified Continuous Stirred Tank Reactor (CSTR) assumption in CANTERA. The NO_x emissions in the low pressure turbine exhaust stream are presented.     

Multi-criteria evaluation of hydrogen and natural gas fuelled power plant technologies

This paper evaluates nine types of electrical energy generation options with regard to seven criteria. The options use natural gas or hydrogen as a fuel. The Analytic Hierarchy Process was used to perform the evaluation, which allows decision-making when single or multiple criteria are considered.The options that were evaluated are the hydrogen combustion turbine, the hydrogen internal combustion engine, the hydrogen fuelled phosphoric acid fuel cell, the hydrogen fuelled solid oxide fuel cell, the natural gas fuelled phosphoric acid fuel cell, the natural gas fuelled solid oxide fuel cell, the natural gas turbine, the natural gas combined cycle and the natural gas internal combustion engine.The criteria used for the evaluation are CO₂ emissions, NO_X emissions, efficiency, capital cost, operation and maintenance costs, service life and produced electricity cost.A total of 19 scenarios were studied. In 15 of these scenarios, the hydrogen turbine ranked first and proved to be the most preferred electricity production technology. However since the hydrogen combustion turbine is still under research, the most preferred power generation technology which is available nowadays proved to be the natural gas combined cycle which ranked first in five scenarios and second in eight. The last in ranking electricity production technology proved to be the natural gas fuelled phosphoric acid fuel cell, which ranked in the last position in 13 scenarios.     

Thermo‐economic Optimization of Gas Turbine Power Plant with Details in Intercooler

In this paper a gas turbine power plant with intercooler is modeled and optimized. The intercooler is modeled in details using the ε ? NTU method. Air compressor pressure ratio, compressor isentropic efficiency, gas turbine isentropic efficiency, turbine inlet temperature, cooling capacity of the absorption chiller, recuperator effectiveness as well as eight parameters for configuration of the intercooler are selected as design variables. Multi‐objective genetic algorithm is applied to optimize the total cost rate and total cycle efficiency simultaneously. Two plants including an intercooler and with/without air preheater are studied separately. It is observed that the air compressor pressure ratio in the HP compressor is higher than the LP compressor in both cases and its differences are higher for a plant without an air preheater. Actually the air compressor pressure ratio is found to be about 8.5% lower than the ideal value and 9.5% higher than the ideal value in the LP compressor and HP compressor, respectively, in the case with an air preheater. Moreover, a correlation for intercooler pressure drop in terms of its effectiveness was derived in the optimum situation for each case. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 42(8): 704–723, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21051     

Transient performances of the gas turbine recuperating waste heat through hydrogen rich fuels

Operational rules and control strategies of the chemically recuperated gas turbine (CRGT) in the marine propulsion are investigated in this paper. The Minimization of Gibbs free energy method is used to calculate the diesel-steam reforming reaction which products synthetic hydrogen rich fuels, and a universal model of the chemical regenerator which is easily applied to different application environments is created. The hydrogen production and hydrogen molar fraction are investigated to verify that the CRGT improve the combustion performances under low working conditions. Off-design calculations are performed to derive proper operational rules, and transient calculations are performed to investigate the best control strategies for the systems. The modelling approach of the chemical regenerator can be generally used in the chemically recuperated gas turbine. The elaborate operational rules can greatly improve the thermal efficiencies under every working condition. The system using synchronous control strategies have better regulation speed and operation stability than that using asynchronous control strategies.     

应用于平抑风功率的燃氢燃气轮机储能系统控制策略研究

储能技术可用于提高风电并网能力,因此其储能系统及控制策略成为研究热点。提出将燃氢燃气轮机作为储能系统主要部分,低通滤波器结合模糊控制作为其平抑风功率的控制策略。通过设定储氢罐容量,对15台1.5 MW风机的历史风功率数据进行了处理。结果表明：低通滤波器结合模糊控制能有效平抑风功率至限制值,实现平抑指标,并得到储氢罐容量的设置限制;可实现储能时燃气轮机不工作,耗能时燃气轮机工作,当储氢罐容量为0.017 m³时,燃气轮机输出功率为0.1 MW。在将燃气轮机作为平抑风功率的储能系统时,需将燃气轮机的启停控制作为今后的研究重点。     

The effects and characteristics of hydrogen in SNG on gas turbine combustion using a diffusion type combustor

Converting coal to natural gas may be one of the alternative solutions for satisfying the demand for natural gas. However, synthetic natural gas (SNG) has not been proven effective in natural gas-fired power plants. In this research, several combustion tests using a diffusion type combustor were conducted to determine the effect of hydrogen content in SNG on gas turbine combustion. Three kinds of SNG with different H₂ content up to 3%vol were used for the combustion tests. Even a small amount of hydrogen in SNG affects the flame structure: it shortened the flame length and enlarged the flame angle slightly. However, hydrogen content up to 3% in SNG did not affect the gas turbine combustion characteristics, which are emission performance and combustion efficiency. Due to a similarity with real gas turbine combustor conditions for power generation, a high pressure combustion test helped us verify the ambient pressure combustion tests conducted to determine the effect of hydrogen in SNG. In the high pressure combustion test, the pattern factors were identical even though the hydrogen content was varied from 0% to 3%.     

Assessment of thermal performance improvement of GT-MHR by waste heat utilization in power generation and hydrogen production

The Gas Turbine Modular Helium Reactor (GT-MHR) uses two compression stages to compress the helium and a pre-cooler and an intercooler to reduce the compressors inlet temperature, that dissipate around 308.36 MW_th at the design operational conditions. This dissipated thermal energy can be used as an energy source to produce hydrogen. An energy analysis is conducted for a proposed system that includes GT-MHR combined with Organic Rankine Cycle (GT-MHR/ORC) and a Proton Exchange Membrane (PEM) electrolyzer (GT-MHR/ORC-PEM) for hydrogen production. The optimum operating parameters values of the new cycle are obtained using the Engineering Equation Solver (EES) software. Thermal efficiency has been improved from 48.6% for the simple GT-MHR cycle to 49.8% for the new combined (GT-MHR/ORC-PEM) cycle including hydrogen production at a rate of 0.0644 kg/s at the same operating conditions. However, the thermal efficiency for the combined GT-MHR/ORC was higher and reaches 50.68%. Moreover, a parametric study is carried out over a wide range of some operating conditions such as turbine inlet temperature, Compressor pressure ratio and compressor inlet temperature to investigate their effect on the new cycle performance. Results revealed that increasing the low-pressure compressor inlet temperature increases the amount of hydrogen produced while decreasing thermal efficiencies for the three cycles. Furthermore, increasing compressor pressure ratio reduces the mass flow rate of hydrogen produced util it reaches a minimum value then it starts to increase slightly, on the contrary, an opposite relationship is observed between thermal efficiencies and compressor pressure ratio. Moreover, at low compressor pressure ratio, the rate of hydrogen produced increases with increasing turbine inlet temperature; however, it decreases by increasing the turbine inlet temperature at high compressor pressure ratio. Nevertheless, a direct correlation is noticed between thermal efficiencies and turbine inlet temperature.     

一种多孔介质蒸发冷却中冷器性能的初步研究

文中简介蒸发冷却中冷器的原理和结构,并通过风洞实验检验各种填料的阻力特性和降温特性,选取合适的填料介质试验。结果表明：蒸发冷却式中冷器原理简单,将其替换原有中冷器应用是可行的,可用于柴油机、燃气轮机进口及ICR船用燃气轮机上。     

两型间冷器流道气动性能试验研究

间冷器是间冷循环燃气轮机的核心部件,气流流过间冷器的压力损失是衡量间冷器性能的主要指标之一。本文设计了两种不同的间冷器流道结构,并对两种间冷器流道进行了不同工况的气动特性试验,测得间冷器流道不同位置的温度、压力值,得出两种间冷器流道结构的气动特性。试验结果表明：间冷器总压损失主要产生于从进口到导流板前的折转扩散段,且总压损失系数随折合流量的变化曲线为抛物线型,与进口动压呈正比例关系;而改进型间冷器的总压损失有所降低,相同折合流量对应的总压损失系数相对原型间冷器结构降低约20%。     

浮式风电制氢装置设计研究

对浮式风电制氢装置工程化进行了研究,并基于8～10 MW的浮式风电平台,设计了3 MW独立式风电制氢装置,制定了利用风机发电提供的能源,提取海水进行纯化和电解水制氢的技术路线,提出了关键设备的技术要求,并进行了系统的布置及初步的安全性和经济性分析。结果表明,由于经济性差,海工应用还不成熟,目前海上浮式制氢的工程化还需要一个过程,进行工程试验是大规模工程化的前提。     

Performance assessment of a direct steam solar power plant with hydrogen energy storage: An exergoeconomic study

Power generation and its storage using solar energy and hydrogen energy systems is a promising approach to overcome serious challenges associated with fossil fuel-based power plants. In this study, an exergoeconomic model is developed to analyze a direct steam solar tower-hydrogen gas turbine power plant under different operating conditions. An on-grid solar power plant integrated with a hydrogen storage system composed of an electrolyser, hydrogen gas turbine and fuel cell is considered. When solar energy is not available, electrical power is generated by the gas turbine and the fuel cell utilizing the hydrogen produced by the electrolyser. The effects of different working parameters on the cycle performance during charging and discharging processes are investigated using thermodynamic analysis. The results indicate that increasing the solar irradiation by 36%, leads to 13% increase in the exergy efficiency of the cycle. Moreover, the mass flow rate of the heat transfer fluid in solar system has a considerable effect on the exergy cost of output power. Solar tower has the highest exergy destruction and capital investment cost. The highest exergoeconomic factor for the integrated cycle is 60.94%. The steam turbine and PEM electrolyser have the highest share of exergoeconomic factor i.e., 80.4% and 50%, respectively.