Comparison of evaporative inlet air cooling systems to enhance the gas turbine generated power

The gas turbine performance is highly sensitive to the compressor inlet temperature. The output of gas turbine falls to a value that is less than the rated output under high temperature conditions. In fact increase in inlet air temperature by 1°C will decrease the output power by 0.7% approximately. The solution of this problem is very important because the peak demand season also happens in the summer. One of the convenient methods of inlet air cooling is evaporating cooling which is appropriate for warm and dry weather. As most of the gas turbines in Iran are installed in such ambient conditions regions, therefore this method can be used to enhance the performance of the gas turbines. In this paper, an overview of technical and economic comparison of media system and fog system is given. The performance test results show that the mean output power of Frame‐9 gas turbines is increased by 11 MW (14.5%) by the application of media cooling system in Fars power plant and 8.1 MW (8.9%) and 9.5 MW (11%) by the application of fog cooling system in Ghom and Shahid Rajaie power plants, respectively. The total enhanced power generation in the summer of 2004 was 2970, 1701 and 1340 MWh for the Fars, Ghom and Shahid Rajaie power plants, respectively. The economical studies show that the payback periods are estimated to be around 2 and 3 years for fog and media systems, respectively. This study has shown that both methods are suitable for the dry and hot areas for gas turbine power augmentation. Copyright © 2007 John Wiley & Sons, Ltd.     

Humid air turbine cycle blade cooling exergetic analysis

Starting from the first steam injection cycles (GE‐STIG; Cheng), the technique of increasing gas turbine performances by injecting water/steam somewhere before the combustion chamber, has shown very interesting results for power and efficiency increase and for NO_x emissions. Very interesting performances are achieved by evaporative cycles, such as the HAT (Humid Air Turbine), which is capable of achieving 50% conversion efficiency with lower investment costs compared to combined cycles. Other advantages of the steam injected cycle include the power modulation that is possible by varying the injected steam flow rate, keeping the maximum temperature constant. In particular, for the HAT cycle, it is possible to choose different temperature, pressure and compositions for the blade cooling fluid, depending on the bleed point. In this paper, a second law analysis of the HAT cycle and its components, has been performed. In particular, the exergetic analysis of blade cooling has been carefully analysed. Copyright © 1999 John Wiley & Sons, Ltd.     

On the technical feasibility of gas turbine inlet air cooling utilizing thermal energy storage

The potential of using thermal energy storage (TES) in the form of ice or chilled water to cool gas turbine inlet air is evaluated for a remote oil field location in the Sultanate of Oman using local hourly typical meteorological year weather data. It is found that under the conditions investigated seasonal TES in chilled water storage tanks or ice bins for the location considered is prohibitively expensive and thus not recommended. Application of partial TES option shows that the cool storage does not result in any noticeable reduction in the chiller size. Hence, TES whether seasonal, partial, or full storage is not a viable option for the considered location, especially in the absence of time‐of‐use utility rate structure. Copyright © 2005 John Wiley & Sons, Ltd.     

Effect of various inlet air cooling methods on gas turbine performance

Turbine air inlet cooling is one of many available commercial methods to improve the efficiency of an existing gas turbine. The method has various configurations which could be utilized for almost all installed gas turbines. This paper presents a comparison between two commons and one novel inlet air cooling method using turbo-expanders to improve performance of a gas turbine located at the Khangiran refinery in Iran. These methods have been applied to one of the refinery gas turbines located at the Khangiran refinery in Iran. Two common air cooling methods use evaporative media or a mechanical chiller. The idea behind the novel method is to utilize the potential cooling and power capacity of the refinery natural gas pressure drop station by replacing throttling valves with a turbo-expander. The study is part of a comprehensive program with the goal of enhancing gas turbine performance at the Khangiran gas refinery. Based on the results, it is found that using turbo-expanders is the most economically feasible option and so is recommended to be utilized for improving gas turbine performance at the Khangiran refinery.     

大型燃气轮机透平冷却空气量估算

大型燃气轮机透平冷却空气量一般难以直接获得。本文从燃机总体物质与能量平衡的角度,结合透平一级静叶的冷却模型,给出了一种估算大型燃气轮机冷却空气量的方法,并对GE公司系列燃气轮机和西门子公司V94．3燃气轮机冷却空气量进行了估算。结果表明采用本文的方法估算的燃气轮机透平冷却空气量是合理的。     

Analytical method for evaluation of gas turbine inlet air cooling in combined cycle power plant

Gas turbine inlet air cooling technologies (GTIAC), mainly including chilling with LiBr/water absorption chiller and fogging as well, are being used during hot seasons to augment the power output. To evaluate the general applicability of inlet air cooling for gas–steam combined cycle power plant (GTCCIAC), parameters such as efficiency ratio, profit ratio and relative payback period were defined and analyzed through off-design performances of both gas turbine and inlet air cooling systems. An analytical method for applicability evaluation of GTCCIAC with absorption chiller (inlet chilling) and saturated evaporative cooler (inlet fogging) was presented. The applicability study based on typical off-design performances of the components in GTCCIAC shows that, the applicability of GTCCIAC with chilling and fogging depends on the design economic efficiency of GTCC power plant. In addition, it relies heavily on the climatic data and the design capacity of inlet air cooling systems. Generally, GTCCIAC is preferable in the zones with high ambient air temperature and low humidity. Furthermore, it is more appropriate for those GTCC units with lower design economic efficiency. Comparison of the applicability between chilling and fogging shows that, inlet fogging is superior in power efficiency at t_a = 15–20 °C though it gains smaller profit margin than inlet chilling. GTCC inlet chilling with absorption chiller is preferable in the zones with t_a > 25 °C and RH > 0.4.     

回热燃气轮机余热利用进气冷却的研究

本文研究了利用余热制冷进气冷却的回热燃气轮机系统,并对该系统性能进行了模拟计算,得到了压比、流量比等参数对系统性能的影响规律。并通过与常规回热循环比较,指出利用余热制冷来进气冷却的方式能使系统效率提高11%,是提高燃气轮机系统性能的有效途径之一。     

燃气轮机进气冷却技术发展现状及前景分析

分析了燃气轮机进气冷却的必要性，介绍了国内外目前应用的几种燃气轮机进气冷却技术的发展现状，分析了各自特点并对发展前景进行了展望。     

西门子公司V94.3燃气轮机冷却空气信息推测

作为建立燃用低热值合成气的燃气轮机变工况模型的一个关键步骤，对西门子V94.3燃气轮机冷却空气参数及其分配进行了研究，试图从公开发表的燃气轮机功率、压比、排气温度、三亿透平初温等数据中推测出冷却空气量的分配规律。计算和推测所得到的冷却空气参数和分配规律与燃机净功率以及ISO温度基本吻合。     

Thermodynamic performance assessment of an indirect intercooled reheat regenerative gas turbine cycle with inlet air cooling and evaporative aftercooling of the compressor discharge

This study provides a computational analysis to investigate the effects of cycle pressure ratio, turbine inlet temperature (TIT), and ambient relative humidity (φ) on the thermodynamic performance of an indirect intercooled reheat regenerative gas turbine cycle with indirect evaporative cooling of the inlet air and evaporative aftercooling of the compressor discharge. Combined first and second‐law analysis indicates that the exergy destruction in various components of gas turbine cycles is significantly affected by compressor pressure ratio and turbine inlet temperature, and is not at all affected by ambient relative humidity. It also indicates that the maximum exergy is destroyed in the combustion chamber; which represents over 60% of the total exergy destruction in the overall system. The net work output, first‐law efficiency, and the second‐law efficiency of the cycle significantly varies with the change in the pressure ratio, turbine inlet temperature and ambient relative humidity. Results clearly shows that performance evaluation based on first‐law analysis alone is not adequate, and hence more meaningful evaluation must include second‐law analysis. Decision makers should find the methodology contained in this paper useful in the comparison and selection of gas turbine systems. Copyright © 2006 John Wiley & Sons, Ltd.     

Analysis of parameters affecting the performance of gas turbines and combined cycle plants with vapor absorption inlet air cooling

The integration of an aqua‐ammonia inlet air‐cooling scheme to a cooled gas turbine‐based combined cycle has been analyzed. The heat energy of the exhaust gas prior to the exit of the heat recovery steam generator has been chosen to power the inlet air‐cooling system. Dual pressure reheat heat recovery steam generator is chosen as the combined cycle configuration. Air film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor–pressure ratio, compressor inlet temperature, turbine inlet temperature, ambient relative humidity, and ambient temperature on performance parameters of plants has been carried out. It has been observed that vapor absorption inlet air cooling improves the efficiency of gas turbine by upto 7.48% and specific work by more than 18%, respectively. However, on the adoption of this scheme for combined cycles, the plant efficiency has been observed to be adversely affected, although the addition of absorption inlet air cooling results in an increase in plant output by more than 7%. The optimum value of compressor inlet temperature for maximum specific work output has been observed to be 25 °C for the chosen set of conditions. Further reduction of compressor inlet temperature below this optimum value has been observed to adversely affect plant efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

CO2应用于燃机进口空气冷却的实验研究

运用CO2作冷却介质建立高低压闭式循环系统是对燃气轮机预冷的一种尝试。针对某自备电厂联合循环机组的实际情况,设计搭建了一套实验系统。本文主要介绍了实验装置的结构尺寸、数据采集控制系统以及实验数据处理方法。通过实验,验证了该套冷却设备对于燃机进口空气的冷却效果,并达到实际燃气轮机压缩机进口空气冷却的工作要求。     

Influence of multi-irreversibilities on the performance of a Brayton refrigeration cycle working with an ideal Bose or Fermi gas

An irreversible cycle model of the quantum Brayton refrigeration cycle using an ideal Bose or Fermi gas as the working substance is established. Based on the theory of statistical mechanics and thermodynamic properties of ideal quantum gases, expressions for several important performance parameters such as the cooling rate, coefficient of performance and power input, are derived. The influence of the degeneracy of quantum gases, the internal irreversibility of the working substance and the finite-rate heat transfer between the working substance and the heat reservoirs on the optimal performance of the cycle is investigated. By using numerical solutions, the cooling rate of the cycle is optimized for a set of given parameters. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal boundaries of the coefficient of performance and power input are given. The optimally operating region of the cycle is determined. The expressions of some performance parameters for some special cases are derived analytically.     

Performance enhancement of gas turbines by inlet air‐cooling in hot and humid climates

In this paper, a model to study the effect of inlet air‐cooling on gas turbines power and efficiency is developed for two different cooling techniques, direct mechanical refrigeration and an evaporative water spray cooler. Energy analysis is used to present the performance improvement in terms of power gain ratio and thermal efficiency change factors. Relationships are derived for an open gas turbine cycle with irreversible compression and expansion processes coupled to air‐cooling systems. The obtained results show that the power and efficiency improvements are functions of the ambient conditions and the gas turbine pressure ratio. The performance improvement is calculated for, ambient temperatures from 30 to 50°C, the whole range of humidity ratio (10–100%) and pressure ratio from 8 to 12. For direct mechanical refrigeration air‐cooling, the power improvement is associated with appreciable drop in the thermal efficiency. The maximum power gain can be obtained if the air temperature is reduced to its lowest limit that is the refrigerant evaporation temperature plus the evaporator design temperature difference. Water spray cooling process is sensitive to the ambient relative humidity and is suitable for dry air conditions. The power gain and efficiency enhancement are limited by the wet bulb temperature. The performance of spray evaporative cooler is presented in a dimensionless working graph. The daily performance of the cooling methods is examined for an ABB‐11D5 gas turbine operating under the hot humid conditions of Jeddah, Saudi Arabia. The results indicate that the direct mechanical refrigeration increased the daily power output by 6.77% versus 2.57% for the spray air‐cooling. Copyright © 2005 John Wiley & Sons, Ltd.     

微型燃气轮机涡轮背盘冲击冷却特性研究

受可靠性和成本制约,微型燃气轮机冷却技术的发展和应用一直较为缓慢,已成为其进一步提升热效率的主要瓶颈。针对此问题,提出了一种简单可靠的径流涡轮新型冷却技术-背盘冲击冷却,使用气热耦合的方法对该冷却技术的冷却特性进行了仿真研究。结果表明:背盘冲击冷却可以大幅降低径流涡轮背盘的温度。当冷却气体流量为主流的2%时,冷却流体温度从473.0降到323.0 K,背盘平均温度降低了143.0～202.0 K;当冷却温度为323.0 K时,冷却气体消耗量从主流质量流量的1%增加到4%时,背盘平均温度降低150.0～252.0 K。冷却流体流入主流后会对其产生一定的影响,每增加1%的冷却流量,涡轮机效率下降约1%。     

燃气轮机进气喷雾蒸发式冷却与Li-Br吸收式制冷冷却增能对比分析

燃气轮机进气冷却技术是一种能够有效提高高温环境下燃气轮机发电机组输出功率的重要手段。介绍了几种主要的进气冷却技术方法,并分析了进气冷却技术的作用机理。着重对比分析了华菱涟钢能源中心所采用的两种进气冷却技术对燃气轮机输出功率的影响规律,并阐明了两种进气冷却技术各自的优缺点。根据运行参数以及相关数据分析的对比研究结果,为燃气轮机进气冷却技术在实际工程上的应用提供一定的参考。     

利用燃气—蒸汽联合循环改造老电厂

利用燃气－蒸汽联合循环对老电厂进行改造,能够提高能源的综合使用率,降低能耗,并有效利用老电厂的现有设备,可以减少投资并见效快,文章对利用燃气－蒸汽联合循环对老电厂进行改造的主要方式和热效率进行了分析。     

燃气轮机进气蓄冰冷却系统的运行优化

燃气轮机的输出功率受环境温度的影响,对燃气轮机的进口空气进行冷却,能提高其输出功率。当前工程中采用的是在夜间用电低谷期制冰蓄冷,白天用电高峰期融冰供冷保证最大出力的运行方式。本文在采用冰蓄冷的基础上,引入时间变量建立燃料消耗最少的积分型性能指标,在时变环境的意义下,对燃气轮机进气蓄冰冷却系统提出基于用户负荷和环境温度预测曲线的新的运行优化方式,并考虑负荷预测的不确定。通过建模仿真表明这一技术可行,具有进一步研究的价值。     

9FA型燃气轮机联合循环性能研究

1引言西气东输工程促进了沿线燃气轮机联合循环电厂的建设,减轻了中东部地区的环境排放压力。燃气轮机联合循环发电系统高效低污染、启停迅速、调峰能力强。西气东输管道沿线有25台F级燃气轮机联合循环机组,其中GE公司9FA型燃气轮机联合循环发电机组13台。如何保证系统的稳定安     

Effects of evaporative inlet and aftercooling on the recuperated gas turbine cycle

Inlet air cooling and cooling of the compressor discharge using water injection boost both efficiency and power of gas turbine cycles. Four different layouts of the recuperated gas turbine cycle are presented. Those layouts include the effect of evaporative inlet and aftercooling (evaporative cooling of the compressor discharge). A parametric study of the effect of turbine inlet temperature (TIT), ambient temperature, and relative humidity on the performance of all four layouts is investigated. The results indicate that as TIT increases the optimum pressure ratio increases by 0.45 per 100 K for the regular recuperated cycle and by 1.4 per 100 K for the recuperated cycle with evaporative aftercooling. The cycles with evaporative aftercooling have distinctive pattern of performance curves and higher values of optimum pressure ratios. The results also showed that evaporative cooling of the inlet air could boost the efficiency by up to 3.2% and that evaporative aftercooling could increase the power by up to about 110% and cycle efficiency by up to 16%.