Development of an Improved Desiccant-Based Evaporative Cooling System for Gas Turbines

Author(s):  
Amir Abbas Zadpoor ◽  
Ali Asadi Nikooyan

The evaporative inlet cooling systems do not work well in humid areas. However, desiccant wheels can be used to dehumidify the air before passing it through the evaporative cooler. A previous study of combined direct and indirect evaporative coolers showed that a single desiccant wheel does not offer much higher effectiveness compared with the multistage evaporative systems. In this paper, additional dehumidification and indirect evaporative cooling stages are added to increase the effectiveness of the desiccant-based inlet cooling. A typical gas turbine cycle along with an industrial gas turbine with actual performance curves are used to study the performance of the proposed system in three different climatic conditions. It is shown that the added stages substantially improve the effectiveness of the desiccant-based inlet cooling.

Author(s):  
Amir Abbas Zadpoor ◽  
Ali Asadi Nikooyan

The evaporative inlet cooling systems used for inlet cooling of gas turbines during hot summers do not work well in humid areas. However, desiccant wheels can be used to dehumidify the air before passing it trough the evaporative cooler. Since the desiccant wheels work adiabatically, the resulting air is hotter than the air introduced to the wheel and an evaporative cooling system is used to cool down the dehumidified air. Combined direct and indirect evaporative coolers have been already used to investigate the effects of dehumidification on the effectiveness of the evaporation cooling systems. It is shown that a single desiccant wheel does not offer much higher effectiveness compared to the multiple-stage evaporative systems. In this paper, an improved version of the desiccant inlet cooling system is presented. Additional dehumidification and indirect evaporative cooling stages are added to increase the effectiveness of the inlet cooling. A typical gas turbine cycle along with an industrial gas turbine with actual performance curves are used to simulate the thermal cycle in presence of the different inlet cooling systems. The simulations are carried out for three different climatic conditions. The improved and original desiccant-based systems are compared and it is shown that the added stages substantially improve the effectiveness of the desiccant-based inlet cooling.


Author(s):  
Hemant Gajjar

Inlet Air Cooling of gas turbine engines for power augmentation has seen increasing application over the past decade. Evaporative inlet air cooling has been particularly preferred by the Gas Turbine operators due to its low cost and ease of installation. Two of the important considerations for a GT operator are the proper selection of the EIAC and, after installation, its proper testing to assure required performance. This paper is based on the experience, as a user, of selecting a inlet air cooling system and then implementing a Fogging type Evaporative Cooling system. It highlights the important parameters related to evaporative cooling system and in particular fogging, and how the site testing can be handled to ensure proper performance. Concepts of ‘Conversion Effectiveness’ and ‘Evaporation Effectiveness’ have also been introduced in this paper.


Author(s):  
Albrecht H. Mayer ◽  
Noel W. Lively

To meet peaking power demands the E.W. Brown Station, owned and operated by Kentucky Utilities Company, was extended by two GT24 gas turbines. The project had to meet a 9-month engineering, construction and commissioning schedule. The conceptual design is based on ABB ALSTOM POWER’S reference plant design for combined cycle application. It was adjusted to the requirements of a simple cycle operation. Special plant features such as evaporative cooling of the inlet air, system design of the evaporative cooling system, performance and experience will be discussed in detail. The plant has an aggressive running and starting reliability goal; the approach to meet the required plant reliability will be discussed below. The initial operational feedback will be addressed as well as an outlook on how to meet all project goals.


Author(s):  
Abdallah Bouam ◽  
Slimane Aissani ◽  
Rabah Kadi

The gas turbines are generally used for large scale power generation. The basic gas turbine cycle has low thermal efficiency, which decreases in the hard climatic conditions of operation, so the cycles with thermodynamic improvement is found to be necessary. Among several methods shown their success in increasing the performances, the steam injected gas turbine cycle (STIG) consists of introducing a high amount of steam at various points in the cycle. The main purpose of the present work is to improve the principal characteristics of gas turbine used under hard condition of temperature in Algerian Sahara by injecting steam in the combustion chamber. The suggested method has been studied and compared to a simple cycle. Efficiency, however, is held constant when the ambient temperature increases from ISO conditions to 50°C. Computer program has been developed for various gas turbine processes including the effects of ambient temperature, pressure ratio, injection parameters, standard temperature, and combustion chamber temperature with and without steam injection. Data from the performance testing of an industrial gas turbine, computer model, and theoretical study are used to check the validity of the proposed model. The comparison of the predicted results to the test data is in good agreement. Starting from the advantages, we recommend the use of this method in the industry of hydrocarbons. This study can be contributed for experimental tests.


Author(s):  
Richard R. Trewin

An evaporative cooling system for lowering the inlet temperature of a gas-turbine compressor is described. This system uses the latent enthalpy of evaporation for injected water droplets to decrease the enthalpy of the air. The requirements for compatible operation between this system and the compressor are given.


Author(s):  
A. Behdashti ◽  
M. Ebrahimpour ◽  
B. Vahidi ◽  
V. Omidipour ◽  
A. Alizadeh

This paper discusses an optimized media type evaporative cooling system called Outdoor Movable Media cooler which has been recently implemented on two 160 MW, V94.2 gas turbines of Kerman combined cycle power plant, Iran. The air cooling system can be applied to retrieve the lost power generation capability of gas turbine during hot months. System description is completely presented and optimizations such as making a movable media cooler are described. The moving ability of this system eliminates the power loss related to the conventional media coolers. Furthermore, experimental work including evaluation of humidity effect on the air filters operation is discussed and the results are presented. The cooling system performance curve shows the system capability of cooling the inlet air up to 19°C at the design condition. This cooling capacity leads to power augmentation up to 14% which is noteworthy in responding to the electricity demand in hot months, when air-conditioning loads are maximized. Considering several parameters, a cost analysis is done finally and payback period of the system is calculated.


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