Water Recovery Systems for Steam-Injected Gas Turbines: Size Optimization and Life Cycle Savings

2002 ◽  
Author(s):  
Gabriel Blanco ◽  
Lawrence L. Ambs
Keyword(s):  
Environmental Impacts ◽  
Gas Turbines ◽  
Steam Injection ◽  
Economic Feasibility ◽  
Operating Costs ◽  
Exhaust Gas ◽  
External Costs ◽  
Water Recovery ◽  
Power Requirement ◽  
Injection Technology

Steam injection in gas turbines has been used for many years to increase the power output as well as the efficiency of the system and, more recently, to reduce the formation of NOx during the combustion. The major drawback in steam-injection technology is the need of large amounts of fresh water that is eventually lost into the atmosphere along with the exhaust gas. This loss not only increases the operating costs of the system, but also creates other “external” costs in terms of environmental impacts. In order to take advantage of the steam-injection technology and reduce both operating costs and potential environmental impacts, water recovery systems to recuperate the injected steam from the exhaust gas can be implemented. This paper briefly describes the computer models developed at the University of Massachusetts Amherst to optimize water recovery systems. As an example, the optimum size, power requirement and capital cost for two different systems applied to the GE LM2500 gas turbine are shown. Finally, a comparative economic analysis between the costs of installing and operating a water recovery system and the costs of buying and treating water on a regular basis during the lifetime of the project is presented. The results support the economic feasibility of water recovery for mid-size steam-injected gas turbines before having introduced the external costs associated with the use of water resources.

scholarly journals A Test Rig for the Realization of Water Recovery in a Steam-Injected Gas Turbine

1996 ◽  
Author(s):  
Xueyou Wen ◽  
Jiguo Zou ◽  
Zheng Fu ◽  
Shikang Yu ◽  
Lingbo Li
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Steam Injection ◽  
Water Recovery ◽  
Test Rig ◽  
Design Point ◽  
Test Conditions ◽  
Demineralized Water ◽  
Spiral Plate ◽  
Industrial Gas Turbine

Steam-injected gas turbines have a multitude of advantages, but they suffer from the inability to recover precious demineralized water. The present paper describes the test conditions and results of steam injection along with an attempt to achieve water recovery, which were obtained through a series of tests conducted on a S1A-02 small-sized industrial gas turbine. A water recovery device incorporating a compact finned spiral plate cooling condenser equipped with filter screens has been designed for the said gas turbine and a 100% water recovery (based on the design point) was attained.

Analysis of Efficiency and Water Recovery in Steam Injected Gas Turbines

1997 ◽  
Author(s):  
M. De Paepe ◽  
E. Dick
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Steam Injection ◽  
Combined Cycle ◽  
Dew Point ◽  
Maximum Efficiency ◽  
Water Recovery ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Blade Cooling

The study presented in this paper has two objectives. The first objective is to analyse the efficiency of the steam injected gas turbine by modelling the thermodynamic cycle. This is done by adapting a calculation model for turbine blade cooling proposed by El Masri (1986). The expansion path is divided into small subintervals, to take into account the changing gas properties during the expansion. This model is then verified for four different industrial machines. The basic cycle as well as cycles with thermodynamic improvements as intercooling, heat recuperation by heat exchanger and blade cooling using steam are studied. The calculations are done for a range of pressure ratios (PR) and turbine inlet temperatures (TIT), with methane (CH4) as fuel being representative of natural gas. A comparison is made with a simple cycle gas turbine and with a combined cycle system. The maximum efficiency of the basic cycle is found to be around 49 % with current gas turbine technology. Steam blade cooling is extremely simple to implement in a steam injected gas turbine and is found to be thermodynamically very attractive, bringing the maximum efficiency to about 52 %. Secondly the water recuperation in the condenser is analysed. Due to the combustion of the fuel, water is formed. As a result, the dew point temperature of the combustion gas without steam injection can be rather high, i.e. around 45 °C. As a consequence, the amount of water corresponding to the injected steam can be recuperated by cooling the gas mixture to the original dew point temperature. Closing the cycle for water is in this case thermodynamically possible. The practical recuperation of water in the condenser is studied on a test rig with a simulated gas turbine augmented with a condenser and steam injection. This proves that complete recuperation of the injected water is technically possible. The conclusion of the study is that a steam injected gas turbine with complete water recuperation is possible and has a high efficiency.

Cost Optimization of Water Recovery Systems for Steam Injected Gas Turbines

2002 ◽  
Author(s):  
Gabriel Blanco ◽  
Lawrence L. Ambs
Keyword(s):  
Gas Turbine ◽  
Fresh Water ◽  
Gas Turbines ◽  
Steam Injection ◽  
Computer Models ◽  
Injection System ◽  
Medium Size ◽  
Water Recovery ◽  
Exhaust Gases ◽  
Capital Costs

Steam injection in gas turbines has been used for many years to increase the power output as well as the efficiency of the system and, more recently, to reduce the formation of NOx during the combustion. The major drawback in steam-injected gas turbine technology is the need of large amounts of fresh water that is eventually lost into the atmosphere along with the exhaust gases. Nowadays, fresh water is not readily available in many places due to either local water shortages or environmental legislation that protects water sources from depletion and pollution. In order to deal with water constraints, water recovery systems (WRS) to recuperate the injected steam from the exhaust gases and return it to the steam injection system can be implemented. In this project, computer models for two different WRS configurations have been developed and tested. The computer models allow finding the optimum size, power requirements and capital costs of the heat exchangers involved in a particular WRS configuration. The models can also simulate the performance of WRS during a given period of time, calculating the energy consumed by fans and pumps in the process. This paper explains the details of the computer models and illustrates, as an example, the results obtained when both WRS configurations are applied to the GE LM2500 gas turbine. These results support the technical and economic feasibility of steam recovery for medium-size steam-injected gas turbines.

Development of Gas Turbine Steam-Injection Water Recovery (SIWR) System

1992 ◽  
Author(s):  
H. B. Nguyen ◽  
A. den Otter
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Closed Loop ◽  
Steam Injection ◽  
High Water ◽  
Combined Cycle ◽  
Water Recovery ◽  
Gas Turbine Unit ◽  
Air Emission ◽  
Injection Water

This paper describes and discusses a “closed loop” steam injection water recovery (SIWR) cycle that was developed for steam injected gas turbine applications. This process is needed to support gas turbine steam injection especially in areas where water can not be wasted and complex water treatment is discouraged. The development of the SIWR was initiated by NOVA in an effort to reduce environmental impact of operating gas turbines and to find suitable solutions for its expanding gas transmission system to meet future air emission restrictions. While turbine steam injection provides many benefits, it has not been considered for remote, less supported environments such as gas transmission applications due to its high water consumption. The SIWR process can alleviate this problem regardless of the amount of injection required. The paper also covers conceptual designs of a prototype SIWR system on a small gas turbine unit. However, because of relatively high costs, it is generally believed that the system is more attractive to larger size turbines and especially when it is used in conjunction with co-generation or combined cycle applications.

Steam-Injected Gas Turbines

1987 ◽  
Vol 109 (1) ◽  
pp. 55-63 ◽  
Author(s):  
E. D. Larson ◽  
R. H. Williams
Keyword(s):  
Gas Turbines ◽  
High Efficiency ◽  
Steam Injection ◽  
Capital Cost ◽  
Part Load ◽  
Economic Significance ◽  
Commercial Technology ◽  
Combined Cycles ◽  
Injection Technology ◽  
Central Station

Among cogeneration and central station power generating technologies, gas turbine systems are attractive largely because of their low capital cost and simplicity. However, poor part-load efficiencies have restricted simple-cycle gas turbines largely to base-load cogeneration applications, while relatively low efficiencies for the production of power only have restricted gas turbines largely to peaking central station applications. Steam-injected gas turbines overcome cogeneration part-load problems by providing for steam in excess of process requirements to be injected into the combustor to raise electrical output and generating efficiency. For central station applications, proposed steam-injected gas turbines would achieve higher efficiencies at smaller capacities than any existing commercial technology, including combined cycles. Their high efficiency and expected low capital cost would make them highly competitive for baseload power generation. This paper provides an overview of steam-injection technology, including performance calculations and an assessment of the economic significance of the technology for cogeneration and central station applications.

Development of Gas Turbine Steam Injection Water Recovery (SIWR) System

1994 ◽  
Vol 116 (1) ◽  
pp. 68-74 ◽  
Author(s):  
H. B. Nguyen ◽  
A. den Otter
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Closed Loop ◽  
Steam Injection ◽  
High Water ◽  
Combined Cycle ◽  
Water Recovery ◽  
Gas Turbine Unit ◽  
Air Emission ◽  
Injection Water

This paper describes and discusses a “closed-loop” steam injection water recovery (SIWR) cycle that was developed for steam-injected gas turbine applications. This process is needed to support gas turbine steam injection especially in areas where water cannot be wasted and complex water treatment is discouraged. The development of the SIWR was initiated by NOVA in an effort to reduce the environmental impact of operating gas turbines and to find suitable solutions for its expanding gas transmission system to meet future air emission restrictions. While turbine steam injection provides many benefits, it has not been considered for remote, less supported environments such as gas transmission applications due to its high water consumption. The SIWR process can alleviate this problem regardless of the amount of injection required. The paper also covers conceptual designs of a prototype SIWR system on a small gas turbine unit. However, because of relatively high costs, it is generally believed that the system is more attractive to larger size turbines and especially when it is used in conjunction with cogeneration or combined cycle applications.

scholarly journals Water Treatment and Moisture Separation in Steam-Injected Gas Turbines

1990 ◽  
Author(s):  
D. A. Kolp ◽  
S. R. Gagnon ◽  
M. J. Rosenbluth
Keyword(s):  
Water Treatment ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Steam Injection ◽  
Exhaust Gas ◽  
Steam Quality ◽  
Makeup Water ◽  
Injection Cycle ◽  
Selection Of ◽  
Turbine Exhaust

Steam injection has been employed in gas turbines for over twenty years. Initially the emphasis was on injection for small amounts of power augmentation and NOx reduction in the turbine exhaust gas. More recently it has been used for massive power increases (more than 50% on some gas turbines) and efficiency improvements (more than 20%). Equipment selection, operation and economics are essential ingredients in producing the high-purity steam required in a steam-injected gas turbine cycle. The most common means of producing steam for the steam-injection cycle is by means of a waste heat boiler operating in the turbine exhaust gas stream. Steam generated in this boiler may then be injected into the compressor discharge, combustor or turbine sections of the gas turbine to improve performance. Manufacturers require extremely high purity steam for injection into their gas turbines; less than 30 parts per billion (PPB) of some contaminants is not an unusual requirement. If this steam quality is not obtained, serious damage can occur, particularly in the turbine hot section. To meet these stringent steam quality requirements without excessive amounts of boiler blowdown, it is necessary to provide highly demineralized makeup water to the boiler, i.e. less than 1 PPM TDS (Total Dissolved Solids). Low silica concentrations are particularly important since silica can vaporize at higher boiler pressures, pass through the moisture separators and deposit on turbine components. The selection of equipment required to produce high quality makeup water from various grades of raw water is critical to the successful operation of the steam injection plant. Because the steam cannot be recovered effectively, it is necessary to install a large water treatment system to provide the quantities of makeup required for steam injection. Equally critical to the cycle is the type of drum moisture separation used in achieving manufacturers’ recommended steam quality. Just as the steam injection cycle has a dramatic impact on the economics of a gas turbine power plant, so too do the operation and selection of steam purification equipment influence the overall economics of the steam injection cycle.

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