Evaporative Gas Turbine Cycle: A Description of a Pilot Plant and Operating Experience

2000 ◽  
Author(s):  
Torbjörn O. Lindquist ◽  
Per M. Rosén ◽  
Tord Torisson
Keyword(s):  
Gas Turbine ◽  
Flue Gas ◽  
Pilot Plant ◽  
Operating Experience ◽  
Fully Integrated ◽  
Hydraulic Brake ◽  
Main Emphasis ◽  
Full Power ◽  
Institute Of Technology ◽  
Gas Turbine Cycle

Abstract In recent years the interest for new advanced thermodynamical gas turbine cycles has increased. One of the new designs is the evaporative gas turbine cycle. A lot of effort worldwide has been put into predicting the possible efficiency, pollutants, and dynamic behaviour of the evaporative gas turbine cycle, but all results so far have been affected by uncertain assumptions. Until now this cycle has not been demonstrated in a pilot plant. The purpose of this work has been to identify the potential of this cycle, by erecting a pilot plant at the Lund Institute of Technology. The project was financed on a 50/50 basis from the Swedish National Energy Administration and the industrial partners. Three different thermodynamical cycles have been tested in the pilot plant: the simple, the recuperative, and the evaporative cycle. The final pilot plant roughly consists of a 600 kW gas turbine, a hydraulic brake, a recuperator, a humidification tower, an economiser, and a flue gas condenser. All layout and functional analysis were made within the project. The pilot plant is, however, optimized neither for best efficiency nor for best emissions, due to the choice of standard components out of economical reasons. It has only been built for demonstration purpose. Maximum simplicity, flexibility and safety have been the main emphasis in the design of the EvGT cycle. The flow mismatch that occurs between the compressor and the expander in evaporative cycles makes it hard to use a standard gas turbine unit. To be able to use a standard unit, an air bleed off system has been introduced. The water circuit can, at any time, be connected or disconnected from the humidification tower, thereby creating a possibility of controlling when humidification takes place or not by means of a water bypass past the humidification tower. Two starting sequences have been developed, one with the humidification process fully integrated from the beginning and one without. It has been shown that it is possible to reach full power output from the evaporative gas turbine cycle almost as fast as for the simple cycle. It has also been shown that the process is very stable when operated at various loads and during load transients. Furthermore, it is possible to start the power plant quickly from a remote place.

First Experiments on an Evaporative Gas Turbine Pilot Power Plant: Water Circuit Chemistry and Humidification Evaluation

2000 ◽  
Author(s):  
Niklas D. Ågren ◽  
Mats O. Westermark ◽  
Michael A. Bartlett ◽  
Torbjörn Lindquist
Keyword(s):  
Water Quality ◽  
Gas Turbine ◽  
Flue Gas ◽  
Pilot Plant ◽  
Gas Turbines ◽  
High Efficiency ◽  
Current Contact ◽  
Alkali Compounds ◽  
Water Feed ◽  
Institute Of Technology

The evaporative gas turbine (EvGT), also known as the humid air turbine (HAT) cycle, is a novel advanced gas turbine cycle that has attracted considerable interest for the last decade. This high efficiency cycle shows the potential to be competitive with Diesel engines or combined cycles in small and intermediate scale plants for power production — and/or cogeneration. A 0.6 MW natural gas fired EvGT pilot plant has been constructed by a Swedish national research group in cooperation between universities and industry. The plant is located at the Lund Institute of Technology, Lund, Sweden. The pilot plant uses a humidification tower with metallic packing in which heated water from the flue gas economizer is brought into direct counter current contact with the pressurized air from the compressor. This gives an efficient heat recovery and thereby a thermodynamically sound cycle. As the hot sections in high temperature gas turbines are sensitive to particles and alkali compounds, water quality issues need to be carefully considered. As such, apart from evaluating the thermodynamic and part load performance characteristics of the plant, and verifying the operation of the high pressure humidifier, much attention is focused on the water chemistry issues associated with the recovery and reuse of condensate water from the flue gas. A water treatment system has been designed and integrated into the pilot plant. This paper presents the first water quality results from the plant. The experimental results show that the condensate contains low levels of alkali and calcium, around 2 mg/l Σ(K,Na,Ca), probably originating from the unfiltered compressor intake. About 14 mg/l NO2− + NO3− comes from condensate absorption of flue gas NOx. Some Cu is noted, 16 mg/l, which originates from copper corrosion of the condenser tubes. After CO2-stripping, condensate filtration and a mixed bed ion exchanger, the condensate is of suitable quality for reuse as humidification water. The need for large quantities of demineralized water has by many authors been identified as a drawback for the evaporative cycle. However, by cooling the humid flue gas, the recovery of condensed water cuts the need of water feed. A self supporting water circuit can be achieved, with no need for any net addition of water to the system. In the pilot plant, this was achieved by cooling the flue gas to around 35°C.

Theoretical and Experimental Evaluation of the EvGT-Process

2000 ◽  
Author(s):  
Torbjörn O. Lindquist ◽  
Per M. Rosén ◽  
Tord Torisson
Keyword(s):  
Gas Turbine ◽  
Flue Gas ◽  
Power Output ◽  
Pilot Plant ◽  
Power Plants ◽  
Saturation Temperature ◽  
Combined Cycle ◽  
Small Scale ◽  
Pinch Point ◽  
Gas Turbine Cycle

Abstract In recent years the interest for new advanced thermodynamical gas turbine cycles has increased. One of the new designs is the evaporative gas turbine cycle. A lot of effort worldwide has been put into predicting the possible efficiency, pollutants, and dynamic behaviour of the evaporative gas turbine cycle, but all results so far have been affected by uncertain assumptions. Until now this cycle has not been demonstrated in a pilot plant. The purpose of this work has been to identify the potential of this cycle, by erecting a pilot plant at the Lund Institute of Technology. The project was financed on a 50/50 basis from the Swedish National Energy Administration and the industrial partners. Three different thermodynamical cycles have been tested in the pilot plant: the simple, the recuperative, and the evaporative cycles. The final pilot plant roughly consists of a 600 kW gas turbine, a hydraulic brake, a recuperator, a humidification tower, an economiser, and a flue gas condenser. All layout and functional analysis were made within the project. The pilot plant is, however, optimized neither for best efficiency nor for best emissions. It has only been built for demonstration purpose. It has been shown from the performance tests that the efficiency for the simple, recuperative, and evaporative cycles are 22, 27, and 35%, respectively, at rated power output. The NOx emissions were reduced by 90% to under 10 ppm, and the UHC and CO were not measurable when running the evaporative cycle at rated power output. The performance of the humidification tower was better than expected. The humidified air out from the humidification tower is always saturated. The pinch point, i.e. the temperature difference between the outcoming water from the humidification tower and the saturation temperature of the incoming air, is around 3°C. The water circuit was closed, i.e. there was no need for additional water, when the flue gases after the flue gas condenser reached a temperature of 35° C. The inhouse heat balance program, used for both cycle optimization and evaluation, has been verified. The evaporative gas turbine cycle has, when optimized, at least the same efficiency as the best combined cycle today, based on the same gas turbine. The evaporative cycle will also show very good performance when used in small scale power plants.

First Experiments on an Evaporative Gas Turbine Pilot Power Plant: Water Circuit Chemistry and Humidification Evaluation

2000 ◽  
Vol 124 (1) ◽  
pp. 96-102 ◽  
Author(s):  
N. D. A˚gren ◽  
M. O. Westermark ◽  
M. A. Bartlett ◽  
T. Lindquist
Keyword(s):  
Water Quality ◽  
Gas Turbine ◽  
Flue Gas ◽  
Pilot Plant ◽  
Gas Turbines ◽  
High Efficiency ◽  
Current Contact ◽  
Alkali Compounds ◽  
Water Feed ◽  
Institute Of Technology

The evaporative gas turbine (EvGT), also known as the humid air turbine (HAT) cycle, is a novel advanced gas turbine cycle that has attracted considerable interest for the last decade. This high-efficiency cycle shows the potential to be competitive with Diesel engines or combined cycles in small and intermediate scale plants for power production and/or cogeneration. A 0.6 MW natural gas-fired EvGT pilot plant has been constructed by a Swedish national research group in cooperation between universities and industry. The plant is located at the Lund Institute of Technology, Lund, Sweden. The pilot plant uses a humidification tower with metallic packing in which heated water from the flue gas economizer is brought into direct counter current contact with the pressurized air from the compressor. This gives an efficient heat recovery and thereby a thermodynamically sound cycle. As the hot sections in high-temperature gas turbines are sensitive to particles and alkali compounds, water quality issues need to be carefully considered. As such, apart from evaluating the thermodynamic and part-load performance characteristics of the plant, and verifying the operation of the high-pressure humidifier, much attention is focused on the water chemistry issues associated with the recovery and reuse of condensate water from the flue gas. A water treatment system has been designed and integrated into the pilot plant. This paper presents the first water quality results from the plant. The experimental results show that the condensate contains low levels of alkali and calcium, around 2 mg/l Σ(K,Na,Ca), probably originating from the unfiltered compressor intake. About 14 mg/l NO2−+NO3− comes from condensate absorption of flue gas NOx. Some Cu is noted, 16 mg/l, which originates from copper corrosion of the condenser tubes. After CO2 stripping, condensate filtration and a mixed bed ion exchanger, the condensate is of suitable quality for reuse as humidification water. The need for large quantities of demineralized water has by many authors been identified as a drawback for the evaporative cycle. However, by cooling the humid flue gas, the recovery of condensed water cuts the need of water feed. A self-supporting water circuit can be achieved, with no need for any net addition of water to the system. In the pilot plant, this was achieved by cooling the flue gas to around 35°C.

Thermo-Economic Evaluation of Bio-Ethanol Humidification EvGT Cycle

2005 ◽  
Author(s):  
Marcus Thern ◽  
Torbjo¨rn Lindquist ◽  
Tord Torisson
Keyword(s):  
Gas Turbine ◽  
Equilibrium Model ◽  
Pilot Plant ◽  
Rankine Cycle ◽  
Outlet Temperature ◽  
Humid Air ◽  
Power Cycles ◽  
Air Stream ◽  
Air Turbine ◽  
Institute Of Technology

The evaporative gas turbine pilot plant (EvGT) has been in operation at Lund Institute of Technology in Sweden since 1997. This article presents the latest development in the evaporative technology, the evaporation of bio-ethanol in a gas turbine power plant as a means to reduce the emission of greenhouse gases. Bio-ethanol is produced from a feedstock consisting of corn-stover, and the bio-ethanol is here considered to be a renewable fuel with zero impact regarding CO2 in the exhaust gases. This concept is evaluated and compared to a direct-fired Rankine cycle in the size range of 3–5 MWel and 15–30 MWel concerning plant efficiency and investment cost. The proposed bio-ethanol evaporation technology provides fuel for a Humid Air Turbine by evaporating bio-ethanol into the compressor discharge air. This evaporation process creates a combustible gas that is led to the combustor as the primary fuel. The bio-ethanol used in the process has not been distilled. The bio-ethanol is supplied to the process as a mash, i.e. a mix of water and ethanol with low concentration of ethanol. To extract the ethanol from the mash, energy is required. In this process, low-level heat from the gas turbine cycle is used for the separation process. All power cycles studied have been modeled in IPSEpro™, a heat and mass balance software, using advanced component models developed by the authors. An equilibrium model is used to model the behavior of the evaporation of ethanol and water into an air stream. A correction parameter has been introduced into the equilibrium model to account for the deviation from equilibrium. This parameter has been validated through experimental work on the Evaporative Gas Turbine pilot plant. The evaporation technology can be used with different types of cycle configurations attaining electrical efficiencies of 29% for a simple version of a Humid Air Turbine. The Humid Air Turbine can sustain a combustor outlet temperature of 1100°C without supplementary firing. The proposed cycle configuration also shows to be an economically viable alternative to direct fired Rankine cycle.

Thermoeconomic Optimization of the Part-Flow Evaporative Gas Turbine Cycles

2008 ◽  
Author(s):  
Mortaza Yari
Keyword(s):  
Gas Turbine ◽  
Economic Performance ◽  
Pilot Plant ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Steam Injection ◽  
Humid Air ◽  
Power Cycle ◽  
Testing Stage ◽  
Gas Turbine Cycle

The evaporative gas turbine cycle is a new high-efficiency power cycle that has reached the pilot plant testing stage. The latest configuration proposed for this cycle is known as part flow evaporative gas turbine cycle (PEvGT) in which humidification is combined with steam injection. Having advantages of both steam injected and humid air cycles, it is regarded as a very desirable plant for future. The aim of this work is to investigate the economic performance of the PEvGT cycles: PEvGT and PEvGT-IC (Intercooled PEvGT cycle), based on the thermoeconomic analysis. The results are presented and the influence of the several parameters is discussed: pressure ratio, part-flow humidification rate and the cycle configuration. Also the thermoeconomic optimization of the cycles have been done and discussed.

A Simplified Method for Determining Gas Turbine Performance Parameters Based Upon Available Catalogue Data

2014 ◽  
Author(s):  
Chamila Ranasinghe ◽  
Hina Noor ◽  
Jeevan Jayasuriya
Keyword(s):  
Theoretical Model ◽  
Gas Turbine ◽  
Flue Gas ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Department Of Energy ◽  
Design Parameters ◽  
Learning Platform ◽  
Turbine Performance ◽  
Institute Of Technology

Overall theoretical performance analysis of gas turbines can be conducted by applying design parameters into several thermodynamic theories and equations. However, limited availability of the design parameters will not provide sufficient room for a detailed analysis. Gas turbine manufacturers publish only a limited amount of design/performance data, while important parameters remained hidden and the available information is not sufficiently enough for obtaining a complete gas turbine performance dataset. Five main parameters commonly provided by a gas turbine manufacturer’s catalogues; pressure ratio of the compressor, exhaust mass flow rate, exhaust temperature of flue gas, overall efficiency, and electrical output. A theoretical model developed based on Mathcad software as documented in literature is used to reveal other hidden gas turbine parameters. A similar theoretical model using another solver was developed to obtain a complete dataset by using the available catalogue data with additional assumptions, which correspond to the commercial state of the art. The engineering equation solver (EES) software has been used as a platform to rebuild the theoretical model. As the main development, a graphical user interphase (GUI) has been introduced to the new program with the aim to make it more user friendly. Furthermore on top of obtaining the hidden thermodynamic parameters for the gas turbine, performing flue gas analysis and an exergy analysis has now become possible through this program. The developed EES program is expected to be run in the learning laboratory at the Division of Heat and Power Technology, Department of Energy Technology, Royal Institute of Technology (KTH), Stockholm and finally it is going to be incorporated into CompEdu Learning Platform of the same division.

Theoretical and Experimental Evaluation of a Plate Heat Exchanger Aftercooler in an Evaporative Gas Turbine Cycle

2003 ◽  
Author(s):  
Marcus Thern ◽  
Torbjo¨rn Lindquist ◽  
Tord Torisson
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Gas Turbine ◽  
Flue Gas ◽  
Pilot Plant ◽  
Plate Heat Exchanger ◽  
Gas Temperature ◽  
Plate Heat ◽  
Electrical Efficiency ◽  
Low Level

The evaporative gas turbine pilot plant (EvGT) has been in operation at Lund Institute of Technology in Sweden since 1997. This article presents the experimental and theoretical results of the latest process modifications made, i.e. the effect of the installation of an aftercooler. The purpose of the aftercooler is to increase the performance of the cycle by utilizing more low-level heat in the humidification tower. The chosen aftercooler is of plate heat exchanger type, which is very compact, has high thermal efficiency and low pressure drop. The installation of an aftercooler lowers the temperature of the air entering the humidification tower. This also lowers the temperature of the circulating humidification water, which facilitates the extraction of more low-level heat from the economizer. This low-level heat can be utilized to evaporate more water in the humidification tower and thus increase the gas flow in the expander. The pilot plant has been operated at different loads and the measured results has been evaluated and compared with theoretical models. The performance of a plate heat exchanger in power plant applications has also been evaluated. Experience from the measurements has then been used for the potential cycle calculations. It has been shown that the aftercooler lowers the flue gas temperature in the pilot plant to 93°C, the rate of humidification was increased from 13 wt% to 14.5 wt%, and the pressure drop on the airside in the aftercooler is 1.6%. The electrical efficiency for the pilot plant was increased by 0.4%. The increase in electrical efficiency for a more advanced EvGT cycle with an intercooler, aftercooler and economizer will be around 3.5 percentage units in comparison with a cycle without an aftercooler. The plate heat exchanger showed very good performance in terms of cost, size, pressure drop and thermal efficiency. An alternative to the chosen heat exchanger is the tubular one, but it is 10 times heavier, has a higher pressure drop and is more expensive. The aftercooler increases the electrical efficiency significantly by lowering the flue gas temperature and increasing the expander work.

scholarly journals Direct Coal Firing for Large Combustion Turbines: What Do Economic Projections and Subscale Combustor Tests Show?

1989 ◽  
Author(s):  
P. W. Pillsbury ◽  
R. L. Bannister ◽  
R. C. Diehl ◽  
P. J. Loftus
Keyword(s):  
Gas Turbine ◽  
Flue Gas ◽  
Performance Standards ◽  
Department Of Energy ◽  
Flue Gas Desulfurization ◽  
Steam Generators ◽  
Combined Cycles ◽  
Westinghouse Electric Corporation ◽  
Westinghouse Electric ◽  
Gas Turbine Cycle

Westinghouse Electric Corporation and Avco Research Lab/TEXTRON have been working for three years on a Department of Energy program to establish the technology required for commercially viable direct coal-fueled utility-size gas turbine combined cycles. These plants are to meet the EPA’s New Source Performance Standards for coal-fired steam generators and to generate power at a favorable cost-of-electricity relative to steam plants with flue gas desulfurization. Economic projections indicate that the latter goal is achievable by a method of approach which uses inexpensive utility-grade coal, and removes the resulting sulfur and ash through use of a slagging combustor in the gas turbine cycle. High pressure, subscale slagging combustor tests have been underway for several months at Avco Research Laboratory and are encouraging. Experimental highlights are shown here.

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