Micro Humid Air Cycle: Part B — Thermoeconomic Analysis

2003 ◽  
Author(s):  
J. Parente ◽  
A. Traverso ◽  
A. F. Massardo
Keyword(s):  
Gas Turbines ◽  
Electrical Power ◽  
Specific Work ◽  
Operational Flexibility ◽  
Humid Air ◽  
Capital Costs ◽  
Large Size ◽  
Heat Demand ◽  
Short Period ◽  
Specific Capital

Part A of this paper demonstrated that the HAT cycle, when applied to small-size gas turbines, can significantly enhance the efficiency and specific work of simple and recuperated cycles without the drastic changes to plant layout necessary in medium- and large-size plants. In this part B a complete thermoeconomic analysis is performed for microturbines operating in a Humid Air cycle. The capital cost and internal rate of return for both new machines and existing microturbines working in an mHAT-optimised cycle are presented and analysed. Three different scenarios are considered. The first scenario reflects a distributed electrical power generation application where cogeneration is not taken into account. Instead, the other two scenarios deal with CHP civil applications for different heat demands. The thermoeconomic results of the integrated mHAT cycle, based on a preliminary design of the saturator, demonstrate that microturbine performance can be greatly enhanced, while specific capital costs, in some cases, can be reduced up to 14%, without significant increase in layout complexity. Moreover, thanks to its operational flexibility (able to operate in dry and wet cycles), the mHAT is financially attractive for distributed power and heat generation (micro-cogeneration), particularly when heat demand is commutated in short period.

A Thermoeconomic Comparison Between SOFC Hybrid Systems and the Most Worldwide Used Technologies Towards Competitive Innovative Plants

2009 ◽  
Author(s):  
A. Franzoni ◽  
L. Magistri ◽  
O. Tarnowsky ◽  
A. F. Massardo
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Gas Turbines ◽  
Point Of View ◽  
Thermodynamic Efficiency ◽  
Economic Point ◽  
Capital Costs ◽  
Large Size

This paper investigates options for highly efficient SOFC hybrid systems of different sizes. For this purpose different models of pressurised SOFC hybrids systems have been developed in the framework of the European Project “LARGE SOFC - Towards a Large SOFC Power Plant”. This project, coordinated by VTT Finland, counts numerous industrial partners such as Wartsila, Topsoe and Rolls-Royce FCS ltd. Starting from the RRFCS Hybrid System [1], considered as the reference case, several plant modifications have been investigated in order to improve the thermodynamic efficiency. The main options considered are (i) the integration of a recuperated micro gas turbine and (ii) the replacement of the cathodic ejector with a blower. The plant layouts are analysed in order to define the optimum solution in terms of operating parameters and thermodynamic performances. The study of a large size power plant (around 110 MWe) fed by coal and incorporated with SOFC hybrid systems is also conducted. The aim of this study is to analyse the sustainability of an Integrated Gasification Hybrid System from the thermodynamic and economic point of view in the frame of future large sized power generation. A complete thermoeconomic analysis of the most promising plants is carried out, taking into account variable and capital costs of the systems. The designed systems are compared from the thermodynamic and the thermoeconomic point of view with some of the common technologies used for distributed generation (gas turbines and reciprocating engines) and large size power generation (combined cycles and IGCC). The tool used for this analysis is WTEMP software, developed by the University of Genoa (DIMSET-TPG) [2], able to carry out a detailed thermodynamic and thermoeconomic analysis of the whole plants.

T100 Micro Gas Turbine Converted to Full Humid Air Operation: Test Rig Evaluation

2014 ◽  
Author(s):  
Ward De Paepe ◽  
Marina Montero Carrero ◽  
Svend Bram ◽  
Francesco Contino
Keyword(s):  
Energy Transfer ◽  
Gas Turbines ◽  
Water Injection ◽  
Test Rig ◽  
Humid Air ◽  
Limited Energy ◽  
Surge Margin ◽  
Heat Demand ◽  
Compressor Surge ◽  
Efficiency Increase

Micro Gas Turbines (mGTs) are very cost effective in small-scale Combined Heat and Power (CHP) applications. By simultaneously producing electric and thermal power, a global CHP efficiency of 80 % can be reached. However the low electric efficiency of 30 % makes the mGT profitability strongly dependent on the heat demand. This makes the mGT less attractive for applications with a non-continuous heat demand like domestic applications. Turning the mGT into a micro Humid Air Turbine (mHAT) is a way to decouple the power production from the heat demand. This new approach allows the mGT to keep running with water injection and thus higher electric efficiency during periods with no or lower heat demand. Simulations of the mHAT predicted a substantial electric efficiency increase due to the introduction of water in the cycle. The mHAT concept with saturation tower was however never tested experimentally. In this paper, we present the results of our first experiments on a modified Turbec T100 mGT. As a proof of concept, the mGT has been equipped with a spray saturation tower to humidify the compressed air. The primary goal of this preliminary experiments was to evaluate the new test rig and identify its shortcomings. The secondary goal was to gain insight in the mHAT control, more precisely the start-up strategy. Two successful test runs of more than 1 hour with water injection at 60 kWe were performed, resulting in stable mGT operation at constant rotation speed and pressure ratio. Electric efficiency was only slightly increased from 24.3 % to 24.6 % and 24.9 % due to the limited amount of injected water. These changes are however in the range of the accuracy on the measurements. The major shortcomings of the test rig were compressor surge margin reduction and the limited energy transfer in the saturation tower. Surge margin was reduced due to a pressure loss over the humidification unit and piping network, resulting in possible compressor surge. Bleeding air to increase surge margin was the solution to prevent compressor surge, but it lowers the electric efficiency by approximately 4 % absolute. The limited energy transfer was a result of a low water injection temperature and mass flow rate. The low energy transfer causes the limited efficiency increase. The first experiments on the mHAT test rig indicated its shortcomings but also its potential. Stable mGT operation was obtained and electric efficiency remained stable. By increasing the amount of injected water, the electric efficiency can be increased.

Experimental Characterisation of a Humidified T100 Micro Gas Turbine

2016 ◽  
Author(s):  
Marina Montero Carrero ◽  
Ward De Paepe ◽  
Jan Magnusson ◽  
Alessandro Parente ◽  
Svend Bram ◽  
...  
Keyword(s):  
Power Output ◽  
Rotational Speed ◽  
Gas Turbines ◽  
Electrical Power ◽  
Water Injection ◽  
Hot Water ◽  
Electrical Efficiency ◽  
Exhaust Gases ◽  
Heat Demand ◽  
Experimental Characterisation

Despite the potential of micro Gas Turbines (mGTs) for Combined Heat and Power (CHP), this technology still poses limitations that curb its widespread adoption, especially for applications with a variable heat demand. In fact, whenever the user heat demand is low, mGTs are generally shut down. Otherwise, the high temperature exhaust gases have to be blown off and the resulting electrical efficiency is not high enough to sustain a profitable operation. If, instead of released, the heat in the exhaust gases is re-inserted in the cycle — by injecting hot water and transforming the mGT into a micro Humid Air Turbine (mHAT) — the electrical efficiency can be increased during periods of reduced heat demand, thus improving the economics of the technology. Although the enhanced performance of the mHAT cycle has been thoroughly investigated from a numerical point of view, results regarding the experimental behaviour of this technology remain scarce. In this paper, we present the experimental characterisation of the mHAT located at the Vrije Universiteit Brussel (VUB): based on the T100 mGT and equipped with a spray saturation tower. These are the first experimental results of such an engine working at nominal load with water injection. In addition, the control system of the unit has been modified so that it can operate either at constant electrical power output (the default setting) or at constant rotational speed. The latter option allowed to better assess the effect of water injection. Eperimental results demonstrate the patent benefits of water injection on mGT performance: at fixed rotational speed, the power output of the mHAT increases by more than 30%while the fuel consumption rises only by 11%. Overall, the electrical efficiency in wet operation increases by up to 4.2% absolute points. Future work will involve further optimising the current facility to reduce pressure losses in the air and water circuits. In addition, we will carry out transient simulations and experiments in order to further characterise the facility.

scholarly journals Evaluation Method for Closed Cycle Gas Turbines in Cogeneration Applications

1980 ◽  
Author(s):  
H. C. Daudet ◽  
S. W. Trimble
Keyword(s):  
Gas Turbines ◽  
Evaluation Method ◽  
Electrical Power ◽  
Industrial Process ◽  
District Heating ◽  
Department Of Energy ◽  
Evaluation Procedure ◽  
Closed Cycle ◽  
Study Program ◽  
Capital Costs

The utilization of coal-fired closed cycle gas turbine/atmospheric fluidized bed (CCGT/AFB) electrical power generating plants for cogeneration was investigated in a Department of Energy-sponsored study program conducted by The Garrett Corporation. Both industrial process and district heating and cooling applications in the 10- to 50-MWe range were considered. An evaluation procedure was developed in which cogeneration plant capital, operating, maintenance, and financing costs are calculated and compared with the cost of providing equivalent services by traditional methods. Computer optimized conceptual designs of the CCGT/AFB plants were prepared, and performance and capital costs were estimated. A broad spectrum of applications including towns, military bases, universities, and industrial processes was surveyed. This paper presents the general evaluation procedure, typical plant designs, and the evaluation of two applications.

Transient Simulations of a T100 Micro Gas Turbine Converted Into a Micro Humid Air Turbine

2015 ◽  
Author(s):  
Marina Montero Carrero ◽  
Mario Luigi Ferrari ◽  
Ward De Paepe ◽  
Alessandro Parente ◽  
Svend Bram ◽  
...  
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Water Injection ◽  
Humid Air ◽  
Electrical Efficiency ◽  
Exhaust Gases ◽  
Heat Demand ◽  
Air Turbine ◽  
Static Performance

Micro Gas Turbines (mGTs) have arisen as a promising technology for Combined Heat and Power (CHP) thanks to their overall energy efficiencies of 80% (30% electrical + 50% thermal) and the advantages they offer with respect to internal combustion engines. The main limitation of mGTs lies in their rather low electrical efficiency: whenever there is no heat demand, the exhaust gases are directly blown off and the efficiency of the unit is reduced to 30%. Operation in such conditions is generally not economical and can eventually lead to shutdown of the machine. To address this issue, the mGT cycle can be modified so that in moments of low heat demand the heat in the exhaust gases is used to warm up water which is then re-injected in the cycle, thereby increasing the electrical efficiency. The introduction of a saturation tower allows for water injection in mGTs: the resulting cycle is known as a micro Humid Air Turbine (mHAT). The static performance of the mGT Turbec T100 working as an mHAT has been characterised through previous numerical and experimental work at Vrije Universiteit Brussel (VUB). However, the dynamic behaviour of such a complex system is key to protect the components during transient operation. Thus, we have modelled the Turbec T100 mHAT with the TRANSEO tool in order to simulate how the cycle performs when the demanded power output fluctuates. Steady-state results showed that when operating with water injection, the electrical efficiency of the unit is incremented by 3.4% absolute. The transient analysis revealed that power increase ramps higher than 4.2 kW/s or power decrease ramps lower than 3.5 kW/s (absolute value) lead to oscillations which enter the unstable operation region of the compressor. Since power ramps in the controller of the Turbec T100 mGT are limited to 2kW/s, it should be safe to vary the power output of the T100 mHAT when operating with water injection.

Emergence of Recuperated Gas Turbines for Power Generation

1999 ◽  
Author(s):  
Colin F. McDonald
Keyword(s):  
Power Generation ◽  
Gas Turbines ◽  
Electrical Power ◽  
High Volume ◽  
Medium Size ◽  
Diesel Generator ◽  
Capital Costs ◽  
Ceramic Recuperator ◽  
Industrial Gas Turbines ◽  
Near Term

In the emerging deployment of microturbines (25–75Kw), a recuperator is mandatory to achieve thermal efficiencies of 30 percent and higher, this being important if they are to successfully penentrate the market currently dominated by Diesel generator sets. This will be the first application of gas turbines for electrical power generation, where recuperators will be used in significant quantities. The experience gained with these machines will give users’ confidence that recuperated engines will meet performance and reliability goals. The latter point is particularly important, since recuperated gas turbines have not been widely deployed for power generation, and early variants were a disappointment. Recuperator technology transfer to larger engines will see the introduction of advanced heat exchanged industrial gas turbines for power generation in the 3–15 Mw range. After many decades of development, existing recuperators of both primary surface and plate-fin types, have demonstrated acceptable thermal performance and integrity in the cyclic gas turbine environment, but their capital costs are high. A near-term challenge to recuperator design and manufacturing engineers is to establish lower cost metallic heat exchangers that can be manufactured using high volume production methods. A longer term goal will be the development and utilization of a ceramic recuperator, since this is the key component to realize the full performance potential of very small and medium size gas turbines.

Model Based Diagnostics of AE-T100 Micro Humid Air Turbine Cycle

2018 ◽  
Author(s):  
Mariam Mahmood ◽  
Alessio Martini ◽  
Aristide F. Massardo ◽  
Ward De Paepe
Keyword(s):  
Gas Turbines ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Injection System ◽  
Diagnostic Tools ◽  
Diagnostic Purpose ◽  
Humid Air ◽  
Power Sources ◽  
Heat Demand ◽  
Air Turbine

Micro gas turbines (mGT) are emerging power sources for distributed generation facilities with promising features like environment friendliness, high fuel flexibility, cost effectiveness and efficient cogeneration of heat and power (CHP). However, curtailed heat demand during summers reduces the plant operating hours per year and negatively affects the overall economic feasibility of a CHP project. The micro Humid Air Turbine (mHAT) cycle is one of the novel cycles to increase the electrical efficiency of the gas turbine by utilizing the exhaust gas heat in periods of low heat demand, thus avoiding the system shutdown. However, the water injection system can introduce additional pressure losses in the mGT cycle, which may lead to compressor surge and it may also affect the recuperator performance in the long run due to corrosion. Hence, numerical simulation and diagnostic tools are essential for cycle optimization of mHAT and prediction of performance degradation. This work is focused on the real time application of the AE-T100 model for the mHAT system located at the Vrije Universiteit Brussel (VUB), which is based on the T100 mGT equipped with a spray saturation tower. The AE-T100 model is a steady-state simulation tool for mGT cycles, which has been developed within a collaboration between the University of Genova (Unige) and Ansaldo Energia, and has been successfully applied at the Ansaldo Enegia test rig (AE-T100) for the diagnostic purpose. For this study, the basic AE-T100 model has been modified to simulate the humidified cycle according to the VUB plant configuration. The modified AE-T100 model has been validated against the experimental data obtained from the mHAT unit at nominal and part load. Once the model was validated using real operating conditions, it has been used for monitoring the recuperator performance over large number of tests in dry mode, conducted over the past five years, as well as initial tests in wet mode, from the VUB-mHAT system. This work has proved the modeling capability of the AE-T100 tool to simulate the mHAT cycle with reasonable accuracy and first diagnostic application of the AE-T100 tool, in dry mode. However, the lack of data available at present in wet mode does not allow to provide a complete and robust diagnostics of this novel cycle under wet operation. Hence, this preliminary analysis will provide basis for more detail diagnostics of the mHAT cycle using AE-T100 tool, over a longer time period under wet operation, in future.

scholarly journals Powering Ahead

2011 ◽  
Vol 133 (05) ◽  
pp. 30-33 ◽  
Author(s):  
Lee S. Langston
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Electrical Power ◽  
The United States ◽  
Combined Cycle ◽  
Electrical Power System ◽  
Efficient Technology ◽  
The Military

This article explores the increasing use of natural gas in different turbine industries and in turn creating an efficient electrical system. All indications are that the aviation market will be good for gas turbine production as airlines and the military replace old equipment and expanding economies such as China and India increase their air travel. Gas turbines now account for some 22% of the electricity produced in the United States and 46% of the electricity generated in the United Kingdom. In spite of this market share, electrical power gas turbines have kept a much lower profile than competing technologies, such as coal-fired thermal plants and nuclear power. Gas turbines are also the primary device behind the modern combined power plant, about the most fuel-efficient technology we have. Mitsubishi Heavy Industries is developing a new J series gas turbine for the combined cycle power plant market that could achieve thermal efficiencies of 61%. The researchers believe that if wind turbines and gas turbines team up, they can create a cleaner, more efficient electrical power system.

scholarly journals Clear Skies Ahead

2016 ◽  
Vol 138 (06) ◽  
pp. 38-43
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Electrical Power ◽  
Vital Role ◽  
Medium Size ◽  
Steady Increase ◽  
Innovative Design ◽  
Turbine Engine ◽  
Boom And Bust

This article discusses various fields where gas turbines can play a vital role. Building engines for commercial jetliners is the largest market segment for the gas turbine industry; however, it is far from being the only one. One 2015 military gas turbine program of note was the announcement of an U.S. Air Force competition for an innovative design of a small turbine engine, suitable for a medium-size drone aircraft. The electrical power gas turbine market experienced a sharp boom and bust from 2000 to 2002 because of the deregulation of many electric utilities. Since then, however, the electric power gas turbine market has shown a steady increase, right up to present times. Coal-fired plants now supply less than 5 percent of the electrical load, having been largely replaced by new natural gas-fired gas turbine power plants. Working in tandem with renewable energy power facilities, the new fleet of gas turbines is expected to provide reliable, on-demand electrical power at a reasonable cost.

Pressure Gain Combustion Application to Marine and Industrial Gas Turbines

2012 ◽  
Author(s):  
Philip H. Snyder ◽  
M. Razi Nalim
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Technology Development ◽  
Innovative Technology ◽  
Turbine Engines ◽  
Specific Work ◽  
Compression Pressure ◽  
Pressure Gain Combustion ◽  
Industrial Gas Turbines ◽  
Incremental Improvement

Renewed interest in pressure gain combustion applied as a replacement of conventional combustors within gas turbine engines creates the potential for greatly increased capability engines in the marine power market segment. A limited analysis has been conducted to estimate the degree of improvements possible in engine thermal efficiency and specific work for a type of wave rotor device utilizing these principles. The analysis considers a realistic level of component losses. The features of this innovative technology are compared with those of more common incremental improvement types of technology for the purpose of assessing potentials for initial market entry within the marine gas turbine market. Both recuperation and non-recuperation cycles are analyzed. Specific fuel consumption improvements in excess of 35% over those of a Brayton cycle are indicated. The technology exhibits the greatest percentage potential in improving efficiency for engines utilizing relatively low or moderate mechanical compression pressure ratios. Specific work increases are indicated to be of an equally dramatic magnitude. The advantages of the pressure gain combustion approach are reviewed as well as its technology development status.

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