Assessment of Humid Air Turbines in Coal-Fired High Performance Power Systems

Author(s):  
Julianne M. Klara ◽  
Robert M. Enick ◽  
Scott M. Klara ◽  
Lawrence E. Van Bibber

The purpose of this study is to assess the feasibility of incorporating a Humid Air Turbine (HAT) into a coal-based, indirectly fired High Performance Power System (HIPPS). The HIPPS/HAT power plant exhibits a one percentage point greater thermal efficiency than the combined-cycle HIPPS plant. The capital costs for the HIPPS and HIPPS/HAT plants with identical net power output are nearly equivalent at $1380/kW. Levelized cost of electricity (COE) for the same size plants is 5.3 cents/kWh for the HIPPS plant and 5.4 cents/kWh for the HIPPS/HAT plant; the HIPPS/HAT plant improved thermal efficiency is offset by the higher fuel cost associated with a lower coal/natural gas fuel ratio. However, improved environmental performance is associated with the HIPPS/HAT cycle, as evidenced by lower CO2, SO2, and NOx emissions. Considering the uncertainties associated with the performance and cost estimates of the yet unbuilt components, the HIPPS/HAT and HIPPS power plants are presently considered to be comparable alternatives for future power generation technologies. The Department of Energy’s Combustion 2000 Program will provide revised design specifications and more accurate costs for these components allowing more definitive assessments to be performed.

Author(s):  
Julianne M. Klara

Demand for electricity in the United States is expected to grow in the foreseeable future, requiring approximately 200 gigawatts of new generating capacity by 2010. Coal-based power plants built to supply this additional baseload capacity will be required to perform at high thermal efficiency and meet tough environmental regulations, all at competitive electric generating costs. The Department of Energy (DOE) / Pittsburgh Energy Technology Center (PETC) is managing a program called Combustion 2000 that is aimed at developing technologies that will assure the continued use of coal to meet the Nation’s power generating needs well into the 21st century. The High-Performance Power System (HIPPS) element of Combustion 2000 is based on an indirectly fired combined cycle. By using an indirectly fired gas turbine and a conventional steam cycle, HIPPS cleanly produces electricity from coal at a thermal efficiency that is about one-third higher than that of today’s conventional coal-based power plants. DOE/PETC’s HIPPS program, which is described in this paper, aims to demonstrate a commercial-scale prototype plant by 2004. An engineering analysis was performed to assess the feasibility of accelerating the demonstration of HIPPS by using only those materials available today. Results predict attractive efficiencies and competitive electric generating costs for a near-term design. The feasibility of HIPPS as a repowering option has also been examined. Preliminary projections reveal that added generating capacity and reduced emissions can be accomplished at an increased overall plant efficiency and with the potential to minimize capital expenditure.


Author(s):  
F. L. Robson ◽  
D. J. Seery

The Department of Energy’s Federal Energy Technology Center (FETC) is sponsoring the Combustion 2000 Program aimed at introducing clean and more efficient advanced technology coal-based power systems in the early 21st century. As part of this program, the United Technologies Research Center has assembled a seven member team to identify and develop the technology for a High Performance Power Systems (HIPPS) that will provide in the near term, 47% efficiency (HHV), and meet emission goals only one-tenth of current New Source Performance Standards for coal-fired power plants. In addition, the team is identifying advanced technologies that could result in HIPPS with efficiencies approaching 55% (HHV). The HIPPS is a combined cycle that uses a coal-fired High Temperature Advanced Furnace (HITAF) to preheat compressor discharge air in both convective and radiant heaters. The heated air is then sent to the gas turbine where additional fuel, either natural gas or distillate, is burned to raise the temperature to the levels of modern gas turbines. Steam is raised in the HITAF and in a Heat Recovery Steam Generator for the steam bottoming cycle. With state-of-the-art frame type gas turbines, the efficiency goal of 47% is met in a system with more than two-thirds of the heat input furnished by coal. By using advanced aeroderivative engine technology, HIPPS in combined-cycle and Humid Air Turbine (HAT) cycle configurations could result in efficiencies of over 50% and could approach 55%. The following paper contains descriptions of the HIPPS concept including the HITAF and heat exchangers, and of the various gas turbine configurations. Projections of HIPPS performance, emissions including significant reduction in greenhouse gases are given. Application of HIPPS to repowering is discussed.


2000 ◽  
Vol 123 (1) ◽  
pp. 4-9 ◽  
Author(s):  
Lawrence A. Ruth

The U.S. Department of Energy is partnering with industry to develop advanced coal-fired electric power plants that are substantially cleaner, more efficient, and less costly than current plants. Low-emission boiler systems (LEBS) and high-performance power systems (HIPPS) are based, respectively, on the direct firing of pulverized coal and the indirectly fired combined cycle. LEBS uses a low-NOx slagging combustion system that has been shown in pilot-scale tests to emit less than 86 g/GJ (0.2 lb/106 Btu) of NOx. Additional NOx removal is provided by a moving bed copper oxide flue gas cleanup system, which also removes 97–99 percent of sulfur oxides. Stack levels of NOx can be reduced to below 9 g/GJ (0.02 lb/106 Btu). Construction of an 80 MWe LEBS proof-of-concept plant is scheduled to begin in the spring of 1999. Engineering development of two different HIPPS configurations is continuing. Recent tests of a radiant air heater, a key component of HIPPS, have indicated the soundness of the design for air temperatures to 1150°C. LEBS and HIPPS applications include both new power plants and repowering/upgrading existing plants.


Author(s):  
Michael Nakhamkin ◽  
Robert Pelini ◽  
Manu I. Patel

This paper presents the latest information on Humid Air Injection (HAI) power augmentation technology for Combustion Turbine and Combined Cycle power plants. It describes: a) The summary of the latest activities on the implementation of HAI and Dry Air Injection (DAI) technologies including results of the validations tests conducted on the PG7241 (FA) combustion turbine, and findings of various CT-HAI implementation projects; b) The technical background including the latest CT-HAI and CT-DAI concepts resulting on the performance improvements and reduced emissions; and c) The novel concept for humidification of the injected air that further reduces overall capital costs by 15%.


Author(s):  
Andrea Corti ◽  
Bruno Facchini ◽  
Giampaolo Manfrida ◽  
Umberto Desideri

A comparison between power plants built according to the HAT (Humid Air Turbine) and SCGT/CC (Semi-Closed Gas Turbine/Combined Cycle) concepts is presented, ranging from thermodynamic performance (efficiency and specific power output) to projected data for plant construction and operating costs. Both options appear to be of potential interest to electric utilities considering advanced gas turbine power plants, with significant differences form the point of view of plant size, water consumption, and adaptability to advanced developments for the limitation of environmental impact (CO2 emissions).


Author(s):  
Alberto Vannoni ◽  
Andrea Giugno ◽  
Alessandro Sorce

Abstract Renewable energy penetration is growing, due to the target of greenhouse-gas-emission reduction, even though fossil fuel-based technologies are still necessary in the current energy market scenario to provide reliable back-up power to stabilize the grid. Nevertheless, currently, an investment in such a kind of power plant might not be profitable enough, since some energy policies have led to a general decrease of both the average price of electricity and its variability; moreover, in several countries negative prices are reached on some sunny or windy days. Within this context, Combined Heat and Power systems appear not just as a fuel-efficient way to fulfill local thermal demand, but also as a sustainable way to maintain installed capacity able to support electricity grid reliability. Innovative solutions to increase both the efficiency and flexibility of those power plants, as well as careful evaluations of the economic context, are essential to ensure the sustainability of the economic investment in a fast-paced changing energy field. This study aims to evaluate the economic viability and environmental impact of an integrated solution of a cogenerative combined cycle gas turbine power plant with a flue gas condensing heat pump. Considering capital expenditure, heat demand, electricity price and its fluctuations during the whole system life, the sustainability of the investment is evaluated taking into account the uncertainties of economic scenarios and benchmarked against the integration of a cogenerative combined cycle gas turbine power plant with a Heat-Only Boiler.


Author(s):  
Mohammad Mansouri Majoumerd ◽  
Mohsen Assadi ◽  
Peter Breuhaus ◽  
Øystein Arild

The overall goal of the European co-financed H2-IGCC project was to provide and demonstrate technical solutions for highly efficient and reliable gas turbine technology in the next generation of integrated gasification combined cycle (IGCC) power plants with CO2 capture suitable for combusting undiluted H2-rich syngas. This paper aims at providing an overview of the main activities performed in the system analysis working group of the H2-IGCC project. These activities included the modeling and integration of different plant components to establish a baseline IGCC configuration, adjustments and modifications of the baseline configuration to reach the selected IGCC configuration, performance analysis of the selected plant, performing techno-economic assessments and finally benchmarking with competing fossil-based power technologies. In this regard, an extensive literature survey was performed, validated models (components and sub-systems) were used, and inputs from industrial partners were incorporated into the models. Accordingly, different plant components have been integrated considering the practical operation of the plant. Moreover, realistic assumptions have been made to reach realistic techno-economic evaluations. The presented results show that the efficiency of the IGCC plant with CO2 capture is 35.7% (lower heating value basis). The results also confirm that the efficiency is reduced by 11.3 percentage points due to the deployment of CO2 capture in the IGCC plant. The specific capital costs for the IGCC plant with capture are estimated to be 2,901 €/(kW net) and the cost of electricity for such a plant is 90 €/MWh. It is also shown that the natural gas combined cycle without CO2 capture requires the lowest capital investment, while the lowest cost of electricity is related to IGCC plant without CO2 capture.


Author(s):  
R. M. Kavanagh ◽  
G. T. Parks

The steam injected gas turbine (STIG), humid air turbine (HAT), and TOP Humid Air Turbine (TOPHAT) cycles lie at the center of the debate on which humid power cycle will deliver optimal performance when applied to an aeroderivative gas turbine and, indeed, when such cycles will be implemented. Of these humid cycles, it has been claimed that the TOPHAT cycle has the highest efficiency and specific work, followed closely by the HAT, and then the STIG cycle. In this study, the systems have been simulated using consistent thermodynamic and economic models for the components and working fluid properties, allowing a consistent and nonbiased appraisal of these systems. Part I of these two papers focuses purely on the thermodynamic performance and the impact of the system parameters on the performance; Part II will study the economic performance. The three humid power systems and up to ten system parameters are optimized using a multi-objective Tabu Search algorithm, developed in the Cambridge Engineering Design Centre.


Author(s):  
William L. Kopko ◽  
John S. Hoffman

A proposed topping cycle inserts a free-piston internal-combustion engine between the compressor and the combustor of a combustion turbine. The topping cycle diverts air from the compressor to supercharge the free-piston engine. Because the free-piston engine uses gas bearings to support the piston and is built of high-temperature materials, the engine can increase the pressure and temperature of the gas, exhausting it to a small expander that produces power. The exhaust from the topping-cycle expander is at a pressure that can be re-introduced to the main turbine, allowing almost complete recovery of waste heat. A capacity increase exceeding 35% is possible, and overall cycle efficiency can approach 70% when incorporated into a state-of-the-art combined-cycle plant. The cost of per incremental kW of the topping cycle can be dramatically lower than that of the base turbine because of the high power density and simplicity of the engine. Building on decades of progress in combustion turbines systems, the new cycle promises high performance without the engineering risks of manufacturing a completely new cycle.


Author(s):  
Eiji Akita ◽  
Shin Gomi ◽  
Scott Cloyd ◽  
Michael Nakhamkin ◽  
Madhukar Chiruvolu

The Air Injection (AI) Power Augmentation technology (HAI for humid Air injection and DAI for dry air injection) has primary benefits of increasing power of combustion turbine/combined cycle (CT/CC) power plants by 15–30% at a fraction of the new plant cost with coincidental significant heat rate reductions (10–15%) and NOx emissions reductions (for diffusion type combustors up to 60%) (See References 1, 2, 3): Figure 1A is a simplified heat and mass balance for the PG7241 (FA) combustion turbine with HAI. The auxiliary compressor supplies the additional airflow that is mixed with the steam produced by the HRSG and injected upstream of combustors. Figure 1B presents the heat and mass balance for the PG7142 CT based combined cycle power plant with HAI. It is similar to that presented on Figure 1A except that the humid air is created by mixing of steam, extracted from the steam turbine, with the supplementary airflow from the auxiliary compressor. The maximum acceptable injection rates are evaluated with proper margins by a number of factors established by OEMs: the compressor surge limitations, maximum torque, the generator capacities, maximum moisture levels upstream of combustors, etc.


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