Investigation of the Performance of Air-Steam Combined Cycle for Electric Power Plants Using Low Grade Solid Fuels

2021 ◽  
Author(s):  
Pereddy Nageswara Reddy
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Working Fluid ◽  
Solid Fuels ◽  
Inlet Temperature ◽  
Low Grade ◽  
Turbine Engine ◽  
Coal Fuel ◽  
Air Turbine

Abstract Since the solid fuels like coal produce a lot of ash upon burning, the products of combustion can’t be expanded as it is in a Gas Turbine (GT). Hence, the operation of a combined cycle with solid fuels includes: (i) production of syngas from the coal to operate a gas turbine engine and (ii) using the leftover coal after gasification to produce steam and operate a steam turbine engine. To avoid the coal-gasification and to use the solid coal fuel as it is in a combined cycle power plant, a novel Air-Steam Combined Cycle (ASCC) is proposed in the present work. ASCC comprises a gas turbine cycle (operating by the Brayton cycle) with the air as the working fluid and a steam turbine cycle (operating by the Rankine cycle) with the steam as the working fluid. A fraction F of the air is compressed, regenerated and finally heated to an Air Turbine Inlet Temperature (ATIT) by the hot products of combustion produced upon burning of the bituminous coal in a combustor. The residual heat energy of products of combustion is then utilized in a Heat Recovery Steam Generator (HRSG) to generate the steam initially and subsequently to preheat the remaining fraction (1-F) of the air. After expansion in an air turbine, the hot air passes through a regenerator directly into a combustor along with the preheated air for burning the coal so as to utilize the energy of expanded air completely. ASCC is analyzed based on the first and second laws of thermodynamics and a computer code is developed in MATLAB to simulate the cycle performance at different compressor pressure ratios, ATITs, and HRSG pressures. The performance of ASCC is compared with that of Baseline Steam Turbine Cycle (BSTC) for the same flue gas (stack) temperature. It is found that the overall thermal efficiency of ASCC can go up to 33.0%–37.5% depending on the compressor pressure ratio, ATIT and HRSG pressure as against to 29.0%–29.5% of BSTC.

Air-Steam Dual Loop Gas Turbine Engine With Pulse Detonation Combustion

2021 ◽  
Author(s):  
Pereddy Nageswara Reddy
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Combined Cycle ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Base Line ◽  
Specific Work ◽  
Detonation Products ◽  
Turbine Engine ◽  
Pulse Detonation

Abstract Air-steam Dual Loop Gas Turbine Engine (DLGTE) consists of a gas turbine engine with Pulse Detonation Combustor (PDC) (operating by the Humphrey cycle) with the air as the working fluid and a steam turbine engine (operating by the Rankine cycle) with the steam as the working fluid. The temperature of the hot detonation products is reduced to Turbine Inlet Temperature (TIT) by exchanging heat energy between detonation products and water in a Detonation Products to Water Heat Exchanger (DPWHE). The thermodynamic cycle of operation of DLGTE with PDC is analyzed based on quasi-steady state one dimensional formulation, and a computer code is developed in MATLAB to simulate the engine performance at different compressor pressure ratios and TITs. C2H4/air is taken as the fuel-oxidizer. It is found that DLGTE with PDC achieves 40 to 47% thermal efficiency as against 20 to 35% of Base Line Gas Turbine Engine (BLGTE) and 27 to 40% of Combined Cycle Gas Turbine Engine (CCGTE) with a Steady Flow Combustor (SFC) depending on the cycle pressure ratios and TITs. The specific work output of DLGTE is found to increase from 875 to 1200 kJ/kg air as against 180 to 380 kJ/kg air of BLGTE and 200 to 430 kJ/kg air of CCGTE.

scholarly journals High Temperature Combustor Designed for Operation With Coal Derived Low Btu Gaseous Fuels

1980 ◽  
Author(s):  
T. R. Koblish ◽  
L. M. Nucci
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Coal Gasification ◽  
Gas Turbine Engine ◽  
Combined Cycle ◽  
Department Of Energy ◽  
Turbine Engine ◽  
Gaseous Fuels ◽  
Coal Gasifier ◽  
Engine Components

Studies sponsored by the U. S. Department of Energy (DOE) have indicated that the combined cycle, incorporating an open cycle gas turbine having a Low Btu gas (LBG) fueled combustor operating at temperatures over 2600 F and a closed cycle steam turbine can produce cost competitive electric power from gasified coal. For increased efficiency, the coal gasification system would be integrated with the gas turbine which supplies the compressed air for the coal gasification system, and the steam turbine which supplies the steam for the gasification system. The coal gasifier would provide a pressurized low heating value (LBG) fuel (at the order of ISO Btu/SCF (5590 kJ/m3) for combustion in the gas turbine engine. Under DOE sponsorship, one of the gas turbine engine components being investigated both analytically and experimentally, is the LBG fueled combustor. This paper describes the LBG configuration background technology utilized in the design of the combustor and the test program outline for substantiation of the design approach.

Evaluation of the Effect of Firing Temperature, Cycle, Engine Configuration, Components, and Bottoming Cycle on the Overall Thermal Efficiency of an Indirectly Coal-Fired Gas Turbine Based Power Plant

2006 ◽  
Author(s):  
Richard P. Johnston
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Turbine Engine ◽  
Combined Cycle Plant ◽  
Plant Power

Potential LHV performance of an indirect coal-fired gas turbine-based combined cycle plant is explored and compared to the typical LHV 35–38 % thermal efficiencies achievable with current coal-fired Rankine Cycle power plants. Plant performance with a baseline synchronous speed, single spool 25:1 pressure ratio gas turbine with a Rankine bottoming cycle was developed. A coal-fired High Temperature Advanced Furnace (HITAF) supplying 2000° F. (1093° C.) hot pressurized air for the gas turbine was modeled for the heat source. The HITAF concept along with coal gas for supplemental heating, are two important parts of the clean coal technology program for power plants. [1,2] From this baseline power plant arrangement, different gas turbine engine configurations with two pressure ratios are evaluated. These variations include a dual spool concentric shaft gas turbine, dual spool non-concentric shaft arrangement, intercooler, liquid metal loop re-heater, free power turbine (FPT) and post HITAF duct burner (DB). A dual pressure Heat Recovery Steam Generator (HRSG) with varying steam pressures to fit conditions is used for each engine. A novel steam generating method employing flash tank technology is applied when a water-cooled intercooler is incorporated. A halogenated hydrocarbon working fluid is also evaluated for lower temperature sub-bottoming Rankine cycle equipment. Current technology industrial gas turbine component performance levels are applied to these various engines to produce a range of LHV gross gas turbine thermal efficiency estimates. These estimates range from the lower thirties to over forty percent. Overall LHV combined cycle plant gross thermal efficiencies range from nearly forty to over fifty percent. All arrangements studied would produce significant improvements in thermal efficiency compared to current coal-fired Rankine cycle power plants. Regenerative inter-cooling, free power turbines, and dual-spool non-concentric shaft gas turbine arrangements coupled with post-HITAF duct burners produced the highest gas turbine engine and plant efficiency results. These advanced engine configurations should also produce operational benefits such as easier starting and much improved part power efficiency over the baseline engine arrangement. An inter-turbine liquid metal re-heat loop reduced engine thermal efficiency but did increase plant power output and efficiency for the example studied. Use of halogenated hydrocarbons as a working fluid would add to plant power output, but at the cost of significant additional plant equipment.

scholarly journals The Coal-Fired PFBC Machine: Operating Experience and Further Development

1996 ◽  
Author(s):  
Sven A. Jansson ◽  
Dirk Veenhuizen ◽  
Krishna K. Pillai ◽  
Jan Björklund
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Fluidized Bed ◽  
Future Development ◽  
Operating Experience ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Under Construction ◽  
Further Development

The key components of Pressurized Fluidized Bed Combined Cycle (PFBC) plants are the specially designed gas turbine, which we refer to as the PFBC machine, and the pressurized fluidized bed boiler used to generate and superheat steam for expansion in a steam turbine, in ABB’s P200 and P800 modules, ABB Stal’s 17 MWe GT35P and 70 MWe GT140P machines, respectively, are used. Particulate cleanup before expansion in the turbine sections is with cyclones. So far, over 70,000 hours of operation has been accumulated on P200 modules in the world’s first PFBC plants, demonstrating that PFBC meets the expectations. The GT35P machines have been found to perform as expected, although some teething problems have also been experienced. The next P200 plant will be built in Germany for operation on brown coal. The first GT140P machine has been manufactured. After shop testing in Finspong, it will be shipped to Japan for installation in the first P800 plant, which is under construction. Future development of the PFBC machines are foreseen to include raising the turbine inlet temperature through combustion of a topping fuel in order to reach thermal efficiencies which ultimately may be in the range of 50 to 53% (LHV).

Combined Cycle Gas Turbine (CCGT) with Freon Steam Turbine

2015 ◽  
Vol 792 ◽  
pp. 351-358
Author(s):  
Anton Kuryanov ◽  
Ivo Mõik ◽  
Oksana Grigoryeva
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Economic Efficiency ◽  
Dynamic Characteristics ◽  
Combined Cycle ◽  
Working Fluid ◽  
Gas Dynamic ◽  
Methodical Approach ◽  
Combined Cycle Plant

The article considers the prospect of a combined-cycle plant with freon as the working fluid of the steam turbine. Methodical approach to the study of such plants is expounded. For the option, CCGT with gas turbine M701G2 and use of freon R134a results of calculations of technical and economic efficiency, gas-dynamic characteristics, design-layout parameters are shown. The effectiveness of investments has been assessed.

scholarly journals Research and Development of the Oxy-Fuel Combustion Power Cycles with CO2 Recirculation

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2927
Author(s):  
Andrey Rogalev ◽  
Nikolay Rogalev ◽  
Vladimir Kindra ◽  
Ivan Komarov ◽  
Olga Zlyvko
Keyword(s):  
Gas Turbine ◽  
Carbon Dioxide Emissions ◽  
Fuel Combustion ◽  
Combined Cycle ◽  
Air Separation ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Separation Unit ◽  
Power Cycles ◽  
Modeling Methodology

The transition to oxy-fuel combustion power cycles is a prospective way to decrease carbon dioxide emissions into the atmosphere from the energy sector. To identify which technology has the highest efficiency and the lowest emission level, a thermodynamic analysis of the semiclosed oxy-fuel combustion combined cycle (SCOC-CC), the E-MATIANT cycle, and the Allam cycle was carried out. The modeling methodology has been described in detail, including the approaches to defining the working fluid properties, the mathematical models of the air separation unit, and the cooled gas turbine cycles’ calculation algorithms. The gas turbine inlet parameters were optimized using the developed modeling methodology for the three oxy-fuel combustion power cycles with CO2 recirculation in the inlet temperature at a range of 1000 to 1700 °C. The effect of the coolant flow precooling was evaluated. It was found that a decrease in the coolant temperature could lead to an increase of the net efficiency up to 3.2% for the SCOC-CC cycle and up to 0.8% for the E-MATIANT cycle. The final comparison showed that the Allam cycle’s net efficiency is 5.6% higher compared to the SCOC-CC cycle, and 11.5% higher compared with the E-MATIANT cycle.

Virtual Jet Engine System

2010 ◽  
Vol 638-642 ◽  
pp. 2239-2244 ◽  
Author(s):  
Masafumi Fukuda ◽  
Hiroshi Harada ◽  
Tadaharu Yokokawa ◽  
Tomonori Kitashima
Keyword(s):  
Gas Turbine ◽  
Material Design ◽  
Gas Turbine Engine ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Jet Engine ◽  
Turbine Engine ◽  
Engine System ◽  
Materials Used ◽  
Cooling Air Flow

In 1999, we proposed the concept of a virtual gas turbine system which is a combination of turbine design and material design programs. Using this system, it has become possible to design a gas turbine engine and a combined cycle automatically, by inputting some basic information such as power output, turbine inlet temperature and material specifications. The derived outputs are turbine gas path dimensions, gas and cooling air flow rates, thermal efficiency, CO2 emissions, etc. We use the system to evaluate the potential improvement if a newly developed material is to be used in building the engine. Based on the virtual gas turbine system we have begun developing the virtual jet engine system, which can simulate the operation of a jet engine or a gas turbine engine to predict the degradation of materials used in the high temperature parts of the engine. The system consists of a thermal and aerodynamic analysis of the engine, a thermal and stress analysis of hot parts, and a material degradation analysis. Actual engine dimensions, operation data and material specifications are used to perform the analyses. In this paper, we will show some of the results of the use of the virtual gas turbine system, and then describe the development plan and the preliminary output of the virtual jet engine system.

Combined Steam-Turbine Power Producing Concept With Recirculating Steam Compressor

2007 ◽  
Author(s):  
Branko Stankovic
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Waste Heat ◽  
Combined Cycle ◽  
Steam Flow ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet ◽  
High Temperature Steam

This concept shows that an efficient combined cycle, comprising topping & bottoming cycle, does not have to be privilege of gas turbine plants only, but could also be achieved with steam turbine plants. An efficient power-producing concept of a combined steam-turbine cycle with addition of a recirculating steam compressor is disclosed. Topping part of such a combined steam-turbine cycle operates at elevated steam turbine inlet temperature and pressure, while its “waste heat” is recovered by the bottoming part of the combined cycle in a heat-recovery boiler (steam heat exchanger). The recirculating steam compressor pumps the cooled majority of the entire steam flow to the maximum cycle pressure, while smaller steam flow fraction continues its full expansion to some low pressure in a condenser. The cycle waste heat could be transferred to the bottoming part of the combined cycle in a variety of modalities, depending on the chosen main high-temperature steam-turbine inlet temperature and inlet pressure (supercritical/subcritical). At an assumed constant steam-turbine inlet temperature of 900°C (∼300 bar), a very high gross cycle thermal efficiency could potentially be achieved, ranging from 56 to 62% with the high-temperature steam-turbine pressure ranging from subcritical (30 bar) to supercritical (300 bar). Such a combined steam-turbine cycle seems to be a suitable energy conversion concept that could be applied in classic thermal power plants powered by coal, but also seems as an ideal option for application in the new generation of gas-cooled nuclear rectors, where the gaseous reactor coolant, heated up to 1000°C, would indirectly transfer its heat content to working fluid (superheated steam) of the topping part of the combined steam-turbine cycle. Alternatively, the proposed concept may be combined with renewable energy sources of a sufficient temperature level.

Modeling and Cost Optimization of Combined Cycle Heat Recovery Generator Systems

2003 ◽  
Author(s):  
Yongjun Zhao ◽  
Hongmei Chen ◽  
Mark Waters ◽  
Dimitri N. Mavris
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Heat Recovery ◽  
Combined Cycle ◽  
System Level ◽  
Exhaust Gas ◽  
Heat Recovery Steam Generator ◽  
Turbine Engine ◽  
Investment Cost

The combined cycle power plant is made up of three major systems, the gas turbine engine, the heat recovery steam generator and the steam turbine. Of the major systems the gas turbine engine is a fixed design offered by a manufacturer, and the steam turbine is also a fairly standard design available from a manufacturer, but it may be somewhat customized for the project. In contrast, the heat recovery steam generator (HRSG) offers many different design options, and its design is highly customized and integrated with the steam turbine. The objective of this project is to parametrically investigate the design and cost of the HRSG system, and to demonstrate the impact on the overall cost of electricity (COE) of a combined cycle power plant. There are numerous design parameters that can affect the size and complexity of the HRSG, and it is the plan for the project to identify all the important parameters and to evaluate each. For this study, the design parameter chosen for evaluation is the exhaust gas pressure drop across the HRSG. This parameter affects the performance of both the gas turbine and steam turbine and the size of the heat recovery unit. Single-pressure, two-pressure and three-pressure HRSGs are all investigated, with the tradeoffs between design point size, performance and cost evaluated for each system. A genetic algorithm is used in the design optimization process to minimize the investment cost of the HSRG. Several system level metrics are employed to evaluate a design. They are gas turbine net power, steam turbine net power, fuel consumption of the power plant, net cycle efficiency of the power plant, HRSG investment cost, total investment cost of the power plant and the operating cost measured by the cost of electricity (COE). The impacts of HRSG exhaust gas pressure drop and system complexity on these system level metrics are investigated.

System Analysis of IGFC With Exergy Recuperation Utilizing Low-Grade Coal

2011 ◽  
Author(s):  
Risa Nomura ◽  
Norihiko Iki ◽  
Osamu Kurata ◽  
Masako Kawabata ◽  
Atsushi Tsutsumi ◽  
...  
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Bituminous Coal ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Exergy Loss ◽  
Low Grade ◽  
Generation Efficiency

Integrated Coal Gasification Fuel Cell Combined Cycle (IGFC) is expected to be the most efficient power generation system in coal fired power generation systems [1,2]. The Japanese project of the Strategic Technical Platform for Clean Coal Technology (STEP-CCT) aims a target efficiency of 65% (HHV) with exergy recuperation. We have been analyzing the processes of the exergy recuperated Integrated Coal Gasification Combined Cycle (IGCC) and the Advanced IGCC (A-IGCC) [3] which is expected to be realized in 2040. Previous studies have indicated a limitation of the quantity of high temperature steam in the case of auto-thermal reactions with the fluidized bed coal gasifier in the A-IGCC, in particular for TIT 1500 °C class gas turbine. The Advanced IGFC (A-IGFC) system can reduce the exergy loss resulting from combustion, and its ‘exergy recuperation’ is appealing. The waste heat exhausted from the fuel cells is recycled to the gasifier for steam reforming in an endothermic reaction with a low exergy loss and a high cold gas efficiency. Our current study focuses on the optimization of the unit configurations of the A-IGFC including gasifier, compressor, solid oxide fuel cell (SOFC), combustor, gas turbine, heat recovery steam generator (HRSG), and steam turbine. The process simulator HYSYS®.Plant (Aspen technology Inc.) is employed in order to express the gasifier, the SOFC and the other units. The optimum construction over the whole system by numerical simulation was examined for higher energy utilization efficiency. Under ideal conditions using bituminous coal, we verified the power generation efficiency to be 64.5% (HHV). However, utilizing low-grade coals, i.e., lignite and sub-bituminous coal, is deemed an important future energy resource to compensate for a decreasing supply of good-quality bituminous coal. For these low-grade coals, the power generation efficiency was as high as 53.6% (HHV) under the following conditions: Gasifier inlet: coal 23.6 Kg/s (667 MJ/s), steam 16.44 kg/s; Reactor reforming gas: 30.0, 8.7, 2.0, 0.8, 0.3, 0.05, 0.24, 0.14, 0.1 and 5.5 kg/s for CO, CO2, H2, CH4, C2H4, C2H6, C3H6, HCN, N2 and H2O respectively. The projected power outputs with this system were, SOFC: 214 MW; Gas turbine: 318 MW; Steam turbine: 86 MW.

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