The Thermodynamic Performance of Two Combined Cycle Power Plants Integrated With Two Coal Gasification Systems

1981 ◽  
Vol 103 (3) ◽  
pp. 572-581 ◽  
Author(s):  
F. L. Stasa ◽  
F. Osterle
Keyword(s):  
Power Plants ◽  
Coal Gasification ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Gasification Process ◽  
Heat System ◽  
Thermodynamic Performance ◽  
Gas Recirculation

Thermodynamic models of both an adiabatic and an endothermic coal gasifier integrated with either a waste heat combined cycle or a supercharged boiler combined cycle are developed. The adiabatic gasification process requires air and steam, while the endothermic gasification process requires only steam. The combined cycle is composed of an open Brayton cycle and a superheated regenerative Rankine cycle without reheat. Certain components are added to each configuration in an effort to improve thermodynamic performance. From the results, it appears that with consideration of the pollution criteria, the station efficiencies for each configuration are within 1 percentage point of each other when flue gas recirculation is used as a means to control the nitric oxide. With a gas turbine inlet temperature of 2000°F, and with consideration of the pollution criteria, the configuration employing an adiabatic gasifier and a waste heat system is marginally the best with a station efficiency of only 37 percent.

scholarly journals Ruhrchemie/Ruhrkohle’s Technical Version of the Texaco Coal Gasifier as Part of a Combined Cycle Plant

1982 ◽  
Author(s):  
B. Cornils ◽  
J. Hibbel ◽  
P. Ruprecht ◽  
R. Dürrfeld ◽  
J. Langhoff
Keyword(s):  
High Pressure ◽  
Power Plants ◽  
Coal Gasification ◽  
Operating Time ◽  
Combined Cycle ◽  
Gas Generation ◽  
Load Following ◽  
Gasification Process ◽  
Steady State Operation ◽  
Combined Cycle Plant

The Ruhrchemie/Ruhrkohle variant of the Texaco Coal Gasification Process (TCGP) has been on stream since 1978. As the first demonstration plant of the “second generation” it has confirmed the advantages of the simultaneous gasification of coal: at higher temperatures; under elevated pressures; using finely divided coal; feeding the coal as a slurry in water. The operating time so far totals 9000 hrs. More than 50,000 tons of coal have been converted to syn gas with a typical composition of 55 percent CO, 33 percent H2, 11 percent CO2 and 0.01 percent of methane. The advantages of the process — low environmental impact, additional high pressure steam production, gas generation at high pressure levels, steady state operation, relatively low investment costs, rapid and reliable turn-down and load-following characteristics — make such entrained-bed coal gasification processes highly suitable for power generation, especially as the first step of combined cycle power plants.

scholarly journals Combined Cycles Permit the Most Environmentally Benign Conversion of Fossil Fuels to Electricity

1990 ◽  
Author(s):  
Guenther Haupt ◽  
John S. Joyce ◽  
Konrad Kuenstle
Keyword(s):  
Environmental Impact ◽  
Power Plants ◽  
Fossil Fuels ◽  
Coal Gasification ◽  
High Efficiency ◽  
Waste Heat ◽  
Primary Energy ◽  
Combined Cycle ◽  
Point Of View ◽  
Steam Boiler

The environmental impact of unfired combined-cycle blocks of the GUD® type is compared with that of equivalent reheat steam boiler/turbine units. The outstandingly high efficiency of GUD blocks not only conserves primary-energy resources, but also commensurately reduces undesirable emissions and unavoidable heat rejection to the surroundings. In addition to conventional gas or oil-fired GUD blocks, integrated coal-gasification combined-cycle (ICG-GUD) blocks are investigated from an ecological point of view so as to cover the whole range of available fossil fuels. For each fuel and corresponding type of GUD power plant the most appropriate conventional steam-generating unit of most modern design is selected for comparison purposes. In each case the relative environmental impact is stated in the form of quantified emissions, effluents and waste heat, as well as of useful byproducts and disposable solid wastes. GUD blocks possess the advantage that they allow primary measures to be taken to minimize the production of NOx and SOx, whereas both have to be removed from the flue gases of conventional steam stations by less effective and desirable, albeit more expensive secondary techniques, e.g. flue-gas desulfurization and DENOX systems. In particular, the comparison of CO2 release reveals a significantly lower contribution by GUD blocks to the greenhouse effect than by other fossil-fired power plants.

scholarly journals Combined Closed Cycle (C3) Systems for Underwater Power Generation

1992 ◽  
Author(s):  
Aristide Massardd ◽  
Gian Marid Arnulfi
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Primary Energy ◽  
Combined Cycle ◽  
Working Fluid ◽  
Mass Reduction ◽  
Efficiency Increase

In this paper three Closed Combined Cycle (C3) systems for underwater power generation are analyzed. In the first, the waste heat rejected by a Closed Brayton Cycle (CBC) is utilized to heat the working fluid of a bottoming Rankine Cycle; in the second, the heat of a primary energy loop fluid is used to heat both CBC and Rankine cycle working fluids; the third solution involves a Metal Rankine Cycle (MRC) combined with an Organic Rankine Cycle (ORC). The significant benefits of the Closed Combined Cycle concepts, compared to the simple CBC system, such as efficiency increase and specific mass reduction, are presented and discussed. A comparison between the three C3 power plants is presented taking into account the technological maturity of all the plant components.

Electricity From Coal: The British Gas/Lurgi Gasification for Combined Cycle Power Generation

1986 ◽  
Author(s):  
Helmut E. Vierrath ◽  
Peter K. Herbert ◽  
Claus F. Greil ◽  
Brian H. Thompson
Keyword(s):  
Power Generation ◽  
Gas Turbines ◽  
Power Plants ◽  
Coal Gasification ◽  
Environmental Control ◽  
Combined Cycle ◽  
Flue Gas Desulfurization ◽  
Waste Streams ◽  
Heat System ◽  
Coal Power Plants

It is widely accepted that coal gasification combined-cycle plants represent an environmentally superior alternative to conventional coal fired power plants with flue gas desulfurization. Purpose of this paper is to show that technology is available for all steps required to convert coal to electricity, including treatment of waste streams. Based on examples for power plants in the 200–800 MW range using current and as well as advanced gas turbines, it is shown that under both European and US-conditions cost of electricity from this (new) route of coal based power generation is certainly no higher — and probably even lower — than from conventional PC (pulverized coal) power plants equipped with equivalent environmental control technology. Thus, this technology is likely to be a prime contributor when it comes to enhance environmental acceptability of power plants in general, and to help solve the acid rain problem in particular. In addition the versatility of the proposed technology for repowering, decentralized application and district heat system is explained.

Enhancing Energy and Economic Performances of Combined Cycle Power Plants by Means of Gas-Cycle Regeneration

2014 ◽  
Author(s):  
Roberto Carapellucci ◽  
Lorena Giordano
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Unit Cost ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Efficiency Gain ◽  
Gas Power Plant

Efficiency improvement in the gas turbine sector has been mainly driven by increasing the turbine inlet temperature and compressor pressure ratio. For a fixed technology level, a further efficiency gain can be achieved through the utilization of waste thermal energy. Regeneration is an internal recovery technique that allows the reduction of heat input required at combustor, by preheating the air at compressor outlet. Under certain operating conditions, the temperature of exhaust gas leaving the regenerator is still enough high to allow the steam production via an heat recovery steam generator (HRSG). Regeneration in steam-gas power plants (CCGT) has the potential to enhance thermal efficiency, but reduces the margins for external recovery and then the bottoming steam cycle capacity. Moreover, the reduction of exhausts temperature at gas turbine outlet requires the reconsideration of HRSG operating parameters, in order to limit the increase of waste heat at the stack. The aim of this study is to explore the potential benefits that regeneration in the gas cycle gives on the whole steam-gas power plant. The extent of energy and economic performances improvement is evaluated, varying the gas turbine specifications and the layout and operating conditions of HRSG. Hence simple and regenerative configurations based on single and multi-pressure HRSG are compared, focusing on efficiency, specific CO2 emissions and unit cost of electricity (COE).

Thermodynamic Analysis and Optimization of IT-SOFC-Based Integrated Coal Gasification Fuel Cell Power Plants

2011 ◽  
Vol 8 (4) ◽  
Author(s):  
Matteo C. Romano ◽  
Stefano Campanari ◽  
Vincenzo Spallina ◽  
Giovanni Lozza
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Power Plants ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Utilization Factor ◽  
Best Available Technologies ◽  
Integrated Gasification

This work discusses the thermodynamic analysis of integrated gasification fuel cell plants, where a simple cycle gas turbine works in a hybrid cycle with a pressurized intermediate temperature–solid oxide fuel cell (SOFC), integrated with a coal gasification and syngas cleanup island and a bottoming steam cycle (reflecting the arrangement of integrated gasification combined cycle (IGCC) plants) to optimize heat recovery and maximize efficiency. This work addresses the optimization of the plant layout, discussing the effect of the SOFC fuel utilization factor and the possibility of a fuel bypass to increase the gas turbine total inlet temperature and reduce the plant expected investment costs. Moreover, a discussion of technological issues related to the feasibility of the connection among the plant high temperature components is carried out, presenting the effects of different limitations of the maximum temperatures reached by the plant piping. With the proposed plant configurations, which do not include—apart from the SOFC—any component far from the nowadays best available technologies, a net electric lower heating value efficiency approaching 52–54% was calculated, showing a remarkable increase with respect to state-of-the-art advanced IGCCs.

scholarly journals Thermal Efficiency of Combined Cycle Power Plant

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
R. Rajesh ◽  
P. S. Kishore
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Heat Recovery Boiler ◽  
Brayton Cycle ◽  
Single Cycle ◽  
Working Medium ◽  
Temperature And Pressure

Now a day’s power generation is most important for every country. This power is generated by some thermal cycles. But single cycle cannot be attain complete power requirements and its efficiency also very low so that to fulfill this requirements to combine two or more cycles in a single power plant then we can increase the efficiency of the power plant. Its increased efficiency is more than that of if the plant operated on single cycle. In which we are using two different cycles and these two cycles are operated by means of different working mediums. These type of power plants we can called them like combined cycle power plants. In combined cycle power plants above cycle is known as topping cycle and below cycle is known as bottoming cycle. The above cycle generally brayton cycle which uses air as a working medium. When the power generation was completed the exhaust gas will passes in to the waste heat recovery boiler. Another cycle also involved in bottoming cycle. This cycle works on the basis on rankine cycle. In which steam is used as working medium. The main component in bottoming cycle is waste heat recovery boiler. It will receive exhaust heat from the gas turbine and converts water in to steam. The steam used for generating power by expansion on steam turbine. Combined cycle power plants are mostly used in commercial power plants.In this paper we are analyzing one practical combined cycle power plant. In practical conditions due to some losses it can not be generates complete power. So that we are invistigated why it is not give that much of power and the effect of various operating parameters such as maximum temperature and pressure of rankine cycle, gas turbine inlet temperature and pressure ratio of Brayton cycle on the net output work and thermal efficiency of the combine cycle power plant.The outcome of this work can be utilized in order to facilitate the design of a combined cycle with higher efficiency and output work. Mathematical calculations and simple graphs in ms excel, and auto cad has been carried out to study the effects and influences of the above mentioned parameters on the efficiency and work output.

Coal Gasification/Repowering: A Means of Increasing Plant Capacity While Reducing Oil Consumption

1980 ◽  
Author(s):  
S. J. Lehman ◽  
A. J. Giramonti ◽  
R. H. Meyer
Keyword(s):  
Power Plants ◽  
Coal Gasification ◽  
Waste Heat ◽  
Time Frame ◽  
Combined Cycle ◽  
Heat Recovery Boiler ◽  
Steam Boiler ◽  
Oil Consumption ◽  
Fuel Gas ◽  
Coal Gasifier

An exploratory study was carried out by the United Technologies Research Center and Northeast Utilities Service Company to identify the performance characteristics of power plants based upon the repowering of several existing steam plants. In steam station repowering, an advanced, high temperature gas turbine fired by coal-derived, low-Btu fuel gas would generate power and exhaust to a new waste-heat recovery boiler that replaces the old oil-fired steam boiler. Steam from the new boiler drives the existing steam turbine. Computer models were assembled to simulate the integration of molten salt and Texaco coal gasification systems with combustion turbomachinery representative of the 1990 time frame. The results of this study indicated that either coal gasifier in a combined-cycle repowering application appears attractive as a means of replacing oil-fired systems with coal.

Waste Heat Recovery From Closed Brayton Cycle Using Organic Rankine Cycle: Thermodynamic Analysis

2009 ◽  
Author(s):  
Mortaza Yari
Keyword(s):  
Waste Heat ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Exergy Destruction ◽  
Evaporator Temperature ◽  
Destruction Rate

This study examines the performance of a gas-cooled nuclear power plant with closed Brayton cycle (CBC) combined with an organic Rankine cycle (ORC) plant, as well as the irreversibility within the system. Individual models have been developed for each component, through applications of the first and second laws of thermodynamics. The overall system performance is then analyzed by employing individual models and further application of thermodynamic laws for the entire cycle, to evaluate the thermal efficiency and entropy production of the plant. The effects of the turbine inlet temperature, compressor pressure ratio, evaporator temperature, and temperature difference in the evaporator on the combined cycle first-law, second-law efficiency and exergy destruction rate are studied. Finally optimization of the combined cycle in a systematic way has been developed and discussed. It was found that the combined cycle first-law efficiency is about 9.5–10.1% higher than the simple CBC cycle. Also, the exergy destruction rate for the GT-MHR/ORC combined cycle, is about 6.5–8.3% lower than that of the GT-MHR cycle.

scholarly journals Steam Turbine—Quo Vadis?

2021 ◽  
Vol 8 ◽  
Author(s):  
Seyfettin Can Gülen
Keyword(s):  
Steam Turbine ◽  
Waste Heat Recovery ◽  
Power Plants ◽  
Fossil Fuel ◽  
Waste Heat ◽  
Second Law Of Thermodynamics ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Recovery Capacity ◽  
Quo Vadis

In this article, a close look is taken at the state-of-the-art in steam turbine and steam (Rankine) cycle technology within the framework of conventional steam and gas turbine combined cycle power plants, specifically, the bottoming steam (Rankine) cycle of the latter. Using the second law of thermodynamics and the concept of exergy as a guide, cycle and technology factors are calculated to provide a simple but precise (and unassailable) yardstick to assess where the technology was, where it is at present, and how much farther it can go. In addition, the study takes a critical look at an emerging technology, supercritical CO2 cycle, that is being touted as a serious contender for steam turbine’s place in the fossil fuel-fired electric power generation portfolio—as a standalone system or as a waste heat recovery capacity (i.e., combined cycle).

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