The Closed Cycle Gas Turbine, the Most Efficient Turbine Burning any Fuel

Author(s):  
R. Tom Sawyer

The are two types of gas turbines. The open cycle is very well known as for example the JET. The closed cycle in the U.S.A. is just starting to be well known. In Europe the closed cycle gas turbine has been used in power plants, especially in Germany and have been very efficient burning coal. I am going to concentrate on the CCGT - Closed Cycle Gas Turbine as it is the most efficient type of turbine. First I will give a brief report written by Dr. Curt Keller. Then the main part of this paper will give more details about the closed cycle gas turbine (CCGT) using various fuels.

1979 ◽  
Author(s):  
H. C. Daudet ◽  
C. A. Kinney

This paper presents a discussion of the significant results of a study program conducted for the Department of Energy to evaluate the potential for closed cycle gas turbines and the associated combustion heater systems for use in coal fired public utility power plants. Two specific problem areas were addressed: (a) the identification and analysis of system concepts which offer high overall plant efficiency consistent with low cost of electricity (COE) from coal-pile-to-bus-bar, and (b) the identification and conceptual design of combustor/heat exchanger concepts compatible for use as the cycle gas primary heater for those plant systems. The study guidelines were based directly upon the ground rules established for the ECAS studies to facilitate comparison of study results. Included is a discussion of a unique computer model approach to accomplish the system analysis and parametric studies performed to evaluate entire closed cycle gas turbine utility power plants with and without Rankine bottoming cycles. Both atmospheric fluidized bed and radiant/convective combustor /heat exchanger systems were addressed. Each incorporated metallic or ceramic heat exchanger technology. The work culminated in conceptual designs of complete coal fired, closed cycle gas turbine power plants. Critical component technology assessment and cost and performance estimates for the plants are also discussed.


1995 ◽  
Vol 117 (1) ◽  
pp. 47-52 ◽  
Author(s):  
V. R. Dhole ◽  
J. P. Zheng

Pinch technology has developed into a powerful tool for thermodynamic analysis of chemical processes and associated utilities, resulting in significant energy savings. Conventional pinch analysis identifies the most economical energy consumption in terms of heat loads and provides practical design guidelines to achieve this. However, in analyzing systems involving heat and power, for example, steam and gas turbines, etc., pure heat load analysis is insufficient. Exergy analysis, on the other hand, provides a tool for heat and power analysis, although at times it does not provide clear practical design guidelines. An appropriate combination of pinch and exergy analysis can provide practical methodology for the analysis of heat and power systems. The methodology has been successfully applied to refrigeration systems. This paper introduces the application of a combined pinch and exergy approach to commercial power plants with a demonstration example of a closed-cycle gas turbine (CCGT) system. Efficiency improvement of about 0.82 percent (50.2 to 51.02 percent) can be obtained by application of the new approach. More importantly, the approach can be used as an analysis and screening tool for the various design improvements and is generally applicable to any commercial power generation facility.


Author(s):  
V.D. Molyakov ◽  
B.A. Kunikeev ◽  
N.I. Troitskiy

Closed-cycle gas turbine units can be used as power plants for advanced nuclear power stations, spacecraft, ground, surface and underwater vehicles. The purpose and power capacity of closed gas turbine units (CGTU) determine their specific design schemes, taking into account efficient operation of the units both in the nominal (design) mode and in partial power modes. Control methods of both closed and open gas turbine units depend on the scheme and design of the installation but the former differ from the latter mainly in their ability to change gas pressure at the entrance to the low-pressure compressor. This pressure can be changed by controlling the mass circulating in the CGTU circuit, adding or releasing part of the working fluid from the closed system as well as by internal bypassing of the working fluid. At a constant circulating mass in the single-shaft CGTU, the temperature of the gas before the turbines and the shaft speed can be adjusted depending on the type of load. The rotational speed of the turbine shaft, blocked with the compressor, can be adjusted in specific ways, such as changing the cross sections of the flow of the impellers. At a constant mass of the working fluid, the pressure at the entrance to the low-pressure compressor varies depending on the control program. The efficiency of the CGTU in partial power modes depends on the installation scheme, control method and program. The most economical control method is changing the pressure in the circuit. Extraction of the working fluid into special receivers while maintaining the same temperature in all sections of the unit leads to a proportional decrease in the density of the working fluid in all sections and the preservation of gas-dynamic similarity in the nodes (compressors, turbines and pipelines). Specific heat flux rates, and therefore, temperatures change slightly in heat exchangers. As the density decreases, heat fluxes change, as the heat transfer coefficient decreases more slowly than the density of the working fluid. With a decrease in power, this leads to a slight increase in the degree of regeneration and cooling in the heat exchangers. The underestimation of these phenomena in the calculations can be compensated by the underestimation of the growth of losses in partial power modes.


1966 ◽  
Vol 88 (4) ◽  
pp. 313-320 ◽  
Author(s):  
J. Smith ◽  
D. C. Strimbeck ◽  
N. H. Coates ◽  
J. P. McGee

Closed-cycle developments include tests of a turbocompressor with hydrodynamic gas bearings. The working fluid is inert gas, with turbine inlet temperatures to 1600 F. A refractory-metal turbine for tests at 1950 F is described. Open-cycle operations for 1963 hours with turbine blades specially designed to resist erosion by coal ash particles are described. Estimated life of the rotor and stator blading was 20,000 and 5000 hours, respectively. Efforts to increase blade life by reducing the amount of ash entering the turbine through improvements in combustion and ash separation systems are described.


1970 ◽  
Author(s):  
W. Endres

A short review of the state-of-the-art of the closed cycle gas turbine technology is given and the future requirements for large helium turbines are described. The necessary development of components and turbine sizes is outlined. In a second part of the paper the configuration and layout of power plants with gas turbines are discussed.


Author(s):  
I. G. Wright ◽  
J. Stringer

Considerable interest has been developed over the past few years in the application of gas turbines to expand the hot, dirty flue gases from pressurized fluidized-bed combustors (PFBCs) burning coal. Although no full-size gas turbine has yet operated on a PFBC, firm commitments have been made to build commercial PFBC-GT power plants. In addition, there are a number of projects at various stages of development aimed at operating gas turbines on dirty fuels ranging from the expansion of flue gas from the combustion of pulverized coal, to the direct firing of coal-water mixtures. Common concerns of all these applications include erosion and corrosion of the gas turbine hot gas path components. This paper attempts to provide an overview of results of research and testing so far reported in these areas, and to make an assessment of the engineering trade-offs required for the successful operation of PFBC gas turbine expanders.


Author(s):  
S. G. Liddle ◽  
B. B. Bonzo ◽  
G. P. Purohit

The idea of a coal-fired gas turbine locomotive dates back over a half century with significant developments being made in the decade between 1944 and 1955. These developments did not lead to a locomotive which could compete with the Diesel locomotive. Today, with the increase in the price of Diesel fuel, a new look at coal-fired gas turbines is appropriate. Advances in turbomachinery technology and new means of coal combustion may have made it possible to develop a competitive locomotive. Of the various combinations of combustors, cycles, and turbines, the external combustion, closed cycle regenerative gas turbine with a fluidized bed coal combustor appears to be the best suited to this application. The external combustion, open cycle regenerative gas turbine; and the internal combustion, open cycle regenerative gas turbine with a coal gasifier are the second and third choices.


1978 ◽  
Author(s):  
H. U. Frutschi

Spontaneous response to power demand is essential during autonomous operation of power plants. In this case, only control principles with negligible negative momentary effects can be employed. A further requirement is a good part-load efficiency. After a brief description of the most important control methods of closed-cycle gas turbines, the dynamic behavior of the cycle during gas injection for positive load changes is analyzed. A very attractive method is inter-compressor injection from an intermediate pressure reservoir which can be charged from the compressor exit during load reduction. Based on these results, a control system for closed-cycle gas turbine employing gas injection is presented.


Author(s):  
T. Schobeiri ◽  
H. Haselbacher

The design of modern gas turbines requires the predetermination of their dynamic behavior during transients of various kinds. This is especially true for air storage and closed cycle gas turbine plants. The present paper is an introduction to a computatational method which permits an accurate simulation of any gas turbine system. Starting with the conservation equations of aero/thermodynamics, the modular computer program COTRAN was developed, which calculates the transient behavior of individual components as well as of entire gas turbine systems. For example, it contains modules for compressors, turbines, combustion chambers, pipes etc. To demonstrate the effectiveness of COTRAN the shut-down tests of the air storage gas turbine plant Huntorf were simulated and results compared with experimental data. The agreement was found to be very good.


2002 ◽  
Vol 124 (06) ◽  
pp. 50-52
Author(s):  
Lee Longston

This article focuses on gas turbines that were produced in 2001 spanning a wide range of capacities. As the engineer's most versatile energy converters, gas turbines producing thrust power continued in 2001 to propel most of the world's aircraft, both military and commercial. The largest commercial jet engines today can produce as much as 120,000 pounds thrust, or some 534,000 Newton. More natural gas pipeline capacity will be added to feed the surge in gas-driven electric power plants that have been corning online in the United States and other parts of the world. The gas turbine may come to be used in a new, commercially promising closed-cycle configuration. A South African company has been working on plans to build and test a prototype of a closed-cycle electric power gas turbine, which uses helium gas as the working fluid and a helium-cooled nuclear reactor to provide heat to power the cycle. If the gas turbine-nuclear reactor power plant is successful, the gas turbine may be the key to yet another energy conversion device, as it has been with record-setting numbers of combined-cycle plants installed worldwide.


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