scholarly journals Internal Combustion Steam Cycle (G.I.S.T. Cycle): Thermodynamical Feasibility and Plant Lay-Out Proposals

Author(s):  
C. Caputo ◽  
M. Gambini ◽  
G. L. Guizzi

In this paper a new kind of steam cycle provided with internal combustion is proposed. The internal combustion of natural gas and compressed air inside the steam flow has been conceived to carry out a steam heating (SH a/o RH) until TIT (Turbine Inlet Temperature) much higher than those of the conventional steam power plants. By this internal combustion it seems possible to overcome the present limits to TIT in steam plants which are, as known, especially related to the technological problems of the superheater tube materials in the conventional external combustion steam boilers. The proposed cycle has been named with the acronym GIST (Gas Injection STeam) since the hot gases resulting from a combustion close to stechiometric conditions are injected inside the steam flow. This paper provides a first critical approach to these new kinds of thermodynamical cycles. At the first the thermodynamical and technological problems related to the combustion inside steam are explained and discussed. Then, different plant lay-out solutions are proposed with a critical discussion on their overall performance. At the last two GIST solution have been defined that seem very interesting: the first is an hybrid plant scheme (i.e. provided with multi-fuel supply) which involves performances higher than conventional steam power plants (net electric efficiency of about 47%); the second is a plant scheme with full natural gas supply (i.e. without multi-fuel steam boiler) wich involves very relevant performances (net electric efficiency of about 57%).

1979 ◽  
Vol 101 (4) ◽  
pp. 677-679
Author(s):  
N. Papageorgiou

An attractive and nontraditional method for water production is presented in this paper. The proposed method is to condense the exhaust gases of the natural gas fired steam generators of power plants. In order to achieve this, it is necessary that modification of the convectional steam power cycles be accomplished without sacrificing the efficiency of the power plants. An investigation and modification of the power cycles is proposed. Economic aspects are also considered.


Author(s):  
Sepehr Sanaye ◽  
Younes Hamzeie ◽  
Mohammad Reza Malekian ◽  
Mohammad Reza Sohrabi

There is a rapid growth of electricity consumption in the world. This problem needs enough resources for capital investment for construction of new power plants and/or making all efforts to increase the thermal efficiency of existing power generation cycles. Therefore this situation has lead power generation industries to repower and modify the existing steam power plants which are constructed in the recent three or four decades. In this paper an important method for repowering of old steam power plants which uses a gas turbine is analyzed. Hot Wind Box (HWB) repowering method was technically and economically evaluated to repower the Besat steam power plant. This power plant was constructed and exploited in 1967 in Tehran. The optimum design parameters such as gas turbine power output, compressor and turbine isentropic efficiency, pressure ratio, and the ratio of turbine inlet temperature to compressor inlet temperature were found by defining an objective function the total cost per unit of repowered plant power output and using numerical search optimization technique for its minimizing. The objective function, the total cost, included initial or capital investment, operation and maintenance costs during plant life cycle. The numerical values of optimum design parameters and the results of the sensitivity analysis are reported.


1979 ◽  
Author(s):  
Stewart Way

It is possible to gain 2 percent to 3 percent efficiency points in the MHD/steam combined cycle by application of a hot air turbocompressor. This gain is accomplished without any increase of air preheat temperature. Moreover, the size of the steam boiler and turbines in the bottom plant is reduced In the arrangement here proposed, all the compressed and preheated air expands through the turbine, rather than having a flow division as in older design concepts.


2009 ◽  
Vol 289-292 ◽  
pp. 413-420 ◽  
Author(s):  
F.J. Bolívar ◽  
L. Sánchez ◽  
M.P. Hierro ◽  
F.J. Pérez

The development of new power generation plants firing fossil fuel is aiming at achieving higher thermal efficiencies of the energy conversion process. The major factors affecting the efficiency of the conventional steam power plants are the temperature and, to a lesser extent, the pressure of the steam entering the turbine. The increased operating temperature and pressure require new materials that have major oxidation resistance. Due to this problem, in the last years numerous studies have been conducted in order to develop new coatings to enhance the resistance of steels with chromium contents between 9 and 12% wt against steam oxidation in order to allow operation of steam turbines at 650 0C. In this study, Si protective coatings were deposited by CVD-FBR on ferritic steel P-91. These type of coatings have shown to be protective at 650 0C under steam for at least 3000 hours of laboratory steam exposure under atmospheric pressure. Morphology and composition of coatings were characterized by different techniques, such as scanning electron microscopy (SEM), electron probe microanalysis, and X-ray diffraction (XRD). The results show a substantial increase of steam oxidation protection afforded by Si coating by CVD-FBR process.


Author(s):  
Anis Haj Ayed ◽  
Martin Kemper ◽  
Karsten Kusterer ◽  
Hailu Tadesse ◽  
Manfred Wirsum ◽  
...  

Increasing the efficiency of steam power plants is important to reduce their CO2 emissions and can be achieved by increasing steam temperatures beyond 700 °C. Within the present study, the thermal behavior of a steam by-pass valve subject to cyclic operation with 700 °C steam is investigated experimentally and numerically. An innovative numerical approach was applied to predict the valve’s thermal behavior during cyclic operation, which is essential for fatigue life assessment of such a component. Validation of the applied numerical approach has shown good agreement with measurement results, indicating the potential of its application for the valve design process.


1985 ◽  
Vol 107 (3) ◽  
pp. 569-573 ◽  
Author(s):  
C. M. Harman ◽  
S. Loesch

A method for increasing the peak output of steam power plants through use of a low-pressure feedwater storage system is presented. The generalized availability analysis involves only the low-pressure turbine, low-pressure feedwater heaters, and the storage system. With daily cycling and storage charging at near base load conditions, the turnaround efficiency of the energy storage system was found to approach 100 percent. Storage system turnaround efficiency is decreased when the energy is stored during plant part-load operation.


1959 ◽  
Vol 85 (1) ◽  
pp. 81-114
Author(s):  
R. D. Chellis ◽  
E. Ireland

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