Reduction of Combustion Irreversibility in a Gas Turbine Power Plant Through Off-Gas Recycling

1995 ◽  
Vol 117 (1) ◽  
pp. 24-30 ◽  
Author(s):  
S. P. Harvey ◽  
K. F. Knoche ◽  
H. J. Richter
Keyword(s):  
Gas Turbine ◽  
Conversion Efficiency ◽  
Power Plants ◽  
High Efficiency ◽  
Energy Conversion Efficiency ◽  
Power Cycles ◽  
Exhaust Gases ◽  
Exhaust Heat ◽  
Simplifying Assumptions ◽  
Overall Efficiency

Combustion in conventional fossil-fueled power plants is highly irreversible, resulting in poor overall energy conversion efficiency values (less than 40 percent in many cases). The objective of this paper is to discuss means by which this combustion irreversibility might be reduced in gas turbine power cycles, and the conversion efficiency thus improved upon. One such means is thermochemical recuperation of exhaust heat. The proposed cycle recycles part of the exhaust gases, then mixes them with fuel prior to injection into a reformer. The heat required for the endothermic reforming reactions is provided by the hot turbine exhaust gases. Assuming state-of-the-art technology, and making a number of simplifying assumptions, an overall efficiency of 65.4 percent was attained for the cycle, based on the lower heating value (LHV) of the methane fuel. The proposed cycle is compared to a Humid Air Turbine (HAT) cycle with similar features that achieves an overall efficiency of 64.0 percent. The gain in cycle efficiency that can be attributed to the improved fuel oxidation process is 1.4 percentage points. Compared to current high-efficiency gas turbine cycles, the high efficiency of both cycles studied therefore results mainly from the use of staged compression and expansion with intermediate cooling and reheating, respectively.

FEATURES OF THE METHODOLOGY OF THERMODYNAMIC MODELING OF GAS TURBINE AND COMBINED ON THEIR BASIS POWER PLANTS

2017 ◽  
Author(s):  
Gennadii Liubchik ◽  
◽  
Nataliia Fialko ◽  
Aboubakr Regragui ◽  
Julii Sherenkovskii ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Thermodynamic Modeling ◽  
Power Plants ◽  
High Efficiency ◽  
Technical Facility

The article presents the enthalpy-entropy methodology of thermodynamic analysis of gas turbine and combined power plants on their basis, the results of testing the method on a real technical facility, proving its high efficiency.

Water Production from Exhaust Gases of Steam Power Plants

1979 ◽  
Vol 101 (4) ◽  
pp. 677-679
Author(s):  
N. Papageorgiou
Keyword(s):  
Natural Gas ◽  
Power Plants ◽  
Water Production ◽  
Economic Aspects ◽  
Steam Generators ◽  
Steam Power ◽  
Power Cycles ◽  
Exhaust Gases ◽  
Steam Power Plants ◽  
Nontraditional Method

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.

scholarly journals Thermodynamic Cycle Concepts for High-Efficiency Power Plans. Part A: Public Power Plants 60+

2019 ◽  
Vol 11 (2) ◽  
pp. 554 ◽  
Author(s):  
Krzysztof Kosowski ◽  
Karol Tucki ◽  
Marian Piwowarski ◽  
Robert Stępień ◽  
Olga Orynycz ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Carbon Dioxide Emissions ◽  
Power Plants ◽  
High Efficiency ◽  
Thermodynamic Cycle ◽  
Economic Resilience ◽  
Public Power ◽  
Pass System ◽  
Classical Gas ◽  
Gas Turbine Cycle

An analysis was carried out for different thermodynamic cycles of power plants with air turbines. Variants with regeneration and different cogeneration systems were considered. In the paper, we propose a new modification of a gas turbine cycle with the combustion chamber at the turbine outlet. A special air by-pass system of the combustor was applied and, in this way, the efficiency of the turbine cycle was increased by a few points. The proposed cycle equipped with a regenerator can provide higher efficiency than a classical gas turbine cycle with a regenerator. The best arrangements of combined air–steam cycles achieved very high values for overall cycle efficiency—that is, higher than 60%. An increase in efficiency to such degree would decrease fuel consumption, contribute to the mitigation of carbon dioxide emissions, and strengthen the sustainability of the region served by the power plant. This increase in efficiency might also contribute to the economic resilience of the area.

Comparative Analysis of Conventional and Fuel Cell-Based Gas Turbine Power Plants

2013 ◽  
Author(s):  
Mohamed Gadalla ◽  
Nabil Al Aid
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Power Plants ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Integrated System ◽  
Power Cycles ◽  
Technical Management ◽  
Advantages And Disadvantages ◽  
Gas Turbine Power Plant

The purpose of this paper is to conduct a complete comparative, energy and 2nd low analyses between different types of fuel cells integrated with a gas turbine power plant. Different levels of modeling for the solid oxide fuel cell (SOFC), the proton exchange membrane fuel cell (PEMFC) and the integrated systems are to be presented. The overall system performance is analyzed by employing individual models and further applying energy and exergetic analyses for different configurations of gas turbine power cycles. The study includes applying different proposed methods and techniques to enhance the overall efficiency of the integrated cycle. After performing the complete technical management of the complete system, a comparative study between conventional and PEMFC and SOFC cycles is investigated to highlight the corresponding advantages and disadvantages of each system. The following systems are tested and evaluated: (a) Conventional Gas Turbine System with a combustion Chamber (b) Integrated SOFC Stack into a Gas Turbine System (c) The Proposed Integrated System with both SOFC and PEMFC.

Multimaterial Topology Optimization of Thermoelectric Generators

2019 ◽  
Author(s):  
Xiaoqiang Xu ◽  
Yongjia Wu ◽  
Lei Zuo ◽  
Shikui Chen
Keyword(s):  
Topology Optimization ◽  
Conversion Efficiency ◽  
Thermoelectric Materials ◽  
Power Plants ◽  
High Efficiency ◽  
Waste Heat ◽  
Computational Simulation ◽  
Oil Refining ◽  
Temperature Range ◽  
Multiple Materials

Abstract Over 50% of the energy from power plants, vehicles, oil refining, and steel or glass making process is released to the atmosphere as waste heat. As an attempt to deal with the growing energy crisis, the solid-state thermoelectric generator (TEG), which converts the waste heat into electricity using Seebeck phenomenon, has gained increasing popularity. Since the figures of merit of the thermoelectric materials are temperature dependent, it is not feasible to achieve high efficiency of the thermoelectric conversion using only one single thermoelectric material in a wide temperature range. To address this challenge, this paper proposes a method based on topology optimization to optimize the layouts of functional graded TEGs consisting of multiple materials. The objective of the optimization problem is to maximize the output power and conversion efficiency as well. The proposed method is implemented using the Solid Isotropic Material with Penalization (SIMP) method. The proposed method can make the most of the potential of different thermoelectric materials by distributing each material into its optimal working temperature interval. Instead of dummy materials, both the P and N-type electric conductors are optimally distributed with two different practical thermoelectric materials, namely Bi2Te3 & PbTe for P-type, and Bi2Te3 & CoSb3 for N-type respectively, with the yielding conversion efficiency around 12.5% in the temperature range Tc = 25°C and Th = 400°C. In the 2.5D computational simulation, however, the conversion efficiency shows a significant drop. This could be attributed to the mismatch of the external load and internal TEG resistance as well as the grey region from the topology optimization results as discussed in this paper.

Enhancing Gas Turbine Operation With Heavy Fuel Oil

2013 ◽  
Author(s):  
Vikram Muralidharan ◽  
Matthieu Vierling
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
Combined Cycle ◽  
Fuel Oil ◽  
Residual Oil ◽  
Heavy Fuel Oil ◽  
Hydro Power

Power generation in south Asia has witnessed a steep fall due to the shortage of natural gas supplies for power plants and poor water storage in reservoirs for low hydro power generation. Due to the current economic scenario, there is worldwide pressure to secure and make more gas and oil available to support global power needs. With constrained fuel sources and increasing environmental focus, the quest for higher efficiency would be imminent. Natural gas combined cycle plants operate at a very high efficiency, increasing the demand for gas. At the same time, countries may continue to look for alternate fuels such as coal and liquid fuels, including crude and residual oil, to increase energy stability and security. In over the past few decades, the technology for refining crude oil has gone through a significant transformation. With the advanced refining process, there are additional lighter distillates produced from crude that could significantly change the quality of residual oil used for producing heavy fuel. Using poor quality residual fuel in a gas turbine to generate power could have many challenges with regards to availability and efficiency of a gas turbine. The fuel needs to be treated prior to combustion and needs a frequent turbine cleaning to recover the lost performance due to fouling. This paper will discuss GE’s recently developed gas turbine features, including automatic water wash, smart cooldown and model based control (MBC) firing temperature control. These features could significantly increase availability and improve the average performance of heavy fuel oil (HFO). The duration of the gas turbine offline water wash sequence and the rate of output degradation due to fouling can be considerably reduced.

A Recuperated Gas Turbine Incorporating External Heat Sources in the Combined Gas-Steam Cycle

2000 ◽  
Author(s):  
Ryszard Chodkiewicz ◽  
Jan Krysinski ◽  
Jerzy Porochnicki
Keyword(s):  
Gas Turbine ◽  
High Efficiency ◽  
Waste Heat ◽  
New Technology ◽  
Industrial Process ◽  
Energy System ◽  
Heat Sources ◽  
Exhaust Gases ◽  
Useful Heat ◽  
Steam Cycle

The recuperation by means of external waste heat sources, as opposed to the recuperation of the turbine exhaust gases (to preheat the compressed air), allows one to utilize the hot exhaust gases of the gas turbine in the bottoming steam cycle to produce steam in order to generate additional power. Such a combined gas/steam energy system, closely integrated with the industrial process, can produce electric power (and useful heat) with high efficiency and very low atmospheric air pollution. In the present paper two examples of applications of this new technology have been analyzed from the economic and ecological viewpoint.

Analysis of Electrochemical Performance and Exergy Loss in Solid Oxide Fuel Cell

2003 ◽  
Author(s):  
Kousuke Nishida ◽  
Toshimi Takagi ◽  
Shinichi Kinoshita
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
High Efficiency ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Exergy Loss ◽  
Oxide Fuel ◽  
Electrode Reactions ◽  
Exhaust Heat

A solid oxide fuel cell (SOFC) is expected to be applied to the distributed energy systems because of its high thermal efficiency and exhaust gas utilization. The exhaust heat from the SOFC can be transferred to the electric power by a gas turbine, and the high efficiency power generation can be achieved by constructing the SOFC and gas turbine hybrid system. In this study, the local processes in the electrodes and electrolyte of unit SOFC are analyzed taking into account the heat conduction, mass diffusion, electrode reactions and the transport of electron and oxygen ion. The temperature and concentration distributions perpendicular to the electrolyte membrane are shown. The effects of the operating conditions on the cell performance are also shown. Furthermore, the entropy generation and exergy loss of each process in the electrodes and electrolyte are analyzed and the reason for generating the exergy loss in the SOFC is clarified. It is noted that two electrode reactions are responsible for the major exergy loss.

scholarly journals Assessment on Energy Conversion Efficiency and GHG Emissions Rate for Coal, Natural Gas and Biomass Power Plant in Malaysia

2021 ◽  
Vol 87 (2) ◽  
pp. 145-153
Author(s):  
Radin Diana R. Ahmad ◽  
Tiong Sieh Kiong ◽  
Sazalina Zakaria ◽  
Ahmad Rosly Abbas ◽  
Chen Chai Phing ◽  
...  
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Power Plants ◽  
Emission Rate ◽  
Energy Conversion Efficiency ◽  
Combined Cycle ◽  
Gas Power Plant ◽  
Biomass Power Plant

Three different power plants have been assessed in terms of energy conversion efficiency and GHGs emission rate. The power plants are coal power plant, natural gas power plant and biomass power plant. The assessments are made by collecting fuels consumption data and generated electricity data of each power plant. In addition to the data collection, observation on operational practices have also been carried out. The energy conversion efficiency and the GHGs emission rate for all power plants are recorded to be lower than the typical values proposed by the literature. The biomass power plant recorded the lowest energy conversion efficiency at 6.47 %. Meanwhile, the natural gas power plant utilizing the combined cycle gas turbine technology recorded the highest overall energy conversion efficiency at 48.35 % and rated to emit GHGs at 0.32 kg CO2e per kWh.

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