Prediction of Gas Turbine On- and Off-Design Performance When Firing Coal-Derived Syngas

1992 ◽  
Vol 114 (2) ◽  
pp. 380-385 ◽  
Author(s):  
M. S. Johnson

This paper describes a procedure used to model the performance of gas turbines designed to fire natural gas (or distillate oil) when fired on medium-Btu fuel, such as coal-derived syngas. Results from such performance studies can be used in the design or analysis of Gasification Combined Cycle (GCC) power plants. The primary difficulty when firing syngas in a gas turbine designed for natural gas is the tendency to drive the compressor toward surge. If the gas turbine has sufficient surge margin and mechanical durability, Gas Turbine Evaluation code (GATE) simulations indicate that net output power can be increased on the order of 15 percent when firing syngas due to the advantageous increase in the ratio of the expander-to-compressor mass flow rates. Three classes of single-spool utility gas turbines are investigated spanning firing temperatures from 1985°F-2500°F (1358 K-1644 K). Performance simulations at a variety of part-load and ambient temperature conditions are described; the resulting performance curves are useful in GCC power plant studies.

Author(s):  
Mark S. Johnson

This paper describes a procedure used to model the performance of gas turbines designed to fire natural gas (or distillate oil) when fired on medium-BTU fuel, such as coal-derived syngas. Results from such performance studies can be used in the design or analysis of Gasification Combined-Cycle (GCC) power plants. The primary difficulty when firing syngas in a gas turbine designed for natural gas is the tendency to drive the compressor toward surge. If the gas turbine has sufficient surge margin and mechanical durability, Gas Turbine Evaluation code (GATE) simulations indicate that net output power can be increased on the order of 15% when firing syngas due to the advantageous increase in the ratio of the expander-to-compressor mass flow rates. Three classes of single-spool utility gas turbines are investigated spanning firing temperatures from 1985 F to 2500 F (1358 K to 1644 K). Performance simulations at a variety of part-load and ambient temperature conditions are described; the resulting performance curves are useful in GCC power plant studies.


2013 ◽  
Vol 135 (02) ◽  
pp. 30-35
Author(s):  
Lee S. Langston

This article presents a study on new electric power gas turbines and the advent of shale natural gas, which now are upending electrical energy markets. Energy Information Administration (EIA) results show that total electrical production cost for a conventional coal plant would be 9.8 cents/kWh, while a conventional natural gas fueled gas turbine combined cycle plant would be a much lower at 6.6 cents/kWh. Furthermore, EIA estimates that 70% of new US power plants will be fueled by natural gas. Gas turbines are the prime movers for the modern combined cycle power plant. On the natural gas side of the recently upended electrical energy markets, new shale gas production and the continued development of worldwide liquefied natural gas (LNG) facilities provide the other element of synergism. The US natural gas prices are now low enough to compete directly with coal. The study concludes that the natural gas fueled gas turbine will continue to be a growing part of the world’s electric power generation.


2015 ◽  
Vol 137 (12) ◽  
pp. 54-55
Author(s):  
Lee S. Langston

This article explains how combined cycle gas turbine (CCGT) power plants can help in reducing greenhouse gas from the atmosphere. In the last 25 years, the development and deployment of CCGT power plants represent a technology breakthrough in efficient energy conversion, and in the reduction of greenhouse gas production. Existing gas turbine CCGT technology can provide a reliable, on-demand electrical power at a reasonable cost along with a minimum of greenhouse gas production. Natural gas, composed mostly of methane, is a hydrocarbon fuel used by CCGT power plants. Methane has the highest heating value per unit mass of any of the hydrocarbon fuels. It is the most environmentally benign of fuels, with impurities such as sulfur removed before it enters the pipeline. If a significant portion of coal-fired Rankine cycle plants are replaced by the latest natural gas-fired CCGT power plants, anthropogenic carbon dioxide released into the earth’s atmosphere would be greatly reduced.


Author(s):  
Anup Singh

In the 1970s, power generation from gas turbines was minimal. Gas turbines in those days were run on fuel oil, since there was a so-called “natural gas shortage”. The U.S. Fuel Use Act of 1978 essentially disallowed the use of natural gas for power generation. Hence there was no incentive on the part of gas turbine manufacturers to invest in the development of gas turbine technology. There were many regulatory developments in the 1980s and 1990s, which led to the rapid growth in power generation from gas turbines. These developments included Public Utility Regulatory Policy Act of 1978 (encouraging cogeneration), FERC Order 636 (deregulating natural gas industry), Energy Policy Act of 1992 (creating EWGs and IPPs) and FERC Order 888 (open access to electrical transmission system). There was also a backlash from excessive electric rates due to high capital recovery of nuclear and coal-fired plant costs caused by tremendous cost increase resulting from tightening NRC requirements for nuclear plants and significant SO2/NOx/other emissions controls required for coal-fired plants. During this period, rapid technology developments took place in the metallurgy, design, efficiency, and reliability of gas turbines. In addition, U.S. DOE contributed to these developments by encouraging research and development efforts in high temperature and high efficiency gas turbines. Today we are seeing a tremendous explosion of power generating facilities by electric utilities and Independent Power Producers (IPPs). A few years ago, Merchant Power (generation without power purchase agreements) was unheard of. Today it is growing at a very fast pace. Can this rapid growth be sustained? The paper will explore the factors that will play a significant role in the future growth of gas turbine-based power generation in the U.S. The paper will also discuss the methods and developments that could decrease the capital costs of gas turbine power plants resulting in the lowest cost generation compared to other power generation technologies.


2020 ◽  
Vol 5 (1) ◽  
pp. 066-075
Author(s):  
Ebigenibo Genuine Saturday ◽  
Celestine Ebieto Ebieto

Several cases of the need for continuous utilization of gas turbines for power production and why gas turbines will be relevant in the next 50 years in the Nigerian power sector are presented in this paper. Using 7 criteria; the cost of installation, operation and maintenance costs, levelized cost of electricity, capacity factor, the efficiency of energy conversion, power to size ratio/area coverage and environmental pollution, gas turbine operation was compared with wind and solar energy technologies. Gas turbine for power production appears to be more favourable in 5 out of the 7 criteria including lower installation cost which is a very important factor for poor and developing nations like Nigeria. The quantity of fuel for producing different quantities of power using gas turbines was estimated. Nigeria has huge proven reserves of natural gas which is the fuel for gas turbines. If we go for combined cycle power plants which have low specific fuel consumption (SFC), 50% of the natural gas reserves are enough to produce some 35 GW of electricity for over 50 years. The current rate of natural gas production can produce 27.06 GW of electricity at 0.06kg/s.MW sfc. It was also observed that the current installed power from gas turbines is too low compared to the power demand; hence, further installations are required. Pollution should not be an issue in installing more gas turbine plants because the gas turbine is a clean-burning engine and the present installed capacity is insignificant compared to what is obtainable in some advanced nations. The results in this work will guide gas turbine operators in planning for further installation of gas turbine power plants. The study does not rule out the need to exploit solar photovoltaic system and wind turbines in areas with high sunshine and high wind speeds respectively, for off-grid power production.


Author(s):  
V. A. Bulanin

Abstract. Aim. Despite the obvious expediency of their widespread implementation, gas turbine (GT) and combined cycle gas turbine (CCGT) plants were only used in limited quantities in the former USSR and CIS countries. Due to the exhaustion of possibilities to increase the fuel use efficiency and return on investment (ROI) in steam-turbine combined heat and power (CHP) plants, the development of GT and CCGT plants becomes an urgent problem. In current global practice, the primary fuel for gas turbines and combined cycle gas turbines is natural gas. However, until recently, there has been a lack of experience in the design, construction and operation of GT and CCGT plants in the CIS countries. Method. Due to the ad hoc nature of research in this area, it was necessary to systematise the results of existing studies and assess the state of research at the world level taking regional characteristics into account. Results. The article presents the main considerations and potential effectiveness of the use of gas turbines. Basic gas turbine construction schemes are investigated along with their techno-economic characteristics and an assessment of their comparative utility. Conclusion. Considering the widespread availability of natural gas, it is recommended that gas turbine and combined-cycle plants be installed as part of the process of technical re-equipment in the fuel and energy complex, industry, agriculture and municipal energy sectors as part of the design and construction of new energy sources in the light of positive world experience and the current level of development of gas turbine technologies. Ubiquitous implementation of gas turbine units in the centres supplying heat and electric loads will reduce the regional economy’s need for energy fuel and ensure an increase in energy capacity without the need to construct new complex and uneconomic steam turbine power plants. 


Author(s):  
Nikolett Sipöcz ◽  
Klas Jonshagen ◽  
Mohsen Assadi ◽  
Magnus Genrup

The European electric power industry has undergone considerable changes over the past two decades as a result of more stringent laws concerning environmental protection along with the deregulation and liberalization of the electric power market. However, the pressure to deliver solutions in regard to the issue of climate change has increased dramatically in the last few years and has given rise to the possibility that future natural gas-fired combined cycle (NGCC) plants will also be subject to CO2 capture requirements. At the same time, the interest in combined cycles with their high efficiency, low capital costs, and complexity has grown as a consequence of addressing new challenges posed by the need to operate according to market demand in order to be economically viable. Considering that these challenges will also be imposed on new natural gas-fired power plants in the foreseeable future, this study presents a new process concept for natural gas combined cycle power plants with CO2 capture. The simulation tool IPSEpro is used to model a 400 MW single-pressure NGCC with post-combustion CO2 capture using an amine-based absorption process with monoethanolamine. To improve the costs of capture, the gas turbine GE 109FB is utilizing exhaust gas recirculation, thereby, increasing the CO2 content in the gas turbine working fluid to almost double that of conventional operating gas turbines. In addition, the concept advantageously uses approximately 20% less steam for solvent regeneration by utilizing preheated water extracted from heat recovery steam generator. The further recovery of heat from exhaust gases for water preheating by use of an increased economizer flow results in an outlet stack temperature comparable to those achieved in combined cycle plants with multiple-pressure levels. As a result, overall power plant efficiency as high as that achieved for a triple-pressure reheated NGCC with corresponding CO2 removal facility is attained. The concept, thus, provides a more cost-efficient option to triple-pressure combined cycles since the number of heat exchangers, boilers, etc., is reduced considerably.


Author(s):  
Mun Roy Yap ◽  
Ting Wang

Biomass can be converted to energy via direct combustion or thermo-chemical conversion to liquid or gas fuels. This study focuses on burning producer gases derived from gasifying biomass wastes to produce power. Since the producer gases are usually low calorific values (LCV), the power plants performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for 5MWe power plants. The power plants considered include simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems (STIG) using the producer gas with low calorific values at approximately 30% and 15% of the natural gas heating value (on a mass basis). The LCV fuels are shown to impose high back compressor pressure and produces increased power output due to increased fuel flow. Turbine nozzle throat area is adjusted to accommodate additional fuel flows to allow compressor operate within safety margin. The best performance occurs when the designed pressure ratio is maintained by widening nozzle openings, even though the TIT is reduced under this adjustment. Power augmentations under four different ambient conditions are calculated by employing gas turbine inlet fog cooling. Comparison between inlet fog cooling and steam injection using the same amount of water mass flow indicates that steam injection is less effective than inlet fog cooling in augmenting power output. Maximizing steam injection, at the expense of supplying the steam to the steam turbine, significantly reduces both the efficiency and the output power of the combined cycle. This study indicates that the performance of gas turbine and combined cycle systems fueled by the LCV fuels could be very different from the familiar behavior of natural gas fired systems. Care must be taken if on-shelf gas turbines are modified to burn LCV fuels.


Author(s):  
Nikolett Sipo¨cz ◽  
Klas Jonshagen ◽  
Mohsen Assadi ◽  
Magnus Genrup

The European electric power industry has undergone considerable changes over the past two decades as a result of more stringent laws concerning environmental protection along with the deregulation and liberalization of the electric power market. However, the pressure to deliver solutions in regard to the issue of climate change has increased dramatically in the last few years and given the rise to the possibility that future natural gas-fired combined cycle (NGCC) plants will also be subject to CO2 capture requirements. At the same time, the interest in combined cycles with their high efficiency, low capital costs and complexity has grown as a consequence of addressing new challenges posed by the need to operate according to market demand in order to be economically viable. Considering that these challenges will also be imposed on new natural gas-fired power plants in the foreseeable future, this study presents a new process concept for natural gas combined cycle power plants with CO2 capture. The simulation tool IPSEpro is used to model a 400 MW single-pressure NGCC with post-combustion CO2 capture, using an amine-based absorption process with Monoethanolamine. To improve the costs of capture the gas turbine, GE 109FB, is utilizing exhaust gas recirculation, thereby increasing the CO2 content in the gas turbine working fluid to almost double that of conventional operating gas turbines. In addition, the concept advantageously uses approximately 20% less steam for solvent regeneration by utilizing preheated water extracted from HRSG. The further recovery of heat from exhaust gases for water preheating by use of an increased economizer flow results in an outlet stack temperature comparable to those achieved in combined cycle plants with multiple pressure levels. As a result, overall power plant efficiency as high as that achieved for a triple-pressure reheated NGCC with corresponding CO2 removal facility is attained. The concept thus provides a more cost-efficient option to triple-pressure combined cycles since the number of heat exchangers, boilers, etc. is reduced considerably.


Author(s):  
Peter J. Stuttaford ◽  
Khalid Oumejjoud

CO2 emissions generated by power plants make up a significant portion of global carbon emissions. Although there has been a great deal of focus on new power sources incorporating state of the art environmental protection systems, there has been little focus on addressing the issues of existing power plants. The purpose of this work is to address the options available to existing gas turbine based power plants to retrofit CO2 reduction measures cost effectively at the source of emissions, the combustor. Pre-combustion decarbonization is a highly efficient method of carbon removal, as only a small fraction of the gas turbine system flow needs to be addressed. This results in the requirement to burn a hydrogen based fuel, which presents challenges due to its highly reactive nature. The properties of hydrogen/syngas combustion are reviewed with emphasis on solutions for premixed combustion systems. Premixed combustion as opposed to diffusion combustion systems are key to retrofit solutions for existing gas turbines. Premixed systems provide the life cycle cost benefit, and heat rate benefit of not requiring the addition of diluent to the cycle to control emissions. Fuel flexibility is critical for retrofit systems, allowing operators to run on high hydrogen fuels as well as back-up standard natural gas to maximize power plant availability. Pre-combustion decarbonization may occur remote from the power plant at a centralized fuel processing facility, or it may be integrated into the combined cycle gas turbine power plant. Existing combined cycle power plants operating on natural gas could be modified to incorporate fuel decarbonization into the cycle, minimizing the parasitic loss of such a system while capturing carbon credits which are likely to become of increasing monetary value. An example cycle to address such integrated systems is presented. The focus of this work is to present a cycle to provide decarbonized fuel, cost effectively, from existing natural gas systems, as well as centralized coal/petcoke based fuel processing facilities. An additional focus is on the combustion system design requirements to burn such fuels, which are retrofitable to existing heavy duty gas turbine based power plants.


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