Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
16,078
result(s) for
"CYCLE GAS"
Sort by:
Change is in the air : carbon, climate, Earth, and us
\"The Earth is facing a climate crisis that it can't fight on its own. Luckily, the Earth has another important power: the power of people! And people have the power to change, protect, innovate, and invent. Thanks to the power of nature and the ingenuity of people, change is in the air!\"-- Provided by publisher.
BOOK
The Impact of Retrofitting Natural Gas-Fired Power Plants on Carbon Footprint: Converting from Open-Cycle Gas Turbine to Combined-Cycle Gas Turbine
Since retrofitting existing natural gas-fired (NGF) power plants is an essential strategy for enhancing their efficiency and controlling greenhouse gas emissions, this paper compares the carbon footprint of natural gas-fired power generation from an NGF power plant in Brazil (BR-NGF) with and without retrofitting. The former scenario entails retrofitting the BR-NGF power plant with combined-cycle gas turbine (CCGT) technology. In contrast, the latter involves continuing the BR-NGF power plant operation with open-cycle gas turbine (OCGT) technology. Our analysis considers the BR-NGF power plant’s life cycle (construction, operation, and decommissioning) and the natural gas’ life cycle (natural gas extraction and processing, liquefaction, liquefied natural gas transportation, regasification, and combustion). Moreover, it is based on data from primary and secondary sources, mainly the Ecoinvent database and the ReCiPe 2016 method. For OCGT, the results showed that the BR-NGF power plant and the natural gas life cycles are responsible for 620.87 gCO2eq./kWh and 178.58 gCO2eq./kWh, respectively. For CCGT, these values are 450.04 gCO2eq./kWh and 129.30 gCO2eq./kWh. Our findings highlight the relevance of the natural gas’ life cycle, signaling additional opportunities for reducing the overall carbon footprint of natural gas-fired power generation.
Journal Article
Pet et Répète : la véritable histoire
\"Pet et Répète sont dans un bateau. Pet tombe à l'eau, qui est-ce qui reste? Répète...Pet et Répète sont dans un bateau. Pet tombe à l'eau, qui est-ce qui reste? Répète...Pet et Répète sont dans un bateau. Pet tombe à l'eau, qui est-ce qui reste? Répète...Vous en avez assez de cette question qui tourne en rond depuis trop longtemps? Faisons enfin place à la véritable histoire!\"--Back cover.
Book
Characterisation of gas turbine dynamics during frequency excursions in power networks
Gas turbines inherently depict unique frequency response characteristics compared with other conventional synchronous generation technologies as their active power output is not entirely determined by the governor response during frequency deviations of the power network. Thus, gas turbine dynamics significantly influence on system stability during frequency events in power networks. Power system and power plant operators require improved understanding of the gas turbine characteristics during various frequency events in order to mitigate adverse impact on power system. Therefore a comparative analysis has been performed between combined-cycle gas turbines (CCGTs) and open-cycle gas turbines (OCGTs) in order to characterise the dynamic behaviour considering different types of frequency events in power networks. Study has shown that CCGTs result in significant frequency variations in power networks in comparison with OCGTs because of the temperature control action performed by the fast acting inlet guide vanes at the combustor. In particular, they are susceptible to lean blowout during large frequency increase events such as short-circuit faults in power networks. Furthermore, a case study was developed based on the New England-39 bus system in order to illustrate the impact of gas turbine dynamics on network frequency during short-circuit events in power networks.
Journal Article
Probing the Financial Sustainability of Eskom’s Open Cycle Gas Turbines (OCGTs) Utilisation (2018–2021)
Contributing to achieving sustainability in South Africa’s energy sector, this study probes financial sustainability and its relationship to the environmental sustainability of Eskom. This is because, over the past three financial years (FY2018–2019 to FY2020–2021) of Eskom’s generating plants’ performance, the energy availability factor (EAF) has taken a deep dive, reaching an extremely low generation availability year-end performance of 64.2%, translating to approximately an average of 29,800 MW available generation capacity out of a nominal generation capacity of 46,466 MW in FY2020–2021. Therefore, the study employed a quantitative research methodology, where the relevant financial records were analysed, and the necessary energy calculations made using descriptive analysis in Microsoft Excel. The findings show that the volumes (GWh) produced by the OCGTs during this period far exceed the regulatory approved volumes, thus attracting substantial costs, amounting to ZAR 25.9 bn instead of ZAR 8.9 bn, that could have been spent on the OCGTs if the level of efficiency achieved in FY2016–2017 and FY2017–2018 was maintained. The analysis also revealed that the OCGTs’ long-term financial and environmental sustainability could be achieved through switching from diesel to natural gas, thus resulting in lower fuel costs and lower emissions. Further, potential savings of approximately ZAR 27 bn (excluding capital expenditure) at a 10% load factor can be realised over a ten-year period when the natural gas price is sitting at ZAR 85/GJ (minimum). Finally, in order to attain financial and environmental sustainability, it is recommended that both Eskom’s and the independent power producers’ (IPPs) OCGTs must switch fuel from diesel to natural gas and be run at a 10% load factor, allowing the OCGTs to be run as mid-merit generators.
Journal Article
Technical and Economic Analysis of the Supercritical Combined Gas-Steam Cycle
Combined cycle power plants are characterized by high efficiency, now exceeding 60%. The record-breaking power plant listed in the Guinness Book of World Records is the Nishi-Nagoya power plant commissioned in March 2018, located in Japan, and reaching the gross efficiency of 63.08%. Research and development centers, energy companies, and scientific institutions are taking various actions to increase this efficiency. Both the gas turbine and the steam turbine of the combined cycle are modified. The main objective of this paper is to improve the gas-steam cycle efficiency and to reach the efficiency that is higher than in the record-breaking Nishi-Nagoya power plant. To do so, a number of numerical calculations were performed for the cycle design similar to the one used in the Nishi-Nagoya power plant. The paper assumes the use of the same gas turbines as in the reference power plant. The process of recovering heat from exhaust gases had to be organized so that the highest capacity and efficiency were achieved. The analyses focused on the selection of parameters and the modification of the cycle design in the steam part area in order to increase overall efficiency. As part of the calculations, the appropriate selection of the most favorable thermodynamic parameters of the steam at the inlet to the high-pressure (HP) part of the turbine (supercritical pressure) allowed the authors to obtain the efficiency and the capacity of 64.45% and about 1.214 GW respectively compared to the reference values of 63.08% and 1.19 GW. The authors believe that efficiency can be improved further. One of the methods to do so is to continue increasing the high-pressure steam temperature because it is the first part of the generator into which exhaust gases enter. The economic analysis revealed that the difference between the annual revenue from the sale of electricity and the annual fuel cost is considerably higher for power plants set to supercritical parameters, reaching approx. USD 14 million per annum. It is proposed that investments in adapting components of the steam part to supercritical parameters may be balanced out by a higher profit.
Journal Article
Energy and Exergy Analysis on a Blast Furnace Gas-Driven Cascade Power Cycle
Blast furnace gas is the major combustible by-product produced in the steel industry, where iron ore is reduced by coke into iron. Direct combustion of blast furnace gas after simple treatment for power generation is a common utilization method nowadays. However, this method suffers from low efficiency and high carbon intensity. The use of gas-steam combined cycle is an excellent method to improve the efficiency of blast furnace gas for power generation. However, there is a problem of insufficient utilization of low product heat, and the addition of CCS system can further reduce the power efficiency. To solve these issues, a new blast furnace gas power generation system with a Brayton cycle with supercritical CO2 and a Rankine cycle with transcritical CO2 is proposed in this work. The new system is then thermodynamically simulated by Aspen Plus, after the sub-modules are validated. The effects of molar ratio of steam to carbon, selexol/CO2 mass ratio, compression ratio, turbine import temperature and turbine inlet pressure on the system are investigated. A comparison is also performed between the new combined cycle system and the traditional combined cycle power generation system. The results show that in the new power generation system, net power efficiency of 53.29%, carbon capture efficiency of 95.78% and sulfur capture rate of 94.46% can be achieved, which is significantly better than the performance of the conventional combined cycle.
Journal Article
Research and Development of Trinary Power Cycles
The most effective and environmentally safe fossil fuel power production facilities are the combined cycle gas turbine (CCGT) ones. Electric efficiency of advanced facilities is up to 58% in Russia and up to 64% abroad. The further improvement of thermal efficiency by increase of the gas turbine inlet temperature (TIT) is limited by performance of heat resistance alloys that are used for the hot gas path components and the cooling system efficiency. An alternative method for the CCGT efficiency improvement is utilization of low potential heat of the heat recovery steam generator (HRSG) exhaust gas in an additional cycle operating on a low-boiling heat carrier. This paper describes a thermodynamic analysis of the transition from binary cycles to trinary ones by integration of the organic Rankine cycle (ORC). A mathematical model of a cooled gas turbine plant (GT) has been developed to carry out calculations of high-temperature energy complexes. Based on the results of mathematical modeling, recommendations were made for the choice of the structure and parameters of the steam turbine cycle, as well as the ORC, to ensure the achievement of the maximum thermal efficiency of trinary plants. It is shown that the transition from a single pressure CCGT to a trinary plant allows the electric power increase from 213.4 MW to 222.7 MW and the net efficiency increase of 2.14%. The trinary power facility has 0.45% higher efficiency than the dual pressure CCGT.
Journal Article
Simulation and comprehensive study of a new trigeneration process combined with a gas turbine cycle, involving transcritical and supercritical CO2 power cycles and Goswami cycle
This study introduces and evaluates an innovative combined cooling, heating, and power (CCHP) system integrating a gas turbine cycle with transcritical and supercritical CO
2
cycles, a high-pressure steam cycle, a Goswami cycle, and a heating terminal. The primary objective is to enhance the thermodynamic efficiency and reduce the environmental impact of power generation. Through detailed exergy and energy analyses, we assessed the system’s performance and compared it with traditional energy systems. The methodology included evaluating the irreversibility within each component, particularly highlighting the gas turbine cycle’s significant share of irreversibility at 67% and the chamber’s highest exergy destruction. Our findings reveal that the integrated system achieves total energy, exergy, and electrical efficiencies of 68.83%, 34.63%, and 33.55%, respectively, while significantly reducing CO
2
emissions to 0.298 kg
CO2
/kWh—outperforming coal, oil, and natural gas power plants in environmental sustainability. Furthermore, the integrated CCHP system showcases superior thermodynamic performance by achieving higher efficiency rates compared to existing solutions detailed in recent studies, thereby marking a significant step forward in the development of sustainable power generation technologies. This research underscores the potential of integrating transcritical and supercritical CO
2
cycles with gas turbines to meet energy demands more efficiently and eco-consciously.
Journal Article
Comparative Life-Cycle Assessment of Electricity-Generation Technologies: West Texas Case Study
This comparison of five power plants in West Texas is intended to provide various decision-makers and stakeholders with a holistic picture of the life-cycle environmental impacts associated with these power plants. A key contribution of this analysis is that we assumed all power plants generate the same amount of electricity over a 30-year life, taking a 500 MW combined-cycle gas turbine (CCGT) plant as a benchmark. Also, in two cases, we added battery storage to wind and solar PV facilities to render them nearly as dispatchable as the CCGT. We included the entire supply chain supporting electricity generation, which encompassed raw material sourcing, processing, manufacturing, operations, and product end of life, also called “cradle to grave”. We report on 18 environmental impacts using ReCiPe midpoint (H) impact assessment. The supply chains are global, and impacts are felt differently by host communities across the world. The results can help stakeholders identify hotspots across numerous supply chains with the highest environmental impacts. We discuss some remedial measures and challenges to inform future analysis by the research community.
Journal Article