CO2 Emission Abatement in CC-IGCC Power Plants: Energy and Economic Comparisons

Author(s):  
Marco Gambini ◽  
Michela Vellini

In this paper two methodologies, able to avoid CO2 dispersion in atmosphere, have been analyzed: • treating exhaust gases in order to remove, liquefy and store the produced carbon dioxide; • de-carbonizing fossil fuels before using them in the combustion in order to inhibit completely carbon dioxide production. These methodologies have been implemented in advanced power plants based on gas turbine: a combined cycle power plant (CC), fed by natural gas, and an integrated gasification combined cycle (IGCC), fed by coal. The exhaust gas treatment is based on a chemical process of absorption, while the fossil fuel decarbonization is based on partial oxidation of methane, steam methane reforming and coal gasification. These systems require material and energetic integrations with the power sections and so the best interconnections must be investigated in order to obtain good overall performance. With reference to thermodynamic and economic performance, significant comparisons have been made between the above mentioned reference plants. An efficiency decrease and an increase in the cost of electricity have been obtained when power plants are equipped with systems able to reduce CO2 emissions. However, in order to obtain low CO2 emissions when coal is used, the coal decarbonization must be implemented: in this case it is possible to attain a global efficiency of about 38%, a specific emission of 0.1117 kg/kWh and an increase of kWh cost of about 32%. Vice versa, in order to obtain low CO2 emissions when natural gas is used, the exhaust gas treatment must be implemented: in this case it is possible to attain a global efficiency of about 50.7%, a specific emission of 0.0391 kg/kWh and an increase of kWh cost of about 15%. The clean use of coal seems to have good potential because it allows low energy penalizations (about 7.5 percentage points) and economic increases of about 32%. Because of the great availability, the homogeneous distribution and the low cost of this fuel, these results seem to be very interesting especially in the viewpoint of a transition towards the “hydrogen economy”, based, at least in the medium term, on fossil fuels.

2021 ◽  
Author(s):  
Basavaraja Revappa Jayadevappa

Abstract Operation of power plants in carbon dioxide capture and non-capture modes and energy penalty or energy utilization in such operations are of great significance. This work reports on two gas fired pressurized chemical-looping combustion power plant lay-outs with two inbuilt modes of flue gas exit namely, with carbon dioxide capture mode and second mode is letting flue gas (consists carbon dioxide and water) without capturing carbon dioxide. In the non-CCS mode, higher thermal efficiencies of 54.06% and 52.63% efficiencies are obtained with natural gas and syngas. In carbon capture mode, a net thermal efficiency of 52.13% is obtained with natural gas and 48.78% with syngas. The operating pressure of air reactor is taken to be 13 bar for realistic operational considerations and that of fuel reactor is 11.5 bar. Two power plant lay-outs developed based combined cycle CLC mode for natural gas and syngas fuels. A single lay-out is developed for two fuels with possible retrofit for dual fuel operation. The CLC Power plants can be operated with two modes of flue gas exit options and these operational options makes them higher thermal efficient power plants.


2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3543-3553
Author(s):  
Pavel Charvat ◽  
Lubomir Klimes ◽  
Jiri Pospisil ◽  
Jiri Klemes ◽  
Petar Varbanov

The feasibility and consequences of replacing nuclear power plants (NPP) in the Czech Republic with other energy sources are discussed. The NPP produced about one-third of electricity in the Czech Republic in 2017. Renewable energy sources such as hydropower, wind and solar power plants and biomass/biogas burning power plants produced about 11% of electricity in 2017. Due to the geographical and other constraints (intermittency, land footprint, and public acceptance), the renewables do not have the potential to entirely replace the capacity of the NPP. The only feasible technologies that could replace NPP in the Czech Republic in the near future are the power plants using fossil fuels. The combined cycle power plants running on natural gas (NGCC) are technically and environmentally fea-sible alternative for NPP at the moment. However, the natural gas imports would increase by two-thirds and the total greenhouse gas emissions would go up by about 10% if the power production of the NPP was entirely replaced by NGCC in the Czech Republic.


Author(s):  
Gurbakhash Bhander ◽  
Chun Wai Lee ◽  
Matthew Hakos

Abstract The growing worldwide interest in low carbon electric generation technologies has renewed interest in natural gas because it is considered a cleaner burning and more flexible alternative to other fossil fuels. Recent shale gas developments have increased natural gas production and availability while lowering cost, allowing a shift to natural gas for electricity production to be a cost-effective option. Natural gas generation in the U.S. electricity sector has grown substantially in recent years (over 31 percent in 2012, up from 17 percent in 1990), while carbon dioxide (CO2) emissions of the sector have generally declined. Natural gas-fired electrical generation offers several advantages over other fossil (e. g. coal, oil) fuel-fired generation. The combination of the lower carbon-to-hydrogen ratio in natural gas (compared to other fossil fuels) and the higher efficiency of natural gas combined cycle (NGCC) power plants (using two thermodynamic cycles) than traditional fossil-fueled electric power generation (using a single cycle) results in less CO2 emissions per unit of electricity produced. Furthermore, natural gas combustion results in considerably fewer emissions of air pollutants such as nitrogen oxides (NOx), sulfur dioxide (SO2), and particulate matter (PM). Natural gas is not the main option for deep de-carbonization. If deep reduction is prioritized, whether of the electricity sector or of the entire economy, there are four primary technologies that would be assumed to play a prominent role: energy efficiency equipment, nuclear power, renewable energy, and carbon capture and storage (CCS). However, natural gas with low carbon generation technologies can be considered a “bridge” to transition to these deep decarbonization options. This paper discusses the economics and environmental impacts, focusing on greenhouse gas (GHG) emissions, associated with alternative electricity production options using natural gas as the fuel source. We also explore pairing NGCC with carbon capture, explicitly examining the costs and emissions of amine absorption, cryogenic carbon capture, carbonate fuel cells, and oxy-combustion.


2021 ◽  
Vol 3 (1) ◽  
pp. 104-110
Author(s):  
A. S. SVIRIDOV ◽  
◽  
P. E. NOR ◽  

The Carnol system is the production of methanol from carbon dioxide (obtained from coal-fired power plants) and natural gas, and the use of the resulting methanol as an alternative fuel. The Carnol process produces hydrogen by thermal decomposition of natural gas, which then interacts with the CO2 extracted from the flue emissions of power plants. The resulting carbon can be stored or used as a raw material. The paper provides an estimated characteristic of the reduction of CO2 emissions of the Carnol process and system, and compares it with other traditional methanol production processes, including the use of biomass of industrial raw materials and vehicles powered by methanol fuel cells. CO2 emissions from a Carnol system that uses methanol as an alternative fuel can be reduced by 56 % compared to a conventional coal-fired power plant system. In the case of the use of methanol as fuel for motor vehicles, carbon dioxide emissions.


Author(s):  
Maria Elena Diego ◽  
Jean-Michel Bellas ◽  
Mohamed Pourkashanian

Post-combustion CO2 capture from natural gas combined cycle (NGCC) power plants is challenging due to the large flow of flue gas with low CO2 content (∼3–4%vol.) that needs to be processed in the capture stage. A number of alternatives have been proposed to solve this issue and reduce the costs of the associated CO2 capture plant. This work focuses on the selective exhaust gas recirculation (S-EGR) configuration, which uses a membrane to selectively recirculate CO2 back to the inlet of the compressor of the turbine, thereby greatly increasing the CO2 content of the flue gas sent to the capture system. For this purpose, a parallel S-EGR NGCC system (53% S-EGR ratio) coupled to an amine capture plant using MEA 30%wt. was simulated using gCCS (gPROMS). It was benchmarked against an unabated NGCC system, a conventional NGCC coupled with an amine capture plant (NGCC+CCS), and an EGR NGCC power plant (39% EGR ratio) using amine scrubbing as the downstream capture technology. The results obtained indicate that the net power efficiency of the parallel S-EGR system can be up to 49.3% depending on the specific consumption of the auxiliary S-EGR systems, compared to the 49.0% and 49.8% values obtained for the NGCC+CCS and EGR systems, respectively. A preliminary economic study was also carried out to quantify the potential of the parallel S-EGR configuration. This high-level analysis shows that the cost of electricity for the parallel S-EGR system varies from 82.1–90.0 $/MWhe for the scenarios considered, with the cost of CO2 avoided being in the range of 79.7–105.1 $/tonne CO2. The results obtained indicate that there are potential advantages of the parallel S-EGR system in comparison to the NGCC+CCS configuration in some scenarios. However, further benefits with respect to the EGR configuration will depend on future advancements and cost reductions achieved on membrane-based systems.


1992 ◽  
Vol 114 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Y. Mori ◽  
S. M. Masutani ◽  
G. C. Nihous ◽  
L. A. Vega ◽  
C. M. Kinoshita

A system to reduce carbon dioxide emissions from combustion power plants is described. Unlike earlier proposals based on flue gas treatment, the problem is addressed prior to combustion by reforming the hydrocarbon fuel into H2 and CO2. Following separation, H2 is burned in place of the original fuel and the captured CO2 is liquefied and injected into the deep ocean at a depth sufficient to ensure effective containment, and to minimize damage to the marine environment. Calculations indicate moderate plant thermal efficiency and power cost penalties. In addition, the H2 production potential of this system may be exploited as a means to facilitate the transition from fossil fuels to future hydrogen energy systems.


1991 ◽  
Vol 113 (3) ◽  
pp. 440-447 ◽  
Author(s):  
K. J. Springer

Global what? is a frequent response by those who first hear of the potential for global warming, global climate change, and global catastrophe, potentially brought on by excessive greenhouse gases in the upper atmosphere. The principal greenhouse gas, CO2, is joined by methane, N2O, and other trace gases in absorbing infrared radiation, which would otherwise escape into space, a process thought to be responsible for gradual increase in temperature that will melt ice caps and raise ocean levels. This paper discusses control possibilities that could be considered once there is agreement that CO2 must be controlled. Many of the responses to the energy crisis of 1974 are applicable for CO2 control. A variety of technologies, energy sources, and ideas are offered that, in combination, could be the basis for a global energy policy. Conversion and replacement of coal, oil, and eventually natural gas fired electric power plants with other energy sources such as nuclear, solar, wind, tidal, and geothermal, could significantly reduce CO2 emissions. There are, however, no good alternatives to fossil fuels used in transportation that significantly reduce CO2 emissions. Of all the fossil fuels, natural gas has the least CO2 production. Electric vehicles and hydrogen-fueled engines are future possibilities, but the electricity for the electric cars and for making hydrogen must be from nonfossil fuel driven generators. Conservation, efficiency, and tax incentives are other parts of a control strategy, once the amount of control considered necessary is established. Renewed interest in nonfossil fuel energy sources and their research and development is obviously needed.


2012 ◽  
Vol 16 (3) ◽  
pp. 849-864 ◽  
Author(s):  
Marcos Escudero ◽  
Ángel Jiménez ◽  
Celina González ◽  
Rafael Nieto ◽  
Ignacio López

The utilisation of biofuels in gas turbines is a promising alternative to fossil fuels for power generation. It would lead to a significant reduction of CO2 emissions using an existing combustion technology, although considerable changes appear to be required and further technological development is necessary. The goal of this work is to conduct energy and exergy analyses of the behaviour of gas turbines fired with biogas, ethanol and synthesis gas (bio-syngas), compared with natural gas. The global energy transformation process (i.e., from biomass to electricity) also has been studied. Furthermore, the potential reduction of CO2 emissions attained by the use of biofuels has been determined, after considering the restrictions regarding biomass availability. Two different simulation tools have been used to accomplish this work. The results suggest a high interest in, and the technical viability of, the use of Biomass Integrated Gasification Combined Cycle (BioIGCC) systems for large scale power generation.


2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Stefano Giuliano ◽  
Reiner Buck ◽  
Santiago Eguiguren

Selected solar-hybrid power plants for operation in base-load as well as midload were analyzed regarding supply security (dispatchable power due to hybridization with fossil fuel) and low CO2 emissions (due to integration of thermal energy storage). The power plants were modeled with different sizes of solar fields and different storage capacities and analyzed on an annual basis. The results were compared to each other and to a conventional fossil-fired combined cycle in terms of technical, economical, and ecological figures. The results of this study show that in comparison to a conventional fossil-fired combined cycle, the potential to reduce the CO2 emissions is high for solar-thermal power plants operated in base-load, especially with large solar fields and high storage capacities. However, for dispatchable power generation and supply security it is obvious that in any case a certain amount of additional fossil fuel is required. No analyzed solar-hybrid power plant shows at the same time advantages in terms of low CO2 emissions and low levelized electricity cost (LEC). While power plants with solar-hybrid combined cycle (SHCC®, Particle-Tower) show interesting LEC, the power plants with steam turbine (Salt-Tower, Parabolic Trough, CO2-Tower) have low CO2 emissions.


Author(s):  
Peter Eisenkolb ◽  
Martin Pogoreutz ◽  
Hermann Halozan

Gas-fired combined cycle power plants (CCP) are presently the most efficient systems for producing electricity with fossil fuels. Gas turbines have been and are being improved remarkably during the last years; presently they achieve efficiencies of more than 38% and gas turbine outlet temperatures of up to 610°C. These high outlet temperatures require modifications and improvements of heat recovery steam generators (HRSG). Presently dual pressure HRSGs are most commonly used in combined cycle power stations. The next step seems to be the triple-pressure HRSG to be able to utilise the high gas turbine outlet temperatures efficiently and to reduce exergy losses caused by the heat transfer between exhaust gas and the steam cycle. However, such triple-pressure systems are complicated considering parallel tube bundles as well as start up operation and load changes. For that reason an attempt has been made to replace such multiple pressure systems by a modified Rankine cycle with only a single-pressure level. In the case of the same total heat transfer surfaces this innovative single-pressure system achieves approximately the same efficiency as the triple-pressure system. By optimising the heat recovery from the exhaust gas to the steam/water cycle, i.e. minimising exergy losses, the stack temperature is much higher. Increasing the heat transfer surfaces means a decrease of the stack temperature and a further improvement of the overall CCP-efficiency. Therefore one has to be aware that the proposed system offers advantages not only in the case of a foreseeable increase of gas turbine outlet temperatures but also for presently available gas turbines. Using existing highly efficient gas turbines and subcritical steam conditions, power plants with this proposed Eisenkolb Single Pressure (ESP_CCP) heat recovery steam generator achieve thermal efficiencies of about 58.7% (LHV).


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