scholarly journals Technologies for increasing CO2 concentration in exhaust gas from natural gas-fired power production with post-combustion, amine-based CO2 capture

Energy ◽  
2011 ◽  
Vol 36 (2) ◽  
pp. 1124-1133 ◽  
Author(s):  
Hailong Li ◽  
Mario Ditaranto ◽  
David Berstad
Keyword(s):  
Natural Gas ◽  
Co2 Capture ◽  
Co2 Concentration ◽  
Power Production ◽  
Exhaust Gas

Exhaust Gas Recirculation on Humidified Flexible Micro Gas Turbines for Carbon Capture Applications

2016 ◽  
Author(s):  
Ward De Paepe ◽  
Marina Montero Carrero ◽  
Simone Giorgetti ◽  
Alessandro Parente ◽  
Svend Bram ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Co2 Concentration ◽  
Power Production ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Simulation Results ◽  
Gas Recirculation ◽  
The Impact

From all fossil fuels, natural gas has the lowest carbon to hydrogen ratio, which enables Gas Turbines (GTs) running on natural gas to produce electricity with the lowest CO2 emissions per produced kWh. These lower emissions have pushed power production towards natural gas. However, if we want to move towards a carbon clean power production, the carbon in the exhaust must be captured. This leads to a major challenge since the low CO2 concentration in the exhaust of a GT makes carbon capture much more expensive compared to coal fired power production. The CO2 concentration can be increased by performing Exhaust Gas Recirculation (EGR). However, EGR on GT cycles negatively affects the efficiency. Using the concept of Humid Air Turbine (HAT), we investigate whether the efficiency losses can be compensated by introducing water in the cycle. This paper presents this novel approach by showing the impact of EGR on a flexible humidified micro Gas Turbine (mGT). It is based on results of simulations performed in Aspen® using the Turbec T100 mGT as reference case. Both the dry and wet operation of the Turbec T100 were simulated and validated with experimental results. For improved carbon capture, EGR was simulated in both the dry and the humidified mGT cycle. Simulation results indicate that EGR has no effect on the thermodynamic performance of the mGT and its components (compressor, turbine and recuperator), however efficiency is reduced significantly (up to 3.8% relative at nominal power output) because of additional losses to the fan blower installed to ensure the EGR. Additionally, the cycle performance strongly depends on the degree of cooling of the EGR stream before injection in the compressor inlet. Nevertheless, the simulation results also reveal that mGT humidification increases the total cycle efficiency, entirely compensating the EGR induced losses. Humidifying the mGT with EGR even leads to a higher electric efficiency than the standard mGT cycle, unlocking the idea of carbon capture in mGTs.

Exhaust Gas Recirculation Performance in Dry Low Emissions Combustors

2011 ◽  
Author(s):  
A. M. Elkady ◽  
A. R. Brand ◽  
C. L. Vandervort ◽  
A. T. Evulet
Keyword(s):  
Gas Turbine ◽  
Co2 Capture ◽  
Carbon Capture ◽  
Power Plants ◽  
Nox Reduction ◽  
Co2 Concentration ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Low Oxygen ◽  
Gas Recirculation

In a carbon constrained world there is a need for capturing and sequestering CO2. Post-combustion carbon capture via Exhaust Gas Recirculation (EGR) is considered a feasible means of reducing emission of CO2 from power plants. Exhaust Gas Recirculation is an enabling technology for increasing the CO2 concentration within the gas turbine cycle and allow the decrease of the size of the separation plant, which in turn will enable a significant reduction in CO2 capture cost. This paper describes the experimental work performed to better understand the risks of utilizing EGR in combustors employing dry low emissions (DLE) technologies. A rig was built for exploring the capability of premixers to operate in low O2 environment, and a series of experiments in a visually accessible test rig was performed at representative aeroderivative gas turbine pressures and temperatures. Experimental results include the effect of applying EGR on operability, efficiency and emissions performance under conditions of up to 40% EGR. Findings confirm the viability of EGR for enhanced CO2 capture; In addition, we confirm benefits of NOx reduction while complying with CO emissions in DLE combustors under low oxygen content oxidizer.

Exhaust Gas Recirculation in DLN F-Class Gas Turbines for Post-Combustion CO2 Capture

2008 ◽  
Author(s):  
Ahmed M. ElKady ◽  
Andrei Evulet ◽  
Anthony Brand ◽  
Tord Peter Ursin ◽  
Arne Lynghjem
Keyword(s):  
Co2 Capture ◽  
Experimental Work ◽  
Gas Turbines ◽  
Co2 Concentration ◽  
Exhaust Gas Recirculation ◽  
Inert Gases ◽  
Exhaust Gas ◽  
Enabling Technology ◽  
Series Of Experiments ◽  
Gas Recirculation

This paper describes experimental work performed at General Electric, Global Research Center to evaluate the performance and understand the risks of using Dry Low NOx (DLN) technologies in Exhaust Gas Recirculation (EGR) conditions. Exhaust Gas Recirculation is viewed as an enabling technology for increasing the CO2 concentration of the flue gas while decreasing the volume of the post-combustion separation plant and therefore allowing a significant reduction in CO2 capture cost. A research combustor was developed for exploring the performance of nozzles operating in low O2 environment at representative pressures and temperatures. A series of experiments in a visually accessible test rig have been performed at gas turbine pressures and temperatures, in which inert gases such as N2/CO2 were used to vitiate the fresh air to the levels determined by cycle models. Moreover, the paper will discuss experimental work performed using a DLN nozzle used in GE’s F-class heavy-duty gas turbines. Experimental results using a research combustor operating in partially premixed mode, incorporate the effect of applying EGR on operability, efficiency and emissions performance under conditions of up to 40% EGR. Experiments performed in fully premixed mode using DLN single nozzle combustor revealed that further reductions in NOx could be achieved and at the same time still complying with CO emissions. While most existing studies concentrate on limitations related to the Minimum Oxygen Concentration (MOC) at the combustor exit, we report the importance of CO2 levels in the oxidizer. This limitation is as important as the MOC and it varies with the pressure and firing temperatures.

A Novel Coal Based Cogeneration System for Substitute Natural Gas and Power With CO2 Capture and Moderate Recycle of the Chemical Unconverted Gas

2013 ◽  
Author(s):  
Sheng Li ◽  
Hongguang Jin ◽  
Lin Gao
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Energy Saving ◽  
Co2 Capture ◽  
Co2 Concentration ◽  
Low Energy ◽  
The Novel ◽  
Good Efficiency ◽  
Cogeneration System ◽  
Energy Penalty

Cogeneration of substitute natural gas (SNG) and power from coal efficiently and CO2 capture with low energy penalty during coal utilization are very important technical paths to clean coal technologies for China which is rich in coal but lack of natural gas resources. This paper integrates a novel coal based cogeneration system with CO2 capture for SNG and power, and presents the energetic and exergy analysis based on the thermodynamic formulas and the use of ASPEN PLUS 11.0. In the novel system, instead of separation from the gas before synthesis traditionally, CO2 will be removed from the unconverted gas after synthesis, whose concentration can reach as high as 55% before separation and is much higher than 30% in traditional SNG production system. And by moderate recycle instead of full recycle of chemical unconverted gas back into SNG synthesis, the sharp increase in energy consumption for SNG synthesis with conversion ratios will be avoided, and by using part of the chemical unconverted gas, power is cogenerated efficiently. Thermodynamic analysis shows that the benefit from both systematic integration and high CO2 concentration makes the system have good efficiency and low energy penalty for CO2 capture. The overall efficiency of the system ranges from 53%–62% at different recycle ratios. Compared to traditional single production systems (IGCC with CO2 capture for power, traditional SNG system for SNG production), the energy saving ratio (ESR) of the novel system is 16%–21%. And compared to IGCC and traditional SNG system, the energy saving benefit from cogeneration can even offset the energy consumption for CO2 separation and realize zero energy penalties for CO2 capture systematically. Sensitivity analysis hints that an optimized recycle ratio of unconverted gas and chemicals to power output ratio (CPOR) can maximize system performance and minimize the energy penalty for CO2 capture.

Process Analysis of Selective Exhaust Gas Recirculation for CO2 Capture in Natural Gas Combined Cycle Power Plants Using Amines

2017 ◽  
Author(s):  
Maria Elena Diego ◽  
Jean-Michel Bellas ◽  
Mohamed Pourkashanian
Keyword(s):  
Natural Gas ◽  
Co2 Capture ◽  
Flue Gas ◽  
Power Plants ◽  
Exhaust Gas Recirculation ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Natural Gas Combined Cycle ◽  
The Cost ◽  
Gas Recirculation

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.

High Efficiency SOFC Power Cycles With Indirect Natural Gas Reforming and CO2 Capture

2015 ◽  
Vol 12 (2) ◽  
Author(s):  
Stefano Campanari ◽  
Matteo Gazzani
Keyword(s):  
High Temperature ◽  
Natural Gas ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Power Production ◽  
Operating Conditions ◽  
Power Cycles ◽  
Power Cycle

Driven by the search for the highest theoretical efficiency, several studies have investigated in the last years the adoption of fuel cells (FCs) in the field of power production from natural gas with CO2 capture. Most of the proposed power cycles rely on high temperature FCs, namely, solid oxide FCs (SOFCs) and molten carbonate FCs (MCFCs), based on the concept of hybrid FC plus gas turbine cycles. Accordingly, high temperature FCs are integrated with a simple or modified Brayton cycle. As far as SOFCs are concerned, CO2 can be separated downstream the FC via a range of available technologies, e.g., chemical or physical separation processes, oxy-combustion, and cryogenic methods. Following a literature review on promising plant configurations, this work investigates the potential of adopting an external natural gas conversion section with respect to the plant efficiency. As a reference plant, we considered a power cycle proposed by Adams and Barton (2010, “High-Efficiency Power Production From Natural Gas With Carbon Capture,” J. Power Sources, 195(7), pp. 1971–1983), whose performance is the highest found in literature for SOFC-based power cycles, with 82% LHV electrical efficiency. It is based on a prereforming concept where fuel is reformed ahead the SOFC, which thus works with a high hydrogen content fuel. After reproducing the power cycle with the ideal assumptions proposed by the original authors, as second step, the simulations were focused on revising the power cycle, implementing a complete set of assumptions about component losses and more conservative operating conditions about FC voltage, heat exchangers minimum temperature differences (which were previously neglected), maximum steam temperature (set according to heat recovery steam generator (HRSG) practice), turbomachinery efficiency, component pressure losses, and other adjustments. The simulation also required to design an appropriate heat exchangers network, which turned out to be very complex, instead of relying on the free allocation of heat transfer among all components. Considering the consequent modifications with respect to the original layout, the net electric efficiency changes to around 63% LHV with nearly complete (95%+) CO2 capture, a still remarkable but less attractive value. On the other hand, the power cycle requires a complicated and demanding heat exchangers network and heavily relies on the SOFC performances, not generating a positive power output from the gas turbine loop. Detailed results are presented in terms of energy and material balances of the proposed cycles. All simulations have been carried out with the proprietary code GS, developed by the GECOS group at Politecnico di Milano.

scholarly journals CO2 capture from natural gas power plants using selective exhaust gas recycle membrane designs

2017 ◽  
Vol 66 ◽  
pp. 35-47 ◽  
Author(s):  
Richard W. Baker ◽  
Brice Freeman ◽  
Jay Kniep ◽  
Xiaotong Wei ◽  
Tim Merkel
Keyword(s):  
Natural Gas ◽  
Co2 Capture ◽  
Power Plants ◽  
Exhaust Gas

Exergy Analysis of Gas-Turbine Combined Cycle With CO2 Capture Using Pre-Combustion Decarbonization of Natural Gas

2002 ◽  
Author(s):  
Hanne M. Kvamsdal ◽  
Ivar S. Ertesva˚g ◽  
Olav Bolland ◽  
Tor Tolstad
Keyword(s):  
Natural Gas ◽  
Electric Power ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Exergy Analysis ◽  
Pressure Ratio ◽  
Power Production ◽  
Combined Cycle ◽  
Electric Power Production ◽  
Chemical Exergy

A concept for natural-gas fired power plants with CO2 capture has been investigated using exergy analysis. The present approach involves decarbonization of the natural gas by authothermal reforming prior to combustion, producing a hydrogen-rich fuel. An important aspect of this type of process is the integration between the combined cycle and the reforming process. The net electric power production was 47.7% of the Lower Heating Value (LHV) or 45.8% of the chemical exergy of the supplied natural-gas. In addition, the chemical exergy of the captured CO2 and the compression of this CO2 to 80 bar represented 2.1% and 2.7%, respectively, of the natural-gas chemical exergy. For a corresponding conventional combined cycle without CO2 capture, the net electric power production was 58.4% of the LHV or 56.1% of the fuel chemical exergy. A detailed breakdown of irreversibility is presented. In the decarbonized natural-gas power plant, the effect of varying supplementary firing (SF) for reformer-feed preheating was investigated. This showed that SF increased the total irreversibility and decreased the net output of the plant. Next, the effects of increased gas-turbine inlet temperature and of gas-turbine pressure ratio were studied. For the conventional plant, higher pressure led to increased efficiency for some cases. In the decarbonized natural-gas process, however, higher pressure ratio led to higher irreversibility and reduced thermal-plant efficiency.

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