Assessment of a Power Plant With CO2 Capture Using an Advanced Exergoenvironmental Analysis

This paper presents an evaluation of the environmental performance of an advanced zero emission plant (AZEP) including CO2 capture. The evaluation is conducted with the aid of an advanced exergoenvironmental analysis. The results are compared with those of a reference combined-cycle power plant without CO2 capture. Advanced exergy-based methods are used to (a) quantify the potential for improving individual components or overall systems, and (b) reveal detailed interactions among components—two features not present in conventional analyses, but very useful, particularly when evaluating complex systems. In an advanced exergoenvironmental analysis, the environmental impacts calculated in a conventional exergoenvironmental analysis are split into avoidable/unavoidable (to evaluate the potential for component improvement) and endogenous/exogenous (to understand the interactions among components) parts. As in the reference plant, the potential for reducing the environmental impact of the AZEP has been found to be limited by the relatively low avoidable environmental impact associated with the thermodynamic inefficiencies of several of its components. However, although the environmental impacts for the majority of the components of the plant are related mainly to internal inefficiencies and component interactions are of secondary importance, there are strong interactions between the reactor and some other components.

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Exergy Linked to Environmental Impacts: Advanced Exergoenvironmental Analysis of an Advanced Zero Emission Plant

Volume 4: Energy Systems Analysis, Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy, Parts A and B ◽

10.1115/imece2011-62678 ◽

2011 ◽

Author(s):

F. Petrakopoulou ◽

G. Tsatsaronis ◽

T. Morosuk

Keyword(s):

Environmental Impacts ◽

Environmental Analysis ◽

Co2 Capture ◽

Environmental Performance ◽

Strong Interactions ◽

System A ◽

Energy Conversion Systems ◽

Zero Emission ◽

Exergetic Analysis ◽

Plant Components

Exergy-based analyses are useful means for the evaluation and improvement of energy conversion systems. A life cycle assessment (LCA) is coupled with an exergetic analysis in an exergo-environmental analysis. An advanced exergo-environmental analysis quantifies the environmental impacts estimated in the LCA into avoidable/unavoidable parts and into endogenous/exogenous parts, depending on their source. This analysis reveals the potential for improvement of plant components/processes and the component interactions within a system. In this paper, the environmental performance of an advanced zero emission plant (AZEP) with CO2 capture is evaluated based on an advanced exergoenvironmental analysis. The plant uses oxy-fuel technology and incorporates an oxygen-separating mixed conducting membrane (MCM). To evaluate the operation of the system, a similar plant (reference plant) without CO2 capture is used. It has been found that the improvement potential of the AZEP concept is restricted by the relatively low avoidable environmental impact of exergy destruction of several plant components. Moreover, the endogenous environmental impacts are for the majority of the components significant, while the exogenous values are, generally, kept at low levels. Nevertheless, a closer inspection reveals that there are strong interactions among the components of the MCM reactor and the components constituting the CO2 compression unit. Such results are valuable, when the improvement of the environmental performance of the plant is targeted and they can only be obtained through advanced exergy-based methods.

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Solvent Screening and Feasible Study of Retrofitting CO2 Capture System for Natural Gas Combined Cycle Power Plant

Energy Procedia ◽

10.1016/j.egypro.2014.11.261 ◽

2014 ◽

Vol 63 ◽

pp. 2394-2401

Author(s):

Satoshi Saito ◽

Norihide Egami ◽

Toshihisa Kiyokuni ◽

Mitsuru Udatsu ◽

Hideo Kitamura ◽

...

Keyword(s):

Power Plant ◽

Natural Gas ◽

Co2 Capture ◽

Combined Cycle ◽

Combined Cycle Power Plant ◽

Natural Gas Combined Cycle ◽

Feasible Study

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The environmental impact of post-combustion CO2 capture with MEA, with aqueous ammonia, and with an aqueous ammonia-ethanol mixture for a coal-fired power plant

Energy ◽

10.1016/j.energy.2010.12.060 ◽

2011 ◽

Vol 36 (6) ◽

pp. 3763-3770 ◽

Cited By ~ 37

Author(s):

R. Strube ◽

G. Pellegrini ◽

G. Manfrida

Keyword(s):

Power Plant ◽

Environmental Impact ◽

Co2 Capture ◽

Aqueous Ammonia ◽

Ethanol Mixture

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Postcombustion CO2 Capture for Combined Cycles Utilizing Hot-Water Absorbent Regeneration

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4004146 ◽

2011 ◽

Vol 134 (1) ◽

Cited By ~ 9

Author(s):

Klas Jonshagen ◽

Majed Sammak ◽

Magnus Genrup

Keyword(s):

Power Plant ◽

Temperature Difference ◽

Co2 Capture ◽

Steam Pressure ◽

Low Pressure ◽

Pressure Level ◽

Combined Cycle ◽

Hot Water ◽

Combined Cycle Power Plant ◽

Pressure Plant

The partly hot-water driven CO2 capture plant offers a significant potential for improvement in performance when implemented in a combined-cycle power plant (CCPP). It is possible to achieve the same performance with a dual-pressure steam cycle as in a triple-pressure unit. Even a single-pressure plant can attain an efficiency competitive with that achievable with a triple-pressure plant without the hot-water reboiler. The underlying reasons are better heat utilization in the heat recovery unit and less steam extraction to the absorbent regenerating unit(s). In this paper, the design criteria for a combined cycle power plant utilizing hot-water absorbent regeneration will be examined and presented. The results show that the most suitable plant is one with two steam pressure levels. The low-pressure level should be much higher than in a conventional combined cycle in order to increase the amount of heat available in the economizer. The external heat required in the CO2 capture plant is partly supplied by the economizer, allowing temperature optimization in the unit. The maximum value of the low-pressure level is determined by the reboiler, as too great a temperature difference is unfavorable. This work evaluates the benefits of coupling the economizer and the reboiler in a specially designed CCPP. In the CO2 separation plant both monoethanolamine (MEA) and ammonia are evaluated as absorbents. Higher regeneration temperatures can be tolerated in ammonia-based plants than in MEA-based plants. When using a liquid heat carrier the reboiler temperature is not constant on the hot side, which results in greater temperature differences. The temperature difference can be greatly reduced by dividing the regeneration process into two units operating at different pressures. The possibility of extracting more energy from the economizer to replace part of the extracted steam increases the plant efficiency. The results show that very high efficiencies can be achieved without using multiple pressure-levels.

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Gas Turbine Combined Cycle Optimized for Postcombustion Carbon Capture

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4039733 ◽

2018 ◽

Vol 140 (9) ◽

Cited By ~ 1

Author(s):

S. Can Gülen ◽

Chris Hall

Keyword(s):

Power Plant ◽

Gas Turbine ◽

Co2 Capture ◽

Carbon Capture ◽

Heat Recovery ◽

Combined Cycle ◽

Heat Recovery Steam Generator ◽

Gas Temperature ◽

Design Challenges ◽

Stack Gas

This paper describes a gas turbine combined cycle (GTCC) power plant system, which addresses the three key design challenges of postcombustion CO2 capture from the stack gas of a GTCC power plant using aqueous amine-based scrubbing method by offering the following: (i) low heat recovery steam generator (HRSG) stack gas temperature, (ii) increased HRSG stack gas CO2 content, and (iii) decreased HRSG stack gas O2 content. This is achieved by combining two bottoming cycle modifications in an inventive manner, i.e., (i) high supplementary (duct) firing in the HRSG and (ii) recirculation of the HRSG stack gas. It is shown that, compared to an existing natural gas-fired GTCC power plant with postcombustion capture, it is possible to reduce the CO2 capture penalty—power diverted away from generation—by almost 65% and the overall capital cost ($/kW) by about 35%.

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