A. Doukelis

Inlet Air Cooling Methods for Gas Turbine Based Power Plants

Background: Power generation from gas turbines is penalized by a substantial power output loss with increased ambient temperature. By cooling down the gas turbine intake air the power output penalty can be mitigated. Method of Approach: The purpose of this paper is to review the state of the art in applications for reducing the gas turbine intake air temperature and examine the merits from integration of the different air-cooling methods in gas-turbine-based power plants. Three different intake air-cooling, methods (evaporative cooling, refrigeration cooling, and evaporative cooling of precompressed air) have been applied in two combined cycle power plants and two gas turbine plants. The calculations were performed on a yearly basis of operation. taking into account the time-varying climatic conditions. The economics from integration of the different cooling systems were calculated and compared. Results: The results have demonstrated that the highest incremental electricity generation is realized by absorption intake air-cooling. In terms of the economic performance of the investment, the evaporative cooler has the lowest total cost of incremental electricity generation and the lowest payback period (PB). Concerning the cooling method of pre-compressed air the results show a significant gain in capacity, but the total cost of incremental electricity generation in this case is the highest. Conclusions: Because of the much higher capacity gain by an absorption chiller system. the evaporative cooler and the absorption chiller system may both be selected for boosting the performance of gas-turbine-based power plants, depending on the prevailing requirements of the plant operator.

Techno-Economic Comparison of CO2 Capture Technologies Employed With Natural Gas Derived GTCC

Carbon Capture and Storage can either concern the removal of carbon as CO2 in flue gases (post-combustion option) or before its combustion in a Gas Turbine (pre-combustion option). Among the numerous CO2 capture technologies, amine scrubbing (MEA and MDEA), physical absorption (Selexol™ and Rectisol™) and H2 separator membrane reactors are investigated and compared in this study. In the pre-combustion options, the final fuel combusted in the GT is a rich-H2 fuel. Process simulations in ASPEN Plus™ showed that the case of H2 separation with Pd-based membranes has the greatest performance as far as the net efficiency of the energy system is concerned. The economic assessment reveals that the technology is promising in terms of cost of CO2 avoided, provided that the current high membrane costs are reduced.Copyright

Identification of Process Integration Options for CO2 Capture in Greek Lignite-fired Power Plant

a Centre for Process Integration and Intensification – CPI 2 , Research Institute of Chemical and Process Engineering MŰKKI, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary b National Technical University of Athens, Laboratory of Steam Boilers and Thermal Plants, Heroon Polytechniou 9, 15780 Zografou Campus, Greece c Centre for Process Integration, School of Chemical Engineering Analytical Science, The University of Manchester, Sackville Street, Manchester M13 9PL, UK d Department of Mechanical Engineering, Aristotle University of Thessaloniki, P.O. Box 424, Thessaloniki, 54124, Greece pengyenliew@cpi.uni-pannon.hu

Identification of Process Integration Options for Carbon Capture

Abstract Many industrial sites consume vast amounts of fossil fuels and it is likely that they will continue to do so for the foreseeable future. The reasons for this are of various types, but the main ones are related to the convenience of using fuels as easily manipulated degrees of freedom in operating the plants. One of the options for reducing the emissions of greenhouse gases and most notably CO2 is the CO2 capture and its following sequestration. The present work aims at the optimisation of the performance of the power plants with CO2 capture, examining all possible options for heat integration – including utilisation of low-grade waste heat. The identification of streams containing low-grade or low-value heat are performed in this regard, combined with potential waste streams suitable for generating additional energy. The integration of the capture process into the power plants will also consider the use of fans, coolers, gas polishing and CO2 capture equipment. In power plants the steam extraction from the power train will be targeted for optimisation together with the recirculation of high grade heat. This allows identifying targets for energy recovery potentials and provides a sound design basis for cogeneration systems.

The Integration of Micro-CHP and Biofuels for Decentralized CHP Applications

Renewable micro-CHP systems are a combination of micro-CHP technology and renewable energy technology, such as biomass gasification systems or solar concentrators. The integration of renewable energy sources with micro-CHP allows for the development of sustainable energy systems with the potential for high market penetration; a cost-effective and reliable heat and electricity supply; and a highly beneficial environmental and economical impact on a pan-European scale. The purpose of this chapter is to present results from the European coordination action project MICROCHEAP that intended to bring together industrial specialists and research experts to focus entirely on renewable micro-CHP technology, co-ordinate and steer research in this field, and highlight the most promising technologies with the highest potential for market penetration in existing and future market conditions. The chapter discusses the state of the art technological options in the field of renewable micro-CHP with biofuels with regards to technology, cost, and environmental impacts and presents a market survey concerning the possibility of future penetration of the technology in Europe. The results will provide a coherent overview of the basic technological options for renewable micro-CHP with biofuels and will provide an insight to the market trends within Europe and projected future market scenarios, taking into account cost estimations for various micro-CHP technologies, feedstocks, and electricity and fuel prices in Europe.

CO2 Mitigation Options for Retrofitting Greek Low-Quality Coal-Fired Power Plants

We consider possible application of the state-of-the-art in technological concepts of CO 2 capture and sequestration to retrofitting of low-quality coal-fired power plants. The most promising options, namely the oxy-fuel combustion and the flue gases treatment by amine scrubbing, were evaluated as retrofit options for a typ- ical modern lignite-fired power plant. Results from thermodynamic simulations of the examined cases were used to demonstrate the potential for emissions reduction and evaluate the associated power output and efficiency penalties. Furthermore, an economic assessment of electricity production cost was carried out, in relation to the application of different existing and near future technologies. The economical impact related to fuel prices and CO 2 emission risks was assessed.

Novel Solid Fuel Gasification Power Plant for In Situ CO2 Capture

The work presented in this paper aims to examine and analyse a novel concept dealing with the carbonation-calcination process of lime for CO2 capture from coal-fired power plants. The scheme is based on a novel steam gasification process of low rank coals with calcined limestone where in-situ CO2 capture and steam reforming are performed in a single reactor. CO2 is separated reacting exothermically with CaO based sorbents, providing also the necessary heat for the gasification reactions. The produced gas is a H2 -rich gas with low carbon or near zero carbon content, depending on the ratio of lime added to the process. The produced fuel gas can be used in state-of-the-art combined cycles where it is converted to electricity, generating almost no CO2 emissions. After being captured in the gasification process, CO2 is released in a separate reactor where extra energy is provided through the combustion of low rank coal. Regenerated CaO is produced in this reactor and is continuously recycled within the process. The key element of the concept is the high-pressure steam gasification process where CO2 is captured by CaO based sorbents and fuel gas with high hydrogen content is produced, without using additional shift reactors. Two optimised power plant configurations are presented in detail and examined. In the first case, pure oxygen is utilised for the low rank coal combustion in the limestone regeneration process, while in the second case fuel is combusted with air instead. Results from the equilibrium based mass balance of the two reactors as well as the power plant thermodynamic simulations, dealing with the most important features for CO2 reduction are presented concerning the two different options. The energy penalties are quantified and the power plant efficiencies are calculated. The calculated results demonstrate the capability of the power plant to deliver decarbonised electricity while achieving high overall electrical efficiencies, comparable to other technological alternatives for CO2 capture power plants. The Aspen Plus software is used for the equilibrium based mass balance of the gasifier and the regenerator while the combined cycle power plant cycle calculations are performed with the thermodynamic cycle calculation software ENBIPRO (ENergie-BIllanz-PROgram), a powerful tool for heat and mass balance solving of complex thermodynamic circuits, calculation of efficiency, exergetic and exergoeconomic analysis of power plants [1].Copyright