Herbert Jericha

Thermodynamic and Economic Investigation of an Improved Graz Cycle Power Plant for CO2 Capture

Introduction of closed-cycle gas turbines with their capability of retaining combustion generated CO 2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore, research and development at Graz University of Technology since the 1990s has lead to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen, which enables the cost-effective separation of the combustion CO 2 by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than 60%. In this work a further development, the S-Graz Cycle, which works with a cycle fluid of high steam content, is presented. Thermodynamic investigations show efficiencies up to 70% and a net efficiency of 60%, including the oxygen supply. For a 100 MW prototype plant the layout of the main turbomachinery is performed to show the feasibility of all components. Finally, an economic analysis of a S-Graz Cycle power plant is performed showing very low CO 2 mitigation costs in the range of

Design Optimization of the Graz Cycle Prototype Plant

10/ton CO 2 captured, making this zero emission power plant a promising technology in the case of a future CO 2 tax.

Design Concept for Large Output Graz Cycle Gas Turbines

Introduction of closed-cycle gas turbines with their capability of retaining combustion generated CO 2 can offer a valuable contribution to the Kyoto goal and to future power generation. The use of well-established gas turbine technology enhanced by recent research results enables designers even today to present proposals for prototype plants. Research and development work of TTM Institute of Graz University of Technology since the 1990s has lead to the Graz cycle, a zero-emission power cycle of highest efficiency and with most positive features. In this work the design for a prototype plant based on current technology as well as cutting-edge turbomachinery is presented. The object of such a plant shall be the demonstration of operational capabilities and shall lead to the planning and design of much larger units of highest reliability and thermal efficiency.

Conceptual Design for an Industrial Prototype Graz Cycle Power Plant

The introduction of closed cycle gas turbines with their capability of retaining combustion generated CO 2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore research and development work at the Graz University of Technology since the 1990s has led to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen which enables the cost-effective separation of the combustion CO 2 by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than for modern combined cycle plants. Upon the basis of the previous work, the authors present the design concept for a large power plant of 400 MW net power output making use of the latest developments in gas turbine technology. The Graz Cycle configuration is changed, insofar as condensation and separation of combustion generated CO 2 takes place at the 1 bar range in order to avoid the problems of condensation of water out of a mixture of steam and incondensable gases at very low pressure. A final economic analysis shows promising CO 2 mitigation costs in the range of

Design Optimisation of the Graz Cycle Prototype Plant

20―30/ton CO 2 avoided. The authors believe that they present here a partial solution regarding thermal power production for the most urgent problem of saving our climate.

DESIGN DETAILS OF A 600 MW GRAZ CYCLE THERMAL POWER PLANT FOR CO2 CAPTURE

The gas turbine system GRAZ CYCLE has been thoroughly studied in terms of thermodynamics and turbomachinery layout. What is to be presented here is a prototype design for an industrial size plant, suited for NG-fuel and coal and heavy fuel oil gasification products, capable to retain the CO2 from combustion and at the same time able to achieve maximum thermal efficiency. The authors hope for an international cooperation to make such a plant available within a few years.

A FURTHER STEP TOWARDS A GRAZ CYCLE POWER PLANT FOR CO2 CAPTURE

Introduction of closed cycle gas turbines with their capability of retaining combustion generated CO2 can offer a valuable contribution to the Kyoto goal and to future power generation. The use of well established gas turbine technology enhanced by recent research results enables designers even today to present proposals for prototype plants. Research and development work of TTM Institute of Graz University of Technology since the 90’s has lead to the Graz Cycle, a zero emission power cycle of highest efficiency and with most positive features. In this work the design for a prototype plant based on current technology as well as cutting-edge turbomachinery is presented. The object of such a plant shall be the demonstration of operational capabilities and shall lead to the planning and design of much larger units of highest reliability and thermal efficiency.Copyright

Operational Behavior of a Complex Transonic Test Turbine Facility

The high power highest efficiency zero-emission Graz Cycle plant of 400 MW was presented at ASME IGTI conference 2006 and at CIMAC conference 2007. In continuation of these works a raise of power output to 600 MW is presented and important design details are discussed. The cycle pressure ratio is increased from 40 to 50 bar by a half-speed stage connected via gears to the main compressor shaft allowing to keep the volume flow to the main compressors constant. The compressors are driven by the transonic compressor turbine stage. Mass flow to the compressors is increased by the factor of 1.27, density in blades of the main compressors is raised by the same factor. The turbine inlet temperature is raised to 1500°C together with the increase in the cycle pressure ratio, both are well accepted values in gas turbine technology today. Most important development problems have to be solved in designing the oxy-fuel burners. They are presented here in the form of coaxial jets of fuel (natural gas or coal gas alternatively) held together by a steam vortex providing coherent flow and flame is ignited by its strong suction. Combustion is finalized by the mixing with a counter-rotating outer vortex flow of working gas leading to a well defined position of vortex break down. The transonic stage of the compressor turbine is supplied with innovative steam cooling forming coherent layers outside of the blade shell of which stress deliberations will be presented.Copyright

Multiple Evaporation Steam Bottoming Cycle

Introduction of closed cycle gas turbines with their capability of retaining combustion generated CO2 can offer a valuable contribution to the Kyoto goal and to future power generation. Therefore research and development work at Graz University of Technology since the nineties has led to the Graz Cycle, a zero emission power cycle of highest efficiency. It burns fossil fuels with pure oxygen which enables the costeffective separation of the combustion CO2 by condensation. The efforts for the oxygen supply in an air separation plant are partly compensated by cycle efficiencies far higher than for modern combined cycle plants. At the ASME IGTI conference 2004 in Vienna a high steam content S-Graz Cycle power plant was presented showing efficiencies for syngas firing up to 70 % and a net efficiency of 57 % considering oxygen supply and CO2 compression. A first economic analysis gave CO2 mitigation costs of about 10

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF THE WAKE FLOW DOWNSTREAM OF A LINEAR TURBINE CASCADE

/ton CO2 avoided. These favourable data induced the Norwegian oil and gas company Statoil ASA to order a techno-economic evaluation study of the Graz Cycle. In order to allow a benchmarking of the Graz Cycle and a comparison with other CO2 capture concepts, the assumptions of component efficiency and losses are modified to values agreed with Statoil. In this work the new assumptions made and the resulting power cycle for natural gas firing, which is the most likely fuel of a first demonstration plant, are presented. Further modifications of the cycle scheme are discussed and their potential is analyzed. Finally, an economic analysis of the Graz Cycle power plant is performed showing low CO2 mitigation costs in the range of 20