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Advanced integrated gasification combined cycle (A-IGCC) by exergy recuperation - technical challenges for future generations

Kawabata M., Kurata O., Iki N., Tsutsumi A., Furutani H.

Journal of Power Technologies

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2012

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Vol. 92, nr 2

90--100

EN

With the limited worldwide resource of coal, a new technology has been developed in using a low grade coal to breakthrough the current technical limitation in the IGCC system and attains higher plant efficiency. This study attempts an exergy-recuperation within the combined cycle on HYSYS process simulation, so called Advanced IGCC (A-IGCC), in which the system is designed to increase the cold gas efficiency and save the exergy of the fuel throughout the system by using a gas turbine exhaust as an external heat source encouraging an autothermal reaction. Three types of syngas compositions were investigated depending on the gasifier conditions with exergy recuperation. Plant efficiency was significantly higher with the presence of exergy recuperation in the system. This was attributed to an efficient exergy saving in the system as opposed to a conventional IGCC, which has significant exergy loss in the combustion and gasification processes. Improved plant performance generated from a low temperature gasifier was obtained with the A-IGCC model, although the model requires further developments in technology, such as the gasification at a lower gas temperature, powerful heat exchanger, gas purification at high temperature, etc., for the actual implementation.

2

Methane-oxygen combustion turbine systems for utilization of industrial waste heat

Uzunov N., Furutani H.

Prace Naukowe Politechniki Warszawskiej. Mechanika

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2003

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z. 202

321--330

EN

The aim of this research was to propose new system solutions for utilization of industrial waste heat, evaluate their performance under various operating conditions, and eventually recommend them for further, more detailed applicability investigation. Conventional waste-heat utilization systems are based on the Rankine cycle and characterized by relatively low turbine inlet temperature. In comparison with such systems, significant increases in electric efficiency and output can be expected by introducing methaneoxygen combustion for direct heating of the working medium. Three system configurations were considered, combining low-quality (industrial waste heat) and high-quality (methaneoxygen combustion) heat sources. In two of the configurations investigated, heat transfer from the working to the feeding medium provided heat recirculation. The performance of the proposed systems with various contributions of the two sources to the total heat supply was investigated. Special attention was paid to the combination effect. This is understood as obtaining an output higher thau that obtained with the same sources being separated. The simulation results confirm that two of the systems investigated can provide significant merits under reasonable conditions. They also prove that heat recirculation is indispensable to achieve such performance. The combination effect is obtained with a moderate or manageable turbine inlet temperature. Possible reduction of the system size and cost is another advantage of the combination. The general conclusion is that two of the proposed system solutions are very promising and are recommended for further applicability investigation.

3

Observation of flat-ignition of H2-O2-O3 mixtures with excimer laser

Furutani H., Liu F., Iki N., Hama J., Takahashi S.

Archivum Combustionis

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2000

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Vol. 20 nr 1-2

13-18

EN

To develop a new ignition method, authors carrieg out a series of experiments about the ignition process of H2-O2O3/ H2-O2-O3-Ar mixtures with an excimer laser. From laser-focusing ignition experiments, we found that the Minimum Incident Laser Energy for ignition (MILE) decreased drastically with the concentration of ozone, and the plane ignition was possible with a laser sheet, providing the possibility of the bulk ignition with UV light. The schlieren observation of the process of plane ignition with a high-speed framing camera showed that the float part of mixture irradiated with the laser sheet ignited simultaneously. And then, the flame kernel grew extremely rapidly.