2. STATUS OF IGCC IN USA AND EUROPE(<小特集>石炭ガス化複合発電技術)
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概要
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Spurred by gas turbine advances, IGCC technology is expected to play a key role in meeting world demand for clean and efficient power. Gas turbine technology, now proven in operation above 200 megawatts, has boosted combined cycle efficiencies as high as 54%. This performance, combined with demonstrated high baseload reliability in large combined cycle installations, is directing the increased use of clean coal technologies toward IGCC. The successful demonstrations of several IGCC plants in the utility size range are paving the way for commercial IGCC plants to be sited in the 1990s. Already, IGCC plants totaling 7,000 megawatts are being planned in Europe and the U. S., while feasibility studies are proceeding for 8,000 more megawatts worldwide. The shift toward greater use of IGCC is being driven by major advances in gas turbine technology achieved over the past decade. For example, sophisticated materials and cooling methods developed initially for GE aircraft engines have been adapted to GE's proven heavy-duty gas turbine designs. As a result, GE has been able to raise the firing temperature of the new F technology gas turbines by 200℃ ・ ・to 1288℃ (2,350°F) ・ ・yielding a 10% fuel savings plus higher output levels. This improved performance mitigates the penalty of creating a clean gasified fuel. Operating reliability also has been improved. These advanced, gas turbines frequently are used as baseload machines, often in combined cycle configuration with a steam turbine. Offering a powerful combination of power density, fuel flexibility, efficiency and reliability, these combined cycle power plants are positioned to play a leading role in meeting the demand for new power generation, particularly for IGCC applications. Adding a gasification system to an advanced combined cycle usually involves integrating the technologies into a single power plant although fuel gas can be provided over the fence (Fig 1). IGCC requires close coordination among the gasifier supplier, cleanup system. oxidant system and the combined cycle supplier. Coal is partially oxidized and cooled to a temperature required for cleanup. After sulfur, particulates, Halogens and hazardous air pollutants are removed, the resulting low heating value (LHV) gas is an excellent, fuel, for the combined cycle. This process produces a 15% savings in coal use compared to conventional steam plants using FGD, and can reduce most air emissions by a factor of 10. A new GE hot gas cleanup system, is' being developed that performs gas cleanup without prior cooling of the gas, removing more than 99% of the sulfur and boosting cycle efficiency. The gasification and cleanup stages produce two primary byproducts ・・ saleable elemental sulfur and coal ash. This ash, containing most of the difficult constituents of coal, is in the form of a glassy slag. Today's combined cycle technology delivers superior cycle efficiency which more than offsets the inherent fuel processing losses associated with coal gasification. New gas turbine combined cycles can operate on clean fuel at 54% (LHV) net thermal efficiency while gasification processes operate from 75 to 90% efficiency. Using 85% as a currently feasible level, a 46% net plant efficiency (LHV) can be expected for coal-fired combined cycles. As gas turbine developments continue, the trend for IGCC will follow directly.
- 公益社団法人日本ガスタービン学会の論文
- 1993-06-10