Evaluation of thermal NOx emission characteristics of high efficiency gas turbines using refuse-recovered low BTU gases

Lee

Ahn

2009

SUMMARYIt is becoming more important to realize CO 2 -capturing power generation systems (PGSs) for drastically decreasing an amount of CO 2 emission into the atmosphere. However, net power generation efficiency (NPGE) of a CO 2 -capturing system has been considered to be greatly deteriorated, since capturing CO 2 requires extra energy. This paper proposes a new CO 2 -capturing PGS that has a high-efficient NPGE by utilizing waste heat from factories. As an example of a waste heat, exhaust gas with temperature 2001C from refuse incinerator plants is adopted. In the proposed system, the temperature of saturated steam produced by utilizing the waste heat is raised by combusting fuel with the use of pure oxygen in a combustor, and is used as the main working fluid of a gas turbine PGS. It is estimated that the proposed system has a fuel-to-electricity NPGE of 59.3%, when turbine inlet temperature (TIT) is assumed to be 10001C. The economics of the proposed system is also evaluated and the CO 2 reduction cost is estimated to be small; 4.16 U.S. $ t À1 CO 2 compared with 32.1 U.S. $ t À1 CO 2 for a conventional steam turbine PGS. It is shown that CO 2 -capturing is not cost consuming but becomes to be profitable owing to improved power generation characteristics, when its TIT is increased from 1000 to 12001C.

Section: Outline Of the Proposed Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comprehensive evaluation of a CO2-capturing high-efficiency power generation system for utilizing waste heat from factories

Lee

Ahn

2009

“…The fuel is burnt by using O 2 , and so combustion reaction is taken place in the combustor without N 2 gas. Hence no thermal NO x is produced in the proposed system when carbon hydride fuel is used 6–8.…”

Section: Outline and Advantages Of Proposed Systemmentioning

confidence: 99%

“…As for CO 2 ‐capturing technologies, there exist pre‐combustion, post‐combustion and oxy‐combustion methods 1–3. Among them the oxy‐combustion method has the following novel features: the system based on it becomes a semi‐closed system and so can capture nearly 100% of produced CO 2 in principle 4, 5, and generates no thermal nitrogen 6–8. To produce oxygen (O 2 ), however, equipment for O 2 production and extra much energy are required compared with the system in which no O 2 is produced.…”

Section: Introductionmentioning

confidence: 99%

Characteristic evaluation of a CO2-capturing repowering system based on oxy-fuel combustion and exergetic flow analyses for improving efficiency

Lee

Ahn

2010

SUMMARYA CO 2 -capturing H 2 O turbine power generation system based on oxy-fuel combustion method is proposed to decrease CO 2 emission from an existing thermal power generation system (TPGS) by utilizing steam produced in the TPGS. A high efficient combined cycle power generation system (CCPS) with reheat cycle is adopted as an example of existing TPGSs into which the proposed system is retrofitted. First, power generation characteristics of the proposed CO 2 -capturing system, which requires no modification of the CCPS itself, are estimated. It is shown through simulation study that the proposed system can reduce 26.8% of CO 2 emission with an efficiency decrease by 1.20% and an increase power output by 23.2%, compared with the original CCPS. Second, in order to improve power generation characteristics and CO 2 reduction effect of the proposed system, modifications of the proposed system are investigated based on exergetic flow analyses, and revised systems are proposed based on the obtained results. Finally, it is shown that a revised proposed system, which has the same turbine inlet temperature as the CCPS, can increase power output by 33.6%, and reduce 32.5% of CO 2 emission with exergetic efficiency decrease by 1.58%, compared with the original CCPS.

Thermodynamical, economical and environmental evaluation of high efficiency gas turbine cogeneration systems

Suzuki

1990

Self Cite

The paper evaluates the thermodynamical, economical and environmental characteristics of a cogeneration system composed of a gas turbine and a waste heat boiler (system A). Two other systems for increasing power generating efficiency are also evaluated, namely systems B and C, which are constructed by incorporating a regenerative cycle and a dual fluid cycle, respectively, into system A. It has been estimated that system C satisfies an environmental constraint that the nitrogen oxide density exhausted should be less than 100 parts in 106, and that systems A and B also satisfy this constraint if a small amount of steam is injected into the combustor. The power generating efficiencies of systems A and B, in this case, and that of system C have been estimated to be 33.5%, 38.5% and 41.2%, respectively; i.e. the efficiencies of systems B and C can be improved noticeably compared with that of system A. The economics of these systems have also been evaluated based on the value of a profit index, and the systems are all estimated to be economically viable under the conditions assumed. As a result, it has been shown that it is possible to construct cogeneration systems with satisfactory characteristics of both environmental protection and profitability if system A is used in districts where the heat demand is large, system C in districts where the heat demand is small, and system B in districts with intermediate heat demand.