Characteristics and economics of high-efficiency gas turbine cogeneration systems using low BTU gas

Self Cite

The Economics of a cogeneration system for district heating and cooling (CGS) depend not only on the exergetic efficiencies of generating heat and power, but also on various other factors such as the capacity factor, the construction cost of the CGS, and the annual cost rate for the construction cost. One of economic difficulties of a CGS constructed in Japan lies in the fact that capacity factor of the CGS is very low. A previously proposed profit index has the advantage that it makes it easily possible to evaluate the economic viability of a CGS based on its various fundamental economic and technological factors determining its economics. Sensitivity analyses of the various factors can also easily be performed.

mentioning

confidence: 99%

Reply to comments on ‘derivation of an index for evaluating economics of cogeneration systems and its applications’

Pak¹,

Suzuki²

1990

Self Cite

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

Pak

Suzuki

1989

Self Cite

The paper evaluates thermal NOx formation characteristics of high efficiency gas turbines using refuse‐recovered low Btu gases. First, an estimation model of nitric oxide (NO) formation density for the gas turbine is constructed by revising a model proposed by W. S. Y. Hung. Next, taking a gas turbine burning high Btu gas with a turbine inlet temperature of 1273 K as a reference case, its NO emission density is estimated. Parametric analyses are done on the parameters that greatly affect the NO formation characteristics for the reference gas turbine, and it is shown that there is a limit to the possible NO density reduction by only controlling these parameters. Thirdly, the effects on the NO density of increasing gas turbine efficiency, by incorporating a regenerator or by raising turbine inlet temperature, are investigated. It is shown that the NO density of a gas turbine with a high efficiency is estimated to be higher than the assumed environmental quality standard (EQS) value. Finally, by utilizing these results, the cases are investigated where refuse‐recovered low Btu fuels such as pyrolysis gas from municipal refuse are used. It is shown that the NO densities in these cases are estimated to be notably lower than the EQS value. Further, it is demonstrated that the use of low Btu fuel does not necessarily assure a low NO density, since the NO density is not determined only by the heating value of the fuel.

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

Pak

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.