A CO₂‐recovering nonpolluting high‐efficiency gas‐turbine power‐generation system utilizing saturated steam as its working gas

Abstract

A carbon dioxide‐recovering high‐efficiency gas‐turbine power‐generation system is proposed in which carbon dioxide (CO2) generated is recovered by adopting the oxygen (O2) combustion method and no thermal nitrogen oxide is generated. In the system, saturated steam produced by utilizing waste heat is adopted as the working fluid of the gas turbine. Thus, the compressing process of the working fluid gas, which is the most energy‐consuming process in generating power by using a gas turbine, is not needed. This makes the system extremely high efficient. By taking saturated steam of 210°C as an example, the characteristics of the system were simulated. The net exergetic efficiency of the system has been estimated to be 48.4 percent by considering both the exergy of the saturated steam and the electric power required not only to generate high‐pressure oxygen, but also to liquefy the recovered CO2. The value is higher than the exergetic efficiency 37.8 percent of large‐scale thermal power generation plants using the same natural gas, and is 28.0 percent higher than its efficiency of 37.8 percent, the one estimated if the CO2 generated is removed and recovered from the stack gas by using alkanolamine‐based solvent and the recovered CO2 is liquefied.

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

“…The fuel is burned by using O 2 , and so combustion reaction has 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 [9][10][11].…”

“…As for CO 2 capturing technologies, there exist pre-combustion, post-combustion and oxy-combustion methods [4][5][6]. Among them the oxy-combustion method has the following novel features: the system based on it becomes a semiclosed system and so can capture nearly 100% of produced CO 2 in principle [7,8], and generates no thermal nitrogen [9][10][11]. To produce oxygen, however, equipment for oxygen production and extra energy are required compared with the system in which no oxygen is produced.…”

“…First, a conventional steam turbine power generation system (STPS) is evaluated, and the STPS is shown to be economically infeasible. Second, a CO 2 -capturing PGS based on gas turbine (GT) technologies and on the oxy-combustion method [10][11][12][13][14][15][16][17] is proposed to utilize the exhaust gas. The thermodynamic characteristics of the proposed system are evaluated by setting its turbine inlet temperature (TIT), for example, at 10001C.…”

“…Most of steam included in the regenerator outlet gas is condensed at a condenser outlet, and condensate is reused for producing the low-temperature steam. Thus the separation of CO 2 gas, produced as the result of combustion reaction of the fuel, from H 2 O liquid (condensate) can be physically and automatically performed at the outlet of the condenser in the proposed system [10][11][12][13][14][15][16][17].…”

Comprehensive Evaluation of Repowering Systems for Utilizing Waste Heat from Small Scale Garbage Incineration Plants

“…Hence, the system can be expected to be highly efficient, since the most part of turbine output can be used for driving a generator. This is different from a conventional gas turbine power generation system where approximately two thirds of turbine output is consumed to compress the air which is used as the working fluid of the gas turbine (4) . The following is a brief explanation how electric power is generated.…”