Organic Rankine Cycle
Waste Heat to Power ORC search was updated real-time via Filemaker on:Waste Heat to Power ORC | Return to Search List
Search Completed | Title | Combustion technology developments in power generation in response to environmental challenges
Original File Name Searched: Beer_2000.pdf | Google It | Yahoo | Bing
Text | Combustion technology developments in power generation in response to environmental challenges | 001
PERGAMON Progress in Energy and Combustion Science 26 (2000) 301–327
Combustion technology developments in power generation in response to environmental challenges
J.M. Bee ́r*
Department of Chemical Engineering, Room 66-548, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
Received 27 October 1999; revised 28 March 2000; accepted 28 March 2000
Combustion system development in power generation is discussed ranging from the pre-environmental era in which the objectives were complete combustion with a minimum of excess air and the capability of scale up to increased boiler unit performances, through the environmental era (1970–), in which reduction of combustion generated pollution was gaining increasing importance, to the present and near future in which a combination of clean combustion and high thermodynamic efficiency is considered to be necessary to satisfy demands for CO2 emissions mitigation.
From the 1970s on, attention has increasingly turned towards emission control technologies for the reduction of oxides of nitrogen and sulfur, the so-called acid rain precursors. By a better understanding of the NOx formation and destruction mechanisms in flames, it has become possible to reduce significantly their emissions via combustion process modifications, e.g. by maintaining sequentially fuel-rich and fuel-lean combustion zones in a burner flame or in the combustion chamber, or by injecting a hydrocarbon rich fuel into the NOx bearing combustion products of a primary fuel such as coal.
Sulfur capture in the combustion process proved to be more difficult because calcium sulfate, the reaction product of SO2 and additive lime, is unstable at the high temperature of pulverized coal combustion. It is possible to retain sulfur by the application of fluidized combustion in which coal burns at much reduced combustion temperatures. Fluidized bed combustion is, however, primarily intended for the utilization of low grade, low volatile coals in smaller capacity units, which leaves the task of sulfur capture for the majority of coal fired boilers to flue gas desulfurization.
During the last decade, several new factors emerged which influenced the development of combustion for power generation. CO2 emission control is gaining increasing acceptance as a result of the international greenhouse gas debate. This is adding the task of raising the thermodynamic efficiency of the power generating cycle to the existing demands for reduced pollutant emission. Reassessments of the long-term availability of natural gas, and the development of low NOx and highly efficient gas turbine–steam combined cycles made this mode of power generation greatly attractive also for base load operation.
However, the real prize and challenge of power generation R&D remains to be the development of highly efficient and clean coal-fired systems. The most promising of these include pulverized coal combustion in a supercritical steam boiler, pressurized fluid bed combustion without or with topping combustion, air heater gas turbine-steam combined cycle, and integrated gasification combined cycle. In the longer term, catalytic combustion in gas turbines and coal gasification-fuel cell systems hold out promise for even lower emissions and higher thermodynamic cycle efficiency. The present state of these advanced power-generating cycles together with their potential for application in the near future is discussed, and the key role of combustion science and technology as a guide in their continuing development highlighted. 2000 Elsevier Science Ltd. All rights reserved.
Keywords: Combustion; Power generation; Combined cycles; Air pollution control
* Tel.: 1-617-253-6661; fax: 1-617-253-3122. E-mail address: email@example.com (J.M. Bee ́r).
0360-1285/00/$ - see front matter 2000 Elsevier Science Ltd. All rights reserved. PII: S0360-1285(00)00007-1
Image | Combustion technology developments in power generation in response to environmental challenges
|Waste Heat to Power - ORC - - Waste Heat to Power System - Go to website|
Search Engine Contact: firstname.lastname@example.org