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Title: Increase of unit efficiency by improved waste heat recovery

Abstract

For coal-fired power plants with flue gas desulfurization by wet scrubbing and desulfurized exhaust gas discharge via cooling tower, a further improvement of new power plant efficiency is possible by exhaust gas heat recovery. The waste heat of exhaust gas is extracted in a flue gas cooler before the wet scrubber and recovered for combustion air and/or feedwater heating by either direct or indirect coupling of heat transfer. Different process configurations for heat recovery system are described and evaluated with regard to net unit improvement. For unite firing bituminous coal an increase of net unit efficiency of 0.25 to 0.7 percentage points and for lignite 0.7 to 1.6 percentage points can be realized depending on the process configurations of the heat recovery systems.

Authors:
;
Publication Date:
Research Org.:
Power Generation Group (DE)
OSTI Identifier:
20015053
Resource Type:
Conference
Resource Relation:
Conference: 1998 International Joint Power Generation Conference, Baltimore, MD (US), 08/23/1998--08/26/1998; Other Information: Available as a 2 Volume set for $175.00; PBD: 1998; Related Information: In: Proceedings of the 1998 international joint power generation conference (PWR-Vol. 33). Volume 2: Power, by Legler, J. [ed.], 983 pages.
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 20 FOSSIL-FUELED POWER PLANTS; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; FOSSIL-FUEL POWER PLANTS; COAL; WASTE HEAT UTILIZATION; FLUE GAS; HEAT RECOVERY EQUIPMENT

Citation Formats

Bauer, G., and Lankes, F.. Increase of unit efficiency by improved waste heat recovery. United States: N. p., 1998. Web.
Bauer, G., & Lankes, F.. Increase of unit efficiency by improved waste heat recovery. United States.
Bauer, G., and Lankes, F.. 1998. "Increase of unit efficiency by improved waste heat recovery". United States. doi:.
@article{osti_20015053,
title = {Increase of unit efficiency by improved waste heat recovery},
author = {Bauer, G. and Lankes, F.},
abstractNote = {For coal-fired power plants with flue gas desulfurization by wet scrubbing and desulfurized exhaust gas discharge via cooling tower, a further improvement of new power plant efficiency is possible by exhaust gas heat recovery. The waste heat of exhaust gas is extracted in a flue gas cooler before the wet scrubber and recovered for combustion air and/or feedwater heating by either direct or indirect coupling of heat transfer. Different process configurations for heat recovery system are described and evaluated with regard to net unit improvement. For unite firing bituminous coal an increase of net unit efficiency of 0.25 to 0.7 percentage points and for lignite 0.7 to 1.6 percentage points can be realized depending on the process configurations of the heat recovery systems.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1998,
month = 7
}

Conference:
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  • Possibility of the use of the wasted heat energy of condensation of an old 32 MW steam turbine unit with the cooling tower system in the regimes of the permitted range of the vacuum conditions was analyzed. Using the computer program TURBOEX for this unit, the different regime loads in designed and also low vacuum conditions were calculated. Great coincidence between the results of the calculations and the designed data ground also the validity of the results of the calculations in the extrapolated region of the low vacuum. The obtained disposive temperature level (55 C) of the cooling water atmore » the output of condenser in the range of the permitted operating regime loads (below the alarm limit low vacuum set as 80% of vacuum) enables the economical use of the wasted heat energy of condensation for the low-temperatures consumers, like a green house. The large increase of the efficiency obtained in this way with the electric and heat energy production in cogeneration without steam turbine unit reconstruction gives hope that this proposition could be very profitable and this fact could be a good reason for the new life prolongation of this old unit.« less
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  • Modern diesel engines used in light-duty transportation applications have peak brake thermal efficiencies in the range of 40-42% for high-load operation with substantially lower efficiencies at realistic road-load conditions. Thermodynamic energy and exergy analysis reveals that the largest losses from these engines are due to heat loss and combustion irreversibility. Substantial improvement in overall engine efficiency requires reducing or recovering these losses. Unfortunately, much of the heat transfer either occurs at relatively low temperatures resulting in large entropy generation (such as in the air-charge cooler), is transferred to low-exergy flow streams (such as the oil and engine coolant), or ismore » radiated or convected directly to the environment. While there are significant opportunities for recovery from the exhaust and EGR cooler for heavy-duty applications, the potential benefits of such a strategy for light-duty applications are unknown due to transient operation, low-load operation at typical driving conditions, and the added mass of the system. We have developed an organic Rankine cycle model using GT-Suite to investigate the potential for efficiency improvement through waste-heat recovery from the exhaust and EGR cooler of a light-duty diesel engine. Results from steady-state and drive-cycle simulations are presented, and we discuss strategies to address operational difficulties associated with transient drive cycles and competition between waste-heat recovery systems, turbochargers, aftertreatment devices, and other systems for the limited thermal resources.« less
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