Application of a low pressure economizer for waste heat recovery from the exhaust flue gas in a 600 MW power plant

Wang, Chaojun; He, Boshu; Sun, Song; Wu, Ying; Yan, Ning; Yan, Linbo; Pei, Xiaohui

doi:10.1016/j.energy.2012.01.045

Cited by 164 publications

(65 citation statements)

References 6 publications

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“…As seen in Table 2, considering the flue gas temperature of the LTE is only 131-100 • C, which can only be used to heat the condensed water of RH6 at most (83.3-122.1 • C). On the other hand, the outlet condensed water temperature of the LTE is set to 116 • C, slightly lower than 122.1 • C, which ensures the minimum heat transfer temperature difference of the LTE is maintained over 15 • C [21]. Overall, the total investment cost of the conventional WHUS can be maintained at a relatively acceptable level.…”

Section: Conventional Waste Heat Recovery Systemmentioning

confidence: 97%

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An Improved System for Utilizing Low-Temperature Waste Heat of Flue Gas from Coal-Fired Power Plants

Huang

Tan

et al. 2017

Entropy

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Abstract:In this paper, an improved system to efficiently utilize the low-temperature waste heat from the flue gas of coal-fired power plants is proposed based on heat cascade theory. The essence of the proposed system is that the waste heat of exhausted flue gas is not only used to preheat air for assisting coal combustion as usual but also to heat up feedwater and for low-pressure steam extraction. Air preheating is performed by both the exhaust flue gas in the boiler island and the low-pressure steam extraction in the turbine island; thereby part of the flue gas heat originally exchanged in the air preheater can be saved and introduced to heat the feedwater and the high-temperature condensed water. Consequently, part of the high-pressure steam is saved for further expansion in the steam turbine, which results in additional net power output. Based on the design data of a typical 1000 MW ultra-supercritical coal-fired power plant in China, an in-depth analysis of the energy-saving characteristics of the improved waste heat utilization system (WHUS) and the conventional WHUS is conducted. When the improved WHUS is adopted in a typical 1000 MW unit, net power output increases by 19.51 MW, exergy efficiency improves to 45.46%, and net annual revenue reaches USD 4.741 million while for the conventional WHUS, these performance parameters are 5.83 MW, 44.80% and USD 1.244 million, respectively. The research described in this paper provides a feasible energy-saving option for coal-fired power plants.

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Section: Conventional Waste Heat Recovery Systemmentioning

confidence: 97%

“…To achieve this, low-temperature economizers (LTEs) are usually configured after or parallel to the air preheater to recover the waste heat from the flue gas to heat up a part of the condensate water [21,22].…”

Section: Introductionmentioning

confidence: 99%

An Improved System for Utilizing Low-Temperature Waste Heat of Flue Gas from Coal-Fired Power Plants

Huang

Tan

et al. 2017

Entropy

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“…Comparatively, the utilization of exhaust energy in the heating of condensed water is given considerable attention worldwide [7][8][9][10]. On one hand, energy utilization in the heating of condensed water is a relatively mature technology and easy to realize; on the other hand, it can save a large amount of extracted steam to increase unit efficiency and to reduce energy consumption dramatically.…”

Section: Introductionmentioning

confidence: 99%

Techno-economic analysis and optimization of the heat recovery of utility boiler flue gas

et al. 2013

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“…Boiler flue gases contain substantial heat energy. This energy can be utilized to preheat the boiler feed water through economizer (Chaojun et al, 2012). It is well known that the utilization of waste heat of flue gases is of the best possibilities for reduction of the green house gases emissions.…”

Section: Introductionmentioning

confidence: 99%

Waste Heat Recovery From Boiler of Large-Scale Textile Industry

Pattanapunt¹

2013

American Journal of Environmental Sciences

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Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger. Exhaust gas from boiler dyeing process, which carries a large amount of heat, energy consumptions could be decrease by using of waste-heat recovery systems. In this study, using ANASYS simulation performs a thermodynamics analysis. An energy-based approach is performed for optimizing the effective working condition for wasteheat recovery with exhaust gas to air shell and tube heat exchanger. The variations of parameters, which affect the system performance such as, exhaust gas and air temperature, velocity and mass flow rate and moisture content is examined respectively. From this study, it was found that heat exchanger could be reduced temperature of exhaust gases and emission to atmosphere and the time payback is the fastest. The payback period was determined about 6 months for investigated ANSYS. The air is circulated in four passes from the top to the bottom of the test section, in overall counter-flow with exhaust gas. The front area is 1720×1720 mm, the flow length 7500 mm, the inner and outer diameter of exhaust gas is 800 mm, the tube assembly consist of 196 tubes, the tube diameter is 76.2 mm, the tube thickness is 2.6 mm, the tube length is 4500 mm, the tube length of air inner and outer is 500 mm. The result show that, the boiler for superheated type there are exhaust gas temperature is 190°C, 24% the moisture content of fuel and there are palm kernel shell 70 tons day −1 which there are the high temperature after the heat exchanger, 150°C. It was occurred acid rain. The hot air from heat exchanger process can be reduced the moisture of palm kernel shell fuel to 15%.The fuel consumption is reduced by about 2.05% (322.72 kJ kg −1), while the shell and tube heat exchanger outlet exhaust gas temperature decreases from 190 to 150°C.

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Application of a low pressure economizer for waste heat recovery from the exhaust flue gas in a 600 MW power plant

Cited by 164 publications

References 6 publications

An Improved System for Utilizing Low-Temperature Waste Heat of Flue Gas from Coal-Fired Power Plants

An Improved System for Utilizing Low-Temperature Waste Heat of Flue Gas from Coal-Fired Power Plants

Techno-economic analysis and optimization of the heat recovery of utility boiler flue gas

Waste Heat Recovery From Boiler of Large-Scale Textile Industry

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