Performance Analysis and Optimization of Flue Gas Waste Heat Recovery System of a 600MW Coal-Fired Power Plant

2020 ◽  
Author(s):  
Xun Chen ◽  
Shu Xu ◽  
Yi Yang ◽  
Li-min Wang ◽  
Dun-dun Wang
Keyword(s):  
Performance Analysis ◽  
Flue Gas ◽  
Waste Heat ◽  
Structural Characteristics ◽  
Heating System ◽  
Heat Transfer Process ◽  
Dew Point ◽  
Air Preheater ◽  
Waste Heat Recovery System ◽  
Saving Effect

Abstract Recovering the waste heat of the flue gas from the boilers of coal-fired units, so that part of the boiler’s flue gas waste heat can be utilized in the turbine regenerative heating system is an important way to increase efficiency and reduce emissions of coal-fired units. In this paper, a 600MW supercritical coal-fired unit is taken as an example, and the conceptual design of a flue gas waste heat cascade utilization system is carried out. Based on the first and second laws of thermodynamics, the thermodynamic perfection of the heat transfer process of the rotary regenerative air preheater, the exergy efficiency of the heat displacement process of the flue gas waste heat cascade utilization system, and the overall performance parameters of the coal-fired unit are calculated and analyzed under different parameters such as the bypass flue ratio and the inlet air temperature of the regenerative air preheater. The energy-saving effect of flue gas waste heat cascade utilization system is restricted by factors such as acid dew point temperature, ammonium bisulfate (ABS) deposition inside the air preheater, etc. Based on the performance analysis of regenerative air preheater and ABS deposition law, considering the structural characteristics and operating parameters of air preheater, this paper gives a criterion number (R-number) of ABS deposition tendency, and analyzes the actual operation performance of flue gas waste heat cascade utilization system considering the restrictions.

scholarly journals Modified High Back-Pressure Heating System Integrated with Raw Coal Pre-Drying in Combined Heat and Power Unit

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2487 ◽  
Author(s):  
Heng Chen ◽  
Zhen Qi ◽  
Qiao Chen ◽  
Yunyun Wu ◽  
Gang Xu ◽  
...  
Keyword(s):  
Power Generation ◽  
Flue Gas ◽  
Waste Heat ◽  
Heating System ◽  
Combined Heat And Power ◽  
Back Pressure ◽  
Coal Consumption ◽  
Heating Capacity ◽  
Boiler Efficiency ◽  
Saving Effect

A conceptual high-back pressure (HBP) heating system cooperating raw coal pre-drying for combined heat and power (CHP) was proposed to improve the performance of the HBP-CHP unit. In the new design, besides of heating the supply-water of the heating network, a portion of the exhaust steam from the turbine is employed to desiccate the raw coal prior to the coal pulverizer, which further recovers the waste heat of the exhaust steam and contributes to raising the overall efficiency of the unit. Thermodynamic and economic analyzes were conducted based on a typical 300 MW coal-fired HBP-CHP unit with the application of the modified configuration. The results showed that the power generation thermal efficiency promotion of the unit reaches 1.7% (absolute value) owing to suggested retrofitting, and meanwhile, the power generation standard coal consumption rate is diminished by 5.8 g/kWh. Due to the raw coal pre-drying, the energy loss of the exhaust flue gas of the boiler is reduced by 19.1% and the boiler efficiency increases from 92.7% to 95.4%. The impacts of the water content of the dried coal and the unit heating capacity on the energy-saving effect of the new concept were also examined.

scholarly journals Experiment Comparison between Engineering Acid Dew Point and Thermodynamic Acid Dew Point

2018 ◽  
Vol 38 ◽  
pp. 04008 ◽  
Author(s):  
Jinghui Song ◽  
Hui Yuan ◽  
Jianhua Deng
Keyword(s):  
Flue Gas ◽  
Pipe Wall ◽  
Waste Heat ◽  
Coupling Effect ◽  
Dew Point ◽  
Air Preheater ◽  
Heat Utilization ◽  
Actual Operation ◽  
Waste Heat Utilization ◽  
Coal Type

in order to realize the accurate prediction of acid dew point, a set of measurement system of acid dew point for the flue gas flue gas in the tail of the boiler was designed and built, And measured at the outlet of an air preheater of a power plant of 1 000 MW, The results show that: Under the same conditions, with the test temperature decreases, Nu of heat transfer tubes, fouling and corrosion of pipe wall and corrosion pieces gradually deepened. Then, the measured acid dew point is compared with the acid dew point obtained by using the existing empirical formula under the same coal type. The dew point of engineering acid is usually about 40 ℃ lower than the dew point of thermodynamic acid because of the coupling effect of fouling on the acid liquid, which can better reflect the actual operation of flue gas in engineering and has certain theoretical guidance for the design and operation of deep waste heat utilization system significance.

A study on air-cooling waste heat recovery from molten slag of slag-tap boilers

2017 ◽  
Vol 231 (5) ◽  
pp. 371-381
Author(s):  
Lei Deng ◽  
Chunli Tang ◽  
Xiaowen Tan ◽  
Ke Sun ◽  
Song Wu ◽  
...  
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Molten Slag ◽  
Waste Heat ◽  
Ash Content ◽  
Air Cooling ◽  
Air Preheater ◽  
Hot Air ◽  
Secondary Air

For a better utilization of Zhundong coals which have high fouling and slagging tendency, the slag-tap boiler has attracted much attention. To avoid the high sensible heat loss of discharged molten slag, an air-cooling waste heat recovery system is proposed. Energy and economic analyses are conducted to investigate the effectiveness of heating the desulfurized flue gas by hot air and the influences of partially substituting the secondary air by hot air on heat transfer of air preheater and thermal efficiency of boiler. A case study is performed by referring to a typical 50 MW cyclone boiler with nine types of low fusion temperature coals. The results show that for coals with low ash content, the temperature increment of desulfurized flue gas can be over 7 ℃. While for coals with high ash content, the flue gas temperature can be heated to more than 70 ℃, and the surplus hot air can be sent to the furnace. When the hot air is introduced to partially substitute the secondary air, an instantaneous impact on the air preheater will give rise to a decrement of quantity of heat transferred and increments of temperatures of exit flue gas and hot secondary air. The variations of these thermodynamic parameters become smaller with increasing hot air temperature. After introduction of hot air, the thermal efficiency of boiler can increase, resulting in a decrease of fuel consumption rate. In addition, the heating surface area of air preheater can be reduced.

Novel flue gas waste heat recovery system equipped with enthalpy wheel

2019 ◽  
Vol 196 ◽  
pp. 649-663 ◽  
Author(s):  
Yiyu Men ◽  
Xiaohua Liu ◽  
Tao Zhang ◽  
Xi Xu ◽  
Yi Jiang
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

The Comparison and Analysis of the System Utilizing the General Boiler Flue Gas Waste Heat

2014 ◽  
Vol 926-930 ◽  
pp. 829-832
Author(s):  
Yan Feng Liu ◽  
Peng Cheng Wang ◽  
Shao Shan Zhang
Keyword(s):  
Low Temperature ◽  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System ◽  
Comparison And Analysis ◽  
Gas Recycling

Flue gas recycling system is an effective way of saving energy and improving efficiency for coal-fired power plant. In this paper, the general low-temperature economizer, heat pipe type low temperature economizer, composite phase change heat recovery system are introduced. Combined with a 600MW unit parameters, the economies of various waste heat recovery system are compared.

Methods of Thermal Calculations for a Condensing Waste-Heat Exchanger

2014 ◽  
Vol 35 (4) ◽  
pp. 447-461 ◽  
Author(s):  
Paweł Rączka ◽  
Kazimierz Wójs
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Water Vapour ◽  
Flue Gas ◽  
Waste Heat ◽  
Pilot Scale ◽  
Dew Point ◽  
Steam Boiler ◽  
Heat Transfer Area ◽  
Condensing Heat Exchanger

Abstract The paper presents the algorithms for a flue gas/water waste-heat exchanger with and without condensation of water vapour contained in flue gas with experimental validation of theoretical results. The algorithms were used for calculations of the area of a heat exchanger using waste heat from a pulverised brown coal fired steam boiler operating in a power unit with a capacity of 900 MWe. In calculation of the condensing part, the calculation results obtained with two algorithms were compared (Colburn-Hobler and VDI algorithms). The VDI algorithm allowed to take into account the condensation of water vapour for flue gas temperatures above the temperature of the water dew point. Thanks to this, it was possible to calculate more accurately the required heat transfer area, which resulted in its reduction by 19 %. In addition, the influence of the mass transfer on the heat transfer area was taken into account, which contributed to a further reduction in the calculated size of the heat exchanger - in total by 28% as compared with the Colburn-Hobler algorithm. The presented VDI algorithm was used to design a 312 kW pilot-scale condensing heat exchanger installed in PGE Belchatow power plant. Obtained experimental results are in a good agreement with calculated values.

Performance analysis of a thermoelectric generator applied to wet flue gas waste heat recovery

2018 ◽  
Vol 228 ◽  
pp. 2080-2089 ◽  
Author(s):  
Yulong Zhao ◽  
Shixue Wang ◽  
Minghui Ge ◽  
Yanzhe Li ◽  
Zhaojun Liang ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Thermoelectric Generator ◽  
Waste Heat

scholarly journals The Thermal Economy of a Circulating Medium and Low Temperature Waste Heat Recovery System of Industrial Flue Gas

2021 ◽  
Vol 39 (5) ◽  
pp. 1680-1688
Author(s):  
Xutong Wang ◽  
Meng Zhang
Keyword(s):  
Low Temperature ◽  
Flue Gas ◽  
Industrial Waste ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System ◽  
Industrial Waste Heat

The waste heat recovered by traditional industrial waste heat recovery systems is mostly high-temperature flue gas and combustible gas, while the waste heat of medium and low temperature flue gas that accounts for more than 50% of the total waste heat resources has been ignored, which is not conducive to the effective energy saving of industrial production and manufacturing process. In the meantime, few studies have concerned about the changes in the economy of circulating industrial waste heat recovery system. Therefore, to fill in this research gap, this paper aimed at the economy problem of circulating medium and low temperature industrial waste heat recovery system and carried out a series of research. The paper completed the thermodynamic analysis of different medium and low temperature waste heat recovery modes of industrial flue gas, and gave the analysis steps of the economy of circulating medium and low temperature waste heat recovery system of industrial flue gas. The effectiveness and accuracy of the thermodynamic and thermo-economic models constructed in the paper were proved by experimental results.

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