scholarly journals Performance Analysis of the Technology of High-Temperature Boiler Feed Water to Recover the Waste Heat of Mid–Low-Temperature Flue Gas

ACS Omega ◽  
2021 ◽  
Author(s):  
Weigang Xu ◽  
Yuzhen Jin ◽  
Linhang Zhu ◽  
Zeqing Li
Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3969
Author(s):  
Shidan Chi ◽  
Tao Luan ◽  
Yan Liang ◽  
Xundong Hu ◽  
Yan Gao

To address the large temperature difference in the air heater (AH) inlet of a traditional exhaust heat utilization system and energy grade mismatch problems during the heat and mass transfer processes, this study proposed a new multi-level waste heat cascade utilization system. Based on a principle of “temperature-to-port and cascade utilization”, this system uses the boiler side high-temperature flue gas and low-temperature air, and the turbine side high-temperature feed water and low-temperature condensate water, to conduct cross heat exchange according to the energy grade matching principle. Combined with a typical 1000 MW coal-fired unit, the heat transfer characteristics and energy-saving benefits of the new system were analyzed. The results showed that the new system has excellent performance: the heat rate decreased by 91 kJ/kWh, coal consumption decreased by 3.3 g/kWh, and power generation efficiency increased to 49.39%.


Author(s):  
Maximilian Rödder ◽  
Matthias Neef ◽  
Christoph Laux ◽  
Klaus-P. Priebe

The organic Rankine cycle (ORC) is an established thermodynamic process that converts waste heat to electric energy. Due to the wide range of organic working fluids available the fluid selection adds an additional degree of freedom to the early design phase of an ORC process. Despite thermodynamic aspects such as the temperature level of the heat source, other technical, economic and safety aspects have to be considered. For the fluid selection process in this paper, 22 criteria were identified in six main categories while distinguishing between elimination and tolerance criteria. For an ORC design, the suggested method follows a practical engineering approach and can be used as a structured way to limit the number of interesting working fluids before starting a detailed performance analysis of the most promising candidates. For the first time the selection process is applied to a two-stage reference cycle which uses the waste heat of a large reciprocating engine for cogeneration power plants. It consists of a high temperature and a low temperature cycle in which the condensation heat of the high temperature (HT) cycle provides the heat input of the low temperature (LT) cycle. After the fluid selection process the detailed thermodynamic cycle design is carried out with a thermodynamic design tool that also includes a database for organic working fluids. The investigated ORC cycle shows a net thermal efficiency of about 17,4% in the high temperature cycle with Toluene as the working fluid and 6,2% in low temperature cycle with iso-Butane as the working fluid. The electric efficiency of the cogeneration plant increases from 40,4% to 46,97% with the both stages of the two-stage ORC in operation.


2020 ◽  
Vol 145 ◽  
pp. 02062
Author(s):  
Canzong Zhou ◽  
Shuyi Chen ◽  
Wei Cui ◽  
Zhengmao Yao

According to the research, thermoelectricity generation can recycle the heat contained in the cooling system of internal combustion engine. This paper is about taking advantage of the feature in the huge temperature difference at about 560 °C which is formed between high-temperature engine and LNG (Liquefied Natural Gas) in low temperature and the ability that LNG provides semiconductor with thermoelectric conversion material so as to produce the maximum output voltage in low temperature. We take advantage of lead telluride materials that adapt to the high temperature environment and bismuth telluride materials that adapt to the low temperature environment, both of which forms a circuit and are designed as a thermoelectric power generation device. Also, we confirm the possibility of applying the device to cars.


Author(s):  
Maximilian Roedder ◽  
Matthias Neef ◽  
Christoph Laux ◽  
Klaus-P. Priebe

The organic Rankine cycle (ORC) is an established thermodynamic process that converts waste heat to electric energy. Due to the wide range of organic working fluids available the fluid selection adds an additional degree-of-freedom to the early design phase of an ORC process. Despite thermodynamic aspects such as the temperature level of the heat source, other technical, economic, and safety aspects have to be considered. For the fluid selection process in this paper, 22 criteria were identified in six main categories while distinguishing between elimination (EC) and tolerance criteria (TC). For an ORC design, the suggested method follows a practical engineering approach and can be used as a structured way to limit the number of interesting working fluids before starting a detailed performance analysis of the most promising candidates. For the first time, the selection process is applied to a two-stage reference cycle, which uses the waste heat of a large reciprocating engine for cogeneration power plants. It consists of a high temperature (HT) and a low temperature (LT) cycle in which the condensation heat of the HT cycle provides the heat input of the LT cycle. After the fluid selection process, the detailed thermodynamic cycle design is carried out with a thermodynamic design tool that also includes a database for organic working fluids. The investigated ORC cycle shows a net thermal efficiency of about 17.4% in the HT cycle with toluene as the working fluid and 6.2% in LT cycle with isobutane as the working fluid. The electric efficiency of the cogeneration plant increases from 40.4% to 46.97% with the both stages of the two-stage ORC in operation.


2013 ◽  
Vol 448-453 ◽  
pp. 2777-2780 ◽  
Author(s):  
Yan Feng Liu ◽  
Shi Ping Li ◽  
Xiang Hong Li

A 215MW cogeneration B&W670/13.7-M type high-pressure natural circulation boilers, the exhaust gas temperature is set as 143 °C, while in the actual operation, the average exhaust gas temperature is 155 °C, and when the unit is running at full capacity in summer the highest exhaust gas temperature is 169.6 °C. In order to satisfy the normal operating temperature of bag filter in summer peak load, and recover low temperature waste heat of fule gas, low temperature economizer is added to the thermal system. Therefore, low-temperature economizers are respectively added in four flues which are between the outlet of the air preheater and the entrance of the bag filter, this will achieve the purpose of reducing flue gas temperature by transferring heat between condensate and flue gas, ensuring the units safe operating and improving the overall operating performance of the boiler.


2014 ◽  
Vol 926-930 ◽  
pp. 829-832
Author(s):  
Yan Feng Liu ◽  
Peng Cheng Wang ◽  
Shao Shan Zhang

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.


Author(s):  
Chunli Tang ◽  
Jianbo Li ◽  
Qingwen Qi ◽  
Chang’an Wang ◽  
Defu Che

A novel flue gas treatment system was proposed in this paper. The system integrates the low pressure economizer (LPE) with the desulphurized flue gas heater (DFGH) for both waste heat recovery of the exhaust gas and the desulphurized flue gas heating. A model for the system was established based on the equivalent enthalpy drop theory. The thermal economic comparisons among 5 feasible connection schemes for the flue gas treatment system of a 300 MW unit were executed. The parametric analyses were also performed to evaluate the effects of the outlet flue gas temperature and the condensate temperature of the DFGH. Results indicate that the optimized flue gas treatment system can improve the thermal economy and heat the desulphurized flue gas. Better thermal economy is achieved when the LPE is connected with the high energy level feed water heater, and the low pressure extraction steam is extracted for heating desulphurized flue gas. The thermal economy decreases with the increase of the outlet flue gas temperature of the DFGH while it increases slightly with the decrease of the condensate temperature of the DFGH.


2018 ◽  
Vol 228 ◽  
pp. 2080-2089 ◽  
Author(s):  
Yulong Zhao ◽  
Shixue Wang ◽  
Minghui Ge ◽  
Yanzhe Li ◽  
Zhaojun Liang ◽  
...  

2012 ◽  
Vol 581-582 ◽  
pp. 1172-1175
Author(s):  
Long Fei Yan ◽  
Min Xiao ◽  
Shi Hong Zhang

Because exhaust gas of the natural gas catalytic combustion is clean and sterile, the exhaust gas can be used in aseptic boxes, high-temperature exhaust gas pre-sterilization of the aseptic box, the continuous low temperature flue gas pass into the sterile containers, aseptic containers in during use to maintain a clean and sterile, and has greatly improved the device and working environment of the sterile boxes.


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