Parametric analysis and process optimization of steam cycle in double reheat ultra-supercritical power plants

Zhou, Luyao; Xu, Gang; Zhao, Shifei; Cheng, Xu; Yang, Yongping

doi:10.1016/j.applthermaleng.2016.01.047

Cited by 71 publications

(18 citation statements)

References 17 publications

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“…Therefore, the lowest CO 2 temperature (T 4 , T 4" ) in the tail flue is much higher than the lowest water temperature for the water-steam Rankine cycle which is usually around 340 • C [20]. Here T 4 is considered as the lowest CO 2 temperature in the tail flue.…”

Section: Causes Of Residual Heat Problemmentioning

confidence: 99%

“…Q pri air = a pri m air c p,air T pri air − T priair,in (19) where α pri is the primary air flow rate ratio, T pri air,in is the primary air temperature at the inlet of air preheater. Q sec air = α sec m air c p,air (T sec air − T sec air,in ) (20) where α sec is the secondary air flow rate ratio, T sec air,in is the secondary air temperature at the inlet of air preheater. T fg,o can be obtained from Equations (17)- (20) which is 388.7 • C. This temperature is far below T fg,i which are 580.2 • C and 628.1 • C when turbine inlet temperatures (T 5 ) are 600 • C and 650 • C, respectively.…”

Section: Causes Of Residual Heat Problemmentioning

confidence: 99%

“…For example, recompression cycle is a commonly used S-CO 2 cycle, when the double reheating recompression cycle is applied, the CO 2 temperature at boiler inlet is about 510 • C [18,19]. While this temperature is about 340 • C in the double reheating supercritical water cycle [20]. The great temperature difference means a large amount of residual heat in the tail flue at S-CO 2 coal fired power plant, which restricts the boiler efficiency.…”

Section: Introductionmentioning

confidence: 99%

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How to Construct a Combined S-CO2 Cycle for Coal Fired Power Plant?

Sun

Han

et al. 2018

Entropy

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It is difficult to recover the residual heat from flue gas when supercritical carbon dioxide (S-CO2) cycle is used for a coal fired power plant, due to the higher CO2 temperature in tail flue and the limited air temperature in air preheater. The combined cycle is helpful for residual heat recovery. Thus, it is important to build an efficient bottom cycle. In this paper, we proposed a novel exergy destruction control strategy during residual heat recovery to equal and minimize the exergy destruction for different bottom cycles. Five bottom cycles are analyzed to identify their differences in thermal efficiencies (ηth,b), and the CO2 temperature entering the bottom cycle heater (T4b) etc. We show that the exergy destruction can be minimized by a suitable pinch temperature between flue gas and CO2 in the heater via adjusting T4b. Among the five bottom cycles, either the recompression cycle (RC) or the partial cooling cycle (PACC) exhibits good performance. The power generation efficiency is 47.04% when the vapor parameters of CO2 are 620/30 MPa, with the double-reheating-recompression cycle as the top cycle, and RC as the bottom cycle. Such efficiency is higher than that of the supercritical water cycle power plant.

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Section: Causes Of Residual Heat Problemmentioning

confidence: 99%

Section: Causes Of Residual Heat Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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How to Construct a Combined S-CO2 Cycle for Coal Fired Power Plant?

Sun

Han

et al. 2018

Entropy

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“…The first and second-stage reheat pressure of Case 3 are chosen 90 bar and 27 bar. Because, the first and second stage reheat pressure are equal to 30% of the live steam pressure and first reheat pressure, respectively [28]. The Ebsilon Professional software is used to simulate all the systems in this paper.…”

Section: Case 2 : Single Reheat System With Six-stage Extraction Steamentioning

confidence: 99%

Comparative Energy and Exergy Analysis of a Power Plant With Super-Critical and Sub-Critical

Çetin¹

2018

Journal of Thermal Engineering

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The aim of this study that how to effect live steam parameters reheat and feed water preheater numbers on efficiencies of energy and exergy at coal-fired power plants. Moreover, two desuperheaters and a regenerative turbine are added USCPP (Case 3) to approach best results. Soma Power Plant (Case 1) consists of one reheat stage, two HPRHs and four LPRHs with one DEA. It is operated sub-critic and coal is used for a fuel. Live steam conditions of Soma Power Plant set at 13,92 MPa and 540 C, and the reheat steam is reheated to 540 C. Supercritical Power Plant (Case 2) consists of the same main components of Case 1. However, steam parameters of Case 2 are increased to 262.5 Bar and 600 C to determine impact of the steam parameters on power plant efficiencies. USCPP which consists of two reheat stages, four HPRHs, six LPRHs with one DEA is designed to generate live steam under nominal conditions of 30 Bar and 600 C. Besides, reheat steam are heated to 620 C. Simulations have been carried out Ebsilon Professional software and pressure drops at preheaters and reheats are also considered. Some assumptions are made in the analysis. The thermal and exergy efficiencies of USCPP increase by 9.241 and 8.06 percentage points compared with Soma power plant, respectively. The results of this study that live steam parameters which are increased from sub-critical values to super-critical values have enormous influence on energy and exergy efficiencies. Secondly, adding second reheat stage has positive impact to improve power plant efficiencies. Finally, augmenting feed water preheater number, adding two desuperheater and one regenerative turbine increase power plant efficiencies. However, optimum numbers of feed water preheaters are determined considering economic parameters.

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“…Ekserji analizi uygulanma amacı açısından karar verme mekanizması olarak da kullanılmaktadır. Bu çerçevede, birçok çalışmada sistem performansının olumlu etkilendiği rapor edilmiştir [16][17][18][19][20]. Xiong vd.…”

Section: Introductionunclassified

Çevre Sıcaklığının Dolaşımlı Akışkan Yataklı Kazanın Ekserji Performansı Üzerindeki Etkisi

Yazici

Köse

2019

Bilecik Şeyh Edebali Üniversitesi Fen Bilimleri Dergisi

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Sunulan bu çalışmada, Eskişehir'in Seyitgazi ilçesinde yer alan bir endüstriyel tesisteki 75 t/h buhar kapasiteli dolaşımlı akışkan yataklı kazanın konvansiyonel ekserji analizi yapılmıştır. Yapılan analizde; çevre sıcaklığındaki değişimin, kazan ve hava ısıtıcısının ekserji performansına olan etkisi irdelenmiştir. Bunun için standart ölü hal koşulu 25℃, 101,325 kPa ve ölçüm değerlerinin ortalaması olarak 17,27℃, 89,4 kPa'ın yanı sıra 30℃, 28℃, 20℃, 15℃ ve 12℃ için hesaplamalar yapılmıştır. Dolaşımlı akışkan yataklı kazan bölümler halinde incelenmesinden ziyade bir bütün olarak kabul edilmiştir. Hava ısıtıcısı ise kazandan ayrı olarak değerlendirilmiştir. Yapılan hesaplamalar sonucunda kazan ve hava ısıtıcısında gerçekleşen ekserji kayıpları belirlenmiştir. Ayrıca kazan ve hava ısıtıcısının ekserji verimleri hesaplanarak ekserji performansı ortaya çıkarılmıştır. Bu çalışma, dolaşımlı akışkan yataklı kazanın ve hava ısıtıcının ekserji performans kriterlerinin çevre sıcaklığındaki değişimden önemli ölçüde etkilendiğini göstermiştir.

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Parametric analysis and process optimization of steam cycle in double reheat ultra-supercritical power plants

Cited by 71 publications

References 17 publications

How to Construct a Combined S-CO2 Cycle for Coal Fired Power Plant?

How to Construct a Combined S-CO2 Cycle for Coal Fired Power Plant?

Comparative Energy and Exergy Analysis of a Power Plant With Super-Critical and Sub-Critical

Çevre Sıcaklığının Dolaşımlı Akışkan Yataklı Kazanın Ekserji Performansı Üzerindeki Etkisi

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