Waste Heat and Water Recovery System Optimization for Flue Gas in Thermal Power Plants

Shamsi, Syed Safeer Mehdi; Negash, Assmelash; Cho, Gyu Baek; Kim, Young Min

doi:10.3390/su11071881

Cited by 26 publications

(15 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Boiling number (𝐵𝐵 𝑜𝑜 ) is a dimensionless number which gives the ratio of actual heat flux (𝑞𝑞 𝐻𝐻 " ) to the maximum attainable heat flux (𝐺𝐺 × 𝑙𝑙 𝑅𝑅134𝑎𝑎 ) from complete evaporation of liquid. In Equation (20), 𝐺𝐺 and 𝑙𝑙 𝑅𝑅134𝑎𝑎 are the mass velocity and latent heat of R134a respectively flowing inside the tube respectively.…”

Section: B Flow-boiling Of R134a Inside Tubesmentioning

confidence: 99%

“…al [19] presented an experimental study on lab-scale ORC, and concluded that this ORC system could produce additional power from flue gas at 160 o C with thermal efficiency of 3.3%, and aftercooler could recover 50% of water in the flue gas by cooling it below HTFF 131-3 30-40 o C. In 2019, Shamsi et. al [20] studied a novel waste heat and water recovery system (WHWRS) integrated with ORC and cooling cycles using a singular working fluid undergoing a phase change. From this study, it was found that for a 600 MW power plant the water capture efficiency was 50%.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analytical Modelling on Simultaneous Phase Transitions in Low Temperature Evaporator for Organic Rankine Cycle Applications

Aryal¹,

Abutayehb²,

Kim³

et al. 2022

Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering

View full text Add to dashboard Cite

A lab-scale organic Rankine cycle has equipped a Low Temperature Evaporator (LTE) for water recovery in addition to the High Temperature Evaporator (HTE) for heat recovery. The recovered water is reused as the make-up water line to save the fresh water consumption in the cooling tower [1,2]. Water recovery efficiency was defined as the ratio of the water condensation rate from the flue gas side to the moisture flowrate at the flue gas inlet [3]. The LTE as cross flow heat exchanger is to recover water in condensate form from the combustion flue gas in the duct side while the recovered latent and sensible heats are transferred into the refrigerant R134a in the tube side. The LTE involves complicated phenomena since the condensation of water vapour in the flue gas duct side and the flow boiling of R134a in tube side were taken place simultaneously. Design of a LTE and its optimized operation depend on a knowledge and understanding of the heat and mass transfer occurred in the LTE. Analytical modelling would be essential to derive the critical parameters for design and operation to achieve the goal of the organic Rankine cycle. The objective of this research was to develop an analytical modelling for simulating the simultaneous phase transitions: 1) condensation of water vapour in the duct side and 2) flow boiling of the refrigerant R134a in the tube side. The control volume was confined to the LTE with two working fluids including the combustion flue gas in the duct side and R134a in the tube side. The work scope was to conduct derivations of the governing equations and numerical algorithm, program development, validations and verifications, and extensive case studies. The modelling was able to generate the spatial profiles of temperature and heat transfer coefficients of both sides, vapour quality of R134a, and condensation rate of water vapour in flue gas side, etc. The mean absolute deviation between the calculated and measured heat transfer coefficients was within 18 %. The calculated data including exit temperature of flue gas and R134a, and water recovery efficiency were in good agreement with the measured data within 15 %. The case studies with the developed software were conducted to examine the roles of sensible and latent heat transfer in flue gas side and boiling impact of R134a side with variations of design and operating parameters including heat transfer area, and inlet conditions of flue gas and R134a, etc. The performance was compared with the case of water coolant under same conditions. The results show that the water recovery efficiency was able to enhance from the current 50 wt% to 77 wt% as expanding its total heat transfer area up to 4 times than the baseline dimension. It was found that the ratio of mass flow rate of the coolant to flue gas was a strong function to improve the water recovery efficiency due to the higher heat transfer coefficients in R134a side induced from the flow boiling. The comparison case study predicted the water recovery efficiency of the R134a case to be increased up t...

show abstract

Section: B Flow-boiling Of R134a Inside Tubesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analytical Modelling on Simultaneous Phase Transitions in Low Temperature Evaporator for Organic Rankine Cycle Applications

Aryal¹,

Abutayehb²,

Kim³

et al. 2022

Proceedings of the 8th World Congress on Mechanical, Chemical, and Material Engineering

View full text Add to dashboard Cite

show abstract

“…This study will focus on adapting waste heat recovery (WHR) methods that have been proven to work in applications such as fossil fuel plants [7][8][9] to a low temperature hydrogen fuel cell. WHR is used to recover heat that would otherwise be wasted, boosting the plants overall efficiency by using a secondary, bottoming thermodynamic cycle to generate extra power.…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of a Radial Inflow Turbine for Use with a Low Temperature ORC

et al. 2021

View full text Add to dashboard Cite

This study aims to design and optimize an organic Rankine cycle (ORC) and radial inflow turbine to recover waste heat from a polymer exchange membrane (PEM) fuel cell. ORCs can take advantage of low-quality waste heat sources. Developments in this area have seen previously unusable, small waste heat sources become available for exploitation. Hydrogen PEM fuel cells operate at low temperatures (70 °C) and are in used in a range of applications, for example, as a balancing or backup power source in renewable hydrogen plants. The efficiency of an ORC is significantly affected by the source temperature and the efficiency of the expander. In this case, a radial inflow turbine was selected due to the high efficiency in ORCs with high density fluids. Small scale radial inflow turbines are of particular interest for improving the efficiency of small-scale low temperature cycles. Turbines generally have higher efficiency than positive displacement expanders, which are typically used. In this study, the turbine design from the mean-line analysis is also validated against the computational fluid dynamic (CFD) simulations conducted on the optimized machine. For the fuel cell investigated in this study, with a 5 kW electrical output, a potential additional 0.7 kW could be generated through the use of the ORC. The ORC’s output represents a possible 14% increase in performance over the fuel cell without waste heat recovery (WHR).

show abstract

“…In [7], several thermodynamic cycles were presented for the study of the recovery of waste heat from the exhaust gases of internal combustion engines; it was concluded that, the Rankine cycle has the best performance for heat recovery from exhaust gases. Syed et al [8] showed that ORC cycles are well suited to heat recovery for low and medium temperatures as they offer significant advantages over conventional steam cycles [9] in [8]. Other studies compare an ORC without a recuperator and an ORC with a recuperator [10,11].…”

Section: Introductionmentioning

confidence: 99%

Energy and Exergy Analysis of an Organic Rankine Cycle used for Ylang-Ylang Essential Oil Distillery Waste Heat Recovery for Power Production in Anjouan Island

Ahamadi¹,

Rakotondramiarana

2021

EJENERGY

View full text Add to dashboard Cite

In the ylang-ylang essential oil distillers in Anjouan Island, the used energy is 100% firewood biomass. A large amount of this energy is dissipated in the environment just in the combustion chamber itself. As it turns out, the flue gases in this process take away the most part of it. Thus, in a process of energy efficiency of stills, the present work aims at assessing the possibility to convert the residual heat from the process into electricity. For that purpose, energy and exergy modeling of an organic Rankine cycle was implemented. It was found that a large amount of exergy is destroyed in the evaporator. Similarly, it emerges that the exergy efficiency of the cycle depends on the inlet temperatures of the exhaust gases in the evaporator and on the inlet pressure of the working fluid in the turbine, and that it is much better for low exhaust gas temperatures. At these low values of gas temperatures, it appears that the improvement in exergy efficiency and energy efficiency are linked to the increase in the inlet pressure of the working fluid in the turbine. It follows from the obtained results that the discharged hot water and the residual heat of gases having temperatures ranging from 180°C to 300 °C, could be used for power production which can reach electrical powers between 1.4kW and 4.5kW

show abstract

Waste Heat and Water Recovery System Optimization for Flue Gas in Thermal Power Plants

Cited by 26 publications

References 27 publications

Analytical Modelling on Simultaneous Phase Transitions in Low Temperature Evaporator for Organic Rankine Cycle Applications

Analytical Modelling on Simultaneous Phase Transitions in Low Temperature Evaporator for Organic Rankine Cycle Applications

Design and Optimization of a Radial Inflow Turbine for Use with a Low Temperature ORC

Energy and Exergy Analysis of an Organic Rankine Cycle used for Ylang-Ylang Essential Oil Distillery Waste Heat Recovery for Power Production in Anjouan Island

Contact Info

Product

Resources

About