Design Performance Simulation of a Supercritical CO2 Cycle Coupling With a Steam Cycle for Gas Turbine Waste Heat Recovery

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Ziwei Bai ◽  
Guoqiang Zhang ◽  
Yongping Yang ◽  
Ziyu Wang
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat ◽  
Water Cycle ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Inlet Temperature ◽  
Specific Work ◽  
Reheating Process ◽  
Turbine Exhaust

This study presents a train of thought and method for flue gas energy utilization management by connecting an optimized supercritical carbon dioxide (S-CO2) Brayton cycle with a selected steam/water Rankine cycle to recover the turbine exhaust gas heat with promising flue gas coupling capacity. Better performance over the currently used steam/water bottoming cycle is expected to be obtained by the combined bottoming cycle after the S-CO2 cycle is coupled with the high-temperature flue gas. The performances of several S-CO2 cycles are compared, and the selected steam/water cycle is maintained with constant flue gas inlet temperature to properly utilize the low-temperature flue gas. Aspen Plus is used for simulating the cycle performances and the flue gas heat duty. Results show that the recompression S-CO2 cycle with the reheating process is most recommended to be used in the combined bottoming cycle within the research scope. The suggested combined bottoming cycle may outperform most of the triple reheat steam/water cycles for the turbine exhaust temperature in the range of 602–640 °C. Subsequently, it is found that the intercooling process is not suggested if another heat recovery cycle is connected. Moreover, the specific work of the suggested S-CO2 cycles is calculated, and the bottoming cycle with the preheating cycle with the reheating process is found to be more compact than any other combined bottoming cycles.

Investigation of a Combined Inverted Brayton and Rankine Cycle

2019 ◽  
Author(s):  
Ian Kennedy ◽  
Tomasz Duda ◽  
Zheng Liu ◽  
Bob Ceen ◽  
Andy Jones ◽  
...  
Keyword(s):  
High Performance ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Rankine Cycle ◽  
Steam Pressure ◽  
Thermodynamic System ◽  
Steam Flow ◽  
Inlet Temperature ◽  
Specific Work ◽  
Shaft Power

Abstract Waste heat recovery is a vitally important technology to address increasingly stringent emissions legislation and environmental concerns over CO2. One such means of recovering thermal energy is the inverted Brayton cycle (IBC). This paper presents an experimental study of a novel combination of the IBC with a Rankine cycle for the first time. The IBC requires cooling of the exhaust gases after expansion. If the gases contain water vapour, as is the case for hydrocarbon combustion, and cold enough coolant is available, the water can be condensed, pressurized and re-boiled for expansion in a Rankine cycle. The steam produced from the cycle can be utilized in a number of ways. In this study, steam is injected through a series of de Laval nozzles directed into the main turbine to produce additional shaft power in a compact arrangement. To minimize the size of the system, additive manufacturing was used for the heat exchangers, giving high performance per unit volume. The study demonstrates the feasibility of the cycle in producing power from waste heat using humid gas that already is present in most applications. The experimental results show that the system is able to generate power at very low exhaust temperatures where the standard IBC would cease to operate. With an IBC inlet temperature of 370 °C, approximately 5 kJ/kg of specific shaft work was produced with 5 g/s of steam flow rate. At higher exhaust temperatures, the IBC and the Rankine cycle started to work together to increase the shaft power resulting in much higher specific work. At 620 °C, a specific shaft work of 41 kJ/kg was generated at a steam flow of 9 g/s. For the present turbomachinery sizes, this corresponded to 1933 W of power at 47 g/s of main exhaust flow. A model of the thermodynamic system was created in order to study the sensitivity of the system to parameters such as the steam expander pressure ratio and efficiency. Higher steam pressure and higher steam expander efficiency both led to greater power generated for the same operating point, particularly at high IBC turbine inlet temperatures. The peak specific work for the range of parameters explored in the paper was 68 kJ/kg with a steam expander efficiency of 70% and exhaust conditions of 600 °C and 50 g/s. The plots produced in this study can be used as a guide for others considering this system to understand the expected power generated under a range of conditions.

A Transcritical CO2 Rankine Cycle With LNG Cold Energy Utilization and Liquefaction of CO2 in Gas Turbine Emission

2008 ◽  
Author(s):  
Meibin Huang ◽  
Wensheng Lin ◽  
Hongming He ◽  
Anzhong Gu
Keyword(s):  
Gas Turbine ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
Large Temperature ◽  
Specific Work ◽  
Environment Friendly ◽  
Cold Energy ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

A novel transcritical Rankine cycle is presented in this paper. This cycle adopts CO2 as its working fluid, with exhaust from a gas turbine as its heat source and LNG as its cold sink. With CO2 working transcritically, large temperature difference for the Rankine cycle is realized. Moreover, the CO2 in the gas turbine exhaust is further cooled and liquefied by LNG after transferring heat to the Rankine cycle. In this way, not only the cold energy is utilized, but also a large part of the CO2 from burning of the vaporized LNG is recovered. In this paper, the system performance of this transcritical cycle is calculated. The influences of the highest cycle temperature and pressure to system specific work, exergy efficiency and liquefied CO2 mass flow rate are analyzed. The exergy loss in each of the heat exchangers is also discussed. It turns out that this kind of CO2 cycle is energy-conservative and environment-friendly.

Thermodynamic and Economic Analysis Between Organic Rankine Cycle and Kalina Cycle for Waste Heat Recovery From Steam-Assisted Gravity Drainage Process in Oilfield

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Li Zhang ◽  
Zhen Pan ◽  
Zhien Zhang ◽  
Liyan Shang ◽  
Jiangbo Wen ◽  
...  
Keyword(s):  
Economic Analysis ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Gravity Drainage ◽  
Inlet Temperature ◽  
Kalina Cycle ◽  
Steam Assisted Gravity Drainage

A thermodynamic and economic comparative analysis are presented for waste heat recovery (WHR) from the heavy oil production with steam-assisted gravity drainage (SAGD) process employing organic Rankine cycle (ORC) and Kalina cycle (KC). The liquefied natural gas (LNG) cold energy is employed as the cold source. Thus, a combined cooling heating and power system is proposed. The effect of key parameters on thermodynamic performance is investigated. The results showed that increasing the turbine inlet temperature (TIT), ORC is more appropriate for WHR in SAGD process than KC, but KC provides better energy use and exergy efficiency, while the reverse situation occurs when the evaporation pressure is increased. The compression ratio has little effect on the cold exergy recovery efficiency of the refrigeration cycles. In addition, the total exergy destruction and the total WHR efficiency in the combined SAGD/KC are slightly higher than these in the combined SAGD/ORC. Moreover, for the TIT below 180 °C and the evaporation pressure above 6 MPa, the SAGD/KC can obtain more energy return on investment (EROI) than SAGD/ORC. The results obtained through economic analysis show that the use of the SAGD/ORC is more economical. Through the thermos-economic comparison of the two combined systems, it helps to choose different combined cycles according to the different actual operation, which can facilitate the future engineering applications.

A Transcritical CO2 Rankine Cycle With LNG Cold Energy Utilization and Liquefaction of CO2 in Gas Turbine Exhaust

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Wensheng Lin ◽  
Meibin Huang ◽  
Hongming He ◽  
Anzhong Gu
Keyword(s):  
Gas Turbine ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
Large Temperature ◽  
Specific Work ◽  
Environment Friendly ◽  
Cold Energy ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

A novel transcritical Rankine cycle is presented in this paper. This cycle adopts CO2 as its working fluid with exhaust from a gas turbine as its heat source and liquefied natural gas (LNG) as its cold sink. With CO2 working transcritically, large temperature difference for the Rankine cycle is realized. Moreover, the CO2 in the gas turbine exhaust is further cooled and liquefied by LNG after transferring heat to the Rankine cycle. In this way, not only is the cold energy utilized but also a large part of the CO2 is recovered from burning of the vaporized LNG. In this paper, the system performance of this transcritical cycle is calculated. The influences of the highest cycle temperature and pressure to system specific work, exergy efficiency, and liquefied CO2 mass flow rate are analyzed. The exergy loss in each of the heat exchangers is also discussed. It turns out that this kind of CO2 cycle is energy-conservative and environment-friendly.

scholarly journals Coal-Fired Boiler Flue Gas Desulfurization System Based on Slurry Waste Heat Recovery in Severe Cold Areas

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Chenghu Zhang ◽  
Dezhi Zou ◽  
Xinpeng Huang ◽  
Weijun Lu
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Heat Dissipation ◽  
Waste Heat ◽  
Equilibrium Temperature ◽  
Integrated System ◽  
Flue Gas Desulfurization ◽  
Inlet Temperature ◽  
Waste Heat Recovery System

To reduce operating costs on the basis of ensuring the desulfurization efficiency in a wet flue gas desulfurization system, a theoretical model was put forward, and a calculation method was set up. Correlations between reaction zone height, flue gas inlet temperature, slurry inlet temperature, gas–liquid ratio and desulfurization efficiency were found. Based on the heat and mass transfer model of the spray tower, the integrated system of desulfurization tower and open slurry pool and the flue gas desulfurization-waste heat recovery system were established. Additionally, the effect of outdoor wind speed, heat dissipation area and ambient temperature on the slurry equilibrium temperature in the integrated system were analyzed. The results show the slurry equilibrium temperature of the desulfurization system is negatively correlated with outdoor wind speed and heat dissipation area, and positively related to ambient temperature. The slurry temperature is the main factor that affects the performance of the wet flue gas desulfurization system. Finally, based on the Harbin heating group Hua Hui hotspot energy-saving reconstruction project, a case analysis was conducted, which proves the flue gas desulfurization-waste heat recovery system is profitable, energy saving and a suitable investment project.

Investigation into a Combined Inverted Brayton and Rankine Cycle

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Ian Kennedy ◽  
Tomasz Duda ◽  
Zheng Liu ◽  
Bob Ceen ◽  
Andy Jones ◽  
...  
Keyword(s):  
High Performance ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Rankine Cycle ◽  
Steam Pressure ◽  
Thermodynamic System ◽  
Inlet Temperature ◽  
Specific Work ◽  
Shaft Power ◽  
Laval Nozzles

Abstract Waste heat recovery is a vitally important technology to address increasingly stringent emissions legislation and environmental concerns over CO2. One such means of recovering thermal energy is the inverted Brayton cycle (IBC). This paper presents an experimental study of a novel combination of the IBC with a Rankine cycle for the first time. The IBC requires cooling of the exhaust gases after expansion. If the gases contain water vapor, as is the case for hydrocarbon combustion, and cold enough coolant is available, the water can be condensed, pressurized, and reboiled for expansion in a Rankine cycle. The steam produced from the cycle can be utilized in a number of ways. In this study, steam is injected through a series of de Laval nozzles directed into the main turbine to produce additional shaft power in a compact arrangement. To minimize the size of the system, additive manufacturing was used for the heat exchangers, giving high performance per unit volume. The study demonstrates the feasibility of the cycle in producing power from waste heat using humid gas that already is present in most applications. The experimental results show that the system is able to generate power at very low exhaust temperatures where the standard IBC would cease to operate. With an IBC inlet temperature of 370 °C, approximately 5 kJ/kg of specific shaft work was produced with 5 g/s of steam flowrate. At higher exhaust temperatures, the IBC and the Rankine cycle started to work together to increase the shaft power resulting in much higher specific work. At 620 °C, a specific shaft work of 41 kJ/kg was generated at a steam flow of 9 g/s. For the present turbomachinery sizes, this corresponded to 1933 W of power at 47 g/s of main exhaust flow. A model of the thermodynamic system was created in order to study the sensitivity of the system to parameters such as the steam expander pressure ratio and efficiency. Higher steam pressure and higher steam expander efficiency both led to greater power generated for the same operating point, particularly at high IBC turbine inlet temperatures. The peak specific work for the range of parameters explored in the paper was 68 kJ/kg with a steam expander efficiency of 70% and exhaust conditions of 600 °C and 50 g/s. The plots produced in this study can be used as a guide for others considering this system to understand the expected power generated under a range of conditions.

scholarly journals Waste Heat Recovery from Gas Turbine Flue Gases for Power Generation Enhancement in a Process Plant

2015 ◽  
Vol 12 (1) ◽  
Keyword(s):  
Power Generation ◽  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System ◽  
Generation Capacity

To improve on-site power generation capacity and efficiency in process facilities, the thermal coupling of an industrial gas turbine cycle with a bottoming organic Rankine cycle for power plant flue gas waste heat recovery in a process facility is investigated. Using 1,1,1,3,3-pentafluoropropane (R245fa) as heat carrier in the Rankine cycle, 5.2 MW of additional electric power is generated, enhancing on-site power generation capacity and energy/exergy efficiency by approximately 23% and 6%, respectively. The overall energy and exergy efficiencies of the waste heat recovery system are estimated at 9% and 24%, respectively. Primary energy savings of approximately 1.3 million standard cubic feet per day (MMSCFD) of natural gas, or net annual operating expenditure savings of 1.6 million USD, could be realized with the proposed flue gas waste heat recovery system based on subsidized industrial electricity tariffs in the UAE, with 457 tons of avoided CO2 emissions per year.

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