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Gang Xu
Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation, North China Electric Power University, Beijing 102206, China

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Journal article
Published: 11 December 2020 in Applied Thermal Engineering
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An innovative hybrid solar-municipal solid waste power system has been proposed for advancing the waste-to-energy and solar thermal energy technologies. The integration is realized by exploiting the useful heat harvested from sunlight in the parabolic trough collectors to reheat the working steam of the incineration plant and promote the steam temperature. Consequently, the steam cycle performance can be remarkably improved with the efficient utilization of solar energy. The hybrid design was thermodynamically and economically assessed based on a 500 t/d incineration plant, and the performance enhancement mechanism was revealed. Furthermore, a sensitivity analysis was conducted to examine the performance of the hybrid system under various solar conditions. The results indicated that the ideal steam cycle efficiency is boosted by 0.93 percentage points when adopting the proposed solution. The solar energy contributes to producing 1.17 MW net power with a solar-to-electricity efficiency of 21.59% at the design point. The integrated system performs excellently for most of the year, and the annual solar-to-electricity of 16.19% is achieved. Regarding a lifespan of 30 years, the levelized electricity cost of the solar-aided reheating system is as low as 0.1202 $/(kW∙h). Hence, the novel design is thermodynamically and economically suitable.

ACS Style

Heng Chen; Yunyun Wu; Yuchuan Zeng; Gang Xu; Wenyi Liu. Performance analysis of a solar-aided waste-to-energy system based on steam reheating. Applied Thermal Engineering 2020, 185, 116445 .

AMA Style

Heng Chen, Yunyun Wu, Yuchuan Zeng, Gang Xu, Wenyi Liu. Performance analysis of a solar-aided waste-to-energy system based on steam reheating. Applied Thermal Engineering. 2020; 185 ():116445.

Chicago/Turabian Style

Heng Chen; Yunyun Wu; Yuchuan Zeng; Gang Xu; Wenyi Liu. 2020. "Performance analysis of a solar-aided waste-to-energy system based on steam reheating." Applied Thermal Engineering 185, no. : 116445.

Journal article
Published: 18 November 2020 in Entropy
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A novel compressed air energy storage (CAES) system has been developed, which is innovatively integrated with a coal-fired power plant based on its feedwater heating system. In the hybrid design, the compression heat of the CAES system is transferred to the feedwater of the coal power plant, and the compressed air before the expanders is heated by the feedwater taken from the coal power plant. Furthermore, the exhaust air of the expanders is employed to warm partial feedwater of the coal power plant. Via the suggested integration, the thermal energy storage equipment for a regular CAES system can be eliminated and the performance of the CAES system can be improved. Based on a 350 MW supercritical coal power plant, the proposed concept was thermodynamically evaluated, and the results indicate that the round-trip efficiency and exergy efficiency of the new CAES system can reach 64.08% and 70.01%, respectively. Besides, a sensitivity analysis was conducted to examine the effects of ambient temperature, air storage pressure, expander inlet temperature, and coal power load on the performance of the CAES system. The above work proves that the novel design is efficient under various conditions, providing important insights into the development of CAES technology.

ACS Style

Peiyuan Pan; Meiyan Zhang; Weike Peng; Heng Chen; Gang Xu; Tong Liu. Thermodynamic Evaluation and Sensitivity Analysis of a Novel Compressed Air Energy Storage System Incorporated with a Coal-Fired Power Plant. Entropy 2020, 22, 1316 .

AMA Style

Peiyuan Pan, Meiyan Zhang, Weike Peng, Heng Chen, Gang Xu, Tong Liu. Thermodynamic Evaluation and Sensitivity Analysis of a Novel Compressed Air Energy Storage System Incorporated with a Coal-Fired Power Plant. Entropy. 2020; 22 (11):1316.

Chicago/Turabian Style

Peiyuan Pan; Meiyan Zhang; Weike Peng; Heng Chen; Gang Xu; Tong Liu. 2020. "Thermodynamic Evaluation and Sensitivity Analysis of a Novel Compressed Air Energy Storage System Incorporated with a Coal-Fired Power Plant." Entropy 22, no. 11: 1316.

Journal article
Published: 07 October 2020 in Energy
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A hybrid renewable energy system for combined heat and power production has been developed and evaluated. The integration is achieved by feeding the heat harvested from sunlight by parabolic trough collectors into the steam cycle of a biomass-fired cogeneration plant. Under the cogeneration mode or power generation mode, the obtained solar heat is exploited to drive the absorption heat pump for providing heat or warm the feedwater into the boiler, saving the extraction steam and contributing to additional power output. The thermodynamic and economic performance of the hybrid system was assessed based on a typical biomass-fired cogeneration plant. The performance of the new design under different operation modes and various solar conditions was also explored. The results indicated that the solar-to-electricity conversion efficiency can reach 19.38 % or 16.92 % at the design points under different operation modes (cogeneration or power generation); while the biomass consumption and thermal efficiency of the biomass plant are fixed, the cogeneration mode is superior to the power generation mode. Throughout the year, the solar based electricity of 2803.04 MWh can be generated with an annual solar-to-electricity conversion efficiency of 16.16 %. Besides, the levelized cost of solar aided electricity is only 0.1306 $/kWh.

ACS Style

Heng Chen; Kai Xue; Yunyun Wu; Gang Xu; Xin Jin; Wenyi Liu. Thermodynamic and economic analyses of a solar-aided biomass-fired combined heat and power system. Energy 2020, 214, 119023 .

AMA Style

Heng Chen, Kai Xue, Yunyun Wu, Gang Xu, Xin Jin, Wenyi Liu. Thermodynamic and economic analyses of a solar-aided biomass-fired combined heat and power system. Energy. 2020; 214 ():119023.

Chicago/Turabian Style

Heng Chen; Kai Xue; Yunyun Wu; Gang Xu; Xin Jin; Wenyi Liu. 2020. "Thermodynamic and economic analyses of a solar-aided biomass-fired combined heat and power system." Energy 214, no. : 119023.

Journal article
Published: 22 August 2020 in Energies
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A novel design has been developed to improve the waste-to-energy process through the integration with a biomass-fired power plant. In the proposed scheme, the superheated steam generated by the waste-to-energy boiler is fed into the low-pressure turbine of the biomass power section for power production. Besides, the feedwater from the biomass power section is utilized to warm the combustion air of the waste-to-energy boiler, and the feedwater of the waste-to-energy boiler is offered by the biomass power section. Based on a 35-MW biomass-fired power plant and a 500-t/d waste-to-energy plant, the integrated design was thermodynamically and economically assessed. The results indicate that the net power generated from waste can be enhanced by 0.66 MW due to the proposed solution, and the waste-to-electricity efficiency increases from 20.49% to 22.12%. Moreover, the net present value of the waste-to-energy section is raised by 5.02 million USD, and the dynamic payback period is cut down by 2.81 years. Energy and exergy analyses were conducted to reveal the inherent mechanism of performance enhancement. Besides, a sensitivity investigation was undertaken to examine the performance of the new design under various conditions. The insights gained from this study may be of assistance to the advancement of waste-to-energy technology.

ACS Style

Peiyuan Pan; Meiyan Zhang; Gang Xu; Heng Chen; Xiaona Song; Tong Liu. Thermodynamic and Economic Analyses of a New Waste-to-Energy System Incorporated with a Biomass-Fired Power Plant. Energies 2020, 13, 4345 .

AMA Style

Peiyuan Pan, Meiyan Zhang, Gang Xu, Heng Chen, Xiaona Song, Tong Liu. Thermodynamic and Economic Analyses of a New Waste-to-Energy System Incorporated with a Biomass-Fired Power Plant. Energies. 2020; 13 (17):4345.

Chicago/Turabian Style

Peiyuan Pan; Meiyan Zhang; Gang Xu; Heng Chen; Xiaona Song; Tong Liu. 2020. "Thermodynamic and Economic Analyses of a New Waste-to-Energy System Incorporated with a Biomass-Fired Power Plant." Energies 13, no. 17: 4345.

Journal article
Published: 23 June 2020 in Applied Thermal Engineering
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A hybrid power system including waste-to-energy and coal-fired power generation has been proposed for enhancing the energy utilization of municipal solid waste. The integration is accomplished by using the steam generated by the waste-to-energy boiler to heat partial feedwater of the coal power unit. Consequently, the energy gained from the waste incineration is fed into the steam cycle of the coal power unit, and the waste-to-electricity efficiency can be significantly improved. Based on a 600 t/d incineration unit and a 350 MW coal power unit, the integrated design was comprehensively evaluated in the views of thermodynamics and economics. The results indicate that the waste-to-electricity efficiency is promoted by 6.58 percentage points with an increment of 3.20 MW in the net power output of the waste due to the integration, thereby the dynamic payback period of the waste-to-energy project is shortened by 5.94 years and the net present value rises by 18.41 million USD. The root cause of efficiency enhancement owing to the novel concept was revealed by energy and exergy analyses. Furthermore, the operation strategy of the hybrid system under various loads of the coal power unit was discussed, and two operation modes were developed.

ACS Style

Heng Chen; Meiyan Zhang; Zhidong Chen; Gang Xu; Wei Han; Wenyi Liu; Tong Liu. Performance analysis and operation strategy of an improved waste-to-energy system incorporated with a coal-fired power unit based on feedwater heating. Applied Thermal Engineering 2020, 178, 115637 .

AMA Style

Heng Chen, Meiyan Zhang, Zhidong Chen, Gang Xu, Wei Han, Wenyi Liu, Tong Liu. Performance analysis and operation strategy of an improved waste-to-energy system incorporated with a coal-fired power unit based on feedwater heating. Applied Thermal Engineering. 2020; 178 ():115637.

Chicago/Turabian Style

Heng Chen; Meiyan Zhang; Zhidong Chen; Gang Xu; Wei Han; Wenyi Liu; Tong Liu. 2020. "Performance analysis and operation strategy of an improved waste-to-energy system incorporated with a coal-fired power unit based on feedwater heating." Applied Thermal Engineering 178, no. : 115637.

Journal article
Published: 19 March 2020 in Energy Conversion and Management
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A novel waste incineration power system highly integrated with a supercritical CO2 power cycle and a coal-fired power plant has been developed. In the hybrid configuration, the supercritical CO2 cycle gains energy from the superheater of the waste-to-energy (WTE) boiler, and the saturated steam produced by the WTE boiler is employed to heat the feedwater of the coal power plant. Consequently, the cascade energy utilization of the waste can be realized with the improvement of the WTE process. The performance of the proposed integrated scheme was thermodynamically and economically evaluated as compared to the conventional separate scheme, based on a 500 t/d incineration unit and a 300 MW coal power plant. The results indicate that the waste-to-electricity efficiency is promoted by 8.34 percentage points with an additional net power output of 3.33 MW, when adopting the proposal. The total exergy efficiency and the exergy efficiency of waste-to-electricity are increased by 0.43 and 7.88 percentage points. Additionally, the proposed system performs excellently under various boiler loads. Due to the integration, the net present value of the WTE project rises by 18.17 M$ and the dynamic payback period is reduced by 4.20 years. Therefore, the new design is extremely feasible and profitable.

ACS Style

Heng Chen; Meiyan Zhang; Yunyun Wu; Gang Xu; Wenyi Liu; Tong Liu. Design and performance evaluation of a new waste incineration power system integrated with a supercritical CO2 power cycle and a coal-fired power plant. Energy Conversion and Management 2020, 210, 112715 .

AMA Style

Heng Chen, Meiyan Zhang, Yunyun Wu, Gang Xu, Wenyi Liu, Tong Liu. Design and performance evaluation of a new waste incineration power system integrated with a supercritical CO2 power cycle and a coal-fired power plant. Energy Conversion and Management. 2020; 210 ():112715.

Chicago/Turabian Style

Heng Chen; Meiyan Zhang; Yunyun Wu; Gang Xu; Wenyi Liu; Tong Liu. 2020. "Design and performance evaluation of a new waste incineration power system integrated with a supercritical CO2 power cycle and a coal-fired power plant." Energy Conversion and Management 210, no. : 112715.

Journal article
Published: 01 February 2020 in Applied Thermal Engineering
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An innovative heat supply design for cogeneration systems has been proposed. Instead of the conventional heat source (extraction steam of the turbine), the low-pressure feedwater of the heat regeneration system is employed to provide district heat in the new scheme, through warming the supply-water of the primary heating network in a plate heat exchanger. A detailed thermodynamic analysis was conducted to evaluate the proposed design compared with the traditional one, based on a large-scale coal-fired power plant that needed to be retrofitted into cogeneration. The results show that the net power output of the cogeneration system is boosted by 4.68 MW owing to the novel concept. Furthermore, the total system efficiency and effective electric efficiency of the cogeneration system are promoted by 0.43 and 0.46 percentage points. This is because the exergy efficiency of the supply-water heating process is raised by 29.65 percentage points, and the exergy efficiency of the cogeneration system is improved by 0.42 percentage points. Finally, the new design was economically analyzed, and the results indicate that the net present value reaches 16543.2 thousand USD (8381.5 thousand USD more than that of the conventional design). Therefore, the proposed concept is feasible and profitable in engineering.

ACS Style

Heng Chen; Yunyun Wu; Shuai Xu; Gang Xu; Yongping Yang; Wenyi Liu. Thermodynamic and economic evaluation of a novel heat supply design using low-pressure feedwater in a cogeneration plant. Applied Thermal Engineering 2020, 166, 114672 .

AMA Style

Heng Chen, Yunyun Wu, Shuai Xu, Gang Xu, Yongping Yang, Wenyi Liu. Thermodynamic and economic evaluation of a novel heat supply design using low-pressure feedwater in a cogeneration plant. Applied Thermal Engineering. 2020; 166 ():114672.

Chicago/Turabian Style

Heng Chen; Yunyun Wu; Shuai Xu; Gang Xu; Yongping Yang; Wenyi Liu. 2020. "Thermodynamic and economic evaluation of a novel heat supply design using low-pressure feedwater in a cogeneration plant." Applied Thermal Engineering 166, no. : 114672.

Journal article
Published: 08 January 2020 in Energy
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An advanced waste-to-energy system integrated with a coal-fired power plant has been proposed to improve the energy utilization of municipal solid waste. In the new design, the energy gained from the waste-to-energy boiler is employed to heat the feedwater and partial cold reheat steam of the coal power plant, and the feedwater of the waste-to-energy boiler is provided by the heat regeneration system of the coal power plant. Consequently, the energy obtained from the waste incineration products is injected into the steam cycle of the coal power plant, and the waste-to-electricity efficiency can be significantly boosted. Based on a 500 t/day waste-to-energy plant and a 630 MW coal power plant, the proposed hybrid scheme was evaluated compared with the conventional separate one. The results show that the waste-to-electricity efficiency is promoted by 9.16% points with an additional net power output of 3.71 MW, attributed to the suggested integration. Furthermore, the energy-saving mechanism of the novel concept was revealed by energy and exergy analyses. Finally, the new design was economically examined, which indicates that the dynamic payback period of the proposed waste-to-energy plant is only 3.55 years, which is 5.87 years shorter than that of the conventional one.

ACS Style

Heng Chen; Meiyan Zhang; Kai Xue; Gang Xu; Yongping Yang; Zepeng Wang; Wenyi Liu; Tong Liu. An innovative waste-to-energy system integrated with a coal-fired power plant. Energy 2020, 194, 116893 .

AMA Style

Heng Chen, Meiyan Zhang, Kai Xue, Gang Xu, Yongping Yang, Zepeng Wang, Wenyi Liu, Tong Liu. An innovative waste-to-energy system integrated with a coal-fired power plant. Energy. 2020; 194 ():116893.

Chicago/Turabian Style

Heng Chen; Meiyan Zhang; Kai Xue; Gang Xu; Yongping Yang; Zepeng Wang; Wenyi Liu; Tong Liu. 2020. "An innovative waste-to-energy system integrated with a coal-fired power plant." Energy 194, no. : 116893.

Journal article
Published: 28 March 2019 in Entropy
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High back-pressure (HBP) heating technology has been identified as an effective approach to improve the efficiency of combined heat and power (CHP). In this study, the novel concept of a HBP heating system with energy cascade utilization is developed and its probability examined. In the reformative design, the extracted heating steam from the intermediate-pressure turbine (IPT) is first drawn to an additional turbine where its excess pressure can be converted into electricity, then steam with a lower pressure can be employed to heat the supply water. As a consequence, the exergy destruction in the supply water heating process can be reduced and the efficiency of the cogeneration unit raised. A detailed thermodynamic investigation was performed based on a typical coal-fired HBP–CHP unit incorporating the proposed configuration. The results show that the artificial thermal efficiency (ATE) promotion was as much as 2.01 percentage points, with an additional net power output of 8.4 MW compared to the reference unit. This was attributed to a 14.65 percentage-point increment in the exergy efficiency of the supply water heating process caused by the suggested retrofitting. The influences of the unit power output, unit heat output, supply water and return water temperatures and turbine back pressure on the thermal performance of the modified system are discussed as well. In addition, the economic performance of the new design is assessed, indicating that the proposed concept is financially feasible.

ACS Style

Heng Chen; Yunyun Wu; Jidong Xu; Gang Xu; Yongping Yang; Wenyi Liu; Gangye Shi. Thermodynamic and Economic Analyses of Reformative Design for High Back-Pressure Heating in Coal-Fueled Cogeneration Units. Entropy 2019, 21, 342 .

AMA Style

Heng Chen, Yunyun Wu, Jidong Xu, Gang Xu, Yongping Yang, Wenyi Liu, Gangye Shi. Thermodynamic and Economic Analyses of Reformative Design for High Back-Pressure Heating in Coal-Fueled Cogeneration Units. Entropy. 2019; 21 (4):342.

Chicago/Turabian Style

Heng Chen; Yunyun Wu; Jidong Xu; Gang Xu; Yongping Yang; Wenyi Liu; Gangye Shi. 2019. "Thermodynamic and Economic Analyses of Reformative Design for High Back-Pressure Heating in Coal-Fueled Cogeneration Units." Entropy 21, no. 4: 342.

Journal article
Published: 05 December 2018 in Energy
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In this study, a new concept of the combustion air preheating system integrated with a bypass flue (BPF) configuration was put forward and its feasibility was evaluated. In the proposed system, the primary air and secondary air are heated separately with cascade heat exchange and the hot and cold bypassing primary air mixing is avoided, which contributes to enhancing the air preheating and waste heat utilization. Thermodynamic analysis was performed based on a typical 600 MW coal-fired power unit incorporating the new concept. The results indicated that owing to the proposed design, the power generation efficiency promotion reaches 0.78% (absolute value) with a standard coal consumption rate reduction of 5.52 g/kWh as compared to the reference unit, which are 0.14% (absolute value) higher and 0.94 g/kWh larger than those caused by the regular BPF retrofitting, respectively. The energy utilization is more rational in the new design according to the energy and exergy analysis, and the exergy efficiency of the primary air heating process is improved from 75.75% (original design) or 79.62% (regular BPF design) to 84.46% due to the proposed concept. The volume and heat exchange area of the APH decline significantly as well in the modified system.

ACS Style

Heng Chen; Yunyun Wu; Zhen Qi; Qiao Chen; Gang Xu; Yongping Yang; Wenyi Liu. Improved combustion air preheating design using multiple heat sources incorporating bypass flue in large-scale coal-fired power unit. Energy 2018, 169, 527 -541.

AMA Style

Heng Chen, Yunyun Wu, Zhen Qi, Qiao Chen, Gang Xu, Yongping Yang, Wenyi Liu. Improved combustion air preheating design using multiple heat sources incorporating bypass flue in large-scale coal-fired power unit. Energy. 2018; 169 ():527-541.

Chicago/Turabian Style

Heng Chen; Yunyun Wu; Zhen Qi; Qiao Chen; Gang Xu; Yongping Yang; Wenyi Liu. 2018. "Improved combustion air preheating design using multiple heat sources incorporating bypass flue in large-scale coal-fired power unit." Energy 169, no. : 527-541.

Journal article
Published: 03 December 2018 in Applied Thermal Engineering
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Comprehensive and parametric analyses were conducted to investigate the thermal characteristic of the high back-pressure (HBP) heating process based on a 300 MW coal-fired combined heat and power (CHP) unit. The results indicated that the HBP design promoted the thermal efficiency of the unit by 5.97% (absolute value) and cut down the standard coal consumption rate by 23.52 g/(kW·h), attributing to the exhaust steam recovery efficiency of 57% and the unit generation power increase of 24.58 MW. On the grounds of the first and second laws of thermodynamics, the detailed energy-saving mechanism of the HBP heating concept was synthetically explored by the analyses of energy and exergy flows and graphical exergy, and the results showed that the HBP heating configuration improved the unit performance by reducing the exhaust steam energy loss and the extraction steam flow rate and raising the exergy efficiency of the heat exchange process. The impacts of the primary parameters (unit generation load, unit heating load, supply & return-water temperatures and turbine back-pressure) on the performance of the HBP-CHP unit were also examined and optimization suggestions were put forward. Besides, the heat and power coupling characteristic of the HBP-CHP unit was discussed.

ACS Style

Heng Chen; Yao Xiao; Gang Xu; Jidong Xu; Xianhuai Yao; Yongping Yang. Energy-saving mechanism and parametric analysis of the high back-pressure heating process in a 300 MW coal-fired combined heat and power unit. Applied Thermal Engineering 2018, 149, 829 -840.

AMA Style

Heng Chen, Yao Xiao, Gang Xu, Jidong Xu, Xianhuai Yao, Yongping Yang. Energy-saving mechanism and parametric analysis of the high back-pressure heating process in a 300 MW coal-fired combined heat and power unit. Applied Thermal Engineering. 2018; 149 ():829-840.

Chicago/Turabian Style

Heng Chen; Yao Xiao; Gang Xu; Jidong Xu; Xianhuai Yao; Yongping Yang. 2018. "Energy-saving mechanism and parametric analysis of the high back-pressure heating process in a 300 MW coal-fired combined heat and power unit." Applied Thermal Engineering 149, no. : 829-840.

Journal article
Published: 19 September 2018 in Energies
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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.

ACS Style

Heng Chen; Zhen Qi; Qiao Chen; Yunyun Wu; Gang Xu; Yongping Yang. Modified High Back-Pressure Heating System Integrated with Raw Coal Pre-Drying in Combined Heat and Power Unit. Energies 2018, 11, 2487 .

AMA Style

Heng Chen, Zhen Qi, Qiao Chen, Yunyun Wu, Gang Xu, Yongping Yang. Modified High Back-Pressure Heating System Integrated with Raw Coal Pre-Drying in Combined Heat and Power Unit. Energies. 2018; 11 (9):2487.

Chicago/Turabian Style

Heng Chen; Zhen Qi; Qiao Chen; Yunyun Wu; Gang Xu; Yongping Yang. 2018. "Modified High Back-Pressure Heating System Integrated with Raw Coal Pre-Drying in Combined Heat and Power Unit." Energies 11, no. 9: 2487.

Journal article
Published: 11 June 2018 in Energies
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An improved heating system integrated with waste pressure utilization (WPU) for combined heat and power (CHP) cogeneration was proposed. The new heating system efficiently utilized the excess pressure of the extraction heating steam to drive the WPU turbine and generator for producing electricity, achieving higher energy efficiency and lower fuel consumption of the CHP unit. The results of the detailed thermodynamic analysis showed that applying the proposed concept in a typical 300 MW coal-fired CHP unit could reduce the standard coal consumption rate by 9.84 g/(kW·h), with a thermal efficiency improvement of 1.97% (absolute value). Compared to that of the original heating process, the energy efficiency of the proposed process decreased by 0.55% (absolute value), but its exergy efficiency increased dramatically by 17.97% (absolute value), which meant that the proposed configuration could make better use of the steam energy and contribute to the better performance of the CHP unit. As the unit generation load and supply and return-water temperatures declined and the unit heating load rose, the WPU system would generate more electricity and its energy-saving benefit would be enhanced. This work provides a promising approach to further advance the CHP technology and district heating systems.

ACS Style

Heng Chen; Jidong Xu; Yao Xiao; Zhen Qi; Gang Xu; Yongping Yang. An Improved Heating System with Waste Pressure Utilization in a Combined Heat and Power Unit. Energies 2018, 11, 1515 .

AMA Style

Heng Chen, Jidong Xu, Yao Xiao, Zhen Qi, Gang Xu, Yongping Yang. An Improved Heating System with Waste Pressure Utilization in a Combined Heat and Power Unit. Energies. 2018; 11 (6):1515.

Chicago/Turabian Style

Heng Chen; Jidong Xu; Yao Xiao; Zhen Qi; Gang Xu; Yongping Yang. 2018. "An Improved Heating System with Waste Pressure Utilization in a Combined Heat and Power Unit." Energies 11, no. 6: 1515.

Journal article
Published: 04 June 2018 in Energies
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Efficient utilization of ventilation air methane (VAM) as well as improving the energy efficiency of de-carbonization oxy-coal combustion power plants are intensively studied for achieving energy savings and greenhouse gas (GHG) emission control. Here, an improved VAM-coal hybrid power generation system, which integrates a VAM-based hot air power cycle with a de-carbonization oxy-coal combustion circulating fluid bed (CFB) power plant was proposed. In the proposed system, part of the boiler flue gas was bypassed to feed the VAM auto-oxidation, and the whole VAM oxidation heat was efficiently utilized to drive a hot air power cycle. Meanwhile, the turbine exhaust air was utilized to heat the feed/condensed water within the regenerative heating trains in a cascade way, which was in turn beneficial to de-carbonization oxy-coal combustion plant. The mass and energy balance of the proposed system were determined using the simulation process. The thermodynamic benefits, economic viability and the environmental impacts were discussed. Results showed that energy efficiency of the proposed system reached 27.1% with the energy saving ratio at 0.9%. The cost of electricity (COE) was $118.15/MWh with the specific CO2 emission as low as 17.46 kg CO2/MWh.

ACS Style

Cheng Xu; Yachi Gao; Qiang Zhang; Guoqiang Zhang; Gang Xu. Thermodynamic, Economic and Environmental Evaluation of an Improved Ventilation Air Methane-Based Hot Air Power Cycle Integrated with a De-Carbonization Oxy-Coal Combustion Power Plant. Energies 2018, 11, 1434 .

AMA Style

Cheng Xu, Yachi Gao, Qiang Zhang, Guoqiang Zhang, Gang Xu. Thermodynamic, Economic and Environmental Evaluation of an Improved Ventilation Air Methane-Based Hot Air Power Cycle Integrated with a De-Carbonization Oxy-Coal Combustion Power Plant. Energies. 2018; 11 (6):1434.

Chicago/Turabian Style

Cheng Xu; Yachi Gao; Qiang Zhang; Guoqiang Zhang; Gang Xu. 2018. "Thermodynamic, Economic and Environmental Evaluation of an Improved Ventilation Air Methane-Based Hot Air Power Cycle Integrated with a De-Carbonization Oxy-Coal Combustion Power Plant." Energies 11, no. 6: 1434.

Journal article
Published: 25 September 2017 in Energies
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An improved flexible solar-aided power generation system (SAPG) for enhancing both selective catalytic reduction (SCR) de-NOx efficiency and coal-based energy efficiency of coal-fired power plants is proposed. In the proposed concept, the solar energy injection point is changed for different power plant loads, bringing about different benefits for coal-fired power generation. For partial/low load, solar energy is beneficially used to increase the flue gas temperature to guarantee the SCR de-NOx effectiveness as well as increase the boiler energy input by reheating the combustion air. For high power load, solar energy is used for saving steam bleeds from turbines by heating the feed water. A case study for a typical 1000 MW coal-fired power plant using the proposed concept has been performed and the results showed that, the SCR de-NOx efficiency of proposed SAPG could increase by 3.1% and 7.9% under medium load and low load conditions, respectively, as compared with the reference plant. The standard coal consumption rate of the proposed SAPG could decrease by 2.68 g/kWh, 4.05 g/kWh and 6.31 g/kWh for high, medium and low loads, respectively, with 0.040 USD/kWh of solar generated electricity cost. The proposed concept opens up a novel solar energy integration pattern in coal-fired power plants to improve the pollutant removal effectiveness and decrease the coal consumption of the power plant.

ACS Style

Yu Han; Cheng Xu; Gang Xu; Yuwen Zhang; Yongping Yang. An Improved Flexible Solar Thermal Energy Integration Process for Enhancing the Coal-Based Energy Efficiency and NOx Removal Effectiveness in Coal-Fired Power Plants under Different Load Conditions. Energies 2017, 10, 1485 .

AMA Style

Yu Han, Cheng Xu, Gang Xu, Yuwen Zhang, Yongping Yang. An Improved Flexible Solar Thermal Energy Integration Process for Enhancing the Coal-Based Energy Efficiency and NOx Removal Effectiveness in Coal-Fired Power Plants under Different Load Conditions. Energies. 2017; 10 (10):1485.

Chicago/Turabian Style

Yu Han; Cheng Xu; Gang Xu; Yuwen Zhang; Yongping Yang. 2017. "An Improved Flexible Solar Thermal Energy Integration Process for Enhancing the Coal-Based Energy Efficiency and NOx Removal Effectiveness in Coal-Fired Power Plants under Different Load Conditions." Energies 10, no. 10: 1485.

Journal article
Published: 13 November 2014 in Entropy
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Compressed air energy storage (CAES) is one of the large-scale energy storage technologies utilized to provide effective power peak load shaving. In this paper, a coal-fired external combustion CAES, which only uses coal as fuel, is proposed. Unlike the traditional CAES, the combustion chamber is substituted with an external combustion heater in which high-pressure air is heated before entering turbines to expand in the proposed system. A thermodynamic analysis of the proposed CAES is conducted on the basis of the process simulation. The overall efficiency and the efficiency of electricity storage are 48.37% and 81.50%, respectively. Furthermore, the exergy analysis is then derived and forecasted, and the exergy efficiency of the proposed system is 47.22%. The results show that the proposed CAES has more performance advantages than Huntorf CAES (the first CAES plant in the world). Techno-economic analysis of the coal-fired CAES shows that the cost of electricity (COE) is $106.33/MWh, which is relatively high in the rapidly developing power market. However, CAES will be more likely to be competitive if the power grid is improved and suitable geographical conditions for storage caverns are satisfied. This research provides a new approach for developing CAES in China.

ACS Style

Wenyi Liu; Qing Li; Feifei Liang; Linzhi Liu; Gang Xu; Yongping Yang. Performance Analysis of a Coal-Fired External Combustion Compressed Air Energy Storage System. Entropy 2014, 16, 5935 -5953.

AMA Style

Wenyi Liu, Qing Li, Feifei Liang, Linzhi Liu, Gang Xu, Yongping Yang. Performance Analysis of a Coal-Fired External Combustion Compressed Air Energy Storage System. Entropy. 2014; 16 (11):5935-5953.

Chicago/Turabian Style

Wenyi Liu; Qing Li; Feifei Liang; Linzhi Liu; Gang Xu; Yongping Yang. 2014. "Performance Analysis of a Coal-Fired External Combustion Compressed Air Energy Storage System." Entropy 16, no. 11: 5935-5953.

Journal article
Published: 23 August 2014 in Chinese Science Bulletin
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The lignite pre-drying process plays an important role in modern lignite power plants and the fluidized bed dryer with internal heat utilization is a promising drying method which has both high efficiency and cost-effectiveness. After conducting an in-depth analysis of a typical lignite pre-drying power plant, this work proposed a novel lignite pre-drying system with low-grade heat integration. Through system integration, the low-temperature evaporation of the lignite was recovered to heat the combustion air, while the residual heat from the flue gases was used to heat the feed or condensed water, thereby saving a portion of heat from the steam bleeds of the high and intermediate pressure turbines. The results for a 1,000 MW lignite-fired power plant showed that, the proposed pre-drying system could yield an increase in net plant efficiency of approximately 3.6 % points and a reduction in the cost of electricity of $1.83/(MW h). The thermodynamic and economic performances were each superior to those of the existing pre-drying system, convincingly demonstrating that the research of this paper may provide a promising integrated lignite pre-drying method for the next-generation of lignite-fired power plants.

ACS Style

Cheng Xu; Gang Xu; Yu Han; Feifei Liang; Yaxiong Fang; Yongping Yang. A novel lignite pre-drying system with low-grade heat integration for modern lignite power plants. Chinese Science Bulletin 2014, 59, 4426 -4435.

AMA Style

Cheng Xu, Gang Xu, Yu Han, Feifei Liang, Yaxiong Fang, Yongping Yang. A novel lignite pre-drying system with low-grade heat integration for modern lignite power plants. Chinese Science Bulletin. 2014; 59 (33):4426-4435.

Chicago/Turabian Style

Cheng Xu; Gang Xu; Yu Han; Feifei Liang; Yaxiong Fang; Yongping Yang. 2014. "A novel lignite pre-drying system with low-grade heat integration for modern lignite power plants." Chinese Science Bulletin 59, no. 33: 4426-4435.

Journal article
Published: 04 August 2014 in Energies
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Compressed air energy storage (CAES) is a large-scale technology that provides long-duration energy storage. It is promising for balancing the large-scale penetration of intermittent and dispersed sources of power, such as wind and solar power, into electric grids. The existing CAES plants utilize natural gas (NG) as fuel. However, China is rich in coal but is deficient in NG; therefore, a hybrid-fuel CAES is proposed and analyzed in this study. Based on the existing CAES plants, the hybrid-fuel CAES incorporates an external combustion heater into the power generation subsystem to heat the air from the recuperator and the air from the high-pressure air turbine. Coal is the fuel for the external combustion heater. The overall efficiency and exergy efficiency of the hybrid-fuel CAES are 61.18% and 59.84%, respectively. Given the same parameters, the cost of electricity (COE) of the hybrid-fuel CAES, which requires less NG, is $5.48/MW∙h less than that of the gas-fuel CAES. Although the proposed CAES requires a relatively high investment in the current electricity system in North China, the proposed CAES will be likely to become competitive in the market, provided that the energy supplies are improved and the large scale grid-connection of wind power is realized.

ACS Style

Wenyi Liu; Linzhi Liu; Gang Xu; Feifei Liang; Yongping Yang; Weide Zhang; Ying Wu. A Novel Hybrid-Fuel Storage System of Compressed Air Energy for China. Energies 2014, 7, 4988 -5010.

AMA Style

Wenyi Liu, Linzhi Liu, Gang Xu, Feifei Liang, Yongping Yang, Weide Zhang, Ying Wu. A Novel Hybrid-Fuel Storage System of Compressed Air Energy for China. Energies. 2014; 7 (8):4988-5010.

Chicago/Turabian Style

Wenyi Liu; Linzhi Liu; Gang Xu; Feifei Liang; Yongping Yang; Weide Zhang; Ying Wu. 2014. "A Novel Hybrid-Fuel Storage System of Compressed Air Energy for China." Energies 7, no. 8: 4988-5010.

Journal article
Published: 04 June 2014 in Entropy
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Compressed air energy storage (CAES) is a commercial, utility-scale technology that provides long-duration energy storage with fast ramp rates and good part-load operation. It is a promising storage technology for balancing the large-scale penetration of renewable energies, such as wind and solar power, into electric grids. This study proposes a CAES-CC system, which is based on a conventional CAES combined with a steam turbine cycle by waste heat boiler. Simulation and thermodynamic analysis are carried out on the proposed CAES-CC system. The electricity and heating rates of the proposed CAES-CC system are lower than those of the conventional CAES by 0.127 kWh/kWh and 0.338 kWh/kWh, respectively, because the CAES-CC system recycles high-temperature turbine-exhausting air. The overall efficiency of the CAES-CC system is improved by approximately 10% compared with that of the conventional CAES. In the CAES-CC system, compressing intercooler heat can keep the steam turbine on hot standby, thus improving the flexibility of CAES-CC. This study brought about a new method for improving the efficiency of CAES and provided new thoughts for integrating CAES with other electricity-generating modes.

ACS Style

Wenyi Liu; Linzhi Liu; Luyao Zhou; Jian Huang; Yuwen Zhang; Gang Xu; Yongping Yang. Analysis and Optimization of a Compressed Air Energy Storage—Combined Cycle System. Entropy 2014, 16, 3103 -3120.

AMA Style

Wenyi Liu, Linzhi Liu, Luyao Zhou, Jian Huang, Yuwen Zhang, Gang Xu, Yongping Yang. Analysis and Optimization of a Compressed Air Energy Storage—Combined Cycle System. Entropy. 2014; 16 (6):3103-3120.

Chicago/Turabian Style

Wenyi Liu; Linzhi Liu; Luyao Zhou; Jian Huang; Yuwen Zhang; Gang Xu; Yongping Yang. 2014. "Analysis and Optimization of a Compressed Air Energy Storage—Combined Cycle System." Entropy 16, no. 6: 3103-3120.

Journal article
Published: 23 May 2014 in Energies
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In this study, an improved CO2 separation and purification system is proposed based on in-depth analyses of cryogenic separation and distillation theory as well as the phase transition characteristics of gas mixtures containing CO2. Multi-stage compression, refrigeration, and separation are adopted to separate the majority of the CO2 from the gas mixture with relatively low energy penalty and high purity. Subsequently, the separated crude liquid CO2 is distilled under high pressure and near ambient temperature conditions so that low energy penalty purification is achieved. Simulation results indicate that the specific energy consumption for CO2 capture is only 0.425 MJ/kgCO2 with 99.9% CO2 purity for the product. Techno-economic analysis shows that the total plant investment is relatively low. Given its technical maturity and great potential in large-scale production, compared to conventional MEA and SelexolTM absorption methods, the cost of CO2 capture of the proposed system is reduced by 57.2% and 45.9%, respectively. The result of this study can serve as a novel approach to recovering CO2 from high CO2 concentration gas mixtures.

ACS Style

Gang Xu; Feifei Liang; Yongping Yang; Yue Hu; Kai Zhang; Wenyi Liu. An Improved CO2 Separation and Purification System Based on Cryogenic Separation and Distillation Theory. Energies 2014, 7, 3484 -3502.

AMA Style

Gang Xu, Feifei Liang, Yongping Yang, Yue Hu, Kai Zhang, Wenyi Liu. An Improved CO2 Separation and Purification System Based on Cryogenic Separation and Distillation Theory. Energies. 2014; 7 (5):3484-3502.

Chicago/Turabian Style

Gang Xu; Feifei Liang; Yongping Yang; Yue Hu; Kai Zhang; Wenyi Liu. 2014. "An Improved CO2 Separation and Purification System Based on Cryogenic Separation and Distillation Theory." Energies 7, no. 5: 3484-3502.