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Hydrothermal flame is an effective solution to avoid coking and salt plugging in the preheating section of a supercritical water oxidation (SCWO) system with a transpiring wall reactor (TWR). An SCWO system with an evaporation module (SCWOE) is proposed in this work to concentrate the wastewater and promote the formation of a hydrothermal flame. The SCWOE system is simulated using Aspen Plus, and the simulation model is validated by comparing with the experimental data on the migration of organics in evaporation. The introduction of the evaporation module greatly reduces the exergy input. The exergy destruction mainly comes from the TWR, electric heater, and heat exchangers. The highest exergy destruction in the TWR appears in the reaction section, and the total exergy destruction in the TWR due to the transpiring water injection reaches 89.9%. The increase in concentration ratio (α) and feed concentration (ω) can lower the exergy input and improve the energy efficiency, and an energy self-sufficient rate of 79.7% occurs at ω = 15% and α = 2. Moreover, the involatile property of organics is conducive to improving energy self-sufficient rate, and the volatilization rate of phenol in wastewater must be controlled in this system.
Fengming Zhang; Yufeng Li; Cuijie Jia; Boya Shen. Effect of evaporation on the energy conversion of a supercritical water oxidation system containing a hydrothermal flame. Energy 2021, 226, 120406 .
AMA StyleFengming Zhang, Yufeng Li, Cuijie Jia, Boya Shen. Effect of evaporation on the energy conversion of a supercritical water oxidation system containing a hydrothermal flame. Energy. 2021; 226 ():120406.
Chicago/Turabian StyleFengming Zhang; Yufeng Li; Cuijie Jia; Boya Shen. 2021. "Effect of evaporation on the energy conversion of a supercritical water oxidation system containing a hydrothermal flame." Energy 226, no. : 120406.
Transpiring and cooled-wall reactors are widely used to overcome the corrosion and salt plugging problems in the supercritical water oxidation (SCWO) process. However, energy consumption will significantly increase because the energy grade of the reactor effluent is decreased. In this study, an SCWO system with an inverse cool-wall reactor is proposed and simulated using Aspen Plus 8.2. With the improved cool-wall reactor and corresponding system, the energy consumption can be greatly reduced because the energy recovered from the reactor effluent is upgraded for power generation. High energy output and less exergy input and loss are present, resulting in high exergy efficiency and low energy consumption. The increase in the outlet temperature of the working fluid or feed concentration contributes to achieving energy self-efficiency. However, high reaction temperatures are present at high feed concentrations, and long reactor lengths or additional heat transfer areas are needed at high feed concentrations to cool the reactive fluids. The results of economic analysis show that the SCWO system with a cool-wall reactor is economically competitive.
Fengming Zhang; Yaxin Ding; Chuangjian Su; Zhiyu Chen. Energy self-sufficiency of a supercritical water oxidation system with an improved cooled-wall reactor for power generation. Applied Thermal Engineering 2020, 172, 115158 .
AMA StyleFengming Zhang, Yaxin Ding, Chuangjian Su, Zhiyu Chen. Energy self-sufficiency of a supercritical water oxidation system with an improved cooled-wall reactor for power generation. Applied Thermal Engineering. 2020; 172 ():115158.
Chicago/Turabian StyleFengming Zhang; Yaxin Ding; Chuangjian Su; Zhiyu Chen. 2020. "Energy self-sufficiency of a supercritical water oxidation system with an improved cooled-wall reactor for power generation." Applied Thermal Engineering 172, no. : 115158.
Fengming Zhang; Jianan Ma; Chuangjian Su. Study on the uniformity of water film in a transpiring wall reactor for supercritical water oxidation. The Canadian Journal of Chemical Engineering 2020, 98, 1631 -1644.
AMA StyleFengming Zhang, Jianan Ma, Chuangjian Su. Study on the uniformity of water film in a transpiring wall reactor for supercritical water oxidation. The Canadian Journal of Chemical Engineering. 2020; 98 (7):1631-1644.
Chicago/Turabian StyleFengming Zhang; Jianan Ma; Chuangjian Su. 2020. "Study on the uniformity of water film in a transpiring wall reactor for supercritical water oxidation." The Canadian Journal of Chemical Engineering 98, no. 7: 1631-1644.
The mixing characteristics between bulk flows and transpiring water are critical to feed degradation and water film formation inside a transpiring-wall reactor (TWR). In this study, a supercritical water oxidation system with an inner preheating TWR is established, and special experiments are designed by adding organic matter (glycerol) to the transpiring water to evaluate the mixing degree between the bulk flows and transpiring water in the hydrothermal flame zone. Although the chemical oxygen demand concentration of the reactor effluent increases significantly due to the addition of glycerol to the transpiring water, a certain amount of glycerol is entrapped into the flame zone and degraded. The increase in jet velocity with increased heat source flow or temperature is favorable for mixing and enhances jet entrainment. Moreover, increasing the transpiring coefficient and transpiring water temperature can increase the radial velocity of transpiring water, which also benefits mixing. Possible applications utilizing the mixing characteristics are further proposed.
Fengming Zhang; Chuangjian Su; Zhiyu Chen; Jiulin Chen. Experimental study on the mixing characteristics inside an inner preheating transpiring-wall reactor for supercritical water oxidation. The Journal of Supercritical Fluids 2019, 156, 104682 .
AMA StyleFengming Zhang, Chuangjian Su, Zhiyu Chen, Jiulin Chen. Experimental study on the mixing characteristics inside an inner preheating transpiring-wall reactor for supercritical water oxidation. The Journal of Supercritical Fluids. 2019; 156 ():104682.
Chicago/Turabian StyleFengming Zhang; Chuangjian Su; Zhiyu Chen; Jiulin Chen. 2019. "Experimental study on the mixing characteristics inside an inner preheating transpiring-wall reactor for supercritical water oxidation." The Journal of Supercritical Fluids 156, no. : 104682.
Supercritical water oxidation (SCWO) is a promising technology for treating organic waste and recovering energy. Water film protective reactor (WFPR), which is also referred to as transpiring wall reactor, provides a solution to corrosion and salt plugging issues. Three novel film protective reactors (FPRs) using air, nitrogen, and hydrogen peroxide as protective fluids were proposed to improve the corrosion and cost issues in WFPRs. Detailed optimized process parameters and flow field characteristics within the FPRs were obtained using Aspen Plus and computational fluid dynamics, respectively. The anti-corrosion performance and prevention of salt plugging in the FPRs were analyzed, and economic analyses for SCWO systems with different FPRs were conducted. Results indicate that the WFPR and hydrogen peroxide FPR present good solubility for inorganic salts but a high probability of corrosion. An SCWO system with the WFPR or nitrogen FPR is more competitive for industrial plants compared with other SCWO systems.
Fengming Zhang; Jiulin Chen; Chuangjian Su; Shunquan Chen; Zhiyu Chen; Yaxin Ding. Combined effects of protective film and oxidant on the performance of the supercritical water oxidation system with a film protective reactor: A simulation study. Process Safety and Environmental Protection 2019, 131, 268 -281.
AMA StyleFengming Zhang, Jiulin Chen, Chuangjian Su, Shunquan Chen, Zhiyu Chen, Yaxin Ding. Combined effects of protective film and oxidant on the performance of the supercritical water oxidation system with a film protective reactor: A simulation study. Process Safety and Environmental Protection. 2019; 131 ():268-281.
Chicago/Turabian StyleFengming Zhang; Jiulin Chen; Chuangjian Su; Shunquan Chen; Zhiyu Chen; Yaxin Ding. 2019. "Combined effects of protective film and oxidant on the performance of the supercritical water oxidation system with a film protective reactor: A simulation study." Process Safety and Environmental Protection 131, no. : 268-281.
Based on the mechanism of low-temperature multi-effect distillation combining with super-critical water oxidation (LT-MED&SCWO), a system that disposes phenol wastewater is introduced. Establishing a process of four-effect forward feed LT-MED concentrated phenol waste-water and a SCWO degradation of phenol by Aspen Plus software is essential to compare the effects of in-feed phenol mass concentration, system concentration ratio on phenol concentration ratio and mixing temperature of reaction required for degradation. The study shows that with the increase of in-feed phenol mass concentration, phenol concentration ratio keeps almost constant, 97.7%, but, preheating temperature of the concentrated water decreases when the final product mass phenol concentration is less than 0.5ppm; when system concentration ratio increases, phenol concentration ratio decreases from 99.5%to 96.7%and preheating temperature of the concentrated water also decreases when the final product mass phenol concentration is less than 0.5ppm.
Cuijie Jia; Bo Yuan; Fengming Zhang; Chuan He; Chuangjian Su; Jiulin Chen. Research on phenol wastewater treatment by low-temperature multi-effect distillation combining with super-critical water oxidation. IOP Conference Series: Earth and Environmental Science 2018, 208, 012063 .
AMA StyleCuijie Jia, Bo Yuan, Fengming Zhang, Chuan He, Chuangjian Su, Jiulin Chen. Research on phenol wastewater treatment by low-temperature multi-effect distillation combining with super-critical water oxidation. IOP Conference Series: Earth and Environmental Science. 2018; 208 (1):012063.
Chicago/Turabian StyleCuijie Jia; Bo Yuan; Fengming Zhang; Chuan He; Chuangjian Su; Jiulin Chen. 2018. "Research on phenol wastewater treatment by low-temperature multi-effect distillation combining with super-critical water oxidation." IOP Conference Series: Earth and Environmental Science 208, no. 1: 012063.
Oxygen consumption is one of the factors that contributes to the high treatment cost of a supercritical water oxidation (SCWO) system. In this work, we proposed an oxygen recovery (OR) process for an SCWO system based on the solubility difference between oxygen and CO2 in high-pressure water. A two-stage gas–liquid separation process was established using Aspen Plus software to obtain the optimized separation parameters. Accordingly, energy consumption and economic analyses were conducted for the SCWO process with and without OR. Electricity, depreciation, and oxygen costs contribute to the major cost of the SCWO system without OR, accounting for 46.18, 30.24, and 18.01 $·t−1, respectively. When OR was introduced, the total treatment cost decreased from 56.80 $·t−1 to 46.17 $·t−1, with a reduction of 18.82%. Operating cost can be significantly reduced at higher values of the stoichiometric oxygen excess for the SCWO system with OR. Moreover, the treatment cost for the SCWO system with OR decreases with increasing feed concentration for more reaction heat and oxygen recovery.
Fengming Zhang; Jiulin Chen; Chuangjian Su; Chunyuan Ma. Energy Consumption and Economic Analyses of a Supercritical Water Oxidation System with Oxygen Recovery. Processes 2018, 6, 224 .
AMA StyleFengming Zhang, Jiulin Chen, Chuangjian Su, Chunyuan Ma. Energy Consumption and Economic Analyses of a Supercritical Water Oxidation System with Oxygen Recovery. Processes. 2018; 6 (11):224.
Chicago/Turabian StyleFengming Zhang; Jiulin Chen; Chuangjian Su; Chunyuan Ma. 2018. "Energy Consumption and Economic Analyses of a Supercritical Water Oxidation System with Oxygen Recovery." Processes 6, no. 11: 224.
A computational fluid dynamics model of an inner preheating transpiring wall reactor for supercritical water oxidation was proposed to optimize the structural parameters. Results showed that higher feed degradation efficiencies and lower inner surface temperatures of the porous wall were obtained at higher reactor diameters. Although the increase in reactor length promoted feed degradation, the increased inner surface temperatures of the porous wall were unsuitable for water film formation. A pyknic-type reactor with a lower length/diameter (H/D) value at a constant volume was more beneficial for water film formation and feed degradation. A higher feed concentration or feed flow required a lower H/D value to ensure an ideal water film formation and feed degradation. We proposed the use of sectional heat load as a new parameter for reactor design based on the similarity between the boiler furnace and the transpiring wall reactor. The sectional heat load in a certain range was calculated to serve as guide in the design of transpiring wall reactors.
Fengming Zhang; Jie Yang; Jianan Ma; Chuangjian Su; Chunyuan Ma. Optimization of structural parameters of an inner preheating transpiring-wall SCWO reactor. Chemical Engineering Research and Design 2018, 141, 372 -387.
AMA StyleFengming Zhang, Jie Yang, Jianan Ma, Chuangjian Su, Chunyuan Ma. Optimization of structural parameters of an inner preheating transpiring-wall SCWO reactor. Chemical Engineering Research and Design. 2018; 141 ():372-387.
Chicago/Turabian StyleFengming Zhang; Jie Yang; Jianan Ma; Chuangjian Su; Chunyuan Ma. 2018. "Optimization of structural parameters of an inner preheating transpiring-wall SCWO reactor." Chemical Engineering Research and Design 141, no. : 372-387.
This paper introduces a medium-size low-temperature multi-effect desalination (LT-MED) system. Powered by the cooling water of a 1000 kW diesel power generator set, the system can produce 60 tons of fresh water per day. First, the thermodynamic and heat transfer model of the LT-MED system is derived. Second, an integrated four-effect tower distiller is designed and built. The system is installed in the Guishan Island, Zhuhai, Guangdong, China, and tested comprehensively. In the operation, the evaporation temperature of each effect is linearly proportional to the heat load of the power generator. Additionally, the evaporation temperature in each effect distiller rose linearly when the heat load was gradually increased. The variation of evaporation pressure was consistent with the evaporation temperature. When the heat load of the power generator increases from 300 kW to 530 kW, the fresh water production rate increases from 1.26 m3/h to 2.30 m3/h. The conductivity of the fresh water is usually < 100 μS/cm. Because of electricity and freshwater co-production, the system is environmental friendly and is particularly useful for islands and offshore platforms.
Fengming Zhang; Shiming Xu; Dongdong Feng; Shunquan Chen; Ruxu Du; Chuangjian Su; Boya Shen. A low-temperature multi-effect desalination system powered by the cooling water of a diesel engine. Desalination 2017, 404, 112 -120.
AMA StyleFengming Zhang, Shiming Xu, Dongdong Feng, Shunquan Chen, Ruxu Du, Chuangjian Su, Boya Shen. A low-temperature multi-effect desalination system powered by the cooling water of a diesel engine. Desalination. 2017; 404 ():112-120.
Chicago/Turabian StyleFengming Zhang; Shiming Xu; Dongdong Feng; Shunquan Chen; Ruxu Du; Chuangjian Su; Boya Shen. 2017. "A low-temperature multi-effect desalination system powered by the cooling water of a diesel engine." Desalination 404, no. : 112-120.