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David A. Dzombak - One of the best experts on this subject based on the ideXlab platform.
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Inhibition of Copper Corrosion by Tolyltriazole in Cooling Systems Using Treated Municipal WasteWater as Makeup Water
Arabian Journal for Science and Engineering, 2014Co-Authors: Mahbuboor Rahman Choudhury, Radisav D. Vidic, David A. DzombakAbstract:Tolyltriazole (TTA) has been identified as an effective copper corrosion inhibitor in cooling systems using treated municipal effluent as Makeup Water. Significant removal of TTA from solution has been reported in previous studies in the presence of free chlorine and copper metal. Hence, for effective dosing of TTA in the cooling systems, it is important to understand the depletion scenario of TTA in solution in the presence of free chlorine and copper metal. In this study, TTA depletion in solution was assessed using batch reactor experiments in the presence of varying concentrations of free chlorine and copper metal in synthetic cooling Water simulating treated municipal wasteWater. Increasing free chlorine concentration resulted in more depletion of TTA from solution in the presence of copper metal, which may be due to more adsorption of TTA on to the cuprous oxide surface formed with enhanced corrosion of copper metal and to the formation of insoluble copper–TTA complex with the released copper ions in solution. The enhancement of copper metal corrosion in the presence of TTA and increasing concentration of free chlorine were assessed using electrochemical potentiodynamic polarization experiments. Also, TTA adsorption on cuprous oxide surface was assessed in batch reactor experiments. Packing density of TTA on cuprous oxide surface was found to be pH dependent. More TTA was adsorbed onto cuprous oxide surface at higher pH values. Calculations of TTA free energy of adsorption showed that TTA was chemisorbed onto cuprous oxide.
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Impact of Tertiary Treatment Processes on the Effectiveness of Chloramination for Biological Growth Control in Recirculating Cooling Systems Using Treated Municipal WasteWater
Journal of Environmental Engineering, 2014Co-Authors: Shih-hsiang Chien, David A. Dzombak, Wenshi Liu, Radisav D. VidicAbstract:AbstractAdequate biocide addition is the key to control biological growth-related problems in recirculating cooling systems of thermoelectric power plants. The use of monochloramine (MCA) as the primary biocide is as effective as the use of free-chlorine in cooling systems using secondary-treated municipal wasteWater (MWW) as the sole Makeup Water source. However, severe scaling caused by the secondary effluent necessitates incorporation of an additional treatment of secondary effluent (i.e., tertiary treatment) prior to use as Makeup Water for recirculating cooling systems. In the research reported in this paper, the effectiveness of MCA as a cooling-system biocide was evaluated for three types of tertiary-treated MWW, as follows: (1) acidification, (2) nitrification and sand filtration, and (3) nitrification, sand filtration, and granular activated-carbon adsorption. The impact of these tertiary treatment processes on chloramination was studied in both laboratory and pilot-scale experiments. For the thi...
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Utilization of municipal wasteWater for cooling in thermoelectric power plants: Evaluation of the combined cost of Makeup Water treatment and increased condenser fouling
Energy, 2013Co-Authors: Michael E. Walker, David A. Dzombak, Mingkai Hsieh, Iman Safari, Javad Abbasian, Hamid Arastoopour, Ranjani B. Theregowda, David C. MillerAbstract:A methodology is presented to calculate the TCC (total combined cost) of Water sourcing, Water treatment and condenser fouling in the recirculating cooling systems of thermoelectric power plants. The methodology is employed to evaluate the economic viability of using treated MWW (municipal wasteWater) to replace the use of freshWater as Makeup Water to power plant cooling systems. Cost analyses are presented for a reference power plant and five different tertiary treatment scenarios to reduce the scaling tendencies of MWW. Results indicate that a 550 MW sub-critical coal fired power plant with a Makeup Water requirement of 29.3 ML/day has a TCC of $3.0–3.2 million/yr associated with the use of treated MWW for cooling. (All costs USD (United States dollars) 2009). This translates to a freshWater conservation cost of $0.29/kL, which is considerably lower than that of dry air cooling technology, $1.5/kL, as well as the 2020 conservation cost target set by the U.S. Department of Energy, $0.74/kL. Results also show that if the available price of freshWater exceeds that of secondary-treated MWW by more than $0.13–0.14/kL, it can be economically advantageous to purchase secondary MWW and treat it for utilization in the recirculating cooling system of a thermoelectric power plant.
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Utilization of municipal wasteWater for cooling in thermoelectric power plants
Fuel, 2013Co-Authors: Iman Safari, Radisav D. Vidic, David A. Dzombak, Wenshi Liu, Mingkai Hsieh, Michael E. Walker, David C. Miller, Javad AbbasianAbstract:Abstract A process simulation model has been developed using Aspen Plus® with the OLI (OLI System, Inc.) Water chemistry model to predict Water quality in the recirculating cooling loop utilizing secondary- and tertiary-treated municipal wasteWater as the source of Makeup Water. Simulation results were compared with pilot-scale experimental data on Makeup Water alkalinity, loop pH, and ammonia evaporation. The effects of various parameters including Makeup Water quality, salt formation, NH3 and CO2 evaporation mass transfer coefficients, heat load, and operating temperatures were investigated. The results indicate that, although the simulation model can capture the general trends in the loop pH, experimental data on the rates of salt precipitation in the system are needed for more accurate prediction of the loop pH. It was also found that stripping of ammonia and carbon dioxide in the cooling tower can influence the cooling loop pH significantly. The effects of the NH3 mass transfer coefficient on cooling loop pH appear to be more significant at lower values (e.g., k NH 3 k CO 2
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Effect of CO2 stripping on pH in open‐recirculating cooling Water systems
Environmental Progress, 2013Co-Authors: Iman Safari, Radisav D. Vidic, David A. Dzombak, Shih-hsiang Chien, Mingkai Hsieh, Michael E. Walker, Javad AbbasianAbstract:A simplified mathematical model has been developed to evaluate the effect of CO2 stripping on pH of recirculating cooling Water in power plant cooling systems. Experimental data from three pilot-scale cooling towers using treated municipal wasteWater as Makeup Water were used to determine the CO2 mass transfer coefficients in the gas phase kg and aqueous phase kw. The optimum values of the gas film mass transfer coefficient and Water film mass transfer coefficient were determined by regression to be kg = 8.4 × 10−6 m/s and kw=8.4 × 10−8m/s, respectively. The results also indicate that the model is capable of predicting the pH of the cooling loop as a function of Makeup Water alkalinity and cooling loop alkalinity (in case of salt formation) as well as the operating parameters of the cooling system. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 275–282, 2014
Radisav D. Vidic - One of the best experts on this subject based on the ideXlab platform.
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Inhibition of Copper Corrosion by Tolyltriazole in Cooling Systems Using Treated Municipal WasteWater as Makeup Water
Arabian Journal for Science and Engineering, 2014Co-Authors: Mahbuboor Rahman Choudhury, Radisav D. Vidic, David A. DzombakAbstract:Tolyltriazole (TTA) has been identified as an effective copper corrosion inhibitor in cooling systems using treated municipal effluent as Makeup Water. Significant removal of TTA from solution has been reported in previous studies in the presence of free chlorine and copper metal. Hence, for effective dosing of TTA in the cooling systems, it is important to understand the depletion scenario of TTA in solution in the presence of free chlorine and copper metal. In this study, TTA depletion in solution was assessed using batch reactor experiments in the presence of varying concentrations of free chlorine and copper metal in synthetic cooling Water simulating treated municipal wasteWater. Increasing free chlorine concentration resulted in more depletion of TTA from solution in the presence of copper metal, which may be due to more adsorption of TTA on to the cuprous oxide surface formed with enhanced corrosion of copper metal and to the formation of insoluble copper–TTA complex with the released copper ions in solution. The enhancement of copper metal corrosion in the presence of TTA and increasing concentration of free chlorine were assessed using electrochemical potentiodynamic polarization experiments. Also, TTA adsorption on cuprous oxide surface was assessed in batch reactor experiments. Packing density of TTA on cuprous oxide surface was found to be pH dependent. More TTA was adsorbed onto cuprous oxide surface at higher pH values. Calculations of TTA free energy of adsorption showed that TTA was chemisorbed onto cuprous oxide.
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Impact of Tertiary Treatment Processes on the Effectiveness of Chloramination for Biological Growth Control in Recirculating Cooling Systems Using Treated Municipal WasteWater
Journal of Environmental Engineering, 2014Co-Authors: Shih-hsiang Chien, David A. Dzombak, Wenshi Liu, Radisav D. VidicAbstract:AbstractAdequate biocide addition is the key to control biological growth-related problems in recirculating cooling systems of thermoelectric power plants. The use of monochloramine (MCA) as the primary biocide is as effective as the use of free-chlorine in cooling systems using secondary-treated municipal wasteWater (MWW) as the sole Makeup Water source. However, severe scaling caused by the secondary effluent necessitates incorporation of an additional treatment of secondary effluent (i.e., tertiary treatment) prior to use as Makeup Water for recirculating cooling systems. In the research reported in this paper, the effectiveness of MCA as a cooling-system biocide was evaluated for three types of tertiary-treated MWW, as follows: (1) acidification, (2) nitrification and sand filtration, and (3) nitrification, sand filtration, and granular activated-carbon adsorption. The impact of these tertiary treatment processes on chloramination was studied in both laboratory and pilot-scale experiments. For the thi...
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Utilization of municipal wasteWater for cooling in thermoelectric power plants
Fuel, 2013Co-Authors: Iman Safari, Radisav D. Vidic, David A. Dzombak, Wenshi Liu, Mingkai Hsieh, Michael E. Walker, David C. Miller, Javad AbbasianAbstract:Abstract A process simulation model has been developed using Aspen Plus® with the OLI (OLI System, Inc.) Water chemistry model to predict Water quality in the recirculating cooling loop utilizing secondary- and tertiary-treated municipal wasteWater as the source of Makeup Water. Simulation results were compared with pilot-scale experimental data on Makeup Water alkalinity, loop pH, and ammonia evaporation. The effects of various parameters including Makeup Water quality, salt formation, NH3 and CO2 evaporation mass transfer coefficients, heat load, and operating temperatures were investigated. The results indicate that, although the simulation model can capture the general trends in the loop pH, experimental data on the rates of salt precipitation in the system are needed for more accurate prediction of the loop pH. It was also found that stripping of ammonia and carbon dioxide in the cooling tower can influence the cooling loop pH significantly. The effects of the NH3 mass transfer coefficient on cooling loop pH appear to be more significant at lower values (e.g., k NH 3 k CO 2
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Effect of CO2 stripping on pH in open‐recirculating cooling Water systems
Environmental Progress, 2013Co-Authors: Iman Safari, Radisav D. Vidic, David A. Dzombak, Shih-hsiang Chien, Mingkai Hsieh, Michael E. Walker, Javad AbbasianAbstract:A simplified mathematical model has been developed to evaluate the effect of CO2 stripping on pH of recirculating cooling Water in power plant cooling systems. Experimental data from three pilot-scale cooling towers using treated municipal wasteWater as Makeup Water were used to determine the CO2 mass transfer coefficients in the gas phase kg and aqueous phase kw. The optimum values of the gas film mass transfer coefficient and Water film mass transfer coefficient were determined by regression to be kg = 8.4 × 10−6 m/s and kw=8.4 × 10−8m/s, respectively. The results also indicate that the model is capable of predicting the pH of the cooling loop as a function of Makeup Water alkalinity and cooling loop alkalinity (in case of salt formation) as well as the operating parameters of the cooling system. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 275–282, 2014
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Control of biological growth in recirculating cooling systems using treated secondary effluent as Makeup Water with monochloramine.
Water Research, 2012Co-Authors: Shih-hsiang Chien, David A. Dzombak, Mingkai Hsieh, Indranil Chowdhury, Radisav D. VidicAbstract:Secondary-treated municipal wasteWater, an abundant and widely distributed impaired Water source, is a promising alternative Water source for thermoelectric power plant cooling. However, excessive biological growth is a major challenge associated with wasteWater reuse in cooling systems as it can interfere with normal system operation as well as enhance corrosion and scaling problems. Furthermore, possible emission of biological aerosols (e.g., Legionella pneumophila) with the cooling tower drift can lead to public health concerns within the zone of aerosol deposition. In this study, the effectiveness of pre-formed and in-situ-formed monochloramine was evaluated for its ability to control biological growth in recirculating cooling systems using secondary-treated municipal wasteWater as the only Makeup Water source. Bench-scale studies were compared with pilot-scale studies for their ability to predict system behavior under realistic process conditions. Effectiveness of the continuous addition of pre-formed monochloramine and monochloramine formed in-situ through the reaction of free chlorine with ammonia in the incoming Water was evaluated in terms of biocide residual and its ability to control both planktonic and sessile microbial populations. Results revealed that monochloramine can effectively control biofouling in cooling systems employing secondary-treated municipal wasteWater and has advantages relative to use of free chlorine, but that bench-scale studies seriously underestimate biocide dose and residual requirements for proper control of biological growth in full-scale systems. Pre-formed monochloramine offered longer residence time and more reliable performance than in-situ-formed monochloramine due to highly variable ammonia concentration in the recirculating Water caused by ammonia stripping in the cooling tower. Pilot-scale tests revealed that much lower dosing rate was required to maintain similar total chlorine residual when pre-formed monochloramine was used as compared to in-situ-formed monochloramine. Adjustment of biocide dose to maintain monochloramine residual above 3 mg/L is needed to achieve successful biological growth control in recirculating cooling systems using secondary-treated municipal effluent as the only source of Makeup Water.
Mingkai Hsieh - One of the best experts on this subject based on the ideXlab platform.
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Utilization of municipal wasteWater for cooling in thermoelectric power plants: Evaluation of the combined cost of Makeup Water treatment and increased condenser fouling
Energy, 2013Co-Authors: Michael E. Walker, David A. Dzombak, Mingkai Hsieh, Iman Safari, Javad Abbasian, Hamid Arastoopour, Ranjani B. Theregowda, David C. MillerAbstract:A methodology is presented to calculate the TCC (total combined cost) of Water sourcing, Water treatment and condenser fouling in the recirculating cooling systems of thermoelectric power plants. The methodology is employed to evaluate the economic viability of using treated MWW (municipal wasteWater) to replace the use of freshWater as Makeup Water to power plant cooling systems. Cost analyses are presented for a reference power plant and five different tertiary treatment scenarios to reduce the scaling tendencies of MWW. Results indicate that a 550 MW sub-critical coal fired power plant with a Makeup Water requirement of 29.3 ML/day has a TCC of $3.0–3.2 million/yr associated with the use of treated MWW for cooling. (All costs USD (United States dollars) 2009). This translates to a freshWater conservation cost of $0.29/kL, which is considerably lower than that of dry air cooling technology, $1.5/kL, as well as the 2020 conservation cost target set by the U.S. Department of Energy, $0.74/kL. Results also show that if the available price of freshWater exceeds that of secondary-treated MWW by more than $0.13–0.14/kL, it can be economically advantageous to purchase secondary MWW and treat it for utilization in the recirculating cooling system of a thermoelectric power plant.
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Utilization of municipal wasteWater for cooling in thermoelectric power plants
Fuel, 2013Co-Authors: Iman Safari, Radisav D. Vidic, David A. Dzombak, Wenshi Liu, Mingkai Hsieh, Michael E. Walker, David C. Miller, Javad AbbasianAbstract:Abstract A process simulation model has been developed using Aspen Plus® with the OLI (OLI System, Inc.) Water chemistry model to predict Water quality in the recirculating cooling loop utilizing secondary- and tertiary-treated municipal wasteWater as the source of Makeup Water. Simulation results were compared with pilot-scale experimental data on Makeup Water alkalinity, loop pH, and ammonia evaporation. The effects of various parameters including Makeup Water quality, salt formation, NH3 and CO2 evaporation mass transfer coefficients, heat load, and operating temperatures were investigated. The results indicate that, although the simulation model can capture the general trends in the loop pH, experimental data on the rates of salt precipitation in the system are needed for more accurate prediction of the loop pH. It was also found that stripping of ammonia and carbon dioxide in the cooling tower can influence the cooling loop pH significantly. The effects of the NH3 mass transfer coefficient on cooling loop pH appear to be more significant at lower values (e.g., k NH 3 k CO 2
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Effect of CO2 stripping on pH in open‐recirculating cooling Water systems
Environmental Progress, 2013Co-Authors: Iman Safari, Radisav D. Vidic, David A. Dzombak, Shih-hsiang Chien, Mingkai Hsieh, Michael E. Walker, Javad AbbasianAbstract:A simplified mathematical model has been developed to evaluate the effect of CO2 stripping on pH of recirculating cooling Water in power plant cooling systems. Experimental data from three pilot-scale cooling towers using treated municipal wasteWater as Makeup Water were used to determine the CO2 mass transfer coefficients in the gas phase kg and aqueous phase kw. The optimum values of the gas film mass transfer coefficient and Water film mass transfer coefficient were determined by regression to be kg = 8.4 × 10−6 m/s and kw=8.4 × 10−8m/s, respectively. The results also indicate that the model is capable of predicting the pH of the cooling loop as a function of Makeup Water alkalinity and cooling loop alkalinity (in case of salt formation) as well as the operating parameters of the cooling system. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 275–282, 2014
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Control of biological growth in recirculating cooling systems using treated secondary effluent as Makeup Water with monochloramine.
Water Research, 2012Co-Authors: Shih-hsiang Chien, David A. Dzombak, Mingkai Hsieh, Indranil Chowdhury, Radisav D. VidicAbstract:Secondary-treated municipal wasteWater, an abundant and widely distributed impaired Water source, is a promising alternative Water source for thermoelectric power plant cooling. However, excessive biological growth is a major challenge associated with wasteWater reuse in cooling systems as it can interfere with normal system operation as well as enhance corrosion and scaling problems. Furthermore, possible emission of biological aerosols (e.g., Legionella pneumophila) with the cooling tower drift can lead to public health concerns within the zone of aerosol deposition. In this study, the effectiveness of pre-formed and in-situ-formed monochloramine was evaluated for its ability to control biological growth in recirculating cooling systems using secondary-treated municipal wasteWater as the only Makeup Water source. Bench-scale studies were compared with pilot-scale studies for their ability to predict system behavior under realistic process conditions. Effectiveness of the continuous addition of pre-formed monochloramine and monochloramine formed in-situ through the reaction of free chlorine with ammonia in the incoming Water was evaluated in terms of biocide residual and its ability to control both planktonic and sessile microbial populations. Results revealed that monochloramine can effectively control biofouling in cooling systems employing secondary-treated municipal wasteWater and has advantages relative to use of free chlorine, but that bench-scale studies seriously underestimate biocide dose and residual requirements for proper control of biological growth in full-scale systems. Pre-formed monochloramine offered longer residence time and more reliable performance than in-situ-formed monochloramine due to highly variable ammonia concentration in the recirculating Water caused by ammonia stripping in the cooling tower. Pilot-scale tests revealed that much lower dosing rate was required to maintain similar total chlorine residual when pre-formed monochloramine was used as compared to in-situ-formed monochloramine. Adjustment of biocide dose to maintain monochloramine residual above 3 mg/L is needed to achieve successful biological growth control in recirculating cooling systems using secondary-treated municipal effluent as the only source of Makeup Water.
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Ammonia stripping in open‐recirculating cooling Water systems
Environmental Progress, 2012Co-Authors: Mingkai Hsieh, Radisav D. Vidic, Shih-hsiang Chien, Iman Safari, Michael E. Walker, Javad Abbasian, David A. DzombakAbstract:A mathematical model was developed to simulate ammonia stripping in wet recirculating cooling systems. The model can be used to predict ammonia concentration in cooling systems using Makeup Water containing ammonia, such as secondary treated municipal wasteWater (MWW). The model revealed that ammonia stripping in a cooling system is a function of Makeup Water quality, pH, and air and Water flow rates in the cooling tower. Pilot-scale cooling towers designed and constructed previously for the investigation of biofouling, scaling, and corrosion issues in the reuse of treated MWW for cooling were used in this study for model verification. Data from pilot-scale testing using a particular ammonia-containing Makeup Water were used to calibrate the model. The overall mass transfer coefficient based on gas film for ammonia stripping in the cooling tower was found to be 2.3 × 10−3 m/s. Sensitivity analysis showed that even under only slightly alkaline conditions (pH 8), a significant portion of ammonia can be removed through Water-to-air stripping, which is consistent with low ammonia measurements in cooling towers reported in the literature. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 489–495, 2013
A. B. Larin - One of the best experts on this subject based on the ideXlab platform.
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Estimating the effectiveness of using atmospheric deaerators for decarbonizing Makeup Water
Thermal Engineering, 2015Co-Authors: B. M. Larin, A. B. LarinAbstract:According to the Water coolant quality standards, the Makeup Water supplied to a thermal power plant’s (TPP) steam-generating systems must not have any content of free carbonic acid. As a rule, free and partially bound carbonic acid is removed from Makeup Water supplied to the power-generating boilers at TPPs in atmospheric deaerators. Their performance as decarbonizers can be evaluated by measuring the pH values of Water supplied to the deaerator and of the deaerated Water. A procedure for calculating the residual concentration of carbonic acid in deaerated Water and the decarbonization effect from the change in the pH value (ΔpH) is presented together with an example of calculation carried out by specialists of the Ivanovo State Power Engineering University based on a long-term industrial experiment performed on DSA-300 atmospheric deaerators.
S. K. Ziganshina - One of the best experts on this subject based on the ideXlab platform.
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Estimating the efficiency of the vacuum deaerators used for treating network Water at the Samara cogeneration station and their modernization
Thermal Engineering, 2010Co-Authors: A. A. Kudinov, D. V. Obukhov, S. K. ZiganshinaAbstract:Results from experimental studies on analyzing the operating conditions of the vacuum deaerators used to treat Makeup Water for the heat supply network connected to the Samara cogeneration station are presented. Proposals for improving the design of the DB-800 deaerator No. 5 at the Samara cogeneration station were worked out, its retrofitting was completed, and thermal tests were carried out.
