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Andrea Cipollina - One of the best experts on this subject based on the ideXlab platform.

  • New considerations for modelling a MED-TVC plant under dynamic conditions
    Desalination, 2019
    Co-Authors: L. Guimard, Andrea Cipollina, G Micale, Bartolomé Ortega-delgado, Françoise Couenne, P. Bandelier, Christian Jallut
    Abstract:

    Abstract The multiple-effect distillation (MED) technology is nowadays the most promising desalination process to be coupled with variable heat sources, thus leading to a more sustainable way to produce water. In order to prove the potential of this, it is of major interest to develop powerful modelling tools to predict the performance of this coupling. Only a few models have been presented so far. They show promising results but were based on some simplifying assumptions and non-physical constraints that could limit the analysis of the dynamic behaviour of a MED plant. This paper presents new considerations for the dynamic modelling of a MED plant associated with a Thermal Vapour Compression unit, starting from a previous work “A dynamic model for MED-TVC transient operation”. After several improvements, this model is now more representative of the real operating modes of a MED-TVC plant by considering real process inputs. This paper also highlights the importance of accurately modelling the interconnection between effects, the evaporation and condensation processes and the other components, such as the pre-heaters. Here is also presented a control strategy for operating a MED plant under dynamic conditions. Indeed, when a perturbation occurs in the motive steam pressure, it is possible to stabilize the whole plant by a simultaneous variation in the intake seawater mass flow rate at the final condenser. The model has been validated in steady-state conditions with experimental data from a MED-TVC plant operated in Trapani (Sicily) and was used to perform dynamic simulation to prove the feasibility of operating a MED-TVC plant under dynamic conditions, which is a major step toward proving the possibility of a coupling with renewable energies.

  • exergy analysis and thermoeconomic cost accounting of a combined heat and power steam cycle integrated with a multi effect distillation Thermal Vapour Compression desalination plant
    Energy Conversion and Management, 2017
    Co-Authors: Pietro Catrini, Antonio Piacentino, Andrea Cipollina, Gdm Micale, Alessandro Tamburini
    Abstract:

    Abstract In this paper an exergy analysis and thermoeconomic cost accounting of a Combined Heat and Power steam cycle integrated with Multi Effect Distillation-Thermal Vapour Compression plant is performed; the goal of the study is to show how these methodologies provide a rational criterion to allocate production costs on electricity and freshwater in such a dual purpose system. After a brief overview on the methodology and a description of reference plant, exergy analysis is carried out to calculate exergy flows and exergy efficiencies at component level. A detailed description of the adopted thermoeconomic model is given. In a first scenario, cost accounting is performed assuming that the concentrated brine is disposed back to sea, thus being its exergy content definitively wasted; furthermore, a sensitivity analysis is carried out in order to assess the changes in the unit cost of electricity and freshwater with several design and operation parameters. In a second scenario, conversely, part of brine exergy is used in a Reverse Electrodialysis unit to produce further electricity. In both cases results show that high unit costs are obtained for the material streams or energy flows which involve major exergy destruction along their production process, particularly freshwater in the former configuration and Reverse Electrodialysis electric output in the latter one.

  • chp combined heat and power retrofit for a large med tvc multiple effect distillation along with Thermal Vapour Compression desalination plant high efficiency assessment for different design options under the current legislative eu framework
    Energy, 2016
    Co-Authors: Alessandro Tamburini, Andrea Cipollina, G Micale, Antonio Piacentino
    Abstract:

    Integrated power plants in “dual purpose” configuration may represent a viable option for energy cost abatement of desalted water produced by MED-TVC (Multiple Effect Distillation along with Thermal Vapour Compression).

  • CHP (combined heat and power) retrofit for a large MED-TVC (multiple effect distillation along with Thermal Vapour Compression) desalination plant: High efficiency assessment for different design options under the current legislative EU framework
    Energy, 2016
    Co-Authors: Alessandro Tamburini, Andrea Cipollina, G Micale, Antonio Piacentino
    Abstract:

    Abstract Integrated power plants in “dual purpose” configuration may represent a viable option for energy cost abatement of desalted water produced by MED-TVC (Multiple Effect Distillation along with Thermal Vapour Compression). In this paper an existing large MED-TVC plant with a 36,000 m 3 /day capacity is studied: a plant retrofit is designed, based on a steam power plant with condensation and steam extraction used to drive the steam ejector. As the plant operates in CHP (Combined Heat and Power) mode, the possibility to assess the integrated “CHP + MED-TVC” as high efficiency cogeneration according to Directive 2004/8/EC is discussed. Based on a model developed in Engineering Equation Solver, a sensitivity analysis is performed: the influence of several design and operation parameters on the fraction of energy outputs assessed as “from efficient cogeneration” is investigated. This fraction was found to increase almost linearly with the number of MED units supplied with steam. Also, when all the MED units are supplied and the steam extraction pressure is decreased from 4.89 MPa down to 0.29 MPa, the CHP fraction increased from ∼54% to ∼77%. The assessment of the plant as “high efficiency CHP” was found highly dependent on the specific fuel adopted.

  • Integrated production of fresh water, sea salt and magnesium from sea water
    Desalination and Water Treatment, 2012
    Co-Authors: Andrea Cipollina, G Micale, Angelo Misseri, Giacomo D'alì Staiti, Alessandro Galia, Onofrio Scialdone
    Abstract:

    Abstract Seawater desalination is becoming an important source of fresh water in several countries all around the world. One of the main drawbacks of desalination processes, however, is related to the disposal of large quantities of concentrated brine, which is an always-present by-product of the process. An integrated production of fresh water and salts may be achieved using the discharge brine from a desalination plant as a feed for conventional salt ponds, with the advantages of using brine more concentrated than sea water and, in the case of Thermal desalination plants, warmer than sea water. By doing so, the process is faster as a consequence of the enhancement of evaporation rate on the surface of ponds. The above concept has been proposed already several years ago, but only rare examples exist of real applications. A pilot test has been performed in the last 4 years in Trapani (Italy), where a 36,000-m3/d multiple effects desalination with Thermal Vapour Compression plant is operating very close to...

Yan Yang - One of the best experts on this subject based on the ideXlab platform.

  • performance of steam ejector with nonequilibrium condensation for multi effect distillation with Thermal Vapour Compression med tvc seawater desalination system
    Desalination, 2020
    Co-Authors: Hongbing Ding, Yan Yang
    Abstract:

    Abstract The single-phase and two-phase flow models are developed and compared for the performance evaluation of a steam ejector for the multi-effect distillation with Thermal Vapour Compression (MED-TVC) seawater desalination system. The results show that a single-phase flow model with ignoring the phase change predicts an unphysical temperature of the steam in the supersonic flow with the minimum value of approximately 122 K, which raises the query of the formation of the ice. The two-phase wet steam model corrects the distribution of the flow parameter by predicting the heat and mass transfer during the phase change. The steam achieves the first nonequilibrium condensation process inside the primary nozzle and another four alternating condensation and re-evaporation processes. The single-phase flow model under-predicts the entropy loss coefficient by approximately 15% than the two-phase wet steam model. The performance comparison is achieved against the single-phase model to present the accuracy of the two-phase model for the steam ejector simulation. This demonstrates that the nonequilibrium condensation is essential for the performance analysis of steam ejectors for MED-TVC seawater desalination system.

  • Steam ejector performance considering phase transition for multi-effect distillation with Thermal Vapour Compression (MED-TVC) desalination system
    Applied Energy, 2020
    Co-Authors: Chuang Wen, Hongbing Ding, Liang Gong, Yan Yang
    Abstract:

    Abstract The multi-effect distillation with Thermal Vapour Compression (MED-TVC) desalination system is efficient to produce freshwater. The steam ejector performance is not fully understood as the phase transition has been ignored in many studies. The present work develops a two-phase condensing flow model to assess the steam ejector performance considering nonequilibrium condensation phenomena. The transition of the flow structure from an under-expanded flow to an over-expanded flow in the steam ejector is investigated in detail. We present that the maximum Mach number can reach 4.02 in the under-expanded flow, which is weakened to 2.88 in the over-expanded flow. The steam undergoes several expansion-Compression processes in the steam ejector in the under-expanded flow, which induces the formation and evaporation of massive droplets. In the over-expanded flow, the steam is compressed and then expanded after leaving the primary nozzle and the condensation process is not observed in mixing and constant sections. The increasing suction chamber pressure significantly improves the entrainment ratio while leading to an increasing entropy loss coefficient. The entrainment ratio is improved from 0.25 for the under-expanded flow to 1.69 for the over-expanded flow, while the entropy loss increases from 0.081 for the under-expanded flow to 0.29 for the over-expanded flow. This indicates that the transition of the flow structure from an under-expanded flow to an over-expanded flow can entrain more steam from the last effect while causes more entropy losses in a steam ejector for the MED-TVC desalination system.

G Micale - One of the best experts on this subject based on the ideXlab platform.

  • New considerations for modelling a MED-TVC plant under dynamic conditions
    Desalination, 2019
    Co-Authors: L. Guimard, Andrea Cipollina, G Micale, Bartolomé Ortega-delgado, Françoise Couenne, P. Bandelier, Christian Jallut
    Abstract:

    Abstract The multiple-effect distillation (MED) technology is nowadays the most promising desalination process to be coupled with variable heat sources, thus leading to a more sustainable way to produce water. In order to prove the potential of this, it is of major interest to develop powerful modelling tools to predict the performance of this coupling. Only a few models have been presented so far. They show promising results but were based on some simplifying assumptions and non-physical constraints that could limit the analysis of the dynamic behaviour of a MED plant. This paper presents new considerations for the dynamic modelling of a MED plant associated with a Thermal Vapour Compression unit, starting from a previous work “A dynamic model for MED-TVC transient operation”. After several improvements, this model is now more representative of the real operating modes of a MED-TVC plant by considering real process inputs. This paper also highlights the importance of accurately modelling the interconnection between effects, the evaporation and condensation processes and the other components, such as the pre-heaters. Here is also presented a control strategy for operating a MED plant under dynamic conditions. Indeed, when a perturbation occurs in the motive steam pressure, it is possible to stabilize the whole plant by a simultaneous variation in the intake seawater mass flow rate at the final condenser. The model has been validated in steady-state conditions with experimental data from a MED-TVC plant operated in Trapani (Sicily) and was used to perform dynamic simulation to prove the feasibility of operating a MED-TVC plant under dynamic conditions, which is a major step toward proving the possibility of a coupling with renewable energies.

  • chp combined heat and power retrofit for a large med tvc multiple effect distillation along with Thermal Vapour Compression desalination plant high efficiency assessment for different design options under the current legislative eu framework
    Energy, 2016
    Co-Authors: Alessandro Tamburini, Andrea Cipollina, G Micale, Antonio Piacentino
    Abstract:

    Integrated power plants in “dual purpose” configuration may represent a viable option for energy cost abatement of desalted water produced by MED-TVC (Multiple Effect Distillation along with Thermal Vapour Compression).

  • CHP (combined heat and power) retrofit for a large MED-TVC (multiple effect distillation along with Thermal Vapour Compression) desalination plant: High efficiency assessment for different design options under the current legislative EU framework
    Energy, 2016
    Co-Authors: Alessandro Tamburini, Andrea Cipollina, G Micale, Antonio Piacentino
    Abstract:

    Abstract Integrated power plants in “dual purpose” configuration may represent a viable option for energy cost abatement of desalted water produced by MED-TVC (Multiple Effect Distillation along with Thermal Vapour Compression). In this paper an existing large MED-TVC plant with a 36,000 m 3 /day capacity is studied: a plant retrofit is designed, based on a steam power plant with condensation and steam extraction used to drive the steam ejector. As the plant operates in CHP (Combined Heat and Power) mode, the possibility to assess the integrated “CHP + MED-TVC” as high efficiency cogeneration according to Directive 2004/8/EC is discussed. Based on a model developed in Engineering Equation Solver, a sensitivity analysis is performed: the influence of several design and operation parameters on the fraction of energy outputs assessed as “from efficient cogeneration” is investigated. This fraction was found to increase almost linearly with the number of MED units supplied with steam. Also, when all the MED units are supplied and the steam extraction pressure is decreased from 4.89 MPa down to 0.29 MPa, the CHP fraction increased from ∼54% to ∼77%. The assessment of the plant as “high efficiency CHP” was found highly dependent on the specific fuel adopted.

  • Integrated production of fresh water, sea salt and magnesium from sea water
    Desalination and Water Treatment, 2012
    Co-Authors: Andrea Cipollina, G Micale, Angelo Misseri, Giacomo D'alì Staiti, Alessandro Galia, Onofrio Scialdone
    Abstract:

    Abstract Seawater desalination is becoming an important source of fresh water in several countries all around the world. One of the main drawbacks of desalination processes, however, is related to the disposal of large quantities of concentrated brine, which is an always-present by-product of the process. An integrated production of fresh water and salts may be achieved using the discharge brine from a desalination plant as a feed for conventional salt ponds, with the advantages of using brine more concentrated than sea water and, in the case of Thermal desalination plants, warmer than sea water. By doing so, the process is faster as a consequence of the enhancement of evaporation rate on the surface of ponds. The above concept has been proposed already several years ago, but only rare examples exist of real applications. A pilot test has been performed in the last 4 years in Trapani (Italy), where a 36,000-m3/d multiple effects desalination with Thermal Vapour Compression plant is operating very close to...

  • A critical assessment of desalination operations in Sicily
    Desalination, 2005
    Co-Authors: Andrea Cipollina, G Micale, Lucio Rizzuti
    Abstract:

    In this paper a brief history of desalination plants in Sicily is presented together with an in-depth description of processes and operating data, relevant to the plants actually operating on the island. 5 multi stage flash (MSF) units and one reverse osmosis (RO) plant are operating in Gela (total nominal production of about 80,000 m 3 /d), thus providing drinking water for more than 300,000 people living in the southern coast of the island. A Thermal Vapour Compression multiple effect distillation (TVC-MED) plant (36,000 m 3 /d) is operating in Trapani and a small mechanical Vapour Compression (MVC) unit (5000 m 3 /d) is located in Porto Empedocle. In the oldest MSF units in Gela, several revamping actions have been done in order to maintain an outstanding efficient operation of the plant, regardless its long working history, whereas the other plants have shown some difficulties in operation. All these matters, together with an analysis of consumptions and operating costs, are critically and thoroughly discussed in the paper. Finally some proposals of new plants in severely droughty areas are given.

Alessandro Tamburini - One of the best experts on this subject based on the ideXlab platform.

Hongbing Ding - One of the best experts on this subject based on the ideXlab platform.

  • performance of steam ejector with nonequilibrium condensation for multi effect distillation with Thermal Vapour Compression med tvc seawater desalination system
    Desalination, 2020
    Co-Authors: Hongbing Ding, Yan Yang
    Abstract:

    Abstract The single-phase and two-phase flow models are developed and compared for the performance evaluation of a steam ejector for the multi-effect distillation with Thermal Vapour Compression (MED-TVC) seawater desalination system. The results show that a single-phase flow model with ignoring the phase change predicts an unphysical temperature of the steam in the supersonic flow with the minimum value of approximately 122 K, which raises the query of the formation of the ice. The two-phase wet steam model corrects the distribution of the flow parameter by predicting the heat and mass transfer during the phase change. The steam achieves the first nonequilibrium condensation process inside the primary nozzle and another four alternating condensation and re-evaporation processes. The single-phase flow model under-predicts the entropy loss coefficient by approximately 15% than the two-phase wet steam model. The performance comparison is achieved against the single-phase model to present the accuracy of the two-phase model for the steam ejector simulation. This demonstrates that the nonequilibrium condensation is essential for the performance analysis of steam ejectors for MED-TVC seawater desalination system.

  • Steam ejector performance considering phase transition for multi-effect distillation with Thermal Vapour Compression (MED-TVC) desalination system
    Applied Energy, 2020
    Co-Authors: Chuang Wen, Hongbing Ding, Liang Gong, Yan Yang
    Abstract:

    Abstract The multi-effect distillation with Thermal Vapour Compression (MED-TVC) desalination system is efficient to produce freshwater. The steam ejector performance is not fully understood as the phase transition has been ignored in many studies. The present work develops a two-phase condensing flow model to assess the steam ejector performance considering nonequilibrium condensation phenomena. The transition of the flow structure from an under-expanded flow to an over-expanded flow in the steam ejector is investigated in detail. We present that the maximum Mach number can reach 4.02 in the under-expanded flow, which is weakened to 2.88 in the over-expanded flow. The steam undergoes several expansion-Compression processes in the steam ejector in the under-expanded flow, which induces the formation and evaporation of massive droplets. In the over-expanded flow, the steam is compressed and then expanded after leaving the primary nozzle and the condensation process is not observed in mixing and constant sections. The increasing suction chamber pressure significantly improves the entrainment ratio while leading to an increasing entropy loss coefficient. The entrainment ratio is improved from 0.25 for the under-expanded flow to 1.69 for the over-expanded flow, while the entropy loss increases from 0.081 for the under-expanded flow to 0.29 for the over-expanded flow. This indicates that the transition of the flow structure from an under-expanded flow to an over-expanded flow can entrain more steam from the last effect while causes more entropy losses in a steam ejector for the MED-TVC desalination system.