Energy Efficiency of a PRO Process

Energy Efficiency of a master ProcessIntroductionThe global zip demand is expeditiously increasing due to rapidly expanding population and their improved living standard. Although fogey fuels are mostly contributing to fulfilling this demand, the consumption has already exceeded the capacity of sustainable efficiency labor (Efraty, 2013)(Yip et al., 2011). It is often claimed that we have enough reserves of coal, gas, and oil while the real scenario is varied. Environment scientists reported that energy reserves are decreasing with time, which would be diminished within few decades (Figure 1). The lifetime of these reserves would be extended slightly if naked as a jaybird reservoirs can be identified. Discovering new wells is becoming harder day-by-day and if it is discovered, the amounts of fuels would be significantly lower than the ones that have been found in the past1.Figure 1 The trends of global fossil fuels reserves1The rising energy demand and limited reserves of foss il fuels have motivated to researchers for exploring alternatives sources of renewable energy. Researchers have already discovered various sources of energy while wind, solar, tidal and bio skunk have been used for sustainable energy production (Straub, Deshmukh, Elimelech, 2015). However, expensive equipment and high trigger cost coupled with the uneven distribution of energy throughout the year have prevented them from being used widely (Sharif, Merdaw, Aryafar, Nicoll, 2014). Recently, a newly emerging source of clean energy c in alled Osmotic force play has attracted much attention to the researcher, which derived from salt gradients found worldwide where two sources of wet with different salinities are available next to each other (Y. C. Kim Elimelech, 2013). The availability and assureability of osmotic baron are much greater than the intermittent renewables like wind and solar. common salt gradient is the difference in salt concentration between two solutions. The en ormous amount of energy released from the potpourri of two solutions of different salinities and this amount rises for high concentration difference between the solutions. Small-scale investigations have been done for the salmagundi of freshwater and brine, which reported that 2.6 MW energy produced for a flow of 1m3/s freshwater when entangled with seawater (Veerman, Saakes, Metz, Harmsen, 2009). Several technologies are being used to harvest osmotic federal agency such as countermand electrodialysis (RED) (Achilli Childress, 2010) (Yip Elimelech, 2012), pressure retarded osmosis ( professional) (Altaee Sharif, 2015)(Thorsen Holt, 2009)(Norman S., 2016), capacitive mixing (CAPMIX) (Reuters News Agency, n.d.), and hydrogel mixing (J. Kim, Jeong, Park, Shon, Kim, 2015). Among the technologies, RED and master are more advanced and demonstrated at pilot scale and both converts chemical effectiveness to effective work by the controlled mixing of two solutions of differen t salt concentration (Achilli Childress, 2010)(Yip Elimelech, 2014).RED is a membrane-based technology, which is driven by the Nernst potential, a manifestation of chemical potential difference. It uses a stack of altering ion exchange membranes that selectively allows ion permeation across the membranes. The net ion flux across the membranes is converted directly to electric current (Norman S., 2016)(Pattle, 1954). The transit is very efficient for power times but economically inefficient. The cost prices of available RED membrane is out of range, and recent investigations have showed that the price has to be reduced a hundred times to make the technology affordable (Post et al., 2010). The development of such type of membranes is very time consuming and difficult to master (Turek Bandura, 2007). Also, The operations of the RED process is complex and highly sensitive to the process parameters, which requires elaborate control carcass (Altaee Sharif, 2015).Alike reverse ele ctrodialysis, PRO is also a membrane-based technology, but the difference is, PRO uses a single salt-rejecting semipermeable membrane instead of a stack of ion-exchange membranes. It utilizes the salinity gradient as osmotic power difference to drive the water permeation across the membrane from low salinity feed solution to high salinity arrive at solution. The expanding tawdriness of draw solution flows through a hydro-turbine that generates useful mechanical and electrical works 1819. The design and operations of PRO are much simpler, and it does not depend besides much on operational parameters except operating pressure of membrane at draw solution side. The recent analysis shows that PRO can progress to both greater efficiencies and power densities than RED and other existing technologies 14.Most of the PRO studies have been focused on the mixing of seawater and freshwater, but this mixing scheme has been found to be unfeasible due to the lower power densities. Researchers agree that more study is necessary to pass judgment the feasibility of processes based on streams of higher salinity. One of such processes is the energy recovery from desalination units by taking advantages of the mixing of discharged brine and seawater. Another process is the mixing of seawater with high salinity produced water from oil and inbred gas exploration. However, the main problems of these process are concentraion polarization and salt leakage, which limit the PRO performance by reducing the driving force across the membrane. Before investigations to establish a viable PRO process for the large-scale operation, have focused on growth high-performance membrane and setting up suitable conditions to increase the energy yields.Several thermodynamic properties are necessary to set up appropriate conditions to assess the performance of PRO process. The first of them is the Gibbs free energy of mixing because it provides the upper limit to the shaft power that is possible t o recover from a mixing process, which occurs at constant temperature and pressure. Another property is osmotic pressure, which in necessary to establish operating pressure at different parts of the plant. Entropies and enthalpies are needed to prize the mechanical power of the rotary equipment involved. This work demonstrates a thermodynamic model to evaluate all of them in order to maximize the power recovery from PRO process. The Q-electrolattice equation of (EOS), which extends a lattice-based fluid model for electrolyte solutions, is adopted. The model also includes recently developed equations for PRO that considers concentration polarization reverse salt permeability, and membrane fouling to predict water and salt flux across the membrane.In addition, most PRO models are based on solutions of Na+ and Cl ions only, whereas, in practice, saline water contains other ions in addition to these two. This work reports simulations of PRO processes that consider the presence of quad ruple ions in solutions (Na+, K+, Mg2+, Ca2+, Cl- and SO42-). The existing model mostly uses different platforms to wait osmotic power, power density, and flux across the membrane (e.g. OLI-software is used to calculate osmotic power and another program for flux and power density), that increase the speculation of getting erroneous value because all these are inter-dependent. On the other hand, this model constantly and accurately determines all of them by a single program. sign investigations have been done for freshwater+sewater and seawater+brine systems with single-stage PRO configuration. The predicted osmotic pressure, water flux across the membrane and recoveries of mechanical power are in very good agreement with experimental literature data. This set of results suggests that the Q-electrolattice EOS is a suitable model for the calculation of thermodynamic properties needed to assess the performance of PRO plants. Now, it is planning this model for very high salinity solut ions with multiple stage configurations. A techno-economic analysis will be done for the feasibility study of PRO process devouring at industrial scale.Aim and Objectives The aim of this work is to develop a thermoynamic model based on Q-electrolattice equation of state for PRO process, and implement it to predict different thermodynamic properties in order to caltulate water and salt flux across the membrane and power densities. The various objectives associated with this aim are delineated belowImplement Q-electrolattice equation of state for the solutions of multiple salts to calculate osmotic power and verify the results with literature experimental data.Implement recently developed mass and salt flux equations, which considered concentration polarization, reverse salt flux and fouling of membrane.Implement basic thermodynamic relations for PRO units to determine entropies and enethalpies accurately.Develop the model for freshwater-seawater system with single stage configurati on and extended it for higher salinity system with multiple stage configuration.Implement the cost equations to determine the capital cost for installation of the PRO units.Literature ReviewQ-elctrolattice equation of stateThe elctrolattice equation of state (EOS) was developed using the same methodology presented by Myers et al. (Myers, Sandler, Wood, 2002), based on the Helmholtz energy approach. The residual Helmholtz energy at a given temperature and volume is calculated by the addition various contributions along a hypothetical path. These contributions consist of ion-solvent and solvent-solvent interaction over the short range, solvation effects, and ion-ion interactions over the long range.The total process is divided into four steps along a thermodynamic path( a. Zuber et al., 2013)Step-1 It is assumed that a name mixture consisting of charged ions and molecules is in a hypothetical ideal gas state at temperature T and volume V. In the first step, the charges on all ions are removed. The change in Helmholtz energy is accounted by the innate(p) equation for ions in a vacuum, Step-2 The short-range attractive dispersion and repulsive forces due to excluded volume are turned on. Also, self-association of solvent molecules can occur. The MTC EOS is used to calculate the change in Helmholtz energy for this step,.Step-3 The ions are recharged. The change in Helmholtz energy is accounted for by the Born equation for ions in a dielectric solvent, Step-4 The long-range interactions among the ions in solution are taken into account using the Mean Spherical Approximation (MSA), and the corresponding change in the molar Helmholtz free energy is denoted by .The residual Helmholtz energy for forming an electrolyte solution is thus given bywhereinSo,To model electrostatic interactions, a single salt electrolyte solution is divided into five regions three for solvent (D, , and ), one for cation (C) and one for anion (A).To determine the MTC Helmholtz energy change , the model uses seven parameters to represent pure solvents. The model assumes that the region-region interaction (except for -) are dispersion interactions, which are temperature dependent. In addition, it also assumed that the short-range interactions between the and region are zero. This is summarized belowIn addition, atomic number 1 bonding interactions are taken to be temperature independent.It is assumed that the interaction between the solvent and each charged species is equal short-range interaction between reverse gear ions and same charge are neglected altogether. This is summarized belowThe Q-electrolattice equation of state is an extended version of the EOS in which an explicit MSA term is used which allows for unequal dome diameters (which are ultimately regressed using experimental data).PRO principlesBasic TheoryReferenceAchilli, A., Childress, A. E. (2010). pull retarded osmosis From the vision of Sidney Loeb to the first mental image installation Review. Desalination, 261(3), 205-211. https//doi.org/10.1016/j.desal.2010.06.017Altaee, A., Sharif, A. (2015). obligate retarded osmosis advancement in the process applications for power generation and desalination. In Desalination (Vol. 356, pp. 31-46). Elsevier B.V. https//doi.org/10.1016/j.desal.2014.09.028Efraty, A. (2013). Pressure retarded osmosis in closed traffic circle a new technology for clean power generation without need of energy recovery. Desalination and pee Treatment, 51(40-42), 7420-7430. https//doi.org/10.1080/19443994.2013.793499Kim, J., Jeong, K., Park, M. J., Shon, H. K., Kim, J. H. (2015). Recent advances in osmotic energy generation via pressure-retarded osmosis (PRO) A review. Energies, 8(10), 11821-11845. https//doi.org/10.3390/en81011821Kim, Y. C., Elimelech, M. (2013). potency of osmotic power generation by pressure retarded osmosis using seawater as feed solution Analysis and experiments. journal of Membrane light, 429, 330-337. https//doi.org/10.1016/ j.memsci.2012.11.039Myers, J. a., Sandler, S. I., Wood, R. H. (2002). An equality of State for Electrolyte Solutions Covering Wide Ranges of Temperature, Pressure, and Composition. Industrial Engineering Chemistry Research, 41(13), 3282-3297. https//doi.org/10.1021/ie011016gNorman, S. L., S., R. (2016). Osmotic Power Plants Author ( s ) Sidney Loeb and Richard S . Norman. Science, 189(4203), 654-655.Pattle, R. E. (1954). Production of galvanic Power by mixing Fresh and Salt Water in the Hydroelectric Pile. Nature.Post, J. W., Goeting, C. H., Valk, J., Goinga, S., Veerman, J., Hamelers, H. V. M., Hack, P. J. F. M. (2010). Towards implementation of reverse electrodialysis for power generation from salinity gradients. Desalination and Water Treatment, 16(1-3), 182-193. https//doi.org/10.5004/dwt.2010.1093Reuters News Agency. (n.d.). Norway Opens Worlds scratch Osmotic Power Plant. Retrieved January 17, 2013, from http//www.reuters.com/article/2009/11/24/us-nor way-osmotic-idUSTR E5A-N20Q20091124Sharif, A., Merdaw, A., Aryafar, M., Nicoll, P. (2014). Theoretical and Experimental Investigations of the Potential of Osmotic Energy for Power Production. In Membranes (Vol. 4, pp. 447-468). https//doi.org/10.3390/membranes4030447Straub, A. P., Deshmukh, A., Elimelech, M. (2015). Pressure-retarded osmosis for power generation from salinity gradients is it viable? Energy Environ. Sci. https//doi.org/10.1039/C5EE02985FThorsen, T., Holt, T. (2009). The potential for power production from salinity gradients by pressure retarded osmosis, 335, 103-110. https//doi.org/10.1016/j.memsci.2009.03.003Turek, M., Bandura, B. (2007). Renewable energy by reverse electrodialysis. Desalination, 205(1-3), 67-74. https//doi.org/10.1016/j.desal.2006.04.041Veerman, J., Saakes, M., Metz, S. J., Harmsen, G. J. (2009). rear(a) electrodialysis mathematical process of a stack with 50 cells on the mixing of sea and river water. Journal of Membrane Science, 327(1-2), 136-144. https//doi .org/10.1016/j.memsci.2008.11.015Yip, N. Y., Elimelech, M. (2012). Thermodynamic and energy efficiency analysis of power generation from natural salinity gradients by pressure retarded osmosis. Environmental Science and Technology, 46(9), 5230-5239. https//doi.org/10.1021/es300060mYip, N. Y., Elimelech, M. (2014). Comparison of Energy Efficiency and Power Density in Pressure Retarded Osmosis and Reverse Electrodialysis (7th Editio).Yip, N. Y., Tiraferri, A., Phillip, W. A., Schiffman, J. D., Hoover, L. A., Kim, Y. C., Elimelech, M. (2011). Thin-film composite pressure retarded osmosis membranes for sustainable power generation from salinity gradients_. Environmental Science and Technology, 45(10), 4360-4369. https//doi.org/10.1021/es104325zZuber, A., Figueiredo, R., Castier, M. (2014). Fluid Phase Equilibria Thermodynamic properties of aqueous solutions of single and multiple salts using the Q-electrolattice equation of state. Fluid Phase Equilibria, 362, 268-280.Zuber, a., Che coni, R. F., Mathew, R., Santos, J. P. L., Tavares, F. W., Castier, M. (2013). Thermodynamic Properties of 11 Salt Aqueous Solutions with the Electrolattice Equation of State. Oil Gas Science and Technology critical review dIFP Energies Nouvelles, 68(2), 255-270. https//doi.org/10.2516/ogst/2012088This work focuses on developing a thermodynamic model to analyse the energy efficiency of a PRO process in order to maximize the power recovery. It uses Q-electrolattice equation of state (developed for mixtures with mixed electrolytes) that can accurately determine various thermodynamics properties such as vapor pressure, osmotic coefficient, osmotic pressure, entropy and henry at different conditions of concentration temperature and pressure (A. Zuber, Figueiredo, Castier, 2014). The model is implemented to XSEOS excel tool to calculate these thermodynamic properties. Moreover, it does not have any limitations to calculate osmotic pressure and other properties for very high concent raion solution containing multiple salts at extreme high temperation and pressure conditions.Achilli, A., Childress, A. E. (2010). Pressure retarded osmosis From the vision of Sidney Loeb to the first prototype installation Review. Desalination, 261(3), 205-211. https//doi.org/10.1016/j.desal.2010.06.017Altaee, A., Sharif, A. (2015). Pressure retarded osmosis advancement in the process applications for power generation and desalination. In Desalination (Vol. 356, pp. 31-46). Elsevier B.V. https//doi.org/10.1016/j.desal.2014.09.028Efraty, A. (2013). Pressure retarded osmosis in closed circuit a new technology for clean power generation without need of energy recovery. Desalination and Water Treatment, 51(40-42), 7420-7430. https//doi.org/10.1080/19443994.2013.793499Kim, J., Jeong, K., Park, M. J., Shon, H. K., Kim, J. H. (2015). Recent advances in osmotic energy generation via pressure-retarded osmosis (PRO) A review. Energies, 8(10), 11821-11845. https//doi.org/10.3390/en8101182 1Kim, Y. C., Elimelech, M. (2013). Potential of osmotic power generation by pressure retarded osmosis using seawater as feed solution Analysis and experiments. Journal of Membrane Science, 429, 330-337. https//doi.org/10.1016/j.memsci.2012.11.039Myers, J. a., Sandler, S. I., Wood, R. H. (2002). An Equation of State for Electrolyte Solutions Covering Wide Ranges of Temperature, Pressure, and Composition. Industrial Engineering Chemistry Research, 41(13), 3282-3297. https//doi.org/10.1021/ie011016gNorman, S. L., S., R. (2016). Osmotic Power Plants Author ( s ) Sidney Loeb and Richard S . Norman. Science, 189(4203), 654-655.Pattle, R. E. (1954). Production of Electric Power by mixing Fresh and Salt Water in the Hydroelectric Pile. Nature.Post, J. W., Goeting, C. H., Valk, J., Goinga, S., Veerman, J., Hamelers, H. V. M., Hack, P. J. F. M. (2010). Towards implementation of reverse electrodialysis for power generation from salinity gradients. Desalination and Water Treatment, 16(1-3) , 182-193. https//doi.org/10.5004/dwt.2010.1093Reuters News Agency. (n.d.). Norway Opens Worlds First Osmotic Power Plant. Retrieved January 17, 2013, from http//www.reuters.com/article/2009/11/24/us-nor way-osmotic-idUSTRE5A-N20Q20091124Sharif, A., Merdaw, A., Aryafar, M., Nicoll, P. (2014). Theoretical and Experimental Investigations of the Potential of Osmotic Energy for Power Production. In Membranes (Vol. 4, pp. 447-468). https//doi.org/10.3390/membranes4030447Straub, A. P., Deshmukh, A., Elimelech, M. (2015). Pressure-retarded osmosis for power generation from salinity gradients is it viable? Energy Environ. Sci. https//doi.org/10.1039/C5EE02985FThorsen, T., Holt, T. (2009). The potential for power production from salinity gradients by pressure retarded osmosis, 335, 103-110. https//doi.org/10.1016/j.memsci.2009.03.003Turek, M., Bandura, B. (2007). Renewable energy by reverse electrodialysis. Desalination, 205(1-3), 67-74. https//doi.org/10.1016/j.desal.2006.04.041Veerman, J., Saakes, M., Metz, S. J., Harmsen, G. J. (2009). Reverse electrodialysis Performance of a stack with 50 cells on the mixing of sea and river water. Journal of Membrane Science, 327(1-2), 136-144. https//doi.org/10.1016/j.memsci.2008.11.015Yip, N. Y., Elimelech, M. (2012). Thermodynamic and energy efficiency analysis of power generation from natural salinity gradients by pressure retarded osmosis. Environmental Science and Technology, 46(9), 5230-5239. https//doi.org/10.1021/es300060mYip, N. Y., Elimelech, M. (2014). Comparison of Energy Efficiency and Power Density in Pressure Retarded Osmosis and Reverse Electrodialysis (7th Editio).Yip, N. Y., Tiraferri, A., Phillip, W. A., Schiffman, J. D., Hoover, L. A., Kim, Y. C., Elimelech, M. (2011). Thin-film composite pressure retarded osmosis membranes for sustainable power generation from salinity gradients_. Environmental Science and Technology, 45(10), 4360-4369. https//doi.org/10.1021/es104325zZuber, A., Figueiredo, R., Casti er, M. (2014). Fluid Phase Equilibria Thermodynamic properties of aqueous solutions of single and multiple salts using the Q-electrolattice equation of state. Fluid Phase Equilibria, 362, 268-280.Zuber, a., Checoni, R. F., Mathew, R., Santos, J. P. L., Tavares, F. W., Castier, M. (2013). Thermodynamic Properties of 11 Salt Aqueous Solutions with the Electrolattice Equation of State. Oil Gas Science and Technology Revue dIFP Energies Nouvelles, 68(2), 255-270. https//doi.org/10.2516/ogst/20120881 All fossil fuel reserve and consumption data from CIA World Factbook