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M.a. Darwish - One of the best experts on this subject based on the ideXlab platform.
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On the reduction of Desalting energy and its cost in Kuwait
Desalination, 2008Co-Authors: M.a. Darwish, Sorour Alotaibi, S. AlfahadAbstract:Abstract All seawater Desalting processes, multi-stage flash (MSF), multi-effect boiling (MEB), mechanical vapor compression (MVC) and seawater reverse osmosis (SWRO) consume significant amounts of energy. The recent increase of fuel oil cost raises the cost of energy consumed for Desalting water and the final water cost, and creates more interest in using more energy efficient Desalting systems. The most used Desalting systems by distillation (MSF and MEB) are usually combined with power plants in what is called co-generation power Desalting plants, CPDP. Fuel is supplied to the CPDP to produce both desalted water D and power W , and the fuel cost is shared between D and W . Exergy analysis and equivalent work are among the methods used to determine the fuel energy charged to each product. When Desalting systems, such as SWRO and MVC, are not combined with a power plant, the fuel energy can be directly determined from its electrical power consumption. In this paper, the fuel energy cost charged to Desalting seawater in the presently used CPDP in Kuwait is calculated based on exergy analysis. The MSF, known by its high energy consumption, is the only Desalting method used in Kuwait. The MSF units consume 258 kJ/kg thermal energy by steam supplied to the brine heater BH, 16 kJ/kg by steam supplied to steam ejectors, and 4 kWh/m3 mechanical energy for pumping. These MSF units are operated either by: (1) Steam extracted from extraction/condensing steam turbines EC/ST as in as in Doha West, Azzour, and Sabbiya CPDP. This practice is used in most Gulf area. (2) Steam supplied directly from boilers as occurred in single purpose Desalting plants as Al Shuwaikh plant; or in winter time when no steam turbines are in operation in the CPDP to supply steam to the Desalting units. The CPDP have limited water to power production ratio. While they can cope with the increase of power demand, it cannot satisfy the water demand, which is increasing with higher pace than the power demand. The case of steam CPDP used in Kuwait is presented in this paper as a reference plant to evaluate the amount of fuel energy consumed to desalt water in MJ/m3, its cost in $/m3. The resulted high fuel cost calls for some modifications in the reference CPDP to lower the energy cost, and to increase its water to power ratio. The modifications include the use of an auxiliary back-pressure steam turbine ABPST supplied with the steam presently extracted to the MSF units. The power output of the ABPST operates MVC or SWRO Desalting units; while the ABPST discharged steam operates LT-MEB Desalting unit. The Desalting fuel energy costs when applying these modifications are also calculated by the exergy analysis and compared with that present situation. It is also suggested to increase desalted water output by using separate SWRO Desalting units operated by the existing power plants of typical η c = 0.388, or by new combined gas/steam turbines power cycle GT/ST-CC of typical η c = 0.54 under construction. The SWRO with energy recovery is assumed to consume typical 5.2 kWh/m 3 electric energy.
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Feed water arrangements in a multi-effect Desalting system
Desalination, 2008Co-Authors: M.a. Darwish, Hassan K. AbdulrahimAbstract:A multi-effect boiling (MEB) Desalting system with unit capacity up to 5 MIGD becomes a strong competitor to the multi-stage flash (MSF) Desalting system due to its low specific energy consumption and the low temperature steam required to operate the system. A considerable number of units have been installed in the Arabian Gulf area recently. There are many flow sheet variants for the MEB Desalting system. Each variant suits certain design objectives. The schemes of the feed water flow to the effects and implementation of feed water heaters and flash boxes are among the significant differences between these flow sheets that have major influences on the system performance and the adopted analysis to evaluate the system. This paper outlines the commonly used feed water arrangements in multi-effect Desalting systems, e.g. forward, backward, parallel, and mixed feed. For each flow sheet arrangement, the thermodynamic analysis used is presented. These analyses determine the temperature and salinity profiles of the system, the amount of vapor generated by boiling and by flashing in each effect, the required heat transfer areas for the effects and feed heaters, the gain and recovery ratios, and cooling water to distillate ratio. The analytical results obtained in this work are compared with several practical multi-effect Desalting systems of typical capacity and number of effects. This comparison illustrates the logic behind choosing each flow sheet arrangement.
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Suggested modifications of power-Desalting plants in Kuwait
Desalination, 2007Co-Authors: M.a. Darwish, S. Al Otaibi, Khawla Al ShayjiAbstract:Abstract Modifications are suggested to the Kuwaiti cogeneration power-Desalting plants CPDP. The suggestions would increase their Desalting capacity, use more efficient Desalting systems, and solve the acute problem of matching the installed desalted water capacity with the ever increasing demands of potable water. In year 2003, 93% of potable water was satisfied by the desalted water. The suggested modifications for a 300 MW steam turbine combined with two MSF units of 6 MIGD each include: (1) Substitute some of the old and in-efficient MSF units with more efficient multi effect Desalting MED system of almost the same capacity, and gain ratio. The MED system can use low pressure steam of 75EC saturated temperature as heat source, and about 2 kWh/m3 pumping energy (about 50% less than that of MSF units). (2) Adding a back pressure steam turbine BPST. Steam, now extracted from the steam turbine, at pressures ranging from 4.74 to 3.5 bar to the MSF units, is directed to an added BPST to produce more work before its discharge at 0.4 bar (about 75EC saturation temperature), as needed by the suggested MED units. (3) Adding seawater reverse osmosis SWRO Desalting system. The work output from the BPST can be used to operate a seawater reverse osmosis SWRO Desalting plant to produce more desalted water. Details of the modification are given in the paper. The modifications increase the power output of the plant without adding any more fuel. It can add up to three times the Desalting capacity if SWRO system, and without adding any more fuel.
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TOWARDS SUSTAINABLE ENERGY IN SEAWATER Desalting IN THE GULF AREA
2006Co-Authors: M.a. Darwish, N. Al-najem, N. LiorAbstract:Gulf countries, experienced very rapid growth in th e last four decades by the evolution of oil production and its price increase. The main source of portable water, about 93%, was secured by Desalting seawater in 2002. The inc rease of the daily-consumed fresh water in liters per capita (from 137 in 1973 to alm ost 500 in 2003) and population increase (from 900,000 in 1983 to more than 2,540,0 00 in 2003) necessitate the production of large quantities in desalted water wi th huge amounts of consumed fuel energy. Thermally operated Desalting units usually obtain their thermal energy input by steam supply; either extracted from steam turbin es or from heat recovery steam generators HRSG combined with gas turbines. Therefore, most desalted water is produced in cogeneration power Desalting plants CPDP. The effect of fuel consumed for Desalting seawater on environment is underestim ated by desalination expertise by thinking that, “thermal desalination associated to power generation plant will only be minimally responsible for the discharge of the flue gases to the atmosphere as this impact can be associated to the power generation.” However, 21% of the fuel consumed in Kuwait CPDP in 2003 was used for Desalting the water. Burning fuel to desalt water increases the environment pollution by producing the carbon dioxide CO 2, the nitrogen oxides NOx, and sulfuric oxides SOx, w ith quantities directly related with the consumed fuel energy for each Desalting process . As the efficiency in both power and Desalting water increase, the impact on the env ironment decreases. The consumed electric power and desalted water are almost double d every 10 years. If the oil production, (Kuwait main source of income) is 2 mil lion barrels per day, then one tenth of this oil production was consumed by power and water productions in 2003, consequently, 20% and 40% of Kuwait oil production (or total income) will be consumed by water and power productions only in 2013 and 2023 respectively. In about thirty years, the total oil production may no t be enough for people to drink and live in air-conditioned space in Kuwait. The aim of this paper is to look for energy efficie nt ways to desalt water and produce power to save the nation’s income, non-renewable fuel resources, environment, and the life itself in Kuwait. It is equally important promote the conservation measures for both the water and power.
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Co-generation power Desalting plants: new outlook with gas turbines
Desalination, 2004Co-Authors: M.a. Darwish, Najem Al NajemAbstract:Abstract Kuwait is using only MSF Desalting system coupled to steam turbines to desalt seawater. There is shortage in Desalting capacity, and 180 MIGD Desalting units have to be installed within 5 years. Meanwhile there are not enough operating steam turbines to supply steam to Desalting units if MSF units are chosen. At the same time there are peak load gas turbines (GT) that are usually operated for very short times, only 16 h in the year 2001 as example. Also Kuwait is planning to have 400-MW total capacity GT just to be operated at peak load. These GT can be used to operate reverse osmosis (RO) Desalting system, when not needed to carry load. Other Desalting types can be added, beside the RO system, to produce water more efficiently, energy wise than the presently used method. Forming combined gas/steam cycles by adding steam turbines to these GT increases the installed power capacity, efficiency of power production, and ability to produce more water. This paper presents some variants of combining GT with Desalting systems. These variants use standard, well-proven type and reliable equipment, besides being more energy efficient compared to MSF units combined with stearn turbines.
Yoram Cohen - One of the best experts on this subject based on the ideXlab platform.
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evaluation of chemically enhanced seeded precipitation of ro concentrate for high recovery Desalting of high salinity brackish water
Desalination, 2013Co-Authors: Brian C Mccool, Anditya Rahardianto, Jose Faria, Yoram CohenAbstract:Abstract The feasibility of utilizing chemically-enhanced seeded precipitation (CESP) for primary reverse osmosis (PRO) concentrate demineralization was evaluated, via both experimental field tests and process analysis, to assess its potential use in enabling recovery enhancement via secondary RO (SRO) Desalting. Field evaluations of batch CESP along with process simulations for Desalting of agricultural drainage (AD) water (6700–14,400 mg/L TDS, SIg = ~ 0.9) have suggested that a PRO-CESP-SRO Desalting approach is both technically and economically feasible to enable overall Desalting recovery of about 83% and, with partial concentrate recycling, of up to 93%. In the CESP process, initial partial lime treatment provides adsorptive removal of residual antiscalant from the PRO concentrate. This enables subsequent concentrate desupersaturation (with respect to the major scaling salt calcium sulfate) to occur via seeded gypsum precipitation, unimpeded by residual antiscalant. The desupersaturated PRO concentrate (~ 34% reduction in SIg from ~ 1.7 to ~ 1.1) can then be further desalted in an SRO step up to the limit that is feasible with antiscalant dosing for scale control. When considering the cost of residual brine disposal, the cost of AD water desalination by PRO-CESP-SRO on the basis of desalted water volume is lower than RO by up to 39%.
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high recovery membrane Desalting of low salinity brackish water integration of accelerated precipitation softening with membrane ro
Journal of Membrane Science, 2007Co-Authors: Anditya Rahardianto, Junbo Gao, Christopher J Gabelich, Mark D Williams, Yoram CohenAbstract:Abstract The integration of membrane RO Desalting and accelerated precipitation softening (APS) was evaluated for achieving high product water recovery (>95%) from Desalting of mildly brackish surface water. A systematic approach that included laboratory RO demonstrations, membrane scaling diagnostics, and mineral solubility analysis was undertaken to develop an effective physical/chemical APS strategy for reducing the concentration of scale-forming ions in the primary RO (PRO) concentrate. APS demineralization, as an inter-stage process, between the PRO and secondary RO (SRO) Desalting, involved alkaline pH adjustment and calcite crystal seeding of the PRO concentrate, followed by microfiltration and pH reduction by acid dosing to avoid calcite scaling in the SRO stage. Colorado River water Desalting case study demonstrated that, at 90% PRO recovery, the PRO concentrate stream contained barite, calcite, gypsum, and silica above their solubility limits by factors of 122, 47, 1.1, and 0.8, respectively. Further Desalting was not feasible with traditional scale-control strategies (e.g., pH reduction and antiscalant addition). However, APS demineralization enabled significant concentration reduction of calcium (>90%), barium (>95%), and strontium (∼78%) and moderate reduction (10–20%) of magnesium and silica. APS kinetics were favorable even in the presence of antiscalant carryover from the PRO stage. The study demonstrated that high recovery desalination of up to 98% is feasible with the PRO-APS-SRO sequence, which reduces the limitations imposed by membrane scaling.
Anditya Rahardianto - One of the best experts on this subject based on the ideXlab platform.
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evaluation of chemically enhanced seeded precipitation of ro concentrate for high recovery Desalting of high salinity brackish water
Desalination, 2013Co-Authors: Brian C Mccool, Anditya Rahardianto, Jose Faria, Yoram CohenAbstract:Abstract The feasibility of utilizing chemically-enhanced seeded precipitation (CESP) for primary reverse osmosis (PRO) concentrate demineralization was evaluated, via both experimental field tests and process analysis, to assess its potential use in enabling recovery enhancement via secondary RO (SRO) Desalting. Field evaluations of batch CESP along with process simulations for Desalting of agricultural drainage (AD) water (6700–14,400 mg/L TDS, SIg = ~ 0.9) have suggested that a PRO-CESP-SRO Desalting approach is both technically and economically feasible to enable overall Desalting recovery of about 83% and, with partial concentrate recycling, of up to 93%. In the CESP process, initial partial lime treatment provides adsorptive removal of residual antiscalant from the PRO concentrate. This enables subsequent concentrate desupersaturation (with respect to the major scaling salt calcium sulfate) to occur via seeded gypsum precipitation, unimpeded by residual antiscalant. The desupersaturated PRO concentrate (~ 34% reduction in SIg from ~ 1.7 to ~ 1.1) can then be further desalted in an SRO step up to the limit that is feasible with antiscalant dosing for scale control. When considering the cost of residual brine disposal, the cost of AD water desalination by PRO-CESP-SRO on the basis of desalted water volume is lower than RO by up to 39%.
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high recovery membrane Desalting of low salinity brackish water integration of accelerated precipitation softening with membrane ro
Journal of Membrane Science, 2007Co-Authors: Anditya Rahardianto, Junbo Gao, Christopher J Gabelich, Mark D Williams, Yoram CohenAbstract:Abstract The integration of membrane RO Desalting and accelerated precipitation softening (APS) was evaluated for achieving high product water recovery (>95%) from Desalting of mildly brackish surface water. A systematic approach that included laboratory RO demonstrations, membrane scaling diagnostics, and mineral solubility analysis was undertaken to develop an effective physical/chemical APS strategy for reducing the concentration of scale-forming ions in the primary RO (PRO) concentrate. APS demineralization, as an inter-stage process, between the PRO and secondary RO (SRO) Desalting, involved alkaline pH adjustment and calcite crystal seeding of the PRO concentrate, followed by microfiltration and pH reduction by acid dosing to avoid calcite scaling in the SRO stage. Colorado River water Desalting case study demonstrated that, at 90% PRO recovery, the PRO concentrate stream contained barite, calcite, gypsum, and silica above their solubility limits by factors of 122, 47, 1.1, and 0.8, respectively. Further Desalting was not feasible with traditional scale-control strategies (e.g., pH reduction and antiscalant addition). However, APS demineralization enabled significant concentration reduction of calcium (>90%), barium (>95%), and strontium (∼78%) and moderate reduction (10–20%) of magnesium and silica. APS kinetics were favorable even in the presence of antiscalant carryover from the PRO stage. The study demonstrated that high recovery desalination of up to 98% is feasible with the PRO-APS-SRO sequence, which reduces the limitations imposed by membrane scaling.
Jinsheng Gao - One of the best experts on this subject based on the ideXlab platform.
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Effects of Process Conditions on Desalting and Demetalization of Crude Oil
Petroleum Science and Technology, 2006Co-Authors: Jingyi Yang, Ying Jiang, Jinsheng GaoAbstract:Abstract The efficiency of Desalting for six crude oils was studied with a SY-1 dynamic simulation experimental installation. The demulsifier DC2 was examined for 1#, 2#, and 4# crude oil and DC4 was used for 3#, 5#, and 6# crude oil. The effects of temperature, electric field gradient, dosage of demulsifier, and washing water on the Desalting efficiency of six crude oils were investigated. The results showed that at the optimization process condition after Desalting, the Desalting efficiency and the salt content of 1# crude oil reached 89.17% and 1.92 mg/L; that of 2# crude oil reached 85.08% and 1.04 mg/L; that of 3# crude oil reached 91.06% and 1.35 mg/L; that of 4# crude oil reached 81.67% and 1.51 mg/L; that of 5# crude oil reached 81.03% and 2.32 mg/L; and that of 6# crude oil reached 86.64% and 2.67 mg/L. Different crude oils have different metal contents. Three assistants, ammonium nitrate (TJ1), nitric acid (TJ3), and polyamine carboxylate (TJ4), were used to improve the efficiencies of Desalting...
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Study on the Compatibility of High-Paraffin Crude Oil with Electric Desalting Demulsifiers
Energy & Fuels, 2003Co-Authors: Guiling Liu, Jinsheng GaoAbstract:The effect of paraffin in crude oil on the electric Desalting and dewatering process was studied in this paper. The test result manifested that the dynamic viscosity of crude oil increased with the increase of paraffinic content in crude oil. Paraffin in crude oil exerts a great influence on the electric Desalting and dewatering process because paraffin leads to higher viscosity of crude oil and emulsion stability as well as inefficient dewatering, and hence decreases the Desalting efficiency. Some kinds of demulsifier series were tested in the process of the electric Desalting and dewatering. The triblock copolymer structure of PO-EO-PO for polyhydric alcohol is more effective with high-paraffin crude oil than the diblock of PO-EO. Diamine series polymerized with propylene oxide (PO) were the most compatible with this type of crude oil for dewatering, whereas, polyamine series polymerized with propylene oxide (PO) and ethylene oxide (EO) were the most compatible for Desalting.
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Study on the Compatibility of Asphaltic Crude Oil with the Electric Desalting Demulsifiers
Energy & Fuels, 2003Co-Authors: Guiling Liu, Jinsheng GaoAbstract:The compatibility of asphaltic crude oil with demulsifiers in the electric Desalting process was studied in this paper. The test result showed that asphaltene in crude oil causes the raising and abnormal of crude viscosity. Structure and character of asphaltic molecules make them easily gather and associate with each other at the oil/water interface and finally form a viscoelastic interfacial film of great mechanical strength. This not only interferes with the salt transfer from the oil to the aqueous phase, but also hinders the aggregation of the water drops, and thus affects Desalting process of crudes. Several kinds of demulsifier series synthesized were used to investigate Desalting and dewatering efficiencies in the electric Desalting process. It was found that with the same initiator each emulsifier series had got an optimal proportion of propylene oxide (PO) and initiator. There also exists an ideal value of Desalting and dewatering efficiency when demulsifiers were polymerized with ethylene oxide ...
Lisa Henthorne - One of the best experts on this subject based on the ideXlab platform.
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The US Bureau of Reclamation's research programs in water treatment and Desalting technologies
Desalination, 1994Co-Authors: Stan Hightower, Kevin Price, Lisa HenthorneAbstract:Abstract This paper discusses a brief history of Desalting research within the Department of the Interior, Office of Saline Water and the Office of Water Research and Technology, as well as the current Desalting research programs within the Bureau of Reclamation. An overview is provided on the research that has been accomplished under Reclamation's Yuma Desalting Research Program over the past 12 years, as well as its Water Treatment Technology Program over the past 2 years. Information is also presented on specific on-going Desalting research projects. These include a report published on “National Desalting and Water Treatment Needs Survey”, an RO pilot plant being tested to recover groundwater while using the reject flow for a wetlands project; cost-shared studies on improved performance and cost of membranes, membrane fouling, biocides, Desalting cogeneration systems, nanofiltration systems, freeze desalination, an improved RO pumping and energy recovery system, a mobile water treatment pilot plant, as well as a “Desalting and Water Treatment Membrane Manual” that has been published on the latest state-of-the-art membranes.