METHODS OF SEAWATER SOFTENING FOR DESALINATION AND MINERAL EXTRACTION

Abstract

Disclosed are methods for seawater softening for the desalination plants (thermal and membrane) by using the carbon mineralization (CM) technique. Disclosed are several process flow diagrams in which the carbon mineralization is integrated at the upstream and/or downstream of the thermal and membrane desalination processes. By using these methods, the released CO2 from industrial factories, seawater feed minerals solutes shall be removed to improve the performance of the desalination plants. Most importantly, valuable products such as Ca/Mg carbonates and BaSO4, which are being used in building rocks, concrete, cement, paints, plastic, etc., can be produced.

Claims

1. A method of sea water softening comprising: adding buffer solution (NaOH) to sea water to elevate its alkalinity up to pH 10, mixing flue gas with sucked non-condensable gases from thermal desalination unit, bubbling in a reactor to produce carbonates and sulfates by precipitation, washing the precipitate, and filtering and drying the precipitate to yield valuable mineral product, wherein processed filtered saline water, free from most of divalent ions, is directed to a thermal desalination unit for producing fresh water and brine, wherein rejected brine from the desalination unit is partially recycled as feedstock, and at least a portion is blow down and at least a portion is utilized in brine crystallizer to achieve zero liquid discharge.

2. The method of claim 1, wherein the carbonates produced are at least one of CaCO3, MgCO3, Na2CO3, BaCO3.

3. The method of claim 1, the crystallizer is a mechanical vapor compression system.

4. The method of claim 1, wherein the crystallizer is BaCl2.

5. The method of claim 1, wherein the first step is precipitating the sulfates through chemical precipitation.

6. A method of sea water softening comprising: adding buffer solution (NaOH) to sea water to elevate its alkalinity up to pH 10, mixing flue gas with sucked non-condensable gases from thermal desalination unit, bubbling in a reactor to produce carbonates and sulfates by precipitation, washing the precipitate, and filtering and drying the precipitate to yield valuable mineral product, wherein processed filtered saline water, free from most of divalent ions, is directed to membrane-based desalination unit (Reverse Osmosis) for producing fresh water and brine, wherein the rejected brine from desalination unit is partially recycled as feedstock, and at least a portion is blow down and at least a portion is utilized in brine crystallizer to achieve zero liquid discharge.

7. The method of claim 6, wherein the carbonates produced are at least one of CaCO3, MgCO3, Na2CO3, BaCO3.

8. The method of claim 6, wherein the crystallizer is a mechanical vapor compression system.

9. The method of claim 6, wherein the crystallizer is BaCl2.

10. The method of claim 6, wherein the feed water should be filtered first to remove sediments, marine life, and solids.

11. The method of claim 1, wherein the method is performed at a top brine temperature at or above 65 degrees Celsius.

12. The method of claim 1, wherein the flue gas originates from at least one of exhaust of diesel engines, industrial plants, and desalination plants.

13. The method of claim 6, wherein the flue gas originates from at least one of exhaust of diesel engines, industrial plants, and desalination plants.

14. The method of claim 1, wherein the sulfate precipitated is BaSO4.

15. The method of claim 6, wherein the sulfate precipitated is BaSO4.

16. The method of claim 6, wherein a reduction of specific energy consumption equal to or greater than 27%.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0032] FIG. 1 shows Scheme.1: Integrated Sea Water SofteningThermal Desalination.

[0033] FIG. 2 shows Scheme.2: Integrated Sea Water Softening RO.

[0034] FIG. 3 shows Scheme.3: Integrated Sulphate RemovalSea Water SofteningThermal Desalination.

[0035] FIG. 4 shows Scheme.4: Integrated Sulphate RemovalSea Water Softening RO.

[0036] FIG. 5 shows a setup of a CM reaction.

[0037] FIG. 6 shows an XRD analysis for precipitated ions.

[0038] FIG. 7 shows an XRD for stage-1, chemical precipitation to remove sulphates using BaCl2.

[0039] FIG. 8 shows an XRD for stage-2, carbon mineralization to remove rest of divalent ions.

[0040] FIG. 9 shows a Skillman Index.

[0041] FIG. 10 shows a Skillman Index at different RR and for different temperatures.

[0042] FIG. 11 shows an interface of VDS software for conventional MED of 15 MIGD.

[0043] FIG. 12 shows a VSP interface of 18 effects MED evaporator, TBT=65? C.

[0044] FIG. 13 shows specific energy consumption.

[0045] FIG. 14 shows an Umm Al-Houl RO desalination plant, Qatar.

[0046] FIG. 15 shows an interface of RO plant using treated feed seawater.

[0047] FIG. 16 shows a specific energy consumption.

DETAILED DESCRIPTION

[0048] The present disclosure provides methods for seawater softening for the desalination plants (thermal and membrane) by using the carbon mineralization (CM) technique. The present disclosure provides several process flow diagrams in which, the carbon mineralization is integrated at the upstream and/or downstream of the thermal and membrane desalination processes.

[0049] The objective is to remove the most of divalent ions (mainly Ca2+ and Mg2+) that cause scale formation in the desalination plants. It also proposes to integrate CM with further mineralization step chemical precipitation using BaCl2, to remove SO4 anions.

[0050] By using these methods, the released CO2 from industrial factories, seawater feed minerals solutes shall be removed to improve the performance of the desalination plants. Most importantly, valuable products such as Ca/Mg carbonates and BaSO4, which are being used in building rocks, concrete, cement, paints, plastic, etc., can be produced.

[0051] Key commercial application includes desalination and ZLD application.

[0052] Key competitive advantages include the following: The techno-economic analysis revealed that the addition of SS stage could increase TBT up to 90? C. for MED and overall cost of water production is 25% lower than the conventional MED plant, in addition, to produce a valuable mineral, with net revenue of 1 $/ton of seawater feed. Increase the top brine temperature (TBT) of the thermal desalination plants in order to increase the water production rate and accordingly reduce the overall production cost of the desalination process (25% lower compared conventional thermal and RO plants); Decreasing the intake/cooling flow rate of the thermal desalination plant which decrease the thermal energy and environmental press in addition to decrease the capital cost of construction of the intake channel; Minimize maintenance and cleaning frequency in RO membrane desalination technology; Reduce the energy consumption of the RO plant by increasing the process recovery ratio; Increasing the process recovery of the RO plant will reduce the intake seawater channel and construction cost; Achieving zero liquid discharge in an economical way; To reduce CO2 emissions by convert carbon dioxide to a useful product through an economical sequestration process; A sustainable and cost-effective way for brine management/disposal instead of surface water discharge (SWD) technology, which is mostly used to dispose reject brine. SWD has a negative environmental effect on marine life, in addition, to be a costly process ($0.05/m3: $0.30/m3 of brine rejected).

[0053] There is no similar integration to improve the desalination plant. Most of the carbon mineralization just uses the brine of the desalination plant to capture the CO2.

[0054] Demand on fresh water is steadily increasing due to the rapid growth of population. Therefore, water desalination is steadily increasing as a reliable technology to produce fresh water in large scale especially in arid area. On the other hand, carbon dioxide (CO2) emission, considered as one of the main contributors to the greenhouse gases (GHGs), has a negative effect on the environment. In the large size desalination plant, the electricity and thermal energy are provided by power plant where the CO2 is released into the environment as exhaust-stream due to burning of the fuel as source of energy. Recently, there is a lot of interest towards capture of CO2 waste stream and either store it or convert it to valuable products (carbon capture, sequestration and utilization).

[0055] One of the major operational problems encountered in thermal-desalination plants is represented by scale formation. Water scale is a coating or precipitate deposited on surfaces that are in contact with hard water, it can be formed due to the composition of the makeup water, but mostly it is the result of further changes occurring during evaporation. Scale formation is mainly caused by crystallization of alkaline scales, e.g., CaCO3 and Mg(OH)2, and non-alkaline scale, e.g., CaSO4.

[0056] Scale formation is also responsible for membrane fouling, a process whereby a solution or a particle get deposited on a membrane surface, or in membrane pores, so that the membrane's performance decreases, this is typical of processes such as Reverse Osmosis (RO). It represents a major obstacle to the widespread use of this purification technology. Membrane fouling can also cause severe flux drop and affect the quality of the water produced. Severe fouling may require intense chemical cleaning or membrane replacement, increasing the operating costs of a treatment plant. There are various types of foulants: colloidal (clays, flocs), biological (bacteria, fungi), organic (oils, polyelectrolytes, humics) and scaling (mineral precipitates).

[0057] In order to reduce scale formation on the metallic surface or membrane surface, the feed saline water entering a desalination unit requires a softening process. This process would be applied to both the thermal-based techniques, such as MSF/MED, or membrane-based technique, such as RO. The purpose of the softening stage is to reduce the concentration of dissolved salts (solutes) in the feed water (solution), such as seawater, brackish water, or industrial brine solutions, so that it can be more effectively desalinated and higher percentage of fresh water can be recovered. It is a necessary step in order to reduce the salinity and hence reduce, or in some cases eliminate, to a certain extent scale-forming species. This will increase the efficiency of the process, allow relatively higher Top Brine Temperature (TBT) operation or enable separation technology for high concentration feed, reduce the pumping power in RO systems, increase membrane lifetime, reduce or eliminate the anti-scale dosing, reduce cleaning frequency and consequently reduce the overall system cost.

[0058] This invention proposes a method for softening the saline feed by using carbon mineralization (CM) technique to remove the most of divalent ions (mainly Ca2+ and Mg2+) that are the main cause for scale formation/membrane fouling. It also proposes to integrate CM with another purification step, specifically chemical precipitation of sulfate by using BaCl2, to permanently remove the rest of the divalent ions, in particular SO42? anions.

[0059] By using this process, the CO2 waste stream can be utilized instead of flaring to the environment, scale solutes can be removed and utilized rather than being rejected and, most importantly, valuable products such as Ca/Mg carbonates and BaSO4, which are being used in building rocks, concrete, cement, paints, plastic, etc., can be produced.

[0060] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

EXAMPLES

[0061] The following non-limiting examples are experimental examples supporting one or more embodiments provided by the present disclosure.

Example 1: Scheme.1

[0062] FIG. 1 shows that the feed water should be filtered first to remove sediments, marine life, and other solids.

[0063] An optimum amount of buffer solution (NaOH) is added to the sea water to elevate its alkalinity up to pH 10. Then, flue gas from mainly power plant, mixed with sucked non-condensable gases from thermal desalination unit, are bubbled in the CM reactor to produce carbonates by precipitation (e.g. CaCO3, MgCO3, Na2CO3, BaCO3, etc.) and precipitate also portion of the sulfates. Then the precipitate is washed, filtered and dried to yield valuable mineral product. The processed filtered saline water, free from most of divalent ions, is directed to thermal desalination unit for producing fresh water and brine. Rejected brine from desalination unit is partially recycled as feedstock, few portion as blow down to avoid system accumulation and the rest to be utilized in brine crystallizer to achieve zero liquid discharge. The crystallizer would be mechanical vapor compression system or through any precipitation methods, such as using BaCl2.

Example 2: Scheme.2

[0064] FIG. 2 shows that the feed water should be filtered first to remove sediments, marine life, and other solids.

[0065] An optimum amount of buffer solution (NaOH) is added to the sea water to elevate its alkalinity up to pH 10. Then, flue gas from mainly power plant is bubbled in the CM reactor to produce carbonates by precipitation (e.g. CaCO3, MgCO3, Na2CO3, BaCO3, etc.) and precipitate also portion of the sulfates. Then the precipitate is washed, filtered and dried to yield valuable mineral product. The processed filtered saline water, free from most of divalent ions, is directed to membrane-based desalination unit (Reverse Osmosis) for producing fresh water and brine. Rejected brine from desalination unit is partially recycled as feedstock, few portion as blow down to avoid system accumulation and the rest to be utilized in brine crystallizer to achieve zero liquid discharge. The crystallizer would be mechanical vapor compression system or through any precipitation methods, such as using BaCl2.

Example 3: Scheme.3

[0066] FIG. 3 shows that the feed water should be filtered first to remove sediments, marine life, and other solids.

[0067] In this scheme, it is proposed to precipitate first the sulfates through chemical precipitation, using BaCl2 to yield BaSO4, followed by filtration, washing, filtering and drying. The processed filtered saline water go through Carbon mineralization stage. An optimum amount of buffer solution (NaOH) is added to the sea water to elevate its alkalinity up to pH 10. Then, flue gas from mainly power plant, mixed with sucked noncondensable gases from thermal desalination unit, are bubbled in the CM reactor to produce carbonates by precipitation (e.g. CaCO3, MgCO3, Na2CO3, BaCO3, etc.). Then the precipitate is washed, filtered and dried to yield valuable mineral product. The processed filtered saline water, free from most of divalent ions, is directed to thermal desalination unit for producing fresh water and brine. Rejected brine from desalination unit is partially recycled as feedstock, few portion as blow down to avoid system accumulation and the rest to be utilized in brine crystallizer to achieve zero liquid discharge. The crystallizer would be mechanical vapor compression system or through any precipitation methods, such as using BaCl2.

Example 4: Scheme. 4

[0068] FIG. 4 shows that the feed water should be filtered first to remove sediments, marine life, and other solids. In this scheme, it is proposed to precipitate first the sulfates through chemical precipitation, using BaCl2 to yield BaSO4, followed by filtration, washing, filtering and drying. The processed filtered saline water go through Carbon mineralization stage. An optimum amount of buffer solution (NaOH) is added to the sea water to elevate its alkalinity up to pH 10. Then, flue gas from mainly power plant is bubbled in the CM reactor to produce carbonates by precipitation (e.g. CaCO3, MgCO3, Na2CO3, BaCO3, etc.). Then the precipitate is washed, filtered and dried to yield valuable mineral product. The processed filtered saline water, free from most of divalent ions, is directed to membrane-based desalination unit (Reverse Osmosis) for producing fresh water and brine. Rejected brine from desalination unit is partially recycled as feedstock, few portion as blow down to avoid system accumulation and the rest to be utilized in brine crystallizer to achieve zero liquid discharge. The crystallizer would be mechanical vapor compression system or through any precipitation methods, such as using BaCl2.

Example 5: Proof of ConceptCarbon Mineralization for Saline Water Softening

[0069] FIG. 5 shows a setup of a CM reaction.

[0070] In a two-necks round bottom flask, 100 mL of artificial sea water was prepared based on the concentration of Mg2+, Ca2+ and SO4 2? ions in Ras-Laffan water (see Table.1), and kept under continuous stirring, at room temperature upon complete dissolution of solutes. Then, a buffer solution consists of NaOH was prepared to elevate the solution pH up to 10. pH was monitored by pH-meter. CO2 gas (purity 4N) was purged via needle into the solution with a pressure of 1 bar, at room temperature and under continuous stirring (600 rpm). After dosing CO2, the solution turned from clear to milky and a white fine precipitate started crushing out. After 30 minutes, the purging of CO2 was stopped. The solution was filtered under vacuum. The filtrate was washed with deionized water and left to dry at 80? C. overnight. The resulting white solid was characterized by XRD (see FIG. 6), which confirmed the formation of carbonates. The processed filtered solution was analyzed by inductively coupled plasma (ICP) to quantify the remaining ions in the solution (see Table.3).

TABLE-US-00001 TABLE 1 Sea water characteristics based on Ras Laffan area. Parameters RAF Magnesium (mg/L) 1,615 Sulphate (mg/L) 3,200 Sodium (mg/L) 12,200 Chloride (mg/L) 24,800 Calcium (mg/L) 460

Example 5: Proof of ConceptIntegrated Chemical Precipitation-Carbon Mineralization for Saline Water Softening

[0071] In a two-necks round bottom flask, 100 mL of artificial sea water was prepared based on the concentration of Mg2+, Ca2+ and SO4 2? ions in Ras-Laffan water (see Table. 1), and kept under continuous stirring, at room temperature upon complete dissolution of solutes.

[0072] A stoichiometry amount of BaCl2, with respect to the concentration of sulphate, was added and immediately a white fine precipitate started crushing out. Upon BaSO4 precipitation, the solution was filtered under vacuum. The filtrate was washed with deionized water and left to dry in the oven overnight. The resulting white solid was characterized by XRD (see FIG. 7), which confirmed the formation of BaSO4. After that, the filtered solution was used again in a two necks round bottom flask to remove the rest of divalent ions mainly Ca2+/Mg2+ through carbon mineralization stage. Then, a buffer solution consists of NaOH was prepared to elevate the solution pH up to 10. pH was monitored by pH-meter. CO2 gas (purity 4N) was purged via needle into the solution with a pressure of 1 bar, at room temperature and under continuous stirring (600 rpm). After dosing CO2, the solution turned from clear to milky and a white fine precipitate started crushing out. After 30 minutes, the purging of CO2 was stopped. The solution was filtered under vacuum. The filtrate was washed with deionized water and left to dry at 80? C. overnight. The resulting white solid was characterized by XRD (see FIG. 8), which confirmed the formation of carbonates, together with further BaSO4 resulting from the previous precipitation step. The processed filtered solution was analyzed by inductively coupled plasma (ICP) to quantify the remaining ions in the solution (see Table. 3).

TABLE-US-00002 TABLE 2 Process Parameters and System Performance Item Unit Scheme. 1 Scheme. 2 Scheme. 3 Scheme. 4 Flue gas (5-15%) kg-flue gas/m.sup.3 CO.sub.2 concentration saline water Buffer solution NaOH Ton/Ton- 0.00006 Seawater BaCl.sub.2 gm-BaCl.sub.2/ 1.47 gm-SO.sub.4.sup.2? Ca.sup.2+ Removal % >96 >96 Mg.sup.2+ Removal % 63 52.4 SO.sub.4.sup.2? Removal % 59.8 94.7

TABLE-US-00003 TABLE 3 IC analysis for processed filtered solution IC Analysis pH TDS Unit SO.sub.4.sup.2? Mg.sup.2+ Ca.sup.2+ Cl.sup.? Na.sup.+ Feed 8.2 44,750 mg/lit 3,561 1,768 494 24,800 12,200 Scheme 1&2 8.6 18,098 1,432 655 <20 10,150 33,550 Removal % 59.8% 63.0% >96% 59.1% +175.0% pH TDS Unit SO.sub.4.sup.2? Mg.sup.2+ Ca.sup.2+ Cl.sup.? Na.sup.+ Feed 8.2 44,750 mg/lit 3,561 1,768 494 24,800 12,200 Scheme 3&4 8.1 20,922 187 842 <20 11,700 25,826 Removal % 94.7% 52.4% >96% 52.8% +111.7%

Example 6: Proof of ConceptSkillman Index

[0073] FIG. 9 shows a Skillman Index.

[0074] Calcium sulfate (gypsum) is two orders of magnitude more soluble than calcium carbonate. This means that the sulfate is much less likely to drop out of solution when both are present. The solubility of calcium sulfate can be a significant concern in water systems that contain large concentrations of both calcium and sulfate. This type of water might be present with oil-field brines. Skillman developed a simple sulfate solubility index for estimating the likelihood of calcium sulfate scaling in this type of application. It is of the form:

[00001]$\mathrm{Skillman}\mathrm{Index}=\frac{S_{\mathrm{actual}}}{S_{\mathrm{theoretical}}}\mathrm{where}{S}_{\mathrm{theoretical}}=1000?\left(\sqrt{x^2+4k_{\mathrm{sp}})}-x\right)$

[0075] Where the ratio will be for either the calcium or sulfate, whichever is the limiting species. The concentration will be in meq/L. To convert mg/L (ppm) of Ca2+ to meq/L divide ppm by 20. To convert mg/L (ppm) of SO4 2? to meq/L divide ppm by 48. The x in the equation is the excess common-ion concentration of the calcium and sulfate ions and can be calculated by:

x={2.5?|Ca.sup.2+|.Math.1.04?[SO.sub.4.sup.2?]}?10.sup.?3

[0076] Where the square brackets represent the concentrations of the species in mg/L. The ionic strength of the solution is needed for the calculations. It can be calculated from the measured TDS or as Skillman did, estimated its value from the concentrations of some of the main species in water by multiplying each by their respective conversion factors.

U=2.2?[Na.sup.+]+5.0?[Ca.sup.2+]+8.2?[Mg.sup.2+]+1.4+[Cl.sup.?]+2.1?[SO.sub.4.sup.2?]+0.8?[HCO.sub.3.sup.?]?10.sup.?5

[0077] To obtain that ksp value, Skillman developed a family of curves relating the calcium sulfate solubility product constant, ksp with the ionic strength. The ksp was obtained by the value corresponding to the ionic strength on the curve for the appropriate temperature. Later computerized versions did least-squares fits to the curves to approximate them with a polynomial.

[0078] When the value of the Skillman Index is greater than 1.0, it shows the water to be slightly on the scaling side with respect to calcium sulfate.

[0079] Based on the previous equations, the standard ionic concentrations in seawater (RAS plant) was used, together with the corresponding concentrations for brine at recovery ratio from 10% to 90%, to calculate the Skillman index. Recovery ratio calculations have been added in order to verify the maximum ratio before scale precipitation occurs (Skillman index >1). Kps for CaSO4 has been extrapolated from FIG. 10 at 50? C.

TABLE-US-00004 TABLE 4a Recovery ratio (Once through stream) Seawater Feed Recovery ratio ( Once through stream) Conc 10% 20% 30% 40% 50% Na.sup.+ 12200 33555.56 15250 17428.57 20333.33 24400 Ca.sup.2+ 460 511.1111 575 657.1429 766.6667 920 Mg.sup.2+ 1615 1794.444 2018.75 2307.143 2691.667 3230 Cl.sup.? 24800 27555.56 31000 35428.57 41333.33 49600 SO.sub.4.sup.2? 3200 3555.556 4000 4571.429 5333.333 6400 HCO.sub.3.sup.? 153 170 191.25 218.5714 255 306 Ionic strength 0.839454 0.932727 1.049318 1.19922 1.39909 1.678908 CaSO.sub.4 Kps 0.001528 0.0001648 0.001788 0.001951 0.002142 0.002358 Skillman 0.387317 0.422246 0.466631 0.525328 0.607336 0.731484 index Recovery ratio ( Once through stream) 60% 70% 80% 90% Na.sup.+ 30500 40666.67 61000 122000 Ca.sup.2+ 1150 1533.333 2300 4600 Mg.sup.2+ 4037.5 5383.333 8075 16150 Cl.sup.? 62000 82666.67 124000 248000 SO.sub.4.sup.2? 8000 10666.67 16000 32000 HCO.sub.3.sup.? 382.5 510 765 1530 Ionic strength 2.098635 2.79818 4.19727 8.39454 CaSO.sub.4 Kps 0.002582 0.002719 0.002324 0.000241 Skillman 0.944956 1.407689 3.146476 104.5185 index

[0080] Then, the concentration of Ca2+ and S4 2? respectively equal to 10 ppm was considered, in order to simulate the effect of removing a specific ion of the final Skillman index value. As reported in the table below, with values ranging from 0.38 to 0.94, upon reduction of calcium and sulfate to 10 ppm, an average Skillman index of 0.0095 and 0.0029 was obtained, respectively. Demonstrating the both removal have an almost identical effect on reducing the chances of scaling.

[0081] Table 4b: Recovery ratio (Once through stream)

TABLE-US-00005 TABLE 4b Recovery ratio ( Once through stream) Reduced Reduced Reduced Reduced Reduced Ca.sup.2+ Ca.sup.2+ Reduced SO.sub.2.sup.2? SO.sub.2.sup.2? sensor Ca.sup.2+ RR 10% RR 60% SO.sub.2.sup.2? RR 10% RR 60% ppm ppm ppm ppm ppm ppm ppm Na.sup.+ 12200 12200 13555.56 50500 12200 13555.56 30500 Ca.sup.2+ 460 10 10 10 400 511.1111 1150 Mg.sup.2+ 1615 1615 1794.444 4037.5 1615 1764.444 4037.5 Cl.sup.? 24800 24800 27556.56 62000 24800 27565.56 62000 SO.sub.4.sup.2? 3200 3200 3555.556 8000 10 10 10 HCO.sub.3.sup.? 153 153 170 382.5 153 170 382.5 Ionic 0.839454 0.016954 0.007671 2.041035 0.772464 0.85827 1.910845 strength Skillman 0.387317 0.009245 0.008676 0.010444 0.003047 0.003102 0.003759 Index CaSO.sub.4 Kps 0.001528 0.001625 0.001617 0.002559 0.001558 0.001553 0.002507 indicates data missing or illegible when filed

Example 7: Prototype Based Simulation of the MED Desalination

[0082] FIG. 11 shows an interface of VDS software for conventional MED of 15 MIGD.

[0083] FIG. 12 shows a VSP Interface of 18 effects MED evaporator, TBT=65? C.

[0084] The previously developed and verified VSP software is used as a simulation tool to carry out process design calculations at different TBTs. The VSP is also utilized to size tube bundle, and then predict the scale deposit over the evaporator tubes. A process flow diagram of a typical operating medium size MED evaporator (15 MIGD) working at TBT=65? C. is used as a reference case. The process simulation is performed by specifying the heating steam operating conditions (pressure, temperature), the target capacity by evaporator (distillate rate per hour), top brine temperature (TBT), feed seawater conditions (temperature & salinity), blow down (temperature & salinity). Some design parameter such as the number of effects, tube length, diameters, material type are specified. Using VSP, all process stream characteristics are determined (mass, temperature, pressure). Also, the calculated GOR, the heat transfer surface area (number of tubes), the specific power consumption is calculated. Evaporator size, and internal dimensions are sized. Some of the technical limitations are taken into consideration during the design process in order to reduce the relevance thermal and pressure losses. Using the softening seawater feed with MED process either enables the increase of TBT greater than 65? C. The increase of the TBT enables to increasing the number of cells and accordingly reduce the energy consumption and reduce the heat transfer area.

[0085] A comparison between the high TBT MED and the traditional MED is illustrated in Table.5. For the same capacity and same operation and design parameters, the calculated GOR of the high TBT MED is 70% higher than that of the reference MED due to increase the TBT for the heat transfer area. The specific pumping power of high TBT MED is 54% lower than that of the reference MED due to lower cooling water flow also lower heating steam energy requirement. The specific intake flow rate of the high TBT is 57% lower than the conventional plant. The specific energy consumption of the high TBT MED with softening seawater feed is 24% lower than the conventional plant.

TABLE-US-00006 TABLE 5 Comparison between high TBT MED and conventional MED. MED High (Ref.) TBT MED % diff. 1 Plant capacity, MIGD 15 15 2 TBT, ? C. 6 9 3 Seawater feed temperature 3 3 3 Feed salinity, g/l 45 20 5 Brine salinity, g/l 70 70 5 GOR 8.2 15 82% 6 Specific heat transfer 114 100 ?12% area, m.sup.2/(ton/hr) 7 Specific power consumption, kWh/m.sup.3 2 0.9 ? % 9 Process recovery ratio 40% 70% 75% 10 Specific energy consumption kWh/m.sup.3 5.5 4 ?27% indicates data missing or illegible when filed

[0086] The specific energy consumption of the MED requires to calculate the mechanical energy equivalent of thermal energy (heating steam) to be added to the pumping power consumption. Using the VSP, the CCGT with MED power and desalination plant is solved to calculate the specific energy consumption. As shown in FIG. 13, the MED with SS has a specific energy consumption of 27% lower than the conventional MED using row seawater feed. The unit water cost of the MED with SS is 25% lower than the conventional MED.

TABLE-US-00007 TABLE 6 Techno-economic comparison between MED and MED-SS. Cost analysis MED MED-SS Difference 1 Interest rate 0.07 0.07 2 Life span 20.00 20.00 3 amortization 0.094 0.094 4 $/year 8,249,689.25 6,600,203.67 ?20% 5 availability 0.95 0.95 6 S/hr 991.31 793.10 ?20% 7 CAPEX, $/m3 0.34 0.28 ?18% 8 OPEX, $/m3 0.54 0.38 ?30% 9 water unit cost, $/m3 0.88 0.66 ?25%

Example 8: Prototype Based Simulation of the RO Desalination Plant

[0087] FIG. 16 shows specific energy consumption.

[0088] Reverse Osmosis desalination plant is effect desalination plant however it affected also with the seawater feed salinity and purity. FIG. 14 shows the VDS interface of the Umm Al Houl when feed with seawater of 45 g/l while FIG. 15 shows the interface of the same plant with treated seawater.

[0089] Table 7 shows the comparison between the RO plant when feed with seawater and treated seawater. The simulation results show due to treated sweater feed, the production increase 10% while the process recovery ratio increased by 70%. The specific power consumption decreased by 28% and the feed flow rate decreased by 40%.

TABLE-US-00008 TABLE 7 Comparison between high process recovery RO and reference RO plant. RO Softening % (Ref.) seawater RO diff. 1 Plant capacity, MIGD 60 68 10% 2 Feed salinity, g/l 45 20 3 Feed temperature, ? C. 35 35 4 Brine salinity, g/l 75 60 ?13% 5 Recovery ratio 39% 65% 70% 6 Specific membrane area, m.sup.2/(ton/hr) 7 Specific power consumption, 4.5 3.29 ?27% kWh/m.sup.3 8 Specific feed flow rate, ton/ton 2.6 1.5 ?4 % analysis RO Softening (Ref.) seawater RO 1 Chemical cost $/h 599 410 ? 2% 2 Electrical cost $/h 2043 1627 ?20% 3 Blowdown cost $/h 22 7 ?6 % 4 Permeate cost $/h 11,565 11,425 ?1% 5 Unit water cost $/m.sup.3 0.98 0.88 ?10% indicates data missing or illegible when filed

[0090] As reported in Table 7, using softening seawater technique will reduce the specific energy consumption by 27%

Example 9: Commercial Scale Plants for Carbonate

[0091] Examples of companies that are operating commercial-scale projects of CO2 mineralization include Skyonic Corporation and Calera Corporation in the US, and Twence in the Netherlands. The Skymine project of Skyonic has been supported by the US Department of Energy since 2010, for developing a technology to chemically react flue gas with caustic soda obtained from the electrolysis of brine to produce chemicals such as sodium bicarbonate (NaHCO.sub.3). In San Antonio, TX, a plant utilizing CO2 emitted from a cement factory to produce sodium bicarbonate, hydrogen chloride (HCl), bleach (NaOCl) and chlorine(Cl2), has been in operation since October 2014. The plant is capable of utilizing approximately 75,000 tons of CO2 per year to produce 140,000 tons of sodium bicarbonate per year. Alkalinity Based on Low Energy (ABLE) to react calcium and magnesium cations obtained from caustic soda and sea water with CO2 in flue gas to produce calcium carbonate and magnesium carbonate, respectively. Presently, a pilot plant has been constructed and is in operation in California, where CO2 from the Dynegy Moss Landing Power Plant (generation capacity: 1.5 GW) is utilized to produce supplementary cement materials (5 tons/day). Twence, from the Netherlands, has developed a plant capable of utilizing CO2 and sodium carbonate produced by waste-to-energy plants to produce sodium bicarbonate, which in turn is utilized to remove SOx/HCl in flue gas. The plant is capable of utilizing approximately 2000 tons of CO2 per year to produce 8000 tons of sodium bicarbonate per year.

Example 10: Design Basis and Techno-Economics for Commercial Scale Plants

[0092] The calculation basis based on commercial plant to possess an annual capacity of approximately 5000 tons of Ca/Mg Carbonate production. The provision of connecting duct from the stack to the CM has been considered. Piping/Ducting cost are already considered in techno comic analysis. Usually flue gas released at 57? C. (Air cooled condenser design temp). A duct from incinerator stack to CM reactor will be used with the same temperature without cooling/pre-treatment. Key performance data based on a benchscale CO2 mineralization process are used for the technical feasibility analysis of this work. The below table reflects the main reactor design parameters:

TABLE-US-00009 TABLE 8 Capex. Specifications Bench Scale Commercial Scale Reactor Height/Diameter (m) 1.6/0.08 11.5/0.6 Liq flow rate 8.3 (g/min) 2.7 Ton/Ton-carbonate CO.sub.2 flow 2 (kg/day) 0.6 Ton-CO.sub.2/ Ton-carbonate Flooding factor: Top/Bottom (%) 0.8/0.7 55.1/52.4 Gas velocity (m/sec) 0.02 0.13 Material of reactor Glass/Acryl SS-304

TABLE-US-00010 TABLE 9 Assumed parameter values for the economic evaluation: Specification Value Plant Lifetime (years) 20 Equipment Salvage value 0 Construction period (years) 2 Discount rate (%) 5.5

TABLE-US-00011 TABLE 10 Unit price cost per feed: SW CO.sub.2 Equipment $/Ton $/Ton Oven 31.67 6.33 Mechanical Filter 140.00 28.00 Storage Tanks 91.67 18.33 Pumps 108.33 21.67 Reactor 298.33 59.67

TABLE-US-00012 TABLE 11 Total Discounted Capex for each scheme: Scheme No. Scheme. 1 Scheme. 2 Scheme. 3 Scheme. 4 Total Cost 0.076 0.1530 ($/Ton-Seawater Feed)

[0093] OpexMaterial price: BaCl2 dosing: $225/Ton, NaOH dosing: $200/Ton; Operating cost: BaCl2 dosing: 1.47 gm-BaCl2/gm-SO42?; NaOH dosing: 0.06 gm/m3 water

TABLE-US-00013 TABLE 12 Opex OPEX ITEM BaCl.sub.2 NaOH Unit Price $/Ton 225 200 Dosage Ton/Ton SW 0.005235 0.00006 Cost $/Ton 1.18 0.01

TABLE-US-00014 TABLE 13 Total Opex per Scheme: Scheme No. Scheme. 1 Scheme. 2 Scheme. 3 Scheme. 4 Total Cost 0.012 1.1898 ($/Ton-Seawater Feed)

TABLE-US-00015 TABLE 14 Total Capex and Opex per scheme: Scheme No. Scheme. 1 Scheme. 2 Scheme. 3 Scheme. 4 Total Cost 0.088 1.3428 ($/Ton-Seawater Feed)

TABLE-US-00016 TABLE 15 Selling Cost. Total selling cost per scheme w.r.t mineral extraction and based on Ras-laffan seawater characteristics: Scheme Scheme, 1 & Scheme, 2 Scheme, 3 & Scheme, 4 Item CaCO.sub.3 MgCO.sub.3 BaSO.sub.4 CaCO.sub.3 MgCO.sub.3 BaSO.sub.4 Precipitated 494 1113 2129 494 926 3374 product mg/lit Ton-Product/ 0.000494 0.001113 0.002129 0.000494 0.000926 0.003374 Ton-SW Unit Price 170 350 300 170 350 300 ($/Ton-Product) Selling Price 0.08398 0.38955 0.6387 0.08398 0.3241 1.0122 ($/Ton-SW) Total Selling Price 1.11 1.42 (S/Ton-SW)

TABLE-US-00017 TABLE 16 Net Revenue from Seawater Softening w.r.t mineral extraction only. Scheme No. Scheme. 1 Scheme. 2 Scheme. 3 Scheme. 4 Total Cost 1.0237 0.0775 ($/Ton-Seawater Feed)