HYDROMAGNETIC DESALINATION CELL WITH RARE EARTH MAGNETS
20180002202 · 2018-01-04
Assignee
Inventors
Cpc classification
C25B1/34
CHEMISTRY; METALLURGY
C02F1/482
CHEMISTRY; METALLURGY
C25B5/00
CHEMISTRY; METALLURGY
Y02E60/36
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
C25B5/00
CHEMISTRY; METALLURGY
Abstract
A hydromagnetic desalination cell including at least one hollow rectangular flow conduit, a first rectangular magnet and a second rectangular magnet each having a north pole face and a south pole face opposite of each other, wherein the first and second rectangular magnets are disposed along a longitudinal axis and on opposite sides of the rectangular flow conduit, a first opening and a second opening on opposite walls of the rectangular flow conduit extending between the first and second rectangular magnets, and a first and second chamber fluidly connected to the first and second openings. A hydromagnetic desalination system and methods of desalinating brine water with the hydromagnetic desalination system are also disclosed.
Claims
1. A hydromagnetic desalination cell, comprising: a plurality of stacked hollow rectangular flow conduits with each conduit having a conduit inlet on a first end and a conduit outlet on a second end, wherein the hollow rectangular flow conduits are made of a non-magnetic and non-conductive material; a first rectangular magnet and a second rectangular magnet each having a north pole face and a south pole face opposite of each other, wherein the first rectangular magnet and the second rectangular magnet are independently selected from the group consisting of a neodymium iron boride magnet and a samarium cobalt magnet, wherein the first and second rectangular magnets are disposed along a longitudinal axis and on opposite sides of the stacked rectangular flow conduits such that the north pole face of the first rectangular magnet contacts a first face of the stacked rectangular flow conduits and the south pole face of the second rectangular magnet contacts a second face of the stacked rectangular flow conduits conduits, and the first and the second rectangular magnets provide a magnetic field that extends between the magnets; a first opening and a second opening on opposite walls of the stacked rectangular flow conduits extending between the first and second rectangular magnets; a first chamber fluidly connected to the first opening of the stacked rectangular flow conduits; a second chamber fluidly connected to the second opening of the stacked rectangular flow conduits; a positive electrode connected to the first chamber; and a negative electrode connected to the second chamber; wherein the first and second rectangular magnets generate a magnetic field that causes cations to flow from the first opening of the stacked rectangular flow conduits to the first chamber, and anions to flow from the second opening of the stacked rectangular flow conduits to the second chamber.
2. The hydromagnetic desalination cell of claim 1, wherein a distance between the north pole face of the first rectangular magnet and the south pole face of the second rectangular magnet ranges from 0.01-0.035 m.
3. The hydromagnetic desalination cell of claim 1, wherein the first and second rectangular magnets are neodymium iron boride or samarium cobalt magnets.
4. The hydromagnetic desalination cell of claim 1, wherein the stacked hollow rectangular flow conduits have a rectangular cross section with a width dimension that is larger than a height dimension.
5. (canceled)
6. The hydromagnetic desalination cell of claim 1, wherein the non-magnetic and non-conducting material is polyvinyl chloride.
7. (canceled)
8. The hydro-magnetic desalination cell of claim 1, wherein the thickness of the first and second rectangular magnets are the same, and a distance between each stacked hollow rectangular flow conduit is equal to the thickness of the first and second rectangular magnet.
9. The hydromagnetic desalination cell of claim 8, wherein the thickness of the first and second rectangular magnet ranges from 1-6 cm.
10-20. (canceled)
21. The hydromagnetic desalination cell of claim 1, wherein the first and second rectangular magnets provide a magnetic field strength of 0.3 to 0.6 Tesla in the center of the rectangular flow.
22. The hydromagnetic desalination cell of claim 1, wherein the first and second rectangular magnets provide a magnetic field strength of 0.34 to 0.46 Tesla in the center of the rectangular flow.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
[0042]
[0043]
[0044]
[0045]
[0046]
[0047]
[0048]
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0049] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.
[0050] Referring to
[0051] In one embodiment, the hollow rectangular flow conduit comprises a non-magnetic, non-conducting material. Exemplary non-magnetic, non-conducting materials include polymers such as polyether, polyurethane, polyester, polyethylene (i.e. high density, low density, etc.), polyvinylidene chloride, polyvinyl chloride, polystyrene, polyamides, silnylon, acrylonitrile butadiene styrene, polyethylene/Acrylonitrile butadiene styrene, polycarbonate, polycarbonate/acrylonitrile butadiene styrene, and mixtures thereof, ceramics such as glass (e.g. SiO.sub.2), porcelain, clay, quartz, alumina, feldspar, or composite polymer materials. In one embodiment, the non-magnetic, non-conducting material is polyvinyl chloride.
[0052] The hydromagnetic desalination cell 101 also includes a first rectangular magnet 103 and a second rectangular magnet 104 each having a north pole face and a south pole face opposite of each other, wherein the first and second rectangular magnets are disposed along a longitudinal axis and on opposite sides of the rectangular flow conduit (i.e. along the upper and lower walls) such that the north pole face of the first rectangular magnet contacts the rectangular flow conduit and the south pole face of the second rectangular magnet contacts the rectangular flow conduit. By placing magnets having opposite poles oriented toward the longitudinal center of the rectangular flow conduit, a magnetic field is produced that then extends between the magnets. Referring to
[0053] In one embodiment, each of the first and second magnets have a thickness 303 ranging from at least 0.5 cm, at least 1 cm, at least 1.5 cm, at least 2 cm, at least 2.5 cm, at least 3 cm, at least 3.5 cm, at least 4 cm, at least 4.5 cm, at least 5 cm, and no more than 10 cm, no more than 9 cm, no more than 8 cm, no more than 7 cm, no more than 6 cm, no more than 5 cm, no more than 4 cm, for example 2-5 cm (
[0054] As depicted in
[0055] The magnets used for the hydromagnetic desalination cell may be permanent magnets or superconductors rolled in coils around the first and second magnet. The first and second magnets may include iron, nickel, cobalt, rare-earth metals, or alloys thereof, preferably alloys of rare earth metals. In one embodiment, the first and second rectangular magnets are neodymium iron boride or samarium cobalt magnets. At room temperature, neodymium iron boride (Nd.sub.2Fe.sub.14B) magnets exhibit the strongest magnetic properties of all commercial magnets. Samarium Cobalt Sm.sub.2Co.sub.17.sup.− also has high magnetic field strength and inherent stability. In addition to (or in lieu of) neodymium iron boride or samarium cobalt magnets other magnetic materials (e.g. Sm(Co,Fe,Cu,Zr).sub.7, alnico, Sr-ferrite, etc.) may be present in the first and second magnets and the hydromagnetic desalination cell will still function as intended. In one embodiment, the first and second rectangular magnets provide a largest magnetic field strength of 0.2-2 Tesla, preferably 0.8-2 Tesla, preferably 1-1.8 Tesla, preferably 1.2-1.7 Tesla, preferably 1.4-1.6 Tesla. In one embodiment, the magnetic field strength measured in the center of the rectangular flow conduit is 0.3 to 0.6 Tesla, preferably 0.32 to 0.56 Tesla, preferably 0.34 to 0.52 Tesla, preferably 0.36 to 0.48 Tesla, preferably 0.38 to 0.46 Tesla.
[0056] The hydromagnetic desalination cell 101 also includes a first opening 105 and a second opening 106 on opposite walls (opposing side walls) of the rectangular flow conduit extending between the first 103 and second rectangular magnets 104. The first and second openings provide a route for ions (anions and cations) to escape the passageway of the rectangular flow conduit as a fluid containing the ions moves along the longitudinal axis and through the flow conduit. Like the rectangular flow conduit, the first and second openings are generally rectangular shaped, although other may also be possible, such as circular, oval, etc. In one embodiment the first and second opening have identical dimensions, with the length of the first and second openings being 50-99% of the length of the rectangular flow conduit, preferably 60-99%, preferably 70-99%, preferably 80-99%, preferably 90-99%. Further, the height of the first and second openings are 50-99% of the height of the rectangular flow conduit, preferably 60-99%, preferably 70-99%, preferably 80-99%, preferably 90-99%. Therefore, of the possible 100% surface area of each side wall, the first and second openings occupy at least 25%, at least 35%, at least 45%, at least 55%, at least 65%, at least 75%, at least 85%, at least 95% of the surface area of each opposing side wall. While the hydromagnetic desalination cell may include a plurality of openings on each opposing side wall, it is preferable for each opposing side wall to contain only one opening that extends along the length and height of the side wall, as described heretofore, for desirable flow properties and separation efficiency.
[0057] As seen in
[0058] In one embodiment, the first and second rectangular magnets generate a magnetic field that causes any cations present in a feed fluid (e.g. a first brine water) to flow from the first opening 105 of the rectangular flow conduit to the first chamber 109, and any anions present in the feed fluid to flow from the second opening 106 of the rectangular flow conduit to the second chamber 110. When subjected to the magnetic field extending between the magnets, the positively charged, cations and negatively charged anions are deflected laterally away from each other to opposite directions toward the respective first opening or second opening, and are expelled from the conduit through the first or second opening. To prevent external ions from entering (or reentering) the flow conduit through the first or second openings by diffusion or otherwise, fluid adjacent the openings inside and outside (i.e. from the first or second chamber) the flow conduit should maintain parallel flow. An ionized solution, such as seawater, flowing past the first and second openings outside the conduit faster than the partially deionized solution inside the conduit will produce a Venturi suction which draws off some of the desalinated solution having lowered salinity through the openings into the outside flow stream within the first and second chamber. This forms a thin boundary layer of lowered salinity along the first and second openings of the conduit which assists in preventing the external ion intrusion mentioned above.
[0059] As depicted in
[0060] The hydromagnetic desalination cell may also be assembled in series, is parallel and in networks for economic scaling of desalination processes within a production plant, for example.
[0061] In one embodiment, the hydromagnetic desalination cell further comprises a third chamber 209 with a brine discharge outlet, wherein the third chamber is located downstream of and is fluidly connected in parallel to the first chamber 109 through a first chamber outlet 210 line and the second chamber 110 through a second chamber outlet line 211 and wherein the cations from the first chamber and the anions from the second chamber combine in the third chamber and are expelled from the brine discharge outlet of the third chamber (see
[0062] In one embodiment, the hydromagnetic desalination cell further comprises a positive electrode 501 connected to the first chamber 109 and a negative electrode 502 connected to the second chamber 110 (see
[0063] The hydromagnetic desalination cell may further comprise a cation sequestration material and an anion sequestration, material. The cation sequestration material is a material that effectively binds to cations (e.g. sodium cations), incorporates the cations into pores present within cation sequestration material, or reacts with the cations, thereby removing said cations from the solution. Likewise, the anion sequestration material can incorporate the anions (e.g. chloride anions) into pores present within anion sequestration material, or react with the anions, thereby removing said anions from the solution. When paired together, the cation and anion sequestration material may remove salts (e.g. NaCl) from a brine solution or otherwise reduce the total concentration of the salts in the solution. Therefore, when present in the hydromagnetic desalination cell of the present disclosure, the cation sequestration material and the anion sequestration material may aid in removing or lowering the total concentration of cations and anions in a solution passed through the desalination cell. These materials may be present within the rectangular flow conduit, for example as a lining on an interior surface of the passageway of the flow conduit or as a cross sectional filter within the path of a fluid flowing through the flow conduit or through the conduit inlet line 204. Exemplary cation sequestration materials include crown ethers (e.g. such as 18-crown-6 which has high affinity for potassium cation, 15-crown-5 which has a high affinity for sodium cations, and 12-crown-4 which has a high affinity for lithium cations), amino acids, zeolites, or diatomaceous earth [see Heinbigner et al. U.S. 20070256603A1—incorporated herein by reference in its entirety]. Exemplary anion sequestration material includes compounds or compositions comprising calcium oxide, iron, and aluminum oxide, such as the compound/compositions described in U.S. Pat. No. 7,074,263 B2, which is incorporated herein by reference in its entirety.
[0064] Referring now to
[0065] Desalination is a process that removes some amount of salt and/or other minerals from saline water, brackish water, seawater, brine etc. In general brackish water contains 0.05-3% dissolved salts, saline water and seawater contain 3-5% dissolved salts, and brine contains greater than 5% dissolved salts (as presented herein % refers to % by weight based on the total weight of dissolved solids and total solution weight). In terms of the present disclosure, the term “brine water” is used as a general term for any water than contains more salinity than freshwater (freshwater generally contains less than 0.05% salinity), and may therefore refer to saline water, brackish water, seawater, or brine. Further, the term “desalinated water” refers to any water that has been passed through the desalination system described herein that has a salt concentration that is less than the salt concentration of the feed water prior to desalination (i.e. the first brine water). Salts that are present in brine water that may be removed with the hydromagnetic desalination of the present disclosure may be, but are not limited to, cations such as sodium, magnesium, calcium, potassium, ammonium, and iron, and anions such as chloride, bicarbonate, carbonate, sulfate, sulfite, phosphate, iodide, nitrate, acetate, citrate, fluoride, and nitrite. In a preferred embodiment, the first brine water comprises sodium cation and chloride anions. The “first brine water” as used herein refers to an aqueous solution comprising one or more salts that is to be desalinated. The first brine water may come from a variety of sources, including, but not limited to surface water that collects on the ground or in a stream, an aquifer, a river, a lake, a reservoir, an ocean, ground water that is obtained by drilling wells, run-off, industrial water, public water (city water, well water, etc.), an industrial waste water stream, sewage, water treatment facility water, and bodily fluids (urine, blood, etc.). In one embodiment, the first brine water has a salt (e.g. sodium chloride) concentration of 30,000 to 40,000 ppm, preferably 33,000 to 38,000 ppm, more preferably 34,000 to 36,000 ppm, or about 35,000 ppm (about 3.5 % salts by weight).
[0066] In one embodiment, the first brine water is flowed through the hydromagnetic desalination cell 101 to separate the sodium cations into the first chamber 109 through the first opening and the chloride anions into the second chamber 110 through the second opening to produce desalinated water. In non-commercial scale desalination systems (e.g. personal drinking water purification, lab scale water purification, etc.) the first brine water may be flowed through hydromagnetic desalination cell (q.sub.in) with a flow rate of 3.5-5.0 L/min, 4.0-4.8 L/min, 4.4-4.6 L/min. In commercial scale desalination systems (e.g. city water purification, water treatment facilities, etc.) the first brine water may be flowed through hydromagnetic desalination cell with a flow rate of 2.5-3.5 m.sup.3/min, 2.7-3.3 m.sup.3/min, 2.9-3.0 m.sup.3/min. In either scenario, the velocity of the first brine water in the flow conduit is 10 to 17 m/sec, 11 to 16 m/sec, 12 to 15 m/sec.
[0067] The inlet tank 202 is a general holding/storage vessel for the first brine water, and may be of various shapes and size so long as the inlet tank is of sufficient size to store a total volume of the first brine water that is to be desalinated. For example, in a non-commercial application of the hydromagnetic desalination system, whereby 2-20 L of the first brine water is to be desalinated, the inlet tank should have a total volume storage capacity of 5 to 25 L. Further, in a commercial scale application of the hydromagnetic desalination system, whereby 20-100 m.sup.3 of the first brine water is to be desalinated, the inlet tank should have a total volume storage capacity of 25-150 m.sup.3. Various other amounts of first brine water and total volume storage capacity of the inlet tank may also be used in the present hydromagnetic desalination system and the system will still function as intended. The first brine water may be pumped into the inlet tank 202 through an inlet tank feed line 201. The first brine water is preferably pumped out of the inlet tank 202 at a feed rate q.sub.in that is the same or higher than the rate at which the first brine water is led into the inlet tank q.sub.f through the inlet tank feed line 201.
[0068] The hydromagnetic desalination system includes a desalinated water line 205 which connects the conduit outlet 108 to a collection source (e.g. a collection vessel, a potable water network, etc.). The flow rate (q.sub.o or q.sub.p) of the desalinated water through the desalinated water line 205 may be 3.0-4.0 L/min, 3.1-3.5 L/min, 3.1-3.3 L/min for non-commercial scale desalination systems and 1.8-3.0 m.sup.3/min, 2.0-2.5 m.sup.3/min, 2.0-2.2 m.sup.3/min for commercial scale desalination systems.
[0069] The hydromagnetic desalination system includes a desalinated water reflex line 206 that fluidly connects the conduit outlet 108 to the inlet tank 202 for recycling the desalinated water, wherein the desalinated water line 205 and the desalinated water reflux line 206 are fluidly connected in parallel to and downstream of the conduit outlet 108. The desalinated water exiting from the hydromagnetic desalination cell has a concentration of sodium cations and chloride anions that is less than that of the first brine water. The concentration of salt (i.e. sodium cations and chloride anions) in the desalinated water may be less than 500 ppm, preferably less than 450 ppm, preferably less than 400 ppm, preferably less than 350 ppm, preferably less than 300 ppm, preferably less than 250 ppm, preferably less than 200 ppm, preferably less than 150 ppm, preferably less than 100 ppm, preferably less than 50 ppm. In one embodiment, the water recovery ratio, i.e. the percent ratio of the desalinated water to the first brine water is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%.
[0070] In one embodiment, the hydromagnetic desalination system further comprises a pump 203 fluidly connected to the inlet tank 202 and the conduit inlet 107, wherein the pump 203 transfers the first brine water from the inlet tank to the conduit inlet. The pump used to transfer the first brine water to the conduit inlet and/or to flow the brine water through the hydromagnetic desalination cell is non-limiting, and various types of pumps may be used including a centrifugal pump, a rotatory pump, a positive displacement pump, and the like. The pump may have a wide range of power such as 200 W to 900 kW, or 250 W to 850 kW, or 275 W to 830 kW. Depending on the size of the desalination system and the amount of brine water that is to be desalinated, the pump may provide differing flow rates to match such requirements. In one embodiment, the pump flow rate for a non-commercial scale hydromagnetic desalination system is 200-300 L/min, 210-275 L/min, 215-250 L/min, 220-230 L/min. In one embodiment, the pump flow rate for a commercial scale hydromagnetic desalination system is 25-40 m.sup.3/min, 30-38 m.sup.3/min, 32-36 m.sup.3/min.
[0071] In one embodiment, the hydromagnetic desalination system further comprises a first flow valve 207 positioned in the desalinated water line downstream of the conduit outlet, and a second flow valve 208 positioned in the desalinated water reflux line downstream of the conduit outlet, wherein the first flow valve 207 and the second flow valve 208 may be adjusted so that the desalinated water is flowed through the desalinated water line and collected, is returned to the inlet tank through the desalinated water reflex line, or both. The flow rates and the volume of desalinated water flowed through the desalinated water line and the desalinated water reflex line can be adjusted to achieve a desirable reflex ratio. The reflex ratio refers to the volume of desalinated water flowed back to the inlet tank to the volume of desalinated water collected, and therefore the reflex ratio indicates what amount is returned to the inlet tank (i.e. the higher the reflex ratio, the less desalinated water is collected). The reflex ratio may be adjusted to produce a desalinated water with a desired purity (i.e. concentration of sodium cation and chloride anions), where a high reflux ratio results in a higher purity for the resulting desalinated water collected from the desalinated water line. The reflex ratio may therefore be variable depending on the desired final desalinated water purity and may range anywhere from 1:1 to 100:1, or 5:1 to 75:1, or 10:1 to 65:1. For example, a non-commercial scale hydromagnetic desalination system may have use a reflux ratio of 30:1 to 70:1, 35:1 to 60:1, 40:1 to 55:1, 45:1 to 50:1. Former, a commercial scale hydromagnetic desalination system may have use a reflux ratio of 5:1 to 15:1, 6:1 to 14:1, 7:1 to 13:1, 8:1 to 12:1, 9:1 to 11:1.
[0072] The hydromagnetic desalination system may also comprise a plurality of sensors for measurement of one or more physical variables such as temperature, flow rate, pH, salinity, pressure, conductivity, concentration. These sensors may be electrically connected to flow control elements such as pumps and valves, and control loop elements and automatic control units (e.g. operating computers) to set and maintain the operating parameters. In this scenario, the automated control units can receive signals from the plurality of sensors in the form of feedback, and adjust the system parameters (e.g. flow, temperature, etc.) until the desired parameters of the various system components or fluid (e.g. the salinity of the produced desalinated, water) are met.
[0073] As depicted in
[0074] In one embodiment, the sodium cations from the first chamber flow to the third chamber through the first chamber outlet line and the chloride anions from the second chamber flow to the third chamber through the second chamber outlet line to produce a second brine water that is discharged from the third chamber 209 to the brine tank 213 through the brine discharge line 214. The brine discharge line is preferably attached towards or at the bottom of the third chamber to facilitate flow of the second brine water from the third chamber to the brine tank. The brine discharge line may include—a flow control valve to start and stop the flow (q.sub.b) of the second brine water to the brine tank. The brine tank is a general holding and/or storage tank for the second brine water, and thus may be any shape or size. The volume of second brine water produced by the hydromagnetic desalination system is small compared to the volume of desalinated water produced or the volume of the first brine water (i.e. the second brine water is more concentrated and thus has less water). Therefore, in one embodiment, the brine tank has a total volume storage capacity that is less than the total volume storage capacity of the inlet tank. The brine tank may have a maximum volume storage capacity that allows the hydromagnetic desalination system to operate for 1-100 hours, 10-50 hours, or 20-30 hours without the need to remove the second brine water from the brine tank to prevent overflow.
[0075] In one embodiment, the second brine water has a concentration of sodium cations and chloride anions that is greater than that of the first brine water. The concentration of sail (e.g. sodium cations plus chloride anions) in the second brine water may range from 90,000 to 140,000 ppm, 100,000 to 130,000 ppm, 110,000 to 120,000 ppm, 115,000 to 116,000 ppm, or about 115,500 ppm, for example.
[0076] The recombination of the sodium cations and the chloride anions in the third chamber to form the second brine water may also release the ionization energy to produce heat. The heat generated in the third chamber and in the brine tank can be used to increase the temperature of the first brine water in the inlet tank, which may aid the desalination process. For example, the inlet tank may be located inside of the brine tank or the brine tank may in some way jacket the inlet tank, wherein the brine tank acts as a hot water bath and results in the heating of the first brine water held inside the inlet task. In another example, the inlet line may pass through a brine tank conduit in the brine tank such that the first brine water flowing from the inlet tank to the hydromagnetic desalination cell may pass through the brine tank conduit whereby heat from the brine tank is exchanged into the flowing first brine water. In one embodiment, the heat generated from recombining the sodium cations and the chloride anions in the third chamber is used to heat the first brine water and increases the temperature of the first brine water by at least 10 K, at least 11 K, at least 12 K, or at least 13 K, and no more than 25 K, or no more than 20 K.
[0077] According to a fourth aspect, in addition to i) the hydromagnetic desalination cell 101 of the present disclosure, in one or more of its embodiments, ii) the inlet tank 202, iii) the desalinated water line 205, and iv) the desalinated water reflex line 206, the hydromagnetic desalination system also includes v) a positive electrode 501 connected to the first chamber 109 vi) a negative electrode 502 connected to the second chamber 110 vii) a hydrogen outlet line 509 fluidly connected to and downstream of the first chamber 109 viii) a sodium hydroxide outlet line 510 fluidly connected to and downstream of the first chamber 109 and ix) a chlorine outlet line 511 fluidly connected to and downstream of the second chamber 110 (
[0078] In one embodiment, fee positive electrode 501 is electrically connected to the negative electrode 502 through an external circuit to form hydrogen 503 in the first chamber that flows through the hydrogen outlet line 509, sodium hydroxide 505 in the first chamber that flows through the sodium hydroxide line 510, and chlorine 508 in the second chamber that flows through the chlorine outlet line 511. The electrical current that flows from the positive electrode towards the negative electrode electrolyzes the brine that results in the formation of the hydrogen 503, chlorine gas 508, and sodium hydroxide 505 in their respective chambers. The hydrogen gas 503 may be removed from the first chamber 109 using a hydrogen pump 504, and the chlorine gas 508 may be removed from the second chamber 110 with a chlorine pump 507. Further, the flow of the sodium hydroxide may be controlled using, for example, a sodium hydroxide flow valve 506. Rather than discharging the second brine water having high brine content into a waste land or returning to ocean waters, the generated electrical current can instead be directed towards the production of such industrial products (hydrogen, chlorine gas, sodium hydroxide, etc.), which have various uses. The external circuit is not meant to be limiting and can be any circuitry that provides an electrical connection between the negative and positive electrode. The external circuit, may therefore comprise various electrical components including resistors, connecting wires, capacitors, lamps, and the like.
[0079] In addition to sodium hydroxide, magnesium hydroxide may also be produced by connecting the positive electrode 501 to the negative electrode 502, where the magnesium hydroxide is formed in the first, chamber 109. For example, seawater generally has a total dissolved solids (TDS) content of around 35,000 ppm, which equates to about 1.292 kg of magnesium per m.sup.3 of seawater. In the above process any magnesium hydroxide produced may precipitate in the first chamber, and may be separated from other soluble compounds present in the first chamber. Magnesium hydroxide is extensively used in various industries, including the pharmaceutical industry and may also be used as a raw material for production of magnesium metal.
[0080] The chlorine gas 508 produced may have an initial temperature of 50-90° C., 60-86° C., 70-84° C., or about 80° C. and may also include moisture. Chlorine gas in this temperature range can over time corrode metal components within a system such as metal piping. Therefore, in a preferred embodiment, the chlorine gas produced is cooled and dried after exiting the second chamber 110. Cooling the chlorine gas may aid to remove moisture from the gas stream and may also improve the efficiency of both any downstream compression or liquefaction processes. While not a requirement, it is generally preferred that the chlorine gas have a final temperature after cooling between 18° C. and 25° C. In one embodiment, the chlorine outlet line 511 may be fluidly connected to a cooling device such as a quench tower, a heat exchanger, a cooling jacket, or an expander to cool the chlorine gas produced with the disclosed system.
[0081] In one embodiment, at least a portion of the electrical current generated with the hydromagnetic desalination system may be recovered and recycled internally to power secondary production units or can be retained to a power grid or network.
[0082] According to a fifth aspect, the present disclosure relates to a method of desalinating the first brine water with the hydromagnetic desalination system of the present disclosure, in one or more of its embodiments, the method includes flowing the first brine water through the hydromagnetic desalination cell to produce the desalinated water in the desalinated water line and collecting a portion of the desalinated water, recycling a portion of the desalinated water to the inlet tank through the desalinated water reflex line, combining the sodium cations from the first chamber and the chloride anions from the second chamber in the third chamber to produce a second brine water, and discharging the second brine wafer into the brine tank through the brine discharge line.
[0083] The heat generated in the third chamber and in fee brine tank can be used to increase the temperature of the first brine water in the inlet tank, which may aid the desalination process. Therefore, the method may also involve heating the first brine water prior to the flowing using the heat generated from recombining the sodium cations and the chloride anions to form the second brine water, the various system components being discussed heretofore. The heating may be performed by using the second brine water as a heat bath to the inlet tank holding the first brine water. The heating may also be performed by passing the first brine water in the inlet line through the brine tank conduit located in the brine tank. In this scenario, the brine tank may be in the form of a heat exchanger, such as a heating jacket that jackets the inlet line.
[0084] According to a sixth aspect, the present disclosure relates to a method of desalinating the first brine water with the hydromagnetic desalination system of the present disclosure, in one or more of its embodiments, the method includes flowing the first brine water through the hydromagnetic desalination cell to produce the desalinated water in the desalinated water line and collecting a portion of the desalinated water, recycling a portion of the desalinated water to the inlet tank through the desalinated water reflex line, connecting the positive electrode to the negative electrode through the external circuit and delivering electricity to the external circuit, and electrolyzing the first brine water to form hydrogen and sodium hydroxide in the first chamber, and chlorine in the second chamber, and collecting the hydrogen through the hydrogen outlet line, the sodium hydroxide through the sodium hydroxide outlet line, and the chlorine through the chlorine outlet line. The amounts of byproducts (hydrogen, chlorine gas, sodium hydroxide, etc.) and desalinated water can be adjusted based on market demand and market prices.
[0085] In one embodiment, the method further comprises preprocessing the first brine water by returning at least a portion of the sodium hydroxide produced from the electrolyzing back to the inlet tank through the sodium hydroxide outlet line, to precipitate at least some cations (e.g. calcium, magnesium, etc.) present in the first brine water as hydroxide compounds (e.g. calcium hydroxide, magnesium hydroxide, etc.). These hydroxide compounds may then be removed from the preprocessed first brine water to decrease the concentration of at least some cations (calcium, magnesium, etc.) in the first brine water that is to be desalinated.
[0086] In one embodiment, the method further comprises post-processing the desalinated water by mixing at least a portion of the chlorine gas produced during the electrolyzing with the desalinated water. The post-processing may be performed to reduce or remove bacteria or other organisms present in the desalinated water.
[0087] The examples below are intended to further illustrate the hydromagnetic desalination cell, the hydromagnetic desalination system, and uses thereof, and are not intended to limit the scope of the claims.
EXAMPLE 1
Magnetic Field Calculation
[0088] When a moving point charge (an ion) is subjected to a magnetic field, B, a force f, called Lorentz force, will act on the ion, which is given by the following equation
F.sub.m=q.sub.e (v×B) (1)
[0089] Where [0090] F.sub.m is the force (in Newtons), [0091] B is the magnetic field (in Teslas), [0092] q.sub.e is the electric charge of the particle (in coulombs), [0093] v is the instantaneous velocity of the particle (in meters per second), [0094] x is the vector cross product,
[0095] The magnetic force causes the positive charges and the negative charges to move on opposite sides. An electric e.m.f. is then created between the positive charge side and the negative charge side. For simplicity, it is assumed that the magnetic field is perpendicular to the charge velocity vector. The potential difference E.sub.m creates an electric field E.sub.m/L; where L is the distance between the positive and negative charge charges. The electric field produces another electric force given by q E.sub.m/L. At an equilibrium state, the force produced by the electric field balances the magnetic force acting on the point charge, i.e.
[0096] The potential difference due to the magnetic field is given by
E.sub.m=BvL (2)
EXAMPLE 2
Hydromagnetic Desalination Cell
[0097] The basic hydromagnetic desalination cell (HMC) is illustrated in
[0098] It should be clear that the set up in
EXAMPLE 3
[0099] Hydromagnetic Desalination System with Third Chamber
[0100] An illustration diagram of one embodiment is shown in
[0101] The following equations demonstrate the analysis for sodium chloride only as NaCl represents over 85% of the salt contents in the sea water. However, expanding the model to include other salt species will follow the same procedure.
[0102] The mass balance equation of the entire system is given by
q.sub.f=q.sub.b+q.sub.p (3)
[0103] Where [0104] q.sub.f is the salty water inlet volume feed rate (m.sup.3/sec), [0105] q.sub.p is the permeate (distillate) volume flow rate, [0106] q.sub.b is the brine volume flow rate.
[0107] Let RR be the water recovery ratio
[0108] Similarly, the salt mass balance equation
x.sub.fq.sub.f=x.sub.bq.sub.b+x.sub.pq.sub.p (4)
[0109] Where [0110] x.sub.f is the salty concentration in the water in kg/m.sup.3, [0111] x.sub.p is the permeate salt concentration in kg/m.sup.3, [0112] x.sub.b is the brine salt concentration in kg/m.sup.3.
[0113] Equation (4) can be written in terms of RR as
x.sub.f=x.sub.b (1−RR)+x.sub.pRR (5)
[0114] Usually x.sub.f is known from the TDS of the inlet water. It is usually between 35-42 kg/m.sup.3 in seas and oceans, and 4-5 kg/m.sup.3 in brackish water. If x.sub.p is set to a desired value, then
[0115] The mass balance equation for the inlet tank is given by
[0116] Where [0117] V.sub.in the volume of the water in the inlet tank, [0118] q.sub.R is the reflex volume flow rate.
[0119] Let α.sub.R be the reflux ratio
[0121] The salt concentration equation of the inlet tank is
[0122] If V.sub.in is regulated by a separate control loop, V.sub.in can be considered constant. Then,
[0123] At steady state
q.sub.inx.sub.in=q.sub.fx.sub.f+q.sub.Rx.sub.p (10)
[0124] Let V.sub.A be the volume of the water in the HMC conduit
[0125] Where
[0126] x.sub.A is the average concentration in the HMC conduit
[0127] Similarly, the steady state equation becomes
KI=q.sub.inx.sub.in−q.sub.ox.sub.p (12)
[0128] Where
K=M.sub.Ws/F,
[0129] and M.sub.ws is the molecular weight of salt, and F is Faraday's constant and is equal to 96,485 C/mole (Coulombs per mole).
[0130] The average concentration in the HMC conduit is given by
[0131] Finally,
[0132] The brine concentration potential is then given by the Nernst Equation
[0133] For concentration potential:
[0138] For high recovery ratio x.sub.A can be approximated by
[0139] Referring to
[0140] Let Lc, Wc, and dc be the length, width, and height of the HMC conduit, then the resistance of the current loop will be given by
[0141] Where ρ.sub.e is the resistivity of the water. The resistivity of the water depends on temperature and concentration. An approximate formula for salty water is given by
[0142] Where x.sub.A is concentration of salt in kg/m3; and α=0.02.2/C°;
[0143] The electric current can then be given by
[0144] The current is directly related to the rate of retrieval of salt and the larger the current the larger the rate of production of fresh water, and the lower its salt content. However, there are a number of conflicting factors affecting the fresh water production rate. For example q.sub.in can be increased by increasing the reflex flow rate q.sub.R, but this choice is directly related to power consumption and reduces the efficiency. A second choice intuitive solution is to use higher magnetic field. For permanent magnets, the current technology of rare earth magnets provides about 1.6-1.4 Tesla. The magnetic field at the center of the HMC conduit decreases rapidly by the increase of the separation between the two magnets. On the other hand decreasing the separation can lead to rapid increase in the electric resistance and reduction of the net current. The above set of equations are inter-coupled and highly non-linear, but can be solved iteratively.
EXAMPLE 4
Power Balance Equations
[0145]
[0146] From equations (21) and (22)
[0147] Accordingly the power to be delivered by the pump is given by
P.sub.Total=(q.sub.inΔP+0.5 q.sub.in v.sup.2+q.sub.inΔP.sub.fr)η.sub.p (24)
[0148] Where the first term is hydraulic power transferred to electrical power, the second term is the kinetic energy of the water passing through the HMC, and the third term accounts for the friction losses, finally η.sub.p is the efficiency of the pump.
[0149] The friction pressure head loss can be estimated using standard pipe friction calculations.
EXAMPLE 5
Magnetic Field Calculation for Rectangular Magnets
[0150] The magnetic field produced by a pair of rectangular permanent magnets can be estimated with the help of
[0151] Where X=d.sub.g/2; half the gap between the magnets
[0152] Example a magnet A (301)=5.1 cm, B (302)=2.54 cm; L (303)=1.0; x=0.5 cm; Br=1 Tesla
[0153] Then the magnetic field at the center of the gap Bx=0.414 Tesla
[0154] Thick magnets (L) are recommended, for example in the above example if L=5 cm, Bx=0.67 tesla;
[0155] Clearly if separation between magnets is decreased the magnetic field increases, causing a higher magnetic voltage and more current (higher salt removal rate). On the other hand if the separation decreases the electrical resistance of HMC increases and the current decreases. As such there is a desired separation between the magnets and it should be calculated to maximize the efficiency of the HMC.
EXAMPLE 6
[0156] Small Unit (Brackish water) [0157] Feed water salt concentration=5000 ppm=5 kg/m.sup.3. Temperature=300 K; [0158] Desired fresh water salinity=500 ppm=0.5 kg/m.sup.3. [0159] Desired recovery ratio=90%; [0160] Magnets: rare earth magnets, each piece is 5×2.5×2 cm; Br=1 Tesla, [0161] Gap between magnets=0.014 meters. [0162] Magnetic field at the middle of the HMC conduit=0.45 Tesla [0163] The HMO has a single conduit 150×2.5×1.0 cm
[0164] System operating parameters: [0165] Velocity of water in the HMC is set to 12 m/sec; [0166] Reflex ratio=6.47: brine salinity=45,500 ppm. [0167] Feed water flow rate 24.01 Liter/min [0168] Fresh water flow rate=21.68 Liter/min. [0169] Pump Row rate 180 Liter/min [0170] Pump power=288 watts
[0171] It should be noticed also that the recombination of ions in the chamber 209 releases the ionization energy and produce hot brine. The hot brine can be utilized to warm up the inlet water to increase the fresh water production rate. In the above example if the inlet water temperature increase from 300 K to 310 K, the fresh water production increases to 33.93 Liter/min.
[0172] Small Unit (Seawater) [0173] Feed water salt concentration=35000 ppm=35 kg/m.sup.3 . Temperature=300 K; [0174] Desired fresh water salinity=500 ppm=0.5 kg/m.sup.3. [0175] Desired recovery ratio=70%; [0176] Magnets: rare earth magnets, each piece is 5×2.5×2 cm; Br=1 Tesla. [0177] Gap between magnets=0.014 meters. [0178] Magnetic field at the middle of the HMC conduit=0.45 Tesla [0179] The HMC has a single conduit 150×2.5×1.0 cm
[0180] System operating parameters: [0181] Velocity of water in the HMC is set to 15 m/sec; [0182] Reflex ratio=49.25, brine salinity =115,000 ppm. [0183] Feed water flow rate 4.48 Liter/min [0184] Fresh water flow rate=3.13 Liter/min [0185] Pump flow rate 225 liter/min [0186] Pump power=562.5 watts
[0187] The use of a HMC with 16 channels will then produce 50.14 Liter/min using a pump of 9 kw.
EXAMPLE 7
[0188] Hydromagnetic Desalination System with Positive and Negative Electrodes
[0189] An illustration diagram of a second embodiment is shown in
[0190] A positive electrode EP (501) is inserted in zone 109, providing a positive electrical potential, and a negative electrode En (502) is inserted in zone 110, providing a negative electrical potential. The two electrodes can then be connected to external circuit through appropriate electrical cables for recovering the ionic energy in the two zones. The electrical energy can be utilized to derive a secondary smaller water desalination unit, or can be reconnected to the power network. The current flowing out of the positive electrode and returning to the negative electrode will result in the following electrolysis of the brine.
[0191] The ion concentration in chambers 109 and 110 are governed by the differential equations:
[0192] In zone 109, upon receiving two electrons the water is disassociate into hydrogen and hydroxide ions
2H.sub.2O+2e.sup.−.fwdarw.H.sub.2+2OH.sup.−
2OH.sup.−+2Na.sup.+.fwdarw.2NaOH
[0193] While in zone 110, the chloride ions lose their electrons to the negative electrode forming Chlorine gas.
2Cl.sup.−.fwdarw.Cl.sub.2+2e.sup.−
[0194] As a result, the process produces no brine. Instead it produces hydrogen gas (503) and sodium hydroxide (505) in zone 109, and chlorine gas (508) at zone 110, in addition to the fresh water (i.e. the desalinated water).
[0195] Another byproduct is magnesium. Sea water of TDS 33,000 ppm, would typically have 1.292 kg of magnesium/m.sup.3 of sea water. In the above process Mg(OH).sub.2 is precipitated in chamber 109, where it can be easily separated. Mg(OH).sub.2 is extensively used in the pharmaceutical industry. The magnesium hydroxide could be used as raw material for production of magnesium metal. A method for manufacture of magnesium hydroxide is described U.S. Pat. No. 3,170,762 A.
[0196] Furthermore, a part of the produced NaOH can be fed back to the inlet sea water in a preprocessing stage. When NaOH is added to the raw sea water in a preprocessing stage, calcium hydroxide and magnesium hydroxide will be precipitated, and filtered from the inlet water. This preprocessing step substantially improves the quality of the produced NaOH.
[0197] As of 2014, prices per ton of low grade sodium hydroxide was $450 to $550 for textile, oil, pulp and paper; for high grade the price ranges between $700 to $900 per ton for the food industry; and for soap and detergent industry the price ranges between $550 to $650;
[0198] Chloride is produced in equal molar quantities as NaOH. Part of the produced chlorine can be used to disinfect the produced fresh water. Chlorine is used in several petrochemical industry, for example to produce polyvinyl chloride (PVC) for PVC pipes; chlorine gas price range between $900-1600 depending on the purity of the final product. The price of hydrogen gas is between $5-12 per Kg. There are two primary uses for hydrogen. About half is used in the Haber process to produce ammonia (NH.sub.3), which is then used directly or indirectly as fertilizer. Because both the world population and the intensive agriculture used to support it are growing, ammonia demand is also growing. The other half of current hydrogen production is used to convert heavy petroleum sources into lighter fractions suitable for use as fuels. This latter process is known as hydrocracking. Hydrocracking represents an even larger growth area, since rising oil prices encourage oil companies to extract poorer source material, such as tar sands and oil shale.
[0199] Chlorine gas exiting the cell line must be cooled and dried since the exit gas can be over 80° C. and contains moisture that allows chlorine gas to be corrosive to iron piping. Cooling the gas allows for a large amount of moisture from the brine to condense out of the gas stream. Cooling also improves the efficiency of both the compression and the liquefaction stage that follows. The exiting chlorine is ideally between 18° C. and 25° C.
EXAMPLE 8
[0200] Commercial Scale (seawater) [0201] Feed water salt concentration=35000 ppm=35 kg/m.sup.3. Temperature=300 K; [0202] Desired fresh water salinity=500 ppm=0.5 kg/m.sup.3. [0203] Desired recovery ratio=70%; [0204] Magnets: rare earth magnets, each piece is 20×10×4 cm; Br=1 Tesla, [0205] Gap between magnets=0.03 meters. [0206] Magnetic field at the middle of the HMC conduit=0.391 Tesla [0207] The HMC has a single conduit 400×10×3.0 cm [0208] No of channels=16;
[0209] System operating parameters: [0210] Velocity of water in the HMC is set to 12 m/sec; [0211] Reflex ratio=10.89; brine salinity=115,500 ppm. [0212] Feed water flow rate=2.905 m.sup.3/min [0213] Fresh water flow rate=2.033 m.sup.3/min [0214] Pump flow rate=34.56 m.sup.3/min [0215] Pump power=829 Kw [0216] With an average water consumption of 18 litters/day, this unit can feed a city with a population of 160,000.
[0217] The rate of production of NaOH can then be calculated as follows [0218] Rate of salt removal=q.sub.p (x.sub.f−x.sub.p) [0219] NaCl represents 85% by weight of the total salt, then [0220] Rate of NaCl removed=0.85*q.sub.p(x.sub.f−x.sub.p) in kg/sec [0221] Rate of NaCl removal in moles=0.85*q.sub.p(x.sub.f−x.sub.p)*1000/58.44 in moles/sec [0222] Every mole of NaCl produces one mole of NaOH [0223] The rate of production of NaCl=40*0.85*q.sub.p(x.sub.f−x.sub.p)*1000/58.44 gams/sec [0224] This unit will produce 25,916 tons of NaOH/yr. [0225] The rate production of chloride gas, hydrogen, and other species can be calculated similarly.