Patent Application
20240166523
In the oil and gas industry, “produced water” is a term used to describe water that is produced as a byproduct during the extraction of oil or natural gas. Most produced water is brine, and most petroleum formations result in produced water having a total dissolved solids level that is too high for beneficial reuse. Other industrial processes also generate brine as a byproduct (e.g., “brine waste”), with examples including cooling tower and boiler effluent, reverse osmosis and ion exchange waste/reject streams, chlor-alkali and chemical plant waste, acid rock and mine drainage, food preservation and manufacturing waste streams, desalination waste from potable water creation, produced water from CO2 sequestration, and irrigation runoff. Brine produced from petroleum extraction and other industrial processes can frequently have salinity that exceeds that of seawater, and can also contain contaminants such as silica, heavy metals, organic compounds, sulfates, nitrates, phosphates, and suspended solids. If untreated, release of such brines to the environment can cause an assortment of problems such as harm to animal or aquatic life, contamination of ground water, and contamination of soil.
The annual quantity of produced water from petroleum extraction in North Dakota is large. North Dakota's produced water reached a peak in 2019 at 742 MMbbl/yr and has leveled at 643 and 645 MMbbl/yr in 2020 and 2021, respectively. In 2021, the statewide average water-to-oil ratio was nearly 1.6:1, meaning that for every barrel of oil produced in North Dakota, approximately 1.6 barrels of produced water were generated, with the vast majority of that water (approximately 90%) being disposed of using deep well injection. Concentrated disposal of produced water in certain areas of the Bakken has led to localized over-pressurization of the receiving formation to the point of impacting drilling through the formation to access the deeper oil and gas formations. Countering pressurization from produced water disposal has increased oil production costs by requiring the addition of an extra well casing layer, known in the industry as a Dakota string, to keep pressurized water from interfering with the oil well. Combined, NaCl and CaCl2 typically make up more than 95% of the mass of the dissolved solids in produced water from the Bakken.
Conventional treatment of brines for discharge to the environment is expensive and time consuming, and can include treatment with coagulants, polymers, additives, pH adjusters, membranes, electrochemical cells, filtration units, and ion exchange resins. Brines can cause corrosion of metal components and fouling of membranes. Conventional treatments for brine fail to extract significant value from the brine, and the treatment costs are substantially unrecoverable.
Various aspects of the present invention provide a method of treating a brine composition. The method includes hydrolyzing a metal halide salt in the brine composition to form a hydrolysis product including a hydrohalic acid. The metal includes an alkaline earth metal or an alkali metal.
Various aspects of the present invention provide a method of treating a brine composition. The method includes hydrolyzing a metal halide salt in the brine composition to form a hydrolysis product including a hydrohalic acid and a hydroxide salt of the metal in the metal halide salt. The metal includes an alkaline earth metal or an alkali metal.
Various aspects of the present invention provide a method of treating a brine composition, the method including hydrolyzing a metal halide salt in the brine composition, the hydrolyzing including adding CO2 gas to the brine composition, to form a hydrolysis product including a hydrohalic acid and a carbonate salt of the metal in the metal halide salt, a bicarbonate salt of the metal in the metal halide salt, or a combination thereof. The metal includes an alkaline earth metal or an alkali metal.
Various aspects of the present invention provide a method of recovering lithium from a brine composition. The method includes hydrolyzing a lithium halide salt and another metal halide salt in the brine composition to form a hydrolysis product including a hydrohalic acid and a salt of the lithium in the lithium halide salt. The metal includes an alkaline earth metal or an alkali metal.
Various aspects of the present invention have advantages over other methods of treating brine. For example, in various aspects of the present method, the hydrohalic acid produced by the hydrolysis, or other materials produced by the hydrolysis (e.g., metal hydroxide, metal carbonate, or metal bicarbonate), are valuable products that can be used or sold to offset or recover the costs and time expense of performing the method and/or of performing other treatments to the brine. In various aspects of the present method, the method can reduce the volume of brine that ultimately requires disposal. As compared to electrochemical brine splitting which has a primary energy input of electricity, various aspects of the present method have a primary energy input of heat which can be generated at lower cost than electricity using natural gas produced on-site or in a nearby area; as such, various aspects of the present method can be performed with lower cost and greater efficiency than electrochemical brine splitting. Various aspects of the present method can be tolerant of a wide variety of impurities found in brines that could otherwise foul or inactivate membranes or electrocatalysts used in conventional methods of brine treatment. In various aspects of the present method, the thermochemical nature of the method can leverage chemical processing economies of scale to result in a lower cost per unit volume of brine treatment as processing throughput is increased, unlike electrochemical processes which scale linearly by increasing the two-dimensional surface area for selective membranes and electrodes rather than leveraging the exponential economies of scale possible with a reactor with higher volumetric flow capacity.
In various aspects of the present method, the method can convert chloride-dominant salts found in various brines to carbonate form via the absorption of CO2 gas. This feature can allow recovery of HCl in excess of the amount that could be obtained solely via generation from salts that undergo hydrolysis (e.g., CaCl2) and/or MgCl2), by extending chloride to be provided by salts not known to readily undergo hydrolysis (e.g., NaCl). In various aspects, the resulting metal carbonates can be more valuable and/or more easily stored for disposal as compared to the starting chloride form. In various aspects, the CO2 gas used to create the metal carbonates can represent avoided or negative emissions of CO2 to the atmosphere, thereby providing beneficial greenhouse gas reduction.
In various aspects of the present method, the method can remove one or more valuable metals from the brine, such as lithium (e.g., in the form of lithium hydroxide, lithium carbonate, or lithium bicarbonate), or rare-earth elements (REEs), in addition to forming the hydrohalic acid. By generating other valuable products such as hydrohalic acid during the removal of the one or more valuable metals, in various aspects of the present invention, the cost and labor of extracting the low-concentration but potentially high value or importance metals can be at least partially offset, providing a more efficient method of extracting the one or more valuable metals from the brine than other methods.
Bringing water to the surface that is displaced during CO2 sequestration can provide CO2 plume management, increased storage potential within the boundaries of a given storage facility, or a combination thereof. In various aspects, the method of the present invention can offer additional advantages of bringing the water to the surface by providing the hydrohalic acid produced by the hydrolysis, or other materials produced by the hydrolysis (e.g., metal hydroxide, metal carbonate, or metal bicarbonate).
The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments of the present invention.
Reference will now be made in detail to certain aspects of the disclosed subject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.
Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.
In this document, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” or “at least one of A or B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.
In the methods described herein, the acts can be carried out in a specific order as recited herein. Alternatively, in any aspect(s) disclosed herein, specific acts may be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately or the plain meaning of the claims would require it. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.
The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.
The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. The term “substantially free of” as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that about 0 wt % to about 5 wt % of the composition is the material, or about 0 wt % to about 1 wt %, or about 5 wt % or less, or less than, equal to, or greater than about 4.5 wt %, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 wt % or less, or about 0 wt %.
Various aspects of the present invention provide a method of treating a brine composition. The method includes hydrolyzing a metal halide salt (e.g., one or more metal halide salts) in the brine composition to form a hydrolysis product including a hydrohalic acid. The metal includes an alkaline earth metal or an alkali metal. The brine composition can include produced water from petroleum extraction, produced water from CO2 sequestration, water produced from an industrial process, a brine formed from reaction of a hydroxide salt with an ammonium chloride salt wherein the ammonium chloride salt is formed by reaction of a starting material brine with CO2 and ammonia, a concentrate thereof, or a combination thereof. Examples of brines produced by industrial processes can include cooling tower and boiler effluent, reverse osmosis and ion exchange waste/reject streams, chlor-alkali and chemical plant waste, acid rock and mine drainage, food preservation and manufacturing waste streams, desalination waste from potable water creation, irrigation runoff, or a combination thereof. The brine composition can include produced water from oil and/or gas extraction or a concentrate thereof. The brine composition can include produced water from CO2 sequestration or a concentrate thereof. The brine composition can include water produced from an industrial process or a concentrate thereof.
In various aspects, the brine composition is the produced water from petroleum extraction, produced water from CO2 sequestration, water produced from an industrial process, or a combination thereof. In other aspects, the brine composition is a concentrate thereof. In various aspects, the preparation of the concentrate can occur prior to the onset of the method. In other aspects, the method can further include concentrating a starting material brine to form the brine composition.
In various aspects, the method is a method of converting chloride-dominant salts in various brines to alternative carbonate forms through the absorption of CO2 gas, thereby displacing the chloride component and allowing it to be converted to recoverable HCl, a useful commodity chemical. The brine composition can be a brine that has been subjected to CO2 absorption in the presence of NH; to form NH4Cl and metal carbonates including the metal from the metal halide in the brine. The method can include reacting the NH4Cl with a metal hydroxide salt such as Ca(OH)2 in the brine subjected to CO2 absorption to form a CaCl2. The CaCl2) solution can then be used as the brine composition of the present invention and subjected to hydrolysis to form HCl.
The concentrating of the starting material brine can include any suitable method of removing water therefrom, such as subjecting the starting material brine to evaporation remove at least some water therefrom. The evaporation can include thermal treatment, distillation, treatment with an evaporator, a rotary evaporator, a jacketed tank evaporator, a natural or forced recirculation evaporator, a falling film evaporator, a rising film evaporator, a climbing and falling-film plate evaporator, a vacuum evaporator, or a combination thereof.
The metal in the metal halide salt in the brine composition that is an alkaline earth metal or an alkali metal can be beryllium, magnesium, calcium, strontium, barium, radium, lithium, sodium, potassium, rubidium, cesium, francium, a rare-earth element (REE), or a combination thereof. The rare earth element can be any rare earth element found in geologic brines, such as any one or more of the periodic table series lanthanum to lutetium (i.e., La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) and the chemically similar yttrium and scandium. The metal can be calcium, sodium, magnesium, potassium, lithium, or a combination thereof. The halide in the metal halide salt in the brine composition can be any suitable halide, such as chloride, bromide, iodide, or fluoride. The halide can be chloride. The metal halide salt can be a beryllium halide salt, a magnesium halide salt, a calcium halide salt, a strontium halide salt, a barium halide salt, a radium halide salt, a lithium halide salt, a sodium halide salt, a potassium halide salt, a rubidium halide salt, a cesium halide salt, a francium halide salt, a REE halide salt, or a combination thereof. The metal halide salt can be beryllium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, radium chloride, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, francium chloride, an REE chloride, or a combination thereof. The metal halide salt can be calcium chloride, sodium chloride, magnesium chloride, lithium chloride, sodium chloride, or a combination thereof. The brine composition can include a combination of metal halide salts, such as a combination of two or more of beryllium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, radium chloride, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, an REE chloride, and francium chloride. For example, the brine composition can include calcium chloride and sodium chloride.
The hydrohalic acid produced by the hydrolysis can be any suitable hydrohalic acid, such as HCl, HBr, HI, HF, or a combination thereof. The hydrohalic acid can be HCl. The halide in the hydrohalic acid is the halide from the metal halide salt.
The hydrolysis product can include a hydroxide salt of the metal in the metal halide salt. For example, the hydroxide salt can be Be(OH)2, Mg(OH)2, Ca(OH)2, Sr(OH)2, Ba(OH)2, Ra(OH)2, LiOH, NaOH, KOH, RbOH, CsOH, FrOH, a hydroxide salt of a REE, or a combination thereof. The hydroxide salt can be Ca(OH)2, Mg(OH)2, LiOH, NaOH, KOH, or a combination thereof. Prior to the hydrolyzing of the brine composition, the brine composition can be substantially free of the hydroxide salt of the metal in the metal halide salt.
In various aspects, the hydrolyzing of the metal halide salt in the brine composition can be free of adding CO2 gas to the brine composition. In other aspects, the hydrolyzing of the metal halide salt in the brine composition can include adding CO2 gas to the brine composition, wherein the hydrolysis product includes a carbonate salt of the metal in the metal halide salt, a bicarbonate salt of the metal in the metal halide salt, or a combination thereof. The carbonate or bicarbonate salt can include a salt of Be, Mg, Ca, Sr, Ba, Ra, Li, Na, K, Rb, Cs, Fr, a REE, or a combination thereof. The carbonate or bicarbonate salt can include MgCO3, CaCO3, Li2CO3, Na2CO3, K2CO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, NaHCO3, KHCO3, a REE carbonate, a REE bicarbonate, or a combination thereof. In various aspects, the carbonate or bicarbonate salt represents a stable form of the added CO2 that can be safely disposed of; as such, the method can be a method of CO2 sequestration. Prior to the hydrolyzing of the brine composition, the brine composition can be substantially free of the carbonate salt of the metal in the metal halide salt, the bicarbonate salt of the metal in the metal halide salt, or a combination thereof.
Water can be any suitable proportion of the brine composition. For example, water can be 50 wt % to 99 wt % water, or 50 wt % to 93 wt % water, or less than or equal to 99 wt % and greater than or equal to 50 wt % and less than, equal to, or greater than 52 wt %, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, or 98 wt %. The brine composition can have a total concentration of metal halide salts therein of 1 wt % to 50 wt %, or 7 wt % to 50 wt %, or less than or equal to 50 wt % and greater than or equal to 1 wt % and less than, equal to, or greater than 2 wt %, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, or 48 wt %.
In various aspects, the brine composition includes a sodium halide salt and a calcium halide salt. The molar ratio of sodium halide salt to calcium halide salt can be 0:1 (i.e., no sodium halide salt) to 1:0 (i.e., no calcium halide salt), or 0:1 to 100:1, or 0:1 to 1:1, or less than or equal to 1:0 and greater than or equal to 0:1 and less than, equal to, or greater than 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, or 100:1.
The method can include performing the hydrolyzing the brine composition at any suitable temperature, such as at a temperature of room temperature to 1000° C., or 300° C. to 700° C., or 400° C. to 600° C., or less than or equal to 1000° C. and greater than or equal to 0° C. and less than, equal to, or greater than 5° C., 10, 15, 20, 25, 30, 35, 40, 50, 60, 80, 100, 150, 200, 250, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, 500, 520, 540, 560, 580, 600, 620, 640, 660, 680, 700, 750, 800, 850, or 950° C. The method can include performing the hydrolyzing of the brine composition at any suitable pressure, such as ambient pressure, or such as in a pressurized environment, or such as at a pressure of 0.1 MPa to 100 MPa, 0.1 MPa to 10 MPa, 0.1 MPa to 1 MPa, or less than or equal to 100 MPa and greater than or equal to 0.1 MPa and less than, equal to, or greater than 0.2 MPa, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.5, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, or 90 MPa. The method can include performing the hydrolyzing of the brine composition for any suitable duration, such as for a duration of 0.1 second to 5 h, 1 second to 1 h, or less than or equal to 5 h and greater than or equal to 0.1 second and less than, equal to, or greater than 1 second, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 seconds, 1 min, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 minutes, 1 h, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 h. During the hydrolyzing of the brine composition, water in the brine composition and in the hydrolysis product can be in a liquid state, a gaseous state, or a combination thereof. The hydrolyzing of the brine composition can be performed as a batch process or as a continuous process. The hydrolyzing of the brine composition can be performed in a heated and pressurized reactor. The hydrolyzing of the metal halide salt can be performed in an unpressurized heated reactor at ambient pressure. The hydrolyzing of the metal halide salt can produce a vapor stream including water and the hydrohalic acid.
The hydrolyzing of the metal halide salt can also produce a non-vapor (i.e., liquid and/or solid) stream including the hydroxide salt of the metal in the metal halide salt, the carbonate salt of the metal in the metal halide salt, the bicarbonate salt of the metal in the metal halide salt, or a combination thereof. The brine composition can be substantially free of the hydrohalic acid prior to the hydrolyzing of the brine composition. The hydrohalic acid can form any suitable proportion of condensed vapors of the hydrolysis product, such as 1 wt % to 35 wt % of condensed vapors of the hydrolysis product, 10 wt % to 20 wt %, or less than or equal to 35 wt % and greater than or equal to 1 wt % and less than, equal to, or greater than 2 wt %, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, or 34 wt % of the hydrolysis product. Any suitable proportion of the hydrolysis product can be the hydroxide salt of the metal in the metal halide salt, the carbonate salt of the metal in the metal halide salt, or the bicarbonate salt of the metal in the metal halide salt, such as 1 wt % to 100 wt % of a non-vaporous (e.g., liquid or solid) portion of the hydrolysis product, or 10 wt % to 40 wt %, or less than or equal to 100 wt % and greater than or equal to 1 wt % and less than, equal to, or greater than 2 wt %, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, .
Water can form any suitable proportion of condensed vapors of the hydrolysis product. For example, water can be 65 wt % to 99 wt % of condensed vapors of the hydrolysis product, 80 wt % to 90 wt %, or less than or equal to 99 wt % and greater than or equal to 15 wt % and less than, equal to, or greater than 65 wt %, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, or 98 wt % of the hydrolysis product.
In various aspects, the hydrolyzing can include removing one or more products of the hydrolysis from the brine composition to drive the hydrolysis reaction forward. For example, the hydrolyzing can include removing at least part of the hydrohalic acid produced during the hydrolyzing to increase a weight percentage of the hydrohalic acid in the hydrolysis product. The hydrolyzing can include removing at least part of a hydroxide salt of the metal in the metal halide salt, a carbonate salt of the metal in the metal halide salt, or a bicarbonate salt of the metal in the metal halide salt produced during the hydrolyzing to increase a weight percentage of the hydrohalic acid in the hydrolysis product.
The method can include separating at least part of the hydrohalic acid in the hydrolysis product from the hydrolysis product. The separation can include forming a composition from the hydrolysis product that has a higher concentration of the hydrohalic acid than the remaining hydrolysis product. The method can include separating at least part of a hydroxide salt of the metal in the metal halide salt, a carbonate salt of the metal in the metal halide salt, or a bicarbonate salt of the metal in the metal halide salt, in the hydrolysis product from the hydrolysis product. The method can include forming a composition from the hydrolysis product that has a higher concentration of the hydroxide salt of the metal in the metal halide salt, a carbonate salt of the metal in the metal halide salt, or a bicarbonate salt of the metal in the metal halide salt than the remaining hydrolysis product. The method can include separating at least part of the hydrohalic acid in the hydrolysis product from a hydroxide salt of the metal in the metal halide salt, a carbonate salt of the metal in the metal halide salt, or a bicarbonate salt of the metal in the metal halide salt, in the hydrolysis product.
In various aspects, the metal is lithium or includes lithium, and the hydrolysis product includes lithium hydroxide, lithium carbonate, lithium bicarbonate, or a combination thereof. The method can be a method of recovering lithium from the brine composition.
In various aspects, the brine composition includes NaCl and CaCl2. Thermal energy is added to the hydrolysis process and CO2 gas is optionally added. The hydrolysis process can produce Ca(OH)2, and can produce CaCO3 (e.g., if the CO2 is added), which can be precipitated and or flocculated from the hydrolysis product, and which can be used as scrubber reagent, can be sold, or can be sequestered in a landfill. The hydrolysis process can produce a softened brine, which can include soluble carbonates (e.g., if the CO2 is added) such as NaHCO3, HCl, and residuals (e.g., such as potential high value minerals). The HCl can be used for scale control, well rework, or can be sold. The soluble carbonates can be used as softening reagents, for CO2 sequestration, or can be sold.
The method can include disposing of the hydrolysis product. The disposing can occur after removal of at least some of the hydrohalic acid produced by the hydrolysis, or other materials produced by the hydrolysis (e.g., metal hydroxide, metal carbonate, or metal bicarbonate), from the hydrolysis product. The disposing can include placing the remainder of the hydrolysis product downhole (i.e., disposing of the hydrolysis product subterraneously), disposing of the hydrolysis product into natural fresh or salt water, or disposing of the hydrolysis product into the soil.
Various aspects of the present invention can be better understood by reference to the following Examples which are offered by way of illustration. The present invention is not limited to the Examples given herein.
In the Examples herein, each hydrolyzed sample is characterized via online measurement of HCl release using a Fourier transform infrared (FTIR) gas analyzer and posttest analysis of recovered samples including the condensed HCl, hydrolyzed liquid, and precipitated solids. Titration analysis and thermogravimetric analysis (TGA) can be used to characterize the hydrolysis product as well.
Simulated mixtures of NaCl and CaCl2 are hydrolyzed to parametrically study the hydrolysis of mixed salts. Although using only these two salts is a simplification of the composition of produced water, NaCl and CaCl2 represent the bulk constituents of Bakken produced water and will drive the overall economics of the process. The mixtures of salts tested include idealized simulated mixtures of NaCl and CaCl2 over the range spanning 100% NaCl to 100% CaCl2. The mixture of NaCl and CaCl2 is added to a high purity alumina liquid phase reactor with a heater, and steam is added to the reactor as the reactor is heated. The resulting hydrolyzed product is removed and analyzed. Key testing objectives are to identify blended salt mixtures that are beneficial for hydrolysis in terms of increasing the rate of reaction or reducing the operating temperature. The results will provide a simplified, but continuous, set of hydrolysis conversion data to identify preferred operating conditions and provide context for interpreting results with produced water.
Preliminary results identified a preferable range of Na:Ca chloride salt composition for liquid phase hydrolysis to occur: between a Na:Ca molar ratio of 0:1 (i.e., CaCl2 only) up to an equimolar ratio of the salts having a Na:Ca molar ratio of 1:1. At molar ratios of Na:Ca greater than 1, melting of the reactants was impeded at 550° C. which prevented the use of the reactor. Based on qualitative observations during the testing, the addition of NaCl to the salt mixture appeared to speed melting and reduce the viscosity of the liquid reactants. Hypothetically, the use of the preferable range of Na:Ca chloride salt ratios, and the addition of NaCl to the salt mixture, or a combination thereof, may facilitate reactor mixture and overall mass transfer to improve the hydrolysis reaction rate, which will be revealed by further studies. Even if the presence of NaCl does not enhance the hydrolysis rate of CaCl2, Na addition to improve liquid phase behavior is a significant result in itself as it may lead to more efficient reactor design and operation. For example, it appears that a NaCl—CaCl2 eutectic that is formed within the preferable Na:Ca molar range may present a lower risk of solidification resulting from slight reductions in temperature; as such the hydrolysis reactor could hypothetically be operated at a lower temperature to maximize thermal efficiency.
Testing with more complicated salt mixtures taken from real produced water is conducted with a focus on determining the fate of a wider suite of relevant elements. The resulting products from brine hydrolysis are characterized to determine potential uses for them and their value. The tested samples begins with the as-sampled brine composition and proceed to increasing Ca:Na levels by partially evaporating the produced water, which results in a preferential precipitation of NaCl over CaCl2 to increase the Ca:Na salt ratio. Sampling and analysis are identical to Example 1 except that the posttest samples are analyzed for an expanded suite of elements beyond Cl, Ca, and Na to include key additional elements found in produced water such as Br, Li, K, Mg, Sr, and Ba.
The findings are used to develop a preliminary process flow diagram showing the fractionation of produced water into potentially salable products and any remaining disposal streams. This diagram can provide a basic of a techno-economic analysis to evaluate profitability and scalability of the concept relative to the typical production rates and gathering capacities found in the Bakken.
The reactor includes three mass exchange ports: 1) feed port for reactants (e.g., a brine composed of H2O and one or more chloride salts): 2) vapor exhaust port for unreacted gases and vaporized HCl product; and 3) liquid exhaust port for hydrolyzed salt mixture that contains some fraction of recoverable hydroxide compounds, including Ca(OH)2.
Given the phase change behavior of the reactants, it can be desirable to provide two feed ports for the reactants as shown in
The reaction zone within the hydrolysis reactor of
As shown in
The scheme of
The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the aspects of the present invention. Thus, it should be understood that although the present invention has been specifically disclosed by specific aspects and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of aspects of the present invention.
The following exemplary aspects are provided, the numbering of which is not to be construed as designating levels of importance:
This application is a continuation-in-part of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. Utility application Ser. No. 18/515,726 filed Nov. 21, 2023, which is a continuation of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. Utility application Ser. No. 18/170,392 filed Feb. 16, 2023, which is a continuation-in-part of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. Utility application Ser. No. 17/651,520 filed Feb. 17, 2022, which claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 63/200,390 filed Mar. 4, 2021, the disclosures of which are incorporated herein in their entirety by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63200390 | Mar 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18170392 | Feb 2023 | US |
| Child | 18515726 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18515726 | Nov 2023 | US |
| Child | 18522842 | US | |
| Parent | 17651520 | Feb 2022 | US |
| Child | 18170392 | US |
