Plant-based polyelectrolyte, method for producing a polyelectrolyte, and use of a plant-based polyelectrolyte

Abstract

The present invention relates to a plant-based and renewable polyelectrolyte comprising the extract of one or more chemically modified eucalyptus species. The method for producing said polyelectrolyte through chemical modification is also disclosed, as well as the use of the plant-based polyelectrolyte for the treatment of effluents, including those related to the oil and gas industry.

Description

PLANT-BASED POLYELECTROLYTE, METHOD FOR PRODUCING A POLYELECTROLYTE, AND USE OF A PLANT-BASED POLYELECTROLYTE FIELD OF APPLICATION

[0001] The present invention falls within the field of oil extraction and relates to a polyelectrolyte of plant origin, the method for obtaining the same and its use for the treatment of effluents from processes linked to the oil and gas industry. BACKGROUND OF THE INVENTION

[0002] The oil extraction process is a complex operation that generally involves the use of water to facilitate the movement of crude oil from the extraction point. This process results in a mixture of water, oil, and gas, which then undergoes a separation process to isolate the oil and water.

[0003] The water separated from the aforementioned process, called “produced water” contains residual oil that needs to be removed before the water can be reused or properly disposed of at sea.

[0004] Traditionally, a cationic polyacrylamide is used to remove oil from produced water. However, this method has been found to be inefficient due to the oil's nonpolar nature and the reduced presence of negative charge. This inefficiency in oil removal not only impacts the productivity of the oil extraction process but also contributes to environmental pollution when the water is discharged into the sea without proper treatment.

[0005] Furthermore, the presence of residual oil in the produced water can lead to clogging of the filters in the reinjection wells, which in turn requires frequent filter backwashing. This not only negatively impacts the oil extraction process but also reduces the lifespan of the oil well.

[0006] Therefore, there is a need for a more efficient and sustainable method of treating produced water to remove residual oil, where this method should not only improve the oil removal process but also reduce the environmental impact of the oil extraction process.

[0007] Polyelectrolytes are polymers, which can be synthetic or natural, that carry charges throughout their structure and can be cationic, anionic, or amphoteric. These polyelectrolytes can be used in paper production and in a wide range of industries, including food, petroleum, and textiles. Chitosan and cellulose are examples of naturally occurring polyelectrolytes.

[0008] In this scenario, the use of renewable sources to obtain a polyelectrolyte appears to be an ally to more efficient methods of treating produced water, aiming at its appropriate disposal, also taking into account the environmental impact.

[0009] Tannins are water-soluble phenolic compounds with molecular weights between 500 and 3000 Daltons. They are highly reactive and form hydrogen bonds. Tannins are widely found in the plant kingdom and emerge as a potential treatment for water produced in oil extraction processes. However, their source is critical to their effectiveness.

[0010] The scientific article “Production of cationic vegetable coagulant from eucalyptus bark (Eucalyptus tereticornis)'', by Alberto Kuhn Klumb and Osvaldo Luís Vieira Faria, describes the use of tannins extracted from Eucalyptus tereticornis bark as vegetable coagulants, with cationic character, in water treatment systems.

[0011] The master's dissertation entitled "Evaluation of combined methodology with the use of surfactants and polyelectrolytes for the treatment of produced water", by Breno da Silva Rocha, reveals a study to evaluate the effect of the simultaneous use of surfactants and polyelectrolytes for the treatment of water produced by dissolved air flotation, in which the surfactant used was an anionic surfactant, a soap formulated with 5% coconut oil and 95% beef tallow, and the polyelectrolyte used was a commercial product called TANFLOC SS, which contains tannins as its active ingredient. However, in the aforementioned document, the tannin source must act in conjunction with surfactants.

[0012] The scientific article “Evaluation of Anionic Eco-Friendly Flocculants Prepared from Eucalyptus Pulps with Diverse Lignin Contents for Application in Effluent Treatment”, by Kinga Grenda, José AF Gamelas, Julien Arnold, Lorenzo Pellizzer, Olivier J. Cayre and Maria G. Rasteiro, demonstrates a study on the use of eucalyptus pulp as polyelectrolytes in the treatment of effluents from textile industries, however the polyelectrolyte is based on ligninocellulose, and not on tannins.

[0013] However, the master's dissertation, "Study of physical-chemical treatability using plant tannins in water supply and sewage," by Telma Salesa Santana da Silva, describes a study on the treatment of wastewater and sewage using tannins as a coagulant or polyelectrolyte, in which the tannins come from "Mimosa," another name for Black Acacia. The study described, in its methodology, the use of tannin for coagulation / flocculation tests of water and sewage, which were compared to tests using the chemical aluminum sulfate.

[0014] As can be seen, the state of the art foresees a gap regarding polyelectrolytes of plant origin with high tannin contents for efficient use and with low environmental impact in the treatment of water produced in oil extraction processes. BRIEF DESCRIPTION OF THE FIGURES

[0015] Figure 1 represents the results obtained for testing the effect of tannin concentration.

[0016] Figure 2 represents the results obtained for the pH effect test.

[0017] Figure 3 represents the results obtained for the salinity effect test.

[0018] Figure 4 represents the results obtained for the hardness effect test.

[0019] Figure 5 represents the results obtained for the temperature effect test.

[0020] Figure 6 represents the results obtained for the pilot plant test. SUMMARY OF THE INVENTION

[0021] According to one embodiment of the invention, a renewable plant-derived polyelectrolyte comprising the extract of one or more chemically modified eucalyptus species is provided. The method for producing said polyelectrolyte through chemical modification is also disclosed.

[0022] In another embodiment of the invention, the use of polyelectrolyte of plant origin for the treatment of effluents is described. DETAILED DESCRIPTION OF THE INVENTION

[0023] In one embodiment, a plant-derived polyelectrolyte comprising a chemically modified extract of one or more parts of at least one eucalyptus species(s), including Eucalyptus cloeziana, is disclosed, with the bark preferably employed.

[0024] The aforementioned extract may be presented in various forms, with the powder form being most commonly used, and has high amounts of tannins, greater than approximately 65%, preferably between approximately 65 and 85% tannins, more preferably from approximately 70% to approximately 85%, determined using the ISO 14088:2012 / EN ISO 14088 method, with approximately 4.0% to 8.0% moisture, preferably approximately 6% humidity.

[0025] At least one eucalyptus species may additionally comprise Eucalyptus camalduensis, Eucalyptus citriodora, Eucalyptus cloeziana, Eucalyptus CMPC, Eucalyptus grandis, Eucalyptus pellita, Eucalyptus robusta, Eucalyptus saligna, Eucalyptus urophylla, Eucalyptus dunnii, Eucalyptus Cloeziana F.Muell. 4 years, Eucalyptus Cloeziana F.Muell. 5 years, or mixtures thereof.

[0026] The obtained polyelectrolyte has a density in a range between approximately 1.15 and approximately 1.25 kg / m 3 , preferably about 1.20 kg / m 3 , pH in a range between about 3.4 and about 5.0, preferably about 4.0, total solids concentration in a range between about 30.0 and about 50.0 wt%, preferably about 40 wt%, a tanning agent content of about 23 wt% to about 38 wt%, preferably about 30 wt%.

[0027] The bark and other parts of various eucalyptus species are generally discarded after their useful portions are destined for the pulp and paper, furniture, coal, construction, and electrification industries, among others. Thus, this embodiment of the present invention encompasses the reuse of said discarded material, which may include mixtures from different sources, obtaining new products with innovative functionality and helping to reduce the environmental impact related to such waste.

[0028] In another embodiment, the method for producing a polyelectrolyte of plant origin is disclosed, in which the extract is chemically modified.

[0029] When employed, this chemical modification is performed through the sulfonation of the plant extract, in which the sulfonation reaction occurs in an acidic medium. The sulfonation reaction affects both the physical and chemical properties of tannins, making them soluble or more soluble, reducing the viscosity of tannin extracts drastically, as well as increasing their hydrophilicity potential.

[0030] The sulfonation reaction results in the insertion of sulfonic groups. It occurs via the SN2 reaction mechanism, with the opening of the heterocyclic ring. It is an equilibrium reaction, meaning the sulfonic group can be replaced in the presence of strong bases. An acidic medium is necessary to shift this equilibrium toward the product, preventing the replacement of the sulfonic group. Furthermore, the acidic medium catalyzes the reaction via protonation of the heterocycle's oxygen, making the 2-position more electrophilic. Thus, the energy required for the reaction to occur is lower, meaning the reaction occurs in less time and with greater efficiency.

[0031] As sulfonic groups are added to the molecule throughout the reaction, the pH of the medium increases, which should be avoided for the reasons previously described. Therefore, the reaction must be stoichiometrically proportional with excess acid, to prioritize shifting the chemical equilibrium toward the sulfonated product, to prevent the pH from rising too much.

[0032] In light of the above, the method for producing a polyelectrolyte of plant origin initially comprises the step of dissolving the extract, optionally in powder form, from one or more parts of at least one species of eucalyptus, which includes, but is not limited to, the species Eucalyptus cloeziana, in an amount of approximately 380 kilograms to approximately 420 kilograms in the presence of a solvent in an amount of approximately 580 kilograms to approximately 620 kilograms. Said dissolution occurs in a reactor under constant agitation and controlled temperature in the range of approximately 20°C to approximately 80°C, preferably in the range of approximately 50°C to approximately 55°C, until the extract is completely dissolved. The solvent employed may be selected from a group consisting of deionized water, potable water, clarified water, or mixtures thereof, and / or polar solvents such as methanol, ethanol, acetonitrile, dimethylformamide, dimethylsulfoxide, or mixtures thereof, with deionized water being preferred.

[0033] Subsequently, one or more sources of sulfur dioxide selected from the group consisting of sulfur dioxide, sodium sulfite, potassium sulfite, ammonium sulfite, sodium metabisulfite, sodium bisulfite, potassium metabisulfite and ammonium bisulfite or mixtures thereof, preferably sodium metabisulfite in a concentration between about 62.0% SO2 and 67.4% SO2, preferably in a concentration of about 65% SO2, are added to the reactor also until their complete dissolution.

[0034] After the addition of one or more sources of sulfur dioxide, one or more sources of acid selected from the group consisting of formic acid, acetic acid, citric acid, lactic acid, sulfuric acid, hydrochloric acid or a mixture thereof, preferably formic acid (85%) are also added to the reactor under stirring, wherein the pH of the reaction medium is acidic, preferably in a range of about 2.5 to about 5.5, preferably in a range of about 3.7 to about 4.3.

[0035] The reaction mixture is then heated to a constant temperature in the range of about 72°C to about 95°C, preferably from about 80°C to about 85°C for a certain period of time, in a range of about 1.5 hours to about 4 hours, preferably about 2 hours at a pressure of about 10 5 Pa in 5 x 10 5 Pa (from about 1 bar to about 5 bar).

[0036] The system is subsequently cooled through heat exchange using cooling jackets present in the reactor, heat exchanger or cooling to room temperature.

[0037] After the system has cooled, the water content is adjusted. total solids through the use of a solvent, in which water is added to adjust the solids concentration to a range between approximately 30.0% and approximately 50.0% by weight. This parameter is important for the rapid dissolution of the plant-based polyelectrolyte product obtained during its application. At the end of the aforementioned cooling stage, the polyelectrolyte is obtained in liquid form.

[0038] However, in an optional embodiment of the present invention, the method for producing a polyelectrolyte of plant origin further comprises a drying step, aiming to obtain the polyelectrolyte in its powder form.

[0039] In the aforementioned drying step, the solvent contained in the polyelectrolyte in its liquid form is removed using drying equipment, such as a spray dryer, in which the polyelectrolyte in its liquid form is sprayed in an environment with heated air in a temperature range of approximately 160°C to approximately 230°C, preferably in the range of approximately 200°C to approximately 210°C.

[0040] At the end of the drying stage, the polyelectrolyte is obtained in powder form, containing a moisture content of approximately 2% to approximately 12%, preferably approximately 4.5% to approximately 6.5%.

[0041] Thus, the polyelectrolyte obtained at the end of the method described may be in liquid or powder form, in which case for production in powder form an optional drying step is incorporated into the method.

[0042] The stoichiometric proportions of the extract of one or more parts of at least one species(s) of eucalyptus, including Eucalyptus cloeziana, preferably being Eucalyptus cloeziana, of sulfur dioxide and of acid, following molar amounts, are in the range of about 0.75:0.05:0.07 to about 1.50:0.10:0.15, preferably about 1:0.07:0.1.

[0043] The liquid polyelectrolyte product obtained by the method described presents specific physical-chemical characteristics, as revealed in Table 1.

[0044] To illustrate the superior effectiveness of Eucalyptus cloeziana over other species, several eucalyptus sources were evaluated as new renewable raw materials. The premises were technical feasibility, manufacturing viability, and supply availability to enable large-scale processing. Table 2 presents the different eucalyptus species evaluated. Table 2 - Examples of different eucalyptus species evaluated

[0045] The same tests were performed on the bark of the Black Acacia, scientific name Acacia mearnsii De Wildemann, which is produced in the state of Rio Grande do Sul. These parameters were used as reference, in order to better assess the technical and manufacturing viability of other eucalyptus species. The results obtained for this species are described in Table 3. Table 3 - Parameters of the species Acacia mearnsii De Wildeman

[0046] The percentage of tanning agents present in Tables 2 and 3 refers to the percentage amount of tannins present in the powder extract containing 6% moisture.

[0047] In analyzing the data obtained, the inventors surprisingly found that the eucalyptus bark of the Eucalyptus cloeziana species presented good technical and manufacturing viability properties, as well as high availability of raw material supply for processing on an industrial scale in the Minas Gerais region.

[0048] The tannin content was determined using the ISO 14088:2012 / EN ISO 14088 method (“Quantitative analysis of tanning agents by filter method”). This methodology is used worldwide to evaluate the tannin content in leather products and is the only methodology for evaluating Eucalyptus cloeziana extract. The results of determining the tannin content of Eucalyptus cloeziana extract are described in Table 4. Table 4 - Tannin analysis of Eucalyptus cloeziana extract

[0049] In addition to determining the tannin content, it was also The gravimetric yield was assessed, which consists of a solid-liquid extraction of Eucalyptus cloeziana bark in an aqueous medium, in which the amount of extractable matter is determined and the tannin content in the extract obtained is subsequently determined. Table 5 presents the profile evaluated for Eucalyptus cloeziana bark. Table 5 - Filter analysis and gravimetric yield

[0050] Thus, the extract obtained from the bark of Eucalyptus cloeziana demonstrated good viability parameters, in addition to a tannin content relevant for application as a polyelectrolyte, reflected by the percentage of tanning agents of at least 65%.

[0051] In another embodiment, the present invention provides the use of a plant-based polyelectrolyte for treating produced water from petroleum extraction, enhancing the removal of oils and greases. Furthermore, the present invention can be used to treat industrial effluents containing oils, greases, such as onshore produced water, blood, metals, and other difficult-to-remove compounds.

[0052] Offshore oil production accounted for approximately 30% of global production in 2019. Produced water (PW), the largest byproduct of oil and gas production operations on most offshore platforms, is the effluent generated when groundwater is brought to the surface during extraction. Produced water has a complex composition, containing various organic compounds and soluble and insoluble inorganics.

[0053] In oil extraction processes, water is injected into the well through point A to displace the crude oil to the extraction point, called point B. At point B, a mixture of water, oil, and gas is obtained, which passes through a degasser and then a hydrocyclone to separate the oil and water. The water thus separated is called "produced water," containing residual oil, which must be removed in the treatment stage for reuse in the process or for proper disposal at sea.

[0054] Compact physical and chemical methods are used to treat produced water (PW) according to treatment standards, taking into account space and weight constraints. The conventional produced water treatment process involves the use of physical equipment aided by chemical agents, primarily to remove oil and suspended solids (SS), in compliance with regulations and standards. The main conventional processes include primary treatment, secondary treatment, and tertiary treatment, based on the characteristics of the produced water. These three processes are generally used together, taking into account the effluent volume in offshore oil fields.

[0055] Primary treatment refers to the separation of oil, water, and gas into three phases. This is achieved using enhanced gravity sedimentation technology, which utilizes inclined corrugated plates and other internal components to facilitate coalescence.

[0056] Secondary treatment refers to the stage in which produced water, after primary treatment, undergoes a second stage of treatment to meet standards, particularly regarding oil concentration. Two-stage technologies, such as hydrocyclones and flotation equipment, are commonly employed to achieve this goal.

[0057] The so-called hydrocyclone is a static device that uses force Centrifuge for separating and classifying substances. In the treatment of produced water on offshore platforms, the hydrocyclone is used to inject oil-containing wastewater at high velocity along the tangential inlet. Due to the significantly stronger centrifugal force than gravity and the density difference between the phases (oil and water), the oil is directed to the overflow outlets, while the water flows to the underflow, resulting in rapid oil-water separation.

[0058] For the dissolved air flotation system, three processes are required to achieve different types of flotation. These three processes are: i) bubble generation, ii) agglomeration by contact and attachment between bubbles, oil droplets, and suspended solids, and iii) floc flotation due to density differences. Separation efficiency is primarily determined by the collision and adhesion of bubbles to the substances to be separated, resulting in floc formation. These processes occur due to the interaction between solids, liquids, and gases. With the help of the flotation agent, the bubbles attach to the pollutants, separating them from the initial flocs. These flocs continually grow, capturing and enveloping particles, until they can no longer resist the shear force of the fluid or reach the separation area.

[0059] Tertiary treatment is performed at the end of produced water treatment, where oil and suspended solids must be significantly removed for some platforms with stringent standards. Medium filtration is used to remove pollutants using filter media. Filtration technology is primarily used in offshore oil and gas produced water treatment to remove oil and suspended solids. Some soluble organic compounds, such as aromatic hydrocarbons, can also be separated.

[0060] The addition of the modified plant-based polyelectrolyte of the present invention is carried out in the inlet stream of the hydrocyclone (1) to that the hydrodynamics of the system promotes rapid mixing and, consequently, the conditioning of the oil droplets. Subsequently, at the outlet of the hydrocyclone (2), the flocculant is added to promote the formation of flocs, which will be removed by flotation in the next stage.

[0061] The proposed invention describes that, advantageously, said plant-based polyelectrolyte binds more effectively to the oil fraction and adds an anionic characteristic to molecules with a strong apolar character, favoring their removal when a cationic flocculate is added. Particularly, when the plant-based polyelectrolyte from at least one eucalyptus species is added in a step prior to the addition of polyacrylamide, it binds to the oil molecules, increasing the presence of anionic charges adhered to the oil, optimizing the efficiency of the cationic polymer interaction, and increasing its efficiency in separating and removing oil from water.

[0062] It is important to mention that the use of plant extracts, of renewable origin, to increase the efficiency in the removal of oils and greases in the produced water, additionally reduces the environmental impact caused by water discharged into the sea and improves the process in order to reduce the clogging or clogging of water reinjection well filters, reducing the need for filter backwashing, optimizing productivity and increasing the useful life of the oil well.

[0063] After treatment of water produced on offshore platforms, it can be reused as injection water or discharged into the marine environment after complying with current environmental regulations. Produced water must be discharged in accordance with legislation. Platforms located in Brazil, for example, must comply with CONAMA Resolution No. 393 / 2007, with the main monitored parameter being Oil and Grease Content (OG), whose permitted value must be 29 mg / L for a simple monthly arithmetic average and 42 mg / L for a daily maximum. In international waters, the TOG parameters established for the discharge of PW are between 15 mg / L (Venezuela and Argentina) and 50 mg / L (Nigeria, Angola, Cameroon, and Ivory Coast). Other countries stand out, including Malaysia, Middle Eastern countries, Australia, and North Sea countries, all with a limit of 30 mg / L, and the United States, with 29 mg / L. EXAMPLES Tests

[0064] Oil emulsion generation (simulated produced water - SPG) on the bench - The saline solution (in deionized water) used to prepare the SPG has an ionic composition similar to that of offshore platform produced waters, with the following ionic values ​​(mg / L): Cl- = 19,500; K+ = 235 mg / L; Na+ = 11,800; Ca+2 = 200 mg / L; and Mg+2 = 316 mg / L. The oil emulsion was prepared in the experimental apparatus using a 3-L glass beaker and a benchtop emulsifier. Crude oil (30 drops) was slowly added over 5 minutes to 2.5 liters of the saline solution under stirring at 24,000 RPM, and maintained in emulsification for 10 minutes. The free phase was separated in a glass column for 10 min.

[0065] Flocculation-dissolved air flotation (DAF) studies - Flocculation of simulated produced water (SPP) (1 L) was performed in a glass column with a diameter of 90 mm and a height of 30 cm, equipped with a benchtop mechanical stirrer. For bubble generation, a stainless steel saturation vessel with a volume of 2.5 L, a height of 400 mm and a diameter of 110 mm, equipped with a pressure gauge and a relief valve, with adjustable saturation pressure, was used. Bubbles were generated by depressurization and hydrodynamic cavitation after the passage of the air-presaturated aqueous stream through a needle valve positioned at the base of the glass column. DPP was conducted at a saturation pressure (Psat) of 4 x 10 5 Pa (4 bar), with a recycling rate of 20% (volume of injected water / total volume of water to treat) and a separation time of 3 minutes. The treated water samples were taken from the column at a height of 5 cm from the base, for analysis of Oil and Grease Content (TOG) and turbidity. A correction factor of 1.2 was used in the TOG results of the treated water, considering the 20% dilution related to the recycling rate.

[0066] Effect of tannin concentration - The procedures described in the oily emulsion generation and dissolved air flocculation-flotation tests were performed, initially conditioning the simulated produced water with the tannin-based product (at a concentration of 0 to 20 mg / L) for 2 minutes at a rotation of 525 RPM. Subsequently, polyacrylamide PAA-C was added at a concentration of 20 mg / L, followed by 1 minute of slow stirring (120 RPM). After removing the mechanical stirrer, the bubbles were added to the column, with a recycling rate of 20%, with a separation time of 3 minutes and, finally, the treated water was removed (700 ml aliquot) for Oil and Grease Content (OG) analysis.

[0067] Effect of pH - The procedures described in the oily emulsion generation and dissolved air flocculation-flotation tests were performed, initially adjusting the pH with NaOH at a concentration of 1 M or H2SO4 at a concentration of 1 M, followed by conditioning the simulated produced water (APS) with the tannin-based product (at a concentration of 10 mg / L) for 2 minutes at a stirring speed of 525 RPM. Subsequently, polyacrylamide PAA-C (at a concentration of 20 mg / L) was added, followed by 1 minute of slow stirring (120 RPM). After removing the mechanical stirrer, the bubbles were added to the column with a recycle rate of 20%, with a separation time of 3 minutes and, finally, the treated water (700 mL aliquot) was removed for Oil and Grease Content (OG) analysis.

[0068] Effect of salinity - The following procedures were carried out described in the oily emulsion generation and dissolved air flocculation-flotation tests, initially adjusting the salinity with the addition of NaCl at a concentration of 30 to 120 g / L, followed by conditioning the simulated produced water (APS) with the tannin-based product (at a concentration of 20 mg / L) for 2 minutes, under stirring at 525 RPM. Subsequently, polyacrylamide PAA-C (at a concentration of 20 mg / L) was added, followed by 1 minute of slow stirring (120 RPM). After removing the mechanical stirrer, the bubbles were added to the column with a recycle rate equal to 20%, with a separation time of 3 minutes and, finally, the treated water was removed (700 mL aliquot) for Oil and Grease Content (OG) analysis.

[0069] Hardness effect - The procedures described in the oily emulsion generation and dissolved air flocculation-flotation tests were performed, initially adjusting the hardness with a range of 1600 to 7200 mg / L of CaCOs, followed by conditioning the simulated produced water (APS) with the tannin-based product at a concentration of 20 mg / L for 2 minutes under stirring (525 RPM). Subsequently, polyacrylamide PAA-C (20 mg / L) was added, followed by 1 minute of slow stirring (120 RPM). After removing the mechanical stirrer, the bubbles were added to the column with a recycle rate equal to 20%, with a separation time of 3 minutes and, finally, the treated water was removed (700 mL aliquot) for Oil and Grease Content (OG) analysis.

[0070] Temperature effect - The procedures described in the oil emulsion generation and dissolved air flocculation-flotation tests were performed, initially adjusting the temperature of the simulated produced water (SPP) in a thermostatic bath to a temperature between 20°C and 70°C, followed by conditioning the SPP with the tannin-based product at a concentration of 10 mg / L for 2 minutes under agitation (525 RPM). Subsequently, the polyacrylamide PAA-C (at a concentration of 20 mg / L), followed by 1 minute of slow stirring (120 RPM). After removing the mechanical stirrer, the bubbles were added to the column with a recycling rate of 20%, with a separation time of 3 minutes and, finally, the treated water was removed (700 mL aliquot) for analysis of Oil and Grease Content (TOG).

[0071] Continuous studies on the generation and treatment of APS in a pilot plant - The semi-continuous oily water treatment system, equipped with oil emulsion generation units, a Flocculent Generator Reactor (RGF®), a bubble generation system (saturator vessel and needle valve) for recycling treated water, and a separation column. The oil emulsion generation unit consists of a high-pressure helical pump, a piston pump for oil injection, a needle valve, two pressure gauges, and an oil emulsion storage tank, to which industrial salt (NaCl - concentration of 30 g / L) was added, using centrifugal pumps for injection and mixing in the tank. The helical hydraulic flocculator (Flocculent Generator Reactor - RGF®) was designed according to the parameters defined on the bench.For tannin mixing, a 12-meter, 10-inch diameter hose (hydraulic retention time of 37 seconds) and a 1-foot, 12-meter hose (hydraulic retention time of 66 seconds) were used, totaling 103 seconds (1.7 minutes). For flocculation, after polymer injection, a 1-foot, 7-meter hose (hydraulic retention time of 38 seconds) was used. Duplicate experiments were performed for 1 hour and 30 minutes at a surface application rate of 50 m / h (Q = 275 L / h), with aliquots of treated water taken for analysis every 30 minutes. The bubbles were injected at a 20% recycle rate, and the treated water flow rate was 95% (5% to the oily side).

[0072] Oil and Grease Content Analysis (TOG) - TOG analyses were performed on a Horiba brand oil analyzer (OCMA-350, Japan), using a calibration curve prepared with the source oil. Oil concentration determination in the Horiba spectrophotometer is based on energy absorption in the infrared spectrum, in the wavelength range of 3.5–3.6 pm. According to Beer's Law, the amount of energy absorbed in this range is directly proportional to the oil concentration contained in the sample. The solvent tetrachloroethylene was used to extract the oil contained in the sample (dispersed and dissolved phases). Anhydrous sodium sulfate was used to remove residual moisture from the sample to be analyzed.

[0073] Numerous variations affecting the scope of protection of this application are permitted. This reinforces the fact that the present invention is not limited to the particular configurations / embodiments described above.

Claims

CLAIMS 1. Polyelectrolyte of plant origin, characterized by the fact that it comprises the extract of one or more parts of at least one species of eucalyptus, including Eucalyptus cloeziana, chemically modified through a sulfonation reaction in an acidic medium.

2. Polyelectrolyte of plant origin according to claim 1, characterized by the fact that one or more parts of at least one species of eucalyptus are obtained from the waste of one or more paper and cellulose, furniture, coal, civil construction, electrification industries, among other similar industries or mixtures thereof.

3. Polyelectrolyte of plant origin according to claim 1 or 2, characterized by the fact that it has a density in a range between about 1.15 kg / m 3 and about 1.25 kg / m 3 , preferably about 1.20 kg / m 3, pH in a range between about 3.4 and about 5.0, preferably about 4.0, total solids concentration in a range between about 30.0% and about 50.0% by weight, preferably about 40% by weight and a tanning agent content of about 23% by weight to about 38% by weight, preferably about 30% by weight.

4. Polyelectrolyte of plant origin according to any one of claims 1 to 3, characterized in that the extract of one or more parts of at least one species of eucalyptus has a percentage of tannins greater than about 65%, preferably between about 65% and 85%, more preferably between about 70% and about 85%, determined using the ISO 14088:2012 / EN ISO 14088 method, and about 4% to about 8% moisture, preferably about 6% moisture.

5. Polyelectrolyte of plant origin according to any one of claims 1 to 4, characterized in that the at least one species of eucalyptus additionally includes Eucalyptus camalduensis, Eucalyptus citriodora, Eucalyptus grandis, Eucalyptus pellita, Eucalyptus Robusta, Eucalyptus saligna, Eucalyptus urophylla, Eucalyptus dunnii, Eucalyptus Adstringens, Eucalyptus cloeziana, or mixtures thereof.

6. Polyelectrolyte of plant origin according to any one of claims 1 to 5, characterized by the fact that it adds an anionic characteristic to molecules with a non-polar character.

7. Method for producing chemically modified plant-derived polyelectrolyte as defined in any one of claims 1 to 6, characterized in that it comprises the steps of: i) dissolving the extract from one or more parts of at least one species of eucalyptus, including Eucalyptus cloeziana, in the presence of a solvent in an amount of about 580 kilograms to about 620 kilograms in a reactor under constant stirring and controlled temperature; ii) adding one or more sources of sulfur dioxide until its complete dissolution in the reactor; iii) adding one or more sources of acid to the reactor under stirring; vii) heating the mixture at a constant temperature in a range of about 72°C to about 95°C, preferably from about 80°C to about 85°C for a certain period in a range of about 1.5 hours to about 4 hours, at a pressure of about 10 5 Pa (1 bar) at about 5 x 10 5Pa (5 bar); viii) cooling of the system; and ix) adjusting the total solids content to a range between approximately 30% and approximately 50% by weight through the use of a solvent to obtain the polyelectrolyte product of vegetable origin in liquid form.

8. Method according to claim 7, characterized in that it further comprises the drying step, in which the solvent still present in the polyelectrolyte in liquid form is removed through drying equipment in a temperature range between about 160°C and around 230°C, preferably between 200°C and 210°C.

9. Method according to claim 8, characterized in that after the drying step the polyelectrolyte is in its powder form, containing a moisture content of about 2% to about 12%, preferably about 4.5% to about 6.5%.

10. Method according to any one of claims 7 to 9, characterized in that the controlled temperature in the dissolution step is between about 20°C and about 80°C, preferably between about 50°C and about 55°C.

11. Method according to any one of claims 7 to 10, characterized in that the solvent of the dissolution step is selected from a group consisting of deionized water, potable water, clarified water, or mixtures thereof, and / or polar solvents such as methanol, ethanol, acetonitrile, dimethylformamide, dimethylsulfoxide or mixtures thereof, preferably deionized water.

12. Method according to any one of claims 7 to 11, characterized in that said extract from one or more parts of at least one species of eucalyptus is in powder form and is present in an amount of about 380 kilograms to about 420 kilograms.

13. Method according to any one of claims 7 to 12, characterized in that in step ii) said source of sulfur dioxide is selected from the group comprising sulfur dioxide, sodium sulfite, potassium sulfite, ammonium sulfite, sodium metabisulfite, sodium bisulfite, potassium metabisulfite and ammonium bisulfite or mixtures thereof.

14. The method of claim 13, wherein the source of sulfur dioxide is sodium metabisulfite.

15. Method according to claim 14, characterized due to the fact that sodium metabisulfite has a concentration between approximately 62.0% SO2 and 67.4% SO2, preferably with a concentration of approximately 65% ​​SO2.

16. Method according to any one of claims 7 to 15, characterized in that in step iii) said one or more acid source(s) is selected from the group comprising formic acid, acetic acid, citric acid, lactic acid, sulfuric acid, hydrochloric acid or a mixture thereof.

17. Method according to claim 16, characterized in that the one or more acid sources are preferably formic acid (85%).

18. Method according to any one of claims 7 to 17, characterized in that the pH of the reaction medium is in a range of about 2.5 to about 5.5, preferably from about 3.7 to about 4.

3.

19. Method according to any one of claims 7 to 18, characterized in that the cooling step is carried out through heat exchange with the reactor cooling jacket, heat exchanger or cooling to ambient temperature.

20. The method of any one of claims 7 to 19, wherein the stoichiometric ratio of the extract of one or more parts of at least one eucalyptus species(s), sulfur dioxide, and acid is in the range of about 0.15:0.05:0.07 to about 1.50:0.10:0.15, preferably about 1:0.07:0.

1.

21. Use of polyelectrolyte of plant origin as defined in any one of claims 1 to 6, characterized in that it is for the treatment of water produced from the oil extraction process, treatment of water produced in an onshore environment, blood, metals and other compounds that are difficult to remove in its composition.

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