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BR-102024018079-A2 - PROCESS FOR PREPARING STANDARD WATER-IN-OIL SYNTHETIC EMULSIONS AND SAID EMULSIONS

BR102024018079A2BR 102024018079 A2BR102024018079 A2BR 102024018079A2BR-102024018079-A2

Abstract

The present invention falls within the petrochemical field, specifically in the area of developing standards for physicochemical analyses. The present invention describes a process for preparing standard synthetic water-in-oil emulsions, which considers the application of the emulsion, the desired HLB, the type of surfactant to be used, and the characteristics of the aqueous and oily phases. The process results in water-in-oil emulsions with high stability. The emulsions obtained by the process of the present invention comprise a combination of surfactants and exhibit stability for up to 30 hours.

Inventors

  • MARCO ANTONIO GOMES TEIXEIRA
  • AGNIS FERREIRA POLICARPO
  • CLAUDIA REGINA ELIAS MANSUR
  • Rogerio Mesquita De Carvalho
  • SUZANNY PAIVA DE CARVALHO
  • BRUNO DUARTE DA SILVA
  • ANA MEHL

Assignees

  • Petróleo Brasileiro S.A. - Petrobras
  • UNIVERSIDADE FEDERAL DO RIO DE JANEIRO - UFRJ

Dates

Publication Date
20260317
Application Date
20240902

Claims (20)

  1. 1. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS characterized by comprising: (i) defining one or more water:oil ratios in the emulsion, based on the desired application of the standard emulsion; and (ii) defining the composition/salinity of the aqueous phase and the type of oil to be used; based on the information (i) and (ii) above: (iii) choosing the desired HLB for the standard emulsion and one or more surfactants to be used; (iv) dissolving one or more specific surfactants for each phase of interest, where dissolution occurs according to the affinity between the phases, considering the proportions found from the HLB calculation; (v) mixing the phases; and (vi) homogenization.
  2. 2. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to claim 1, characterized in that the water:oil ratio in the emulsion to be prepared is in the range of 10:90 to 40:60, preferably 30:70 to 40:60.
  3. 3. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to claim 1 or 2, characterized in that the aqueous phase has a salinity in the range of 0 to 400,000 mg of salt/L, preferably 0 to 220,000 mg of salt/L.
  4. 4. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 3, characterized in that the oily phase comprises oil selected from the group comprising crude oil, mineral oil, base oil, lubricating oil, drilling oil, synthetic oils, oily materials based on alpha-olefins or other oligomeric types, petroleum derivatives such as aviation kerosene, fuel oil or diesel, crude oil, and combinations thereof.
  5. 5. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 4, characterized by the HLB of interest of the emulsion being in the range of 4.3 to 15, preferably 6 to 10, more preferably where the HLB is equal to 6.
  6. 6. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 5, characterized in that 1% to 5% (w/v), preferably 5% (w/v), of one or more surfactants are added, based on the total quantity of the emulsion.
  7. 7. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 6, characterized in that one or more surfactants are selected from the group comprising sorbitan monooleate, ethoxylated/propoxylated sorbitan monooleate, sorbitan trioleate, ethoxylated/propoxylated sorbitan trioleate, sorbitan sesquioleate, ethoxylated/propoxylated sorbitan sesquioleate, sodium oleate, sodium stearate, calcium stearate, ethoxylated lauryl ether, ethoxylated castor oil, ethoxylated/propoxylated isotridecyl alcohol or combinations thereof.
  8. 8. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 7, characterized in that one or more hydrophilic surfactants are dissolved in the aqueous phase.
  9. 9. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 7, characterized in that one or more hydrophobic surfactants are dissolved in the oil phase.
  10. 10. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 9, characterized in that the mixing of the phases occurs through the conversion of the aqueous phase into the oily phase.
  11. 11. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to claim 10, characterized in that the conversion of the aqueous phase into the oily phase occurs slowly.
  12. 12. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 11, characterized in that homogenization occurs through vigorous stirring, preferably with mechanical stirring systems with a rotational speed of 3000 to 13000 rpm.
  13. 13. PROCESS FOR PREPARING WATER-IN-OIL EMULSIONS, according to any one of claims 1 to 12, characterized by further comprising a step for characterizing the emulsion, in which the droplet size, solubility test in aqueous and oily media, wettability tests, membrane filtration, interface tests, or spectrophotometry are analyzed.
  14. 14. WATER-IN-OIL EMULSION characterized by comprising from 10% to 40% of an aqueous phase, based on the total weight of the emulsion, dispersed in 60% to 90% of an oily phase, based on the total weight of the emulsion; and from 1% (w/v) to 5% (w/v) of one or more surfactants; wherein the water-in-oil emulsion exhibits high stability.
  15. 15. WATER-IN-OIL EMULSION, according to claim 14, characterized by preferably comprising 5% (w/v) surfactants, based on the emulsion.
  16. 16. WATER-IN-OIL EMULSION, according to claim 14 or 15, characterized in that the aqueous phase has a salinity in a range of 0 to 400,000 mg of salt/L, preferably 0 to 220,000 mg of salt/L.
  17. 17. WATER-IN-OIL EMULSION, according to any one of claims 14 to 16, characterized in that the oily phase comprises oil selected from the group comprising crude oil, mineral oil, base oil, lubricating oil, drilling oil, synthetic oils, oily materials based on alpha-olefins or other oligomeric types, petroleum derivatives such as aviation kerosene, fuel oil or diesel, crude oil, and combinations thereof.
  18. 18. WATER-IN-OIL EMULSION, according to any one of claims 14 to 17, characterized by comprising one or more hydrophilic surfactants.
  19. 19. WATER-IN-OIL EMULSION, according to any one of claims 14 to 18, characterized by comprising one or more hydrophobic surfactants.
  20. 20. WATER-IN-OIL EMULSION, according to any one of claims 14 to 19, characterized by comprising a surfactant selected from the group comprising sorbitan monooleate, ethoxylated/propoxylated sorbitan monooleate, sorbitan trioleate, ethoxylated/propoxylated sorbitan trioleate, sorbitan sesquioleate, ethoxylated/propoxylated sorbitan sesquioleate, sodium oleate, sodium stearate, calcium stearate, ethoxylated lauryl ether, ethoxylated castor oil, ethoxylated/propoxylated isotridecyl alcohol or combinations thereof.

Description

FIELD OF THE INVENTION: [001] The present invention is situated in the petrochemical field, specifically in the area of developing standards for physicochemical analyses. The present invention describes processes for the preparation of standard synthetic water-in-oil emulsions, with application in physicochemical analyses of mixtures in the petroleum industry, such as lift and flow technologies, primary processing and oil recovery. BACKGROUND OF THE INVENTION: [002] Emulsions are present in everyday life in various fields of activity, for example, in the petroleum, food, cosmetics and pharmaceutical industries. Emulsions consist of two immiscible liquids, usually oil and water, with one dispersed as small droplets in the other. The classification of emulsions is based on the polarity of the dispersed phase in the external phase, also known as the continuous phase. [003] The most common types of emulsions are oil-in-water (O/W), where a nonpolar liquid (oil) is dispersed in a polar liquid (water), and water-in-oil (W/O) emulsions, where a polar liquid is dispersed in a nonpolar liquid. In addition, multiple emulsions can also be found, in which the dispersed phase is already an emulsion, such as (W/O/W) systems or (O/W/O) systems (MCCLEMENTS, 2015). [004] Considering the different nature of the phases, emulsions are unstable systems. Thus, the stability of emulsions is often maintained through the use of emulsifiers or surfactants that prevent or delay phase separation. Emulsifying agents can be any surfactant compounds capable of reducing the interfacial tension between two liquids and keeping the droplets dispersed, minimizing coalescence and aggregation. These stabilizers are divided into the following classes: anionic, cationic, nonionic, and amphoteric (EL-DIN, 2011, SCHRAMM, 2006). [005] Another very important property in the emulsification process is the hydrophilic-lipophilic balance (HLB) of the surfactant. HLB is an empirical measure that describes the relationship between the hydrophilic and lipophilic parts of a surfactant molecule. This parameter is a useful indicator of surfactant solubility and predicts the type of emulsion to be formed. Thus, the evaluation of HLB serves to empirically classify the type of emulsion that can be formed based on the amounts of lipophilic and hydrophilic systems present in a surfactant chain. Griffin (1949) established an empirical scale as a measure of surfactant HLB values, ranging from 0 to 20. [006] In some cases, the HLB number is calculated from the molecule's structure; in other cases, it is based on experimental emulsification data (MCCLEMENTS, 2015, ROSEN, 2004, SJOBLOM, 2001). There is a relationship between the HLB value of a surfactant and its application. A surfactant with a lower HLB has a lipophilic character and therefore works better to stabilize oil-in-water emulsions. On the other hand, a surfactant with a higher HLB value has a hydrophilic character and is therefore more suitable for water-in-oil emulsions (DELGADO-LINARES, MAJID, et al., 2013, KLOET, 2002). Mixtures of different surfactants can have their HLB calculated by the algebraic sum of the HLB of each surfactant individually, as seen in Equation 1: where: Ma and Mb represent the mass of each of the surfactants and HLBa and HLBb are the HLB values of each of the surfactants. [007] This concept is a great tool when it comes to studying formulations, since from mixtures of pure surfactants a wide range of HLBs can be obtained and, consequently, formulations with different characteristics for various applications. (PASQUALI, TAUROZZI, et al., 2008). Furthermore, for each purpose and application a specific stability of the emulsion used is required. [008] The stability of an emulsion is generally related to the resistance to coalescence of dispersed droplets. Attractive Van der Waals forces and repulsive interactions (electrostatic and steric) between the droplets present in the system play an important role in stabilizing the emulsion (DALTIN, 2011, TADROS, 2009). The stability of an emulsion can be affected by the following factors: droplet size distribution, type and concentration of emulsifier, quality of the interfacial film, viscosity of the continuous phase, temperature and pH, ratio between volume fraction and phase density, and salinity (ROSEN, 2004). [009] The viscosity of the continuous phase plays an important role in the mobility of droplets in the medium; if this phase is too viscous, the Brownian motion (random movement of particles suspended in a fluid) of the droplets may be hindered and, consequently, the frequency of collisions between droplets will decrease (MOBIUS, MILLER, et al., 2001). On the other hand, the distance between the dispersed droplets present in the continuous phase can be reduced depending on the volume fraction of the aqueous and oily phases due to the increase in the population density of the droplets. (MIRHOSSEINI, TAN, et al., 2007). [0010] The eff