Description:FIELD OF THE INVENTION
The present invention relates to a demulsifier additive composition and a process for preparing the same. The present invention also provides a process for demulsification of crude oil. In particular, this invention relates to a chemical demulsifier additive composition comprising (i) 40-42% by weight polysorbate 20 (ii) 38-40% by weight polysorbate 40 and (iii) 18-22% by weight of Xylene. The additive acts as a chemical demulsifier for demulsification of water-in-oil emulsions in crude oil & water mixtures.

BACKGROUND OF THE INVENTION
All crude oils contain dilute dispersion/emulsion of ultrafine water droplets with impurities such as salts, solids and metals. These emulsions might be quite stable due to the presence of natural surfactants in oil such as asphaltenes, resins, etc. Adverse effects of these impurities can result in shortened unit run lengths and reduced equipment reliability. To prevent corrosion, plugging, fouling of equipment, electrical desalting plants are installed in crude oil production units in order to remove water-soluble salts from an oil stream. Desalting involves mixing heated crude oil with washing water, using a mixing valve or static mixers to ensure a proper contact between the crude oil and the water, and then passing it to a separating vessel, where a proper separation between the aqueous and organic phases is achieved. Since emulsions can be formed in this process, there is a risk of water carryover in the organic phase. In order to overcome this problem chemical demulsifies are added to promote the emulsion breaking. When this operation is performed at a refinery, an electric field across the settling vessel is applied to coalesce the salty water droplets, and, therefore, a decrease in water and salt content is achieved.

Nastaran Hayati Roodbari, et al. in an article “Arabian Journal of Chemistry” published in year 2011, titled “Tweens demulsification effects on heavy crude oil/water emulsion” discloses the demulsification role of Tweens (nonionic polymers) was determined in the separation of water from heavy crude oil emulsion. According to the previous research, these nonionic polymers, having hydrophilic and lipophilic groups, are appropriate for making oil in water emulsion. In this research their effects in certain concentrations on demulsifying of water in crude oil emulsion were proved. High molecular weight, alkenes’ chains and groups of ketone and ester in these polymers can improve their performance for the demulsification of water in crude oil emulsion. Their efficiencies are improved with electronegative groups such as oxygen. They leave no corrosion effect because they are neutral and do not leave counter ion.
US 2017/0327753 A1 relates to a crude oil demulsifier comprises a copolymer of styrene with pyridine or a carboxylic acid or its salt selected from methacrylic, acrylic, maleic or fumaric acid with molecular weight in the range of 10000 to 600000 Daltons, dose in the range of 20-1000 ppm. This prior art further relates to a process for demulsification of crude oil by treating crude oil with the copolymer in the range of 20-1000 ppm in the temperature range of 25-40° C. by shaking to obtain demulsified crude oil having crude oil with <1% water, and Water <100 ppm oil.

WO 2020/040633 relates to compounds of Formula (I), methods for their synthesis and uses thereof. The compounds of this prior art may be useful in preventing and/or mitigating microemulsion formation in enhanced oil recovery methods.

WO2013/041876A1 relates to a demulsifiers for use in the demulsification of oils from water and vice versa, including the demulsification of crude oil from sea water or brine. This prior art relates to novel demulsifiers which are environmentally friendly, or 'green', and which can be used without restriction on-site in offshore oil drilling fields, for example in the North Sea. These demulsifiers are based on the reaction product of alkoxylated polyols or polyol esters with dicarboxylic acids.

US9816050B2 relates to a demulsifying composition for aiding extraction of an emulsified oil from an oil and water emulsion. The composition includes one or more non-ionic surfactants having a HLB value of 6 or greater, wherein the non-ionic surfactant is selected from the group consisting of alkoxylated plant oils, alkoxylated plant fats, alkoxylated animal oils, alkoxylated animal fats, alkyl polyglucosides, alkoxylated glycerols, and mixtures thereof. The composition may include silicon containing particles. A method for recovering oil from a corn to ethanol process is also disclosed. The method includes the steps of adding the composition to a process stream of the corn to ethanol process, and extracting oil from the process stream.

JP2020079286A provides a preconcentrate comprising a fatty acid oil mixture and at least one surfactant, and methods of using the same. A preconcentrate comprises a fatty acid oil mixture that contains EPA and DHA, preferably in the form of ethyl ester or triglyceride, and at least one surfactant. The preconcentrate is capable of forming a self-nanoemulsifying drug delivery system (SNEDDS), a self-microemulsifying drug delivery system (SMEDDS) or a self-emulsifying drug delivery system (SEDDS) in an aqueous solution.

CN1348696A discloses triazophos emulsion and its preparation method. (1) Raw material formulation; O,O-diethyl-O-[1-phenyl-1,2,4-triazole-3-radical] thiophosphate 5-35%, ZX-01 emulsifier 1-40%, stabilizer 0.1-10%, solvent 1-30%, cosolvent 1-30%, and the rest is water. (2) Preparation method, the active component O,O-diethyl-O-[1-phenyl-1,2,4-triazole-3-radical] thiophosphate and solvent and cosolvent are mechanically stirred in emulsifying kettle to uniform, then add ZX-01 emulsifier and stabilizer, mix to uniform, add water, stir 20 min. under 20-60 rpm. to form transparent product. It reduced environmental pollution, raised drug efficiency.

The chemical demulsifiers used play a major role in breaking the emulsions and allowing the impurities to settle along with water. When processing heavy or high salt content crudes processing such as Basrah Heavy, the commercial demuslifiers ae not efficient enough in breaking the oil water emulsions. The presence of high amount of natural surfactants such as asphaltenes, increase the stability of the emulsions and leads to formation of rag layer. Limitations in desalter operations is one of the major reasons for not processing discounted crudes (Heavy crudes) which are available at a cheaper price than regular crudes.

Therefore, in order to improve the efficiency of desalter operations through chemical routes, particularly with respect to heavy and high salt content crudes, a novel and effective chemical demulsifier is required to develop.

SUMMARY OF THE INVENTION
Accordingly, the present invention provides a demulsifier additive composition comprising (i) 40-42% by weight polysorbate 20 (ii) 38-40% by weight polysorbate 40 and (iii) 18-22% by weight of Xylene. The present invention also provides a process for preparing the demulsifier additive composition.

The present invention also provides a process for demulsification of a crude oil, said process comprising treating the crude oil with a demulsifier additive composition in the range of 2-20 ppm at a temperature in the range of 90-140ºC to obtain demulsified crude oil, wherein the demulsifier additive composition comprising:
(i) 40-42% by weight polysorbate 20;
(ii) 38-40% by weight polysorbate 40; and
(iii) 18-22% by weight of Xylene.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 represents graph for illustrating that raw crude water content (including water present in crude + added externally for emulsification) and water separated after desalting experiments.
Figure 2 represents graph for discussing the salt content results of the raw and desalted crudes.

DETAILED DESCRIPTION OF THE INVENTION

While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the scope of the invention as defined by the appended claims.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The present invention provides a demulsifier additive composition comprising:
(i) polysorbate 20;
(ii) polysorbate 40; and
(iii) Xylene.

In one of the features of the present invention, the polysorbate 20 is present in amount in the range of 40-42% by weight of the total composition.

In yet another feature of the present invention, the polysorbate 40 is present in amount in the range of 38-40% by weight of the total composition.

In yet another feature of the present invention, the Xylene is present in amount in the range of 18-22% by weight of the total composition.

In one of the features of the present invention, a demulsifier additive composition consisting of:
(i) 40-42% by weight polysorbate 20;
(ii) 38-40% by weight polysorbate 40; and
(iii) 18-22% by weight of Xylene.

In yet another feature of the present invention, the demulsifier additive composition acts as a chemical demulsifier for demulsification of water-in-oil emulsions in crude oil & water mixtures, improving the separation of water and oil and helps in reducing the salt content of the crude oil.

The present invention also provides a process for demulsification of crude oil, said process comprising treating the crude oil with a demulsifier additive composition in the range of 2-20 ppm at a temperature in the range of 90-140ºC to obtain demulsified crude oil,
wherein the demulsifier additive composition comprising:
(i) 40-42% by weight polysorbate 20;
(ii) 38-40% by weight polysorbate 40; and
(iii) 18-22% by weight of Xylene.

In one of the features of the present invention, the demulsification is carried out for a time in the range of 5-60 minutes.

In yet another feature of the present invention, the demulsification is carried out at a Voltage in the range of 1-4 KV.

In yet another feature of the present invention, the crude oil before demulsification having API ranging from 22º to 40º and salt content ranging from 2 to 13 ptb; and demulsified crude oil having reduced salt content in the range of 0.3 to 5 ptb with improved water separation from the raw crude.

The present invention also provides a process for preparing the demulsifier additive composition, the process comprising:
(a) weighing components individually and adding them in a vial/beaker to form a mixture, wherein the component comprises (i) 40-42% by weight polysorbate 20; (ii) 38-40% by weight polysorbate 40; and (iii) 18-22% by weight of Xylene; and
(b) stirring the mixture of step (a) at a temperature in the range of 25-50ºC for 5 to 60 minutes to obtain a transparent and homogeneous mixture.

The present invention describes a demulsifier additive composition containing (i) 40-42% by weight polysorbate 20 (ii) 38-40% by weight polysorbate 40 and (iii) 18-22% by weight of Xylene. The additive acts as a chemical demulsifier for demulsification of water-in-oil emulsions in crude oil & water mixtures improving the separation water and oil. Further, the additive also helps in reducing the salt content of the crude oil.

Examples:
The present disclosure with reference to the accompanying examples describes the present invention. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. It is understood that the examples are provided for the purpose of illustrating the invention only and are not intended to limit the scope of the invention in any way.

Example 1:
Process for preparing of demulsifier additive composition
The process comprises weighing components individually and adding them in a vial/beaker to form a mixture; stirring the obtained mixture at a temperature range of 25-50ºC for 5 to 60 minutes to obtain a transparent and homogeneous mixture.

The demulsifier additive composition prepared by the procedure of above Example 1 along with comparative examples and their results have been tabulated in Table 1.

Table 1
Demulsifier Additive Composition Polysorbate 20
Polysorbate 40
Xylene
Dewatering Efficiency
Comparative Additive 1 72 8 20 77.5
Comparative Additive 2 20 60 20 75
Comparative Additive 3 60 20 20 75
Inventive Additive 4 40 40 20 87.5

Example 2:
EVALUATION METHODOLOGY
The evaluation of the formulations/demulsifier additive composition was carried out based on the inhouse developed methodology using Bench Scale Desalter equipment.
• A water-in-crude oil emulsion with 4 wt% of water is prepared using homogenizer. The emulsion stability in each case was optimized by ensuring the emulsion was firm even after three days.
• The emulsified crude is then transferred into 100 ml desalting test cells.
• Specific quantity (5 ppm) of demulsifier additive composition is added to desalting test cell.
• The test cell is placed in the test cabinet and subjected to following process conditions:
- Test cell temperature: 120oC
- Test duration: 30 minutes
- Voltage: 3 KV
• Dehydration efficiency is calculated as the ratio of quantity of water separated to the quantity of water added initially.
• Salt content is measured using ASTM D3230 for the desalted crude oil to determine the salt removal efficiency.

RESULTS
Experiments were carried out with wide variety crudes with API ranging from 22oC to 40oC and salt content ranging from 3 to 12 ptb. Details of some of the crudes are presented below in table 2.
Table 2
CRUDE API Gravity Sulfur (wt.%) Salt Content (ptb)
CRUDE A 39.6 1.06 2.8
CRUDE B 37.8 0.16 4
CRUDE C 37.4 1.42 4.5
CRUDE D 32.5 2.1 6.5
CRUDE E 28.1 3.2 7.4
CRUDE F 22.6 4.1 8.2
CRUDE G 29.7 1.92 12.4

Raw crude water content (including water present in crude + added externally for emulsification) and water separated after desalting experiments are reported in Figure 1.

Results indicate that the addition of the chemical demulsifier improved the water separation from the raw crude.

The graph as mentioned in figure 2, discusses on the salt content results of the raw and desalted crudes.

The results from the graph of Figure 2 indicates that use of chemical demulsifier additive composition of the present invention significantly reduced the salt content of the raw crudes to a range of 0.3 to 5 ptb.

Therefore, the chemical demulsifier additive composition of the present invention improves the water separation and salt removal from the crude oil and water mixtures. The additive reported showed excellent improvement in water separation and salt reduction compared to no additive scenario.

Following are the potential benefits of the novel demulsifier additive composition of the present invention:
a) Improve the dewatering and desalting efficiency.
b) Promote faster settling of the water & impurities.
c) Reduce the extent of rag layer.
d) Minimize the use of caustic which is added to mitigate overhead corrosion. , Claims:1. A demulsifier additive composition comprising:
(i) polysorbate 20;
(ii) polysorbate 40; and
(iii) Xylene.

2. The additive composition as claimed in claim 1, wherein the polysorbate 20 is present in amount in the range of 40-42% by weight of the total composition.

3. The additive composition as claimed in claim 1, wherein the polysorbate 40 is present in amount in the range of 38-40% by weight of the total composition.

4. The additive composition as claimed in claim 1, wherein the Xylene is present in amount in the range of 18-22% by weight of the total composition.

5. The additive composition as claimed in claim 1 acts as a chemical demulsifier for demulsification of water-in-oil emulsions in crude oil & water mixtures, improving the separation of water and oil and helps in reducing the salt content of the crude oil.

6. A process for demulsification of crude oil, said process comprising treating the crude oil with a demulsifier additive composition in the range of 2-20 ppm at a temperature in the range of 90-140ºC to obtain demulsified crude oil,
wherein the demulsifier additive composition comprising:
(i) 40-42% by weight polysorbate 20;
(ii) 38-40% by weight polysorbate 40; and
(iii) 18-22% by weight of Xylene.

7. The process as claimed in claim 6, wherein the demulsification is carried out for a time in the range of 5-60 minutes

8. The process as claimed in claim 6, wherein the demulsification is carried out at a Voltage in the range of 1-4 KV.

9. The process as claimed in 6, wherein the crude oil before demulsification having API ranging from 22º to 40º and salt content ranging from 2 to 13 ptb; and demulsified crude oil having reduced salt content in the range of 0.3 to 5 ptb with improved water separation from the raw crude.

10. A process for preparing the demulsifier additive composition, the process comprising:
(a) weighing components individually and adding them in a vial/beaker to form a mixture, wherein the component comprises (i) 40-42% by weight polysorbate 20; (ii) 38-40% by weight polysorbate 40; and (iii) 18-22% by weight of Xylene; and
(b) stirring the mixture of step (a) at a temperature in the range of 25-50ºC for 5 to 60 minutes to obtain a transparent and homogeneous mixture.