Claims:1. A pour point depressant polymer of Formula I:
.
2. The pour point depressant as claimed in claim 1, wherein A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; and l, n and m varied between 10 to 100.
3. A process for preparation of a pour point depressant polymer of Formula I:

,
comprising the steps of:
i) dissolving acrylate monomer, styrene and maleic anhydride in xylene to obtain a reaction mass;
ii) adding benzoyl peroxide to the reaction mass;
iii) heating the reaction mass obtained in step ii) for 1-3 hours at 90-140 ℃ followed by cooling to 25 ℃ and removal of the xylene;
iv) adding N-methyl aryl amine to the reaction mass;
v) heating the reaction mass obtained in step iv) for 2-4 hours at 90-140℃ followed by cooling;
vi) concentrating the xylene layer of the reaction mass to obtain the pour point depressant (PPD).
4. The process as claimed in claim 3, wherein A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; and l, n and m varied between 10 to 100.
5. The process as claimed in claim 3, wherein the acrylate monomer, the styrene, the maleic anhydride and the N-methyl-aryl amine are present in 1 Eq, 1 Eq, 0.2-1 Eq and 0.4-2 Eq respectively.
6. The process as claimed in claim 3, wherein the benzoyl peroxide is present in 1 wt % with respect to mixture of the acrylate monomer, the styrene and the maleic anhydride.
7. The process as claimed in claim 3, wherein the acrylate monomer is octadecyl acrylate.
8. A pour point depressant composition, comprising:
a) a pour point depressant of Formula I
; and
b) at least one co-additive.
9. The pour point depressant composition as claimed in claim 8, wherein A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; and l, n and m varied between 10 to 100.
10. The pour point depressant composition as claimed in claim 8, wherein the co-additive is selected from the group consisting of detergents, particulate emission reducers, storage stabilizers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilizers, and lubricity additives.
11. A fuel oil composition, comprising:
(i) a fuel oil; and
(ii) a pour point depressant composition that comprises at least one pour point depressant polymer of formula I:
.
12. The fuel oil composition as claimed in claim 11, wherein A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; and l, n and m varied between 10 to 100.
13. The fuel oil composition as claimed in claim 11, wherein the composition further comprising one or more co-additives selected from the group consisting of detergents, particulate emission reducers, storage stabilizers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilizers, and lubricity additives. , Description:FIELD OF THE INVENTION:
The present invention discloses a low sulphur fuel oil production from a low sulphur high waxy crude oils wherein the desired pour point is not possible to meet without additives, i.e., pour point depressant (PPD). More specifically, the present invention discloses a pour point depressant polymer, a composition containing the pour point depressant polymer and use thereof in a process of obtaining a low sulphur fuel oil from a low sulphur high waxy crude oil. Additionally, the present invention discloses a process for preparation of the pour point depressant polymer and a process for preparation of the composition containing the pour point depressant polymer. The present invention also discloses about a fuel oil composition comprising at least a pour point depressant polymer.

BACKGROUND OF THE INVENTION:

As per International Maritime Organization (IMO) specifications, sulphur limit for marine fuels has been reduced from 3.5 wt% to 0.5 wt%. The high waxy low sulphur short residue (LSSR) does not meet the pour point specifications of low sulphur fuel oils (LSFO) as per ISO 8217:2017. Adding a Pour Point Depressant (PPD) would help in overcoming the limitations in order to make the high waxy low sulphur short residue (LSSR) suitable as low sulphur fuel oils (LSFO).

A typical Pour Point Depressant (PPD) contains an oil soluble long alkyl chain and a polar structural moiety in the macromolecular structure. The long alkyl chain may co-crystallize with wax and the polar moiety exists on the surface of the wax crystal, thereby inhibiting the crystal lattice formation and reducing the wax crystal size. Desired pour point achieved only when the crystallization temperature of wax and polymer overlap. Only a fraction of side chain of poly(meth)acrylates is free to participate in crystallization, i.e., the methylene groups located away from the main chain.

There are several types of PPDs now in use. The most extensively used PPDs are Ethylene-Vinyl Acetate (EVA) copolymers, alkyl ester of unsaturated acid-olefin copolymer and maleic anhydride alkyl esters of unsaturated carboxylic acid copolymer. Monounsaturated acids both from petrochemical and plant oil origin will be used with long chain alcohols to prepare alkyl ester monomers. The α-olefins may be used as co-monomers in the polymerization.

Some of the prior art documents disclosing pour point depressant and their use in fuel(s) for improvement in properties of fuel(s) are mentioned below.

KR20100006061A discloses a pour point depressant for biodiesels is provided to improve a low temperature fluidity of fuel oil containing biodiesel and a plugging point of a cold filter, and to disperse wax extracted at a low temperature in diesel oil.

Zang et al., Fuel 260 (2020) 116381, discloses synthesis and characterization of polyoctadecyl-acrylate (POA), polyoctadecyl-acrylate-maleic anhydride (POA-MA) and its aromatic pendants-modified derivatives, polyoctadecylacrylate-maleic anhydride-aniline (POA-MA-AN) and polyoctadecyl-acrylate-maleic anhydride-naphthylamine (POA-MA-NA).

P. Sivakumar et al., Journal of Petroleum Science and Engineering (2018), discusses the objective of adding PPD to prevent the generation of waxy crystalline clusters. Four major mechanisms of the pour point depressants are discussed and the types of commonly used pour point depressants (copolymers, anionic surfactants, cationic surfactants, non-ionic surfactants, nano-hybrid PPDs, amphoteric and bio based PPDs) are classified.

CN101735788B discloses a pour point depressant for crude oil. The depressant is prepared from methylnaphthalene.

CN106367055B discloses a pour-point depressants and preparation method thereof. The pour-point depressant is copolymerized by maleic anhydride and 2-methyl propane sulfonic acid of 2- acrylamide base.

CN103184043A provides a crude oil pour point depressant and a preparation method of the crude oil pour point depressant and belongs to the field of pour point depressants and preparation thereof. The provided pour point depressant is a ternary polymer. Different types of pour point depressants can be synthesized for the crude oil with different condensation points. Two of three monomers of the pour point depressant polymer are octadecyl acrylate and styrene respectively while the other one is maleic anhydride, ethyl acetate or acrylamide. The monomers are taken as raw materials, which perform free radical polymerization to obtain the molecular weight matched with that of paraffin wax in the crude oil, and then perform composition to obtain the pour point depressant, which is more suitable for the crude oil, so as to greatly reduce the condensation point of the crude oil. The method is low in cost, simple to operate, economic, applicable and convenient for industrialized production.

CN105387347B belongs to oil gas water gathering-transferring technology field, and in particular to a kind of crude oil pour-point depressant and preparation method thereof.

CN105969433A discloses a nano compound pour point depressant and a preparation method thereof. The nano compound pour point depressant disclosed by the invention is compounded from a nano material and a polymer pour point depressant by a melting and blending method. A montmorillonite nano material modified by cetyl trimethylammonium bromide is compounded with the polymer pour point depressant in a certain mass ratio by adopting the melting and blending method so as to obtain the nano compound pour point depressant.

CN105175629B discloses a kind of high wax viscous crude pour-point depressants and preparation method thereof, belong to macromolecule material preparation area.

US20180002626A1 relates to an aqueous pour point depressant dispersion composition comprising an ethylene vinyl acetate copolymer (EVA); a dispersing agent; a polyethoxylated nonionic surfactant, a low level of hydrocarbon solvent, water; optionally one or more of an aqueous freezing point depressant, a stabilizing agent, or a basic metal substance and a method to use said composition.

US9663740B2 relates to oil compositions, primarily to fuel oil and petroleum compositions produced there from susceptible to wax formation at low temperatures, to polymeric imides for use with such fuel oil compositions, and to methods for their manufacture.

US20150369822A1 relates to an aqueous pour point depressant dispersion composition comprising a thermoplastic polymer, preferably ethylene vinyl acetate (EVA); a dispersing agent; water; optionally an aqueous freezing point depressant; and optionally a stabilizing agent wherein the volumn average particle size of the dispersed thermoplastic polymer is equal to or less than 1 micrometers and a method to make and use said composition.

EP2718363B1 discloses an aqueous pour point depressant dispersion composition comprising: i) ethylene vinyl acetate copolymer (EVA) in an amount of from 12 to 50 weight percent; ii) a dispersing agent in an amount of from 1 to 10 weight percent; iii) water; and iv) an aqueous freezing point depressant.

CN102127409B relates to a kind of crude oil viscosity lowering pour point reducer composition that is jointly consisted of by inorganic pour point depressant and organic pour point depressant, and the preparation method and application of this crude oil viscosity lowering pour point reducer composition.

Still, there is a need for a pour point depressant comprising suitable additives which meets pour point specification, provides a lowering of the pour point in fuel oils, exists as a liquid over a broad temperature range, and demonstrates long term stability.

The present invention discloses more effective and economical pour point depressant and composition(s) thereof. Particularly, the present invention discloses that certain polymer(s) can effectively and economically be employed as pour point depressants for various grades of fuel oil.

OBJECTIVES OF THE INVENTION:
It is a primary objective of the invention to provide a low sulphur fuel oil production from a low sulphur high waxy crude oils wherein the desired pour point is achievable with pour point depressant (PPD) polymer and composition thereof.

A further objective of the present invention is to produce a pour point depressant polymer and composition thereof, for fuel oils.

Another objective of the present invention is to produce a low sulphur fuel oil from a low sulphur high waxy crude oils complying pour point specification.

Another objective of the present invention is to produce a fuel oil composition comprising a pour point depressant polymer.

SUMMARY OF THE INVENTION:

In an aspect of the present invention, the present invention discloses a pour point depressant polymer of Formula I:

wherein A=H or CH3, R1 = C10 to C24 alkyl group or cyclo alkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In another aspect of the present invention, the present invention discloses a process for preparation of a pour point depressant polymer of Formula I:
,
comprising the steps of: i) dissolving acrylate monomer, Styrene and maleic anhydride in xylene to obtain a reaction mass; ii) adding benzoyl peroxide to the reaction mass; iii) heating the reaction mass obtained in step ii) for 1-3 hours at 90-140 ℃ followed by cooling to 25 oC and removing the solvent; iv) adding N-methyl-aryl amine to the reaction mass; v) heating the reaction mass obtained in step iv) for 2-4 hours at 90-140℃ followed by cooling; vi) concentrating the xylene layer of the reaction mass to obtain the pour point depressant (PPD).
In an embodiment of the present invention, the present invention discloses A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In an embodiment of the present invention, the acrylate monomer, the styrene, the maleic anhydride and the N-methyl-aryl amine are present in 1 Eq, 1 Eq, 0.2-1 Eq and 0.4-2 Eq respectively.
In an embodiment of the present invention, the benzoyl peroxide is present in 1 wt % with respect to mixture of three monomers, i.e., the acrylate monomer, the styrene monomer and the maleic anhydride monomer.
In an embodiment of the present invention, the acrylate monomer is octadecyl acrylate.
In another aspect of the present invention, the present invention discloses a pour point depressant composition, comprising a) a pour point depressant of Formula I:
; and
b) at least one co-additive.
In an embodiment of the present invention, the present invention discloses A=H or CH3; R1 = C10 to C24 alkyl group or cycloalkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In an embodiment of the present invention, the co-additive is selected from the group consisting of detergents, particulate emission reducers, storage stabilizers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilizers, and lubricity additives.
In another aspect of the present invention, the present invention discloses a fuel oil composition, comprising: (i) a fuel oil; and (ii) an effective amount of a pour point depressant composition that comprises at least one pour point depressant polymer of the Formula I:
.
In an embodiment of the present invention, the present invention discloses A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In an embodiment of the present invention, the composition further comprising one or more co-additives selected from the group consisting of detergents, particulate emission reducers, storage stabilizers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilizers, and lubricity additives.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the present invention relates to a pour point depressant additive and/or composition prepared thereof.

In a second aspect, this invention relates to a pour point depressant additive concentrate composition comprising the aforementioned pour point depressant additive and a compatible solvent thereof.

In a third aspect, the present invention relates to a process for preparation of pour point depressant additive and/or composition prepared thereof.

In fourth aspect, the present invention relates to a fuel oil composition comprising a pour point depressant.

In a fifth embodiment, the present invention relates to a method of improving the low temperature flow properties of a composition that comprises in major part at least one oil, said method comprising admixture of the composition comprising said at least one oil with an effective amount of the aforementioned pour point depressant additive and/or additive concentrate.

In an aspect of the present invention, the present invention discloses a pour point depressant polymer of Formula I:

wherein A=H or CH3; R1 = C10 to C24 alkyl group or cyclo alkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In another aspect of the present invention, the present invention discloses a process for preparation of a pour point depressant polymer of Formula I:

,
comprising the steps of: i) dissolving acrylate monomer, styrene and maleic anhydride in xylene to obtain a reaction mass; ii) adding benzoyl peroxide to the reaction mass; iii) heating the reaction mass obtained in step ii) for 1-3 hours at 90-140 ℃ followed by cooling to 25 oC and the removal of the solvent; iv) adding N-methyl-aryl amine to the reaction mass; v) heating the reaction mass obtained in step iv) for 2-4 hours at 90-140℃ followed by cooling; vi) concentrating the xylene layer of the reaction mass to obtain the pour point depressant (PPD).
In an embodiment of the present invention, the present invention discloses A=H or CH3; R1 = C10 to C24 alkyl or cycloalkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In an embodiment of the present invention, the aromatics comprising benzene, toluene, and xylene.
In an embodiment of the present invention, the acrylate monomer, the styrene, the maleic anhydride and the N-methyl-aryl amine are present in 1 Eq, 1 Eq, 0.2-1 Eq and 0.4-2 Eq respectively.
In an embodiment of the present invention, the benzoyl peroxide is present in 1 wt % with respect to mixture of the acrylate monomer, the styrene and the maleic anhydride.
In an embodiment of the present invention, the acrylate monomer is octadecyl acrylate.
In another aspect of the present invention, the present invention discloses a pour point depressant composition, comprising a) a pour point depressant of Formula I
; and
b) at least one co-additive.
In an embodiment of the present invention, the present invention discloses A=H or CH3; R1 = C10 to C24 alkyl group or cycloalkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In an embodiment of the present invention, the co-additive is selected from the group consisting of detergents, particulate emission reducers, storage stabilizers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilizers, and lubricity additives.
In another aspect of the present invention, the present invention discloses a fuel oil composition, comprising: (i) a fuel oil; and (ii) an effective amount of a pour point depressant composition that comprises at least one pour point depressant polymer of the formula I:
.
In an embodiment of the present invention, the present invention discloses A=H or CH3; R1 = C10 to C24 alkyl group or cycloalkyl group; R2 is C6 to C12 aromatics; l, n and m varied between 10 to 100.
In an embodiment of the present invention, the composition further comprising one or more co-additives selected from the group consisting of detergents, particulate emission reducers, storage stabilizers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilizers, and lubricity additives.
Two important features for the reduction of pour point in the fuel oil are: (i) alkyl chain anchoring in the polymeric backbone and (ii) polar head groups. Accordingly, in the design of polymeric PPDs, the octadecyl acrylate has been chosen as one of the monomer. The octadecyl anchored polymer act as adsorption source for the waxy alkanes, co-crystallization along with wax or nucleation source. The aniline succinic anhydride-amide has been chosen as polar head group in the polymeric structures to stabilize the resins and asphaltene molecules. In addition, surfactants are also reported as pour point depressants for fuel oil, the same is incorporated in the instant polymers (Figure 1).

Scheme 1: Synthesis of alkylacrylate: aniline: succinic anhydride: carboxylate polymers.

Succinic anhydride ring is opened using a secondary amine in order to get desired amide and surfactant functionalities. The use of primary amine is avoided which otherwise leads to the formation of imide rather than surfactant functionality. The novel structure of the present invention consists of both polymer and surfactant, and there is a strong relation between the surface-active properties of pour point depressants in oil/liquid adsorption and their performance to depress the pour point.

Octadecyl polymeric backbone acts as nucleation source. Styrene is to enhance the solubility. Ester and amide polar head groups interact with the strong polar asphaltenes components in crude oil and hinders the wax crystallization growth. Aromatic amine based polar group and surfactant interact with asphaltenes. On the one hand, the polar group can insert into the interior of asphaltene and partly eliminate the interaction among asphaltene molecules, so as to improve the fluidity of crude oil. On the other hand, polar groups can promote the interaction between the wax crystal and colloid/asphaltene and provide more nucleation centers for the wax components in the crude oil.

The terms ‘pour point depressant’ and ‘pour point depressant polymer’ have been used interchangeably in the specification.

EXAMPLES

Example-1 (Polymer-1):
Octadecyl acrylate (13.25 g, 0.04 mol) and maleic anhydride (1 g, 0.01 mol) were dissolved in xylene. Styrene (4.25 g, 0.04 mol) and Benzoyl peroxide (1 % w/w with respect to monomers) were added in portions at room temperature and mixture was heated for 4 hours at 100 ℃. After 4 hours, reaction mixture was cooled and the solvent was concentrated under reduced pressure to get pale brown viscous liquid. IR (neat, cm-1): 2918, 2850, 1779, 1728, 1494, 1465, 1453, 1161, 1065, 961, 698. Then, the compound was dissolved in xylene and N-methyl aniline (2.2 g, 0.02 mol) was added and subsequently heated for 3 hours at 100 ℃. After 3 hours, the reaction mixture was cooled. Methanol (10 mL) was then added and the solvents were concentrated under reduced pressure to yield the PPD polymer-s1 as a brown solid. IR (neat, cm-1): 3417, 2918, 2850, 1728, 1603, 1494, 1465, 1453, 1263, 1160, 747, 697. GPC (Gel Permeation Chromatography): Mw = 18257.

Example-2 (Polymer-2):
Octadecyl acrylate (6.62 g, 0.02 mol) and maleic anhydride (1 g, 0.01 mol) were dissolved in xylene. Styrene (2.13 g, 0.02 mol) and Benzoyl peroxide (200 mg, 2 % w/w with respect to monomers) were added in portions at room temperature and mixture was heated for 4 hours at 100 ℃. After 4 hours, reaction mixture was cooled and the solvent was concentrated under reduced pressure to get pale brown viscous liquid. IR (neat, cm-1): 2918, 2849, 1779, 1728, 1494, 1465, 1453, 1376, 1161, 1066, 961, 698. Then, the compound was dissolved in xylene and N-methyl aniline (2.2 g, 0.02 mol) was added and subsequently heated for 3 hours at 100 ℃. After 3 hours, the reaction mixture was cooled. Methanol (10 mL) was then added and the solvents were concentrated under reduced pressure to yield the PPD polymer-2 as a brown solid. IR (neat, cm-1): 3415, 2918, 2850, 1781, 1728, 1603, 1507, 1495, 1466, 1453, 1263, 1162, 748, 720, 692. GPC (Gel Permeation Chromatography): Mw = 17254.

Performance evaluation for PPD activity:
Subsequent to the synthesis, the polymers have been evaluated for their pour point depressant activity. The evaluation was performed with the vacuum residue of a waxy crude. The results are summarized in Table 1. As it can be inferred from the Table 1, the alkylacrylate: aniline: succinic anhydride: carboxylate polymers showed promising activity with vacuum residue.

Significance: Pour point: IMO specification is 30℃ as per IS 8217.

Table 1: PPD Performance evaluation of alkylacrylate: aniline: succnic anhydride: carboxylate polymers with fuel oil (data has been recorded without cooling the solution).

S. No Polymer Low Sulphur high waxy crude residue PPD, Dosage in ppm Pour Point
1 Blank 80 0 45oC
2 Polymer 1 80 1000 27 oC
4 Polymer 1 80 1500 19 ℃
5 Polymer 2 80 1500 20 ℃

ASTM D97 is a standard test method for measuring pour point of crude oils. ASTM D5949 is a standard test method for pour point of petroleum products (automatic pressure pulsing method) is an alternative to the manual test procedure.

In the specification, the terms “pour point depressant”, “pour point depressant additive” and “pour point depressant polymer” have been used interchangeably.