Claims:1. An additive for optimizing pour point and viscosity of refinery heavy product blends, said additive comprises:
a clarified oil; and
a copolymer of maleic anhydride and alpha olefin,
wherein the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1500:1.
2. The additive as claimed in claim 1, wherein the clarified oil has carbon range above C20, kinematic viscosity ranging from 10 to 50 cSt at 50oC, and boiling point ranging from 340°C to 600°C.
3. The additive as claimed in claim 1, wherein alpha olefin is C25-C35 alpha olefin.
4. The additive as claimed in claim 1, wherein alpha olefin is C30 alpha olefin.
5. A very low sulphur fuel oil composition, said composition comprises:
50% to 85% by weight of a waxy vacuum residue;
5% to 30% by weight of a cutter stock; and
2% to 30% by weight of an additive, wherein said additive comprises a clarified oil and a copolymer of maleic anhydride and alpha olefin, and wherein the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1500:1.
6. The composition as claimed in claim 5, wherein the content of wax in said waxy vacuum residue ranges from 10% to 30% by weight of the waxy vacuum residue.
7. The composition as claimed in claim 5, wherein the waxy vacuum residue has kinematic viscosity ranging from 103 to 109 cSt at 50oC and from 102 to 105 cSt at 100°C.
8. The composition as claimed in claim 5, wherein the cutter stock comprises one or a combination of low sulphur refinery streams.
9. The composition as claimed in claim 5, wherein the cutter stock is selected from any of light kerosene (LK), heavy kerosene (HK), light gas oil (LGO), heavy gas oil (HGO), Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO) and mixtures thereof.
10. The composition as claimed in claim 5, wherein the cutter stock comprises heavy kerosene having a kinematic viscosity ranging from 0.9 to 100 cSt at 50°C and boiling point ranging from 100°C to 500°C.
11. The composition as claimed in claim 5, wherein the clarified oil has kinematic viscosity ranging from 10 to 50 cSt at 50oC and boiling point ranging from 340°C to 600°C.
12. The composition as claimed in claim 5, wherein the alpha olefin is C30 alpha olefin.
, Description:TECHNICAL FIELD
[0001] The present disclosure pertains to the technical field of refinery heavy product blends. In particular, the present disclosure pertains to an additive for optimizing pour point and viscosity of refinery heavy product blends and a very low sulphur fuel oil composition comprising the additive of the present disclosure.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Recently, International Marine Organization (IMO) has restricted the global upper limit on the sulphur content of ship fuel oil to 0.50% from 3.50% (mass by mass) along with meeting other critical specifications such as pour point, viscosity and flash point. This reduced limit is mandatory in all ships operating outside the designated Emission Control Areas. This new restriction results in approx. 77% drop in overall SOx emissions from ships, reducing the risk of asthma, lung cancer, cardiovascular and other pulmonary diseases.
[0004] Attempts have been made for producing ship oil with low sulphur content by utilizing vacuum residues (VR) derived from low sulphur crude oils. However, these vacuum residues are generally, very waxy in nature (has high viscosity) and exhibits high pour point. In order to obtain fuel oil with desired specifications of pour point and viscosity for FO 180-380 cSt grade, VR is blended with costly cutter stocks such as kerosene or diesel. In case of VR with very high pour point, the amount of cutter stock required to reduce the pour point to acceptable level is quite high. Pour Point Depressants (PPDs) can effectively bring down the pour point and thus minimize the use of cutter stock. More often, it has been observed that addition of such high amount of cutter leads to drastic decrease in the viscosity to such an extent that it falls below the desired value of 180 cSt. Such cases necessitate the application of PPDs in order to achieve the desired specification of pour point and viscosity. While in case of viscosity limiting VR, combination of PPD with a suitable viscosity modifier will reduce the cutter stock requirement.
[0005] Significant efforts have been put forward to find new source of feedstock and ingredients to produce oil with low sulphur content. However, none of the current approaches/reports seem to satisfy the existing needs. There is, therefore, a need in the art to develop a new and improved additive that may overcome the drawbacks associated with the existing pour point depressants. Need is also felt of very low sulphur fuel oil (VLSFO) composition with low pour point and viscosity along with other desired characteristics. The current approach can be extended for minimization of cutter and maximization of VLSFO production.
[0006] The present invention satisfies the existing needs, as well as others, and generally overcomes the deficiencies found in the prior art.
[0007] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0008] It is an object of the present disclosure to provide an additive for optimizing pour point and viscosity of refinery heavy product blends. and
[0009] It is an object of the present disclosure to provide a very low sulphur fuel oil composition containing additive that may overcome the limitations associated with the conventional pour point depressant compositions.
[0010] It is an object of the present disclosure to provide a low sulphur marine fuel oil with low pour point and viscosity.
[0011] It is another object of the present disclosure to provide an additive and a very low sulphur fuel oil composition containing additive that is cost-effective.
[0012] It is another object of the present disclosure to provide an additive and composition that is easy to prepare.
[0013] It is another object of the present disclosure to provide a method of preparation of additive.
[0014] It is another object of the present disclosure to provide a method of preparation of very low sulphur fuel oil composition.

SUMMARY
[0015] The present disclosure pertains to the technical field of refinery heavy product blends. In particular, the present disclosure pertains to an additive for optimizing pour point and viscosity of refinery heavy product blends and a very low sulphur fuel oil composition comprising the advantageous additive of the present disclosure.
[0016] An aspect of the present disclosure relates to an additive for optimizing pour point and viscosity of refinery heavy product blends, the additive includes: a clarified oil; and a copolymer of maleic anhydride and alpha olefin, wherein the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1500:1. In an embodiment, the clarified oil has carbon range above C20. In an embodiment, the clarified oil has kinematic viscosity ranging from 10 to 50 cSt at 50oC, and boiling point ranging from 340°C to 600°C. In an embodiment, alpha olefin is C25-C35 alpha olefin. In an embodiment, alpha olefin is C30 alpha olefin.
[0017] Another aspect of the present disclosure relates to a very low sulphur fuel oil composition, the composition includes: 50% to 85% by weight of a waxy vacuum residue; 5% to 30% by weight of a cutter stock; and 2% to 30% by weight of an additive, wherein said additive comprises a clarified oil and a copolymer of maleic anhydride and alpha olefin, and wherein the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1500:1. In an embodiment, the content of wax in waxy vacuum residue ranges from 10% to 30% by weight of the waxy vacuum residue. In an embodiment, the waxy vacuum residue has kinematic viscosity ranges from 103 to 109 cSt at 50oC and from 102 to 105 cSt at 100oC. In an embodiment, the cutter stock comprises one or a combination of low sulphur refinery streams. In an embodiment, the cutter stock is selected from light kerosene (LK), heavy kerosene (HK), light gas oil (LGO), heavy gas oil (HGO), Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO) and mixtures thereof. In an embodiment, the cutter stock comprises heavy kerosene having kinematic viscosity ranging from 0.9 to 100cSt at 50oC and boiling point ranging from 100°C to 500°C. In an embodiment, the clarified oil has kinematic viscosity ranging from 10 to 50 cSt at 50oC, and boiling point ranging from 340°C to 600°C. In an embodiment, alpha olefin is C30 alpha olefin.
[0018] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.

DETAILED DESCRIPTION OF THE INVENTION
[0019] The following is a detailed description of embodiments of the present invention. The embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
[0020] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0021] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability.
[0022] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0023] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0024] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0025] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
[0026] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0027] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0028] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0029] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0030] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0031] The term “waxy vacuum residue” as used herein throughout the present disclosure denotes left over fraction of the crude oil, which is obtained at the bottom of Vacuum Distillation Column (VDU), also known as Short residue (SR) having initial boiling point more than 495°C. Particularly suitable for the purpose of the invention of present disclosure are those having content of wax ranging from 10% to 30% by weight.
[0032] The term “cutter stock” as used herein throughout the present disclosure denotes low sulphur refinery streams including, but not limited to, light kerosene (LK), heavy kerosene (HK), light gas oil (LGO), heavy gas oil (HGO) Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO) and mixtures thereof.
[0033] The term “clarified oil” as used herein throughout the present disclosure denotes a complex combination of hydrocarbons produced as the decanted part of settled residual fraction from distillation of the products from a catalytic cracking process. It includes hydrocarbons having carbon numbers predominantly greater than C20 and boiling point ranging from 340°C to 6000C. Particularly suitable in the invention of the present disclosure is a clarified oil having kinematic viscosity ranging from 10 to 50 cSt at 50oC and boiling point ranging from 340°C to 600°C.
[0034] The term “Very Low Sulphur Fuel Oil" or “VLSFO” as used herein, synonymously and interchangeably, throughout the present disclosure denotes a blend of vacuum residue with other residual products of refinery, having sulphur content less than 0.5 wt%.
[0035] The present disclosure pertains to the technical field of refinery heavy product blends. In particular, the present disclosure pertains to an additive for optimizing pour point and viscosity of refinery heavy product blends and a very low sulphur fuel oil composition comprising the advantageous additive of the present disclosure.
[0036] The present disclosure provides an additive for optimizing pour point and viscosity of refinery heavy product blends. Particularly, during extensive experimentation, the inventors of the present disclosure could surprisingly note that a clarified oil and a copolymer of maleic anhydride and alpha olefin, when used in specific proportions, act in synergistic manner and affords exceptional depression in pour point while optimizing viscosity of the refinery blends. It could also be noted, albeit surprisingly, that when the advantageous additive of the present disclosure is used for preparation of VLSFO, it affords reduction in amounts of the cutter stock making the VLSFO significantly economical as compared to conventionally known VLSFO.
[0037] Accordingly, an aspect of the present disclosure provides an additive for optimizing pour point and viscosity of refinery heavy product blends, the additive includes: a clarified oil; and a copolymer of maleic anhydride and alpha olefin, wherein the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1500:1.
[0038] In an embodiment, the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1000:1. In an embodiment, the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 700:1. In an embodiment, the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 600:1. In an embodiment, the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 500:1.
[0039] In an embodiment, the additive comprises the clarified oil in an amount ranging from 20000 ppm to 300000 ppm, and the copolymer in an amount ranging from 200 ppm to 3000 ppm. In an embodiment, the additive comprises the clarified oil in an amount ranging from 30000 ppm to 300000 ppm, and the copolymer in an amount ranging from 500 ppm to 2500 ppm. In an embodiment, the additive comprises the clarified oil in an amount ranging from 50000 ppm to 300000 ppm, and the copolymer in an amount ranging from 500 ppm to 2000 ppm. In an embodiment, the additive comprises the clarified oil in an amount of about 300000 ppm, and the copolymer in an amount of about 1000 ppm.
[0040] In an embodiment, the clarified oil is a complex combination of hydrocarbons produced as the decanted part of settled residual fraction from distillation of the products from a catalytic cracking process. It includes hydrocarbons having carbon numbers predominantly greater than C20 and boiling point ranging from 3400C to 6000C. In an embodiment, the clarified oil has kinematic viscosity ranging from 10 to 50cSt at 50oC. In an embodiment, alpha olefin is C25-C35 alpha olefin. In an embodiment, alpha olefin is C30 alpha olefin. In an embodiment, the co-polymer has comb like structure having rigid backbone with flexible pendant side chains.
[0041] Another aspect of the present disclosure relates to a very low sulphur fuel oil (VLSFO) composition, the composition includes: 50% to 85% by weight of a waxy vacuum residue; 5% to 30% by weight of a cutter stock; and 2% to 30% by weight of an additive, wherein said additive comprises a clarified oil and a copolymer of maleic anhydride and alpha olefin, and wherein the clarified oil and the copolymer are in a weight ratio ranging from 50:1 to 1500:1.
[0042] In an embodiment, the waxy vacuum residue is a left over fraction of the waxy crude oil obtained at the bottom of Vacuum Distillation Column (VDU) having initial boiling point more than about 495oC. In an embodiment, the content of wax in the waxy vacuum residue ranges from 10% to 30% by weight of the waxy vacuum residue. In an embodiment, the waxy vacuum residue has kinematic viscosity ranges from 103 to 109 cSt at 500C and from 102 to 105 cSt at 100oC.
[0043] In an embodiment, the cutter stock comprises one or a combination of low sulphur refinery streams. In an embodiment, the cutter stock is selected from light kerosene (LK), heavy kerosene (HK), light gas oil (LGO), heavy gas oil (HGO), Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO) and mixtures thereof. In an embodiment, the cutter stock comprises heavy kerosene having kinematic viscosity ranging from 0.9 to 100 cSt at 50oC. In an embodiment, the heavy kerosene has boiling point ranging from 100°C to 500°C. In another embodiment, the heavy kerosene has boiling point ranging from 120°C to 290°C.
[0044] In an embodiment, the clarified oil has kinematic viscosity ranging from10 to 50 cSt at 50oC and boiling point ranging from 340°C to 600°C.
[0045] In an embodiment, alpha olefin is C30 alpha olefin.
[0046] Another aspect of the present disclosure relates to a method of preparation of additive, the method comprising the steps of: taking a clarified oil and a copolymer of maleic anhydride and alpha olefin, and mixing said clarified oil and said copolymer of maleic anhydride and alpha olefin in a weight ratio ranging from 50:1 to 1500:1 to obtain the additive. The clarified oil and the co-polymer act in synergistic manner and can find utility in production of very low sulphur fuel oil (VLSFO) with improved cold flow property.
[0047] Further aspect of the present disclosure relates to a method of preparation of very low sulphur fuel oil composition, the method comprising the steps of: taking 50% to 85% by weight of a waxy vacuum residue; heating the waxy vacuum residue at a temperature ranging from 110oC to 120oC to obtain molten waxy vacuum residue; adding 5% to 30% by weight of a cutter stock; and 2% to 30% by weight of a additive into the above molten waxy vacuum residue under continuous stirring to obtain a very low sulphur fuel oil composition. In an embodiment, the heating temperature ranges from 120oC to 140oC. In an embodiment, the additive comprises a clarified oil and a copolymer of maleic anhydride and alpha olefin, wherein the clarified oil and the copolymer are in a ratio ranging from 50:1 to 1500:1.
[0048] Characterization of molten waxy vacuum residue and heavy kerosene
Table 1 below provides the characteristic features of waxy vacuum residue and heavy kerosene used for the preparation of very low sulphur fuel oil (VLSFO) composition.
Table 1: Characterization of waxy vacuum residue and heavy kerosene
KV, cSt @100 oC KV, cSt @50 oC Sulphur,wt% PP, oC Wax Content, wt%
VR-1 434.5 NA 0.574 57 22
VR-2 224.0 NA 0.521 54 20
VR-3 278 NA 0.560 45 15
HK-1 NA 1.4522 0.0413 -39 NA
HK-2 NA 1.4299 0.0343 -33 NA
HK-3 NA 1.3714 0.0260 -39 NA
VR represents vacuum residue, HK represents heavy kerosene and KV represents kinematic viscosity
VR-1 = vacuum residue obtained from crude mixture comprising of Mumbai High (MH) 35%, Kimanis 20%, Azeri Light (AZ) 38%, Cambay Basin (CB) 5%, Kuwait Super Light (KSL) 2%
VR-2 = vacuum residue obtained from crude mixture comprising ofMumbai High 40%, Cambay Basin 33%, West Texas Intermediate (WTI) 27%
VR-3 = vacuum residue obtainedfromcrude mixture comprising of MH 50%, Saharan Blend 50%

[0049] SYNTHESIS OF CO-POLYMER OF MALEIC ANHYDRIDE AND C30 OLEFIN
About 105 g of C30 alpha-olefin and about 25 g of maleic anhydride were charged into reactor and temperature was set to 145oC. As the solid melts, stirring of the reaction mixture was started. Once the temperature reached to about 145oC, about 2.9g of t-butyl hydroperoxide was added in the above reaction mixture in four lots each at an interval of about 1 hr. After the addition of last lot, the reaction mixture was kept at the above temperature for about 1 hr. Later, the reaction mixture was cooled to around 60oC and the product obtained was precipitated in acetone. The precipitated product was collected by filtration and subjected to acetone washing for 2-3 times and finally dried. The chemical structure of the final co-polymer obtained is shown in Formula 1 below
, x = 28
Formula 1. Chemical Structure of co-polymer of maleic anhydride and C30-alpha olefin
[0050] PREPARATION OF VERY LOW SULPHUR FUEL OIL (VLSFO)
[0051] Multiple samples of very low sulphur fuel oil compositions and controls were prepared in accordance with the amount of components disclosed in Table 2 below.
[0052] A required amount of waxy vacuum residue was heated to a temperature of about 120 to 180oC to obtain a melt of the vacuum residue. Molten waxy vacuum residue was taken in a beaker and heavy kerosene was added to it under stirring. A mixture of clarified oil and co-polymer were added into the above mixture under stirring to obtain a very low sulphur fuel oil composition.
[0053] Three control samples were also prepared. First control sample was prepared by mixing required amounts of molten waxy vacuum residue and heavy kerosene, under continuous stirring and heated for few minutes. Second control sample was prepared by mixing required amounts of molten waxy vacuum residue, heavy kerosene and clarified oil under continuous stirring. Third control sample was prepared by mixing required amount of molten waxy vacuum residue, heavy kerosene and co-polymer under continuous stirring.
[0054] PERFORMANCE OF THE ADDITIVE
[0055] The pour point of samples were measured as per ASTM D97. Performance of the additive was studied by measuring the improvement in pour point depression and reduction in the viscosity of the fuel oil.
Table 2: Improvement in pour point depression and kinematic viscosity of the fuel oil
Sr. No. VR Cutter stock
(Heavy Kerosene), wt% Clarified Oil
(CLO)
wt%
(ppm) Pour Point, oC ?PP, oC Kinematic Viscosity (KV), cSt at 50 oC
Without co-polymer With co-polymer (1000 ppm) Without co-polymer With co-polymer (1000 ppm)
1 VR-1
20 0 15 9 6 492 552
2 20 5
(50000) 15 0 15 411 447
3 20 10
(100000) 12 -3 15 344 398
4 20 20
(200000) 12 -3 15 209 236
5 20 30
(300000) 9 -15 24 141 138.5
6 VR-2 21 0 27 12 15 486 450
7 21 10 30 6 24 288 338
8 VR-3 20 0 12 0 12 452 433
9 20 10 9 -9 18 275 298

Table 3: Reduction of cutter stock requirement
Sr. No. VR Cutter stock
(Heavy Kerosene), wt% Additive
(Y/N) Pour Point, oC
Kinematic Viscosity (KV), cSt at 50 oC
1 VR-1 25 N 0 220
2 20 N 15 492
3 15 Y 6 262
4 10 Y 9 553

[0056] As can be seen from Table 2, when only cutter stock (heavy kerosene) in an amount of 20% was added to vacuum residue-1 (VR-1) without any addition of clarified oil (CLO) and co-polymer (See, Sr. No. 1 in table 2) the pour point of the oil was 15oC, however, on addition of 1000 ppm of co-polymer into the mixture, the pour point reduced significantly to 9oC i.e. a depression (?PP/oC) of 6oC was observed on addition of co-polymer alone. Further, on addition of 5% (50000 ppm) CLO into a mixture of VR-1 and 20% HK, the pour point of the fuel oil was still 15oC (Sr. No. 2), however, on addition of 1000 ppm of co-polymer into the mixture containing VR-1, 20% HK and 5% CLO, the pour point was reduced to 0oC i.e. a depression of 15oC was observed, which is higher than that observed in previous case (Sr. No. 1). As can be observed from the experimental data in Table 2, with addition of only CLO, the effect on pour point is not very significant. However, combination of copolymer and CLO leads to dramatic decrease in the pour point, a depression of 24oC could be observed (from 9oC to -15oC) with 30% CLO and 1000 ppm copolymer for VR 1 (Sr. No.5, Table 2) in contrast to only 6oC depression, when only 1000 ppm of copolymer (without CLO) was added. It is clearly evident from the experimental data in Table 2 that there exists a synergism between co-polymer and CLO with regards reduction of pour point of the fuel oil. The utilization of additive (i.e. a combination of CLO and co-polymer) further afforded reduction in viscosity of the fuel oil. Using only co-polymer additive in case of VR2 (Sr. No. 6), the pour point could be reduced to 12oC from 27oC, however, viscosity was higher than required specification for FO380 cSt grade. By incorporating 10% CLO with co-polymer, the pour point was reduced to 6oC along with reduction in viscosity of the blend to 338 cSt, which satisfies the viscosity specification of FO380. Reduction of cutter stock by 20% leads to increase in viscosity above the required specification (Sr. No. 2).
[0057] The combined effect of co-polymer and clarified oil (CLO) on pour point and viscosity can be extended to achieve cutter stock (HK) reduction in other fuel oil compositions as well. In an example provided in Table 3, in order to meet the required specification for FO380, typical (conventional) cutter stock requirement was of 25% (Sr. No. 1). Even reduction of cutter stock to 20% leads to increase in viscosity to above the required specification (Sr. No. 2). However, on using CLO and co-polymer, viscosity similar to that could previously be achieved only with use of 25% cutter stock (Sr. No. 1), but now can be achieved with only 15% cutter stock (Sr. No. 3).
[0058] Accordingly, the present invention demonstrates that addition of the additive containing a clarified oil and a co-polymer of maleic anhydride and alpha olefin into a given blend of waxy vacuum residue not only affords reduction of the pour point thereof by large degree, but also affords desired viscosity thereof. This consequently reduces the amount of cutter stock (such as heavy kerosene) required to be added to the oil to achieve desired properties.

ADVANTAGES OF THE PRESENT INVENTION
[0059] The present disclosure provides an additive for optimizing pour point and viscosity of refinery heavy product blends and a very low sulphur fuel oil composition that overcomes the limitations associated with the conventional compositions.
[0060] The present disclosure provides a new and improved additive.
[0061] The present disclosure provides a new and improved very low sulphur fuel oil composition.
[0062] The present disclosure provides a fuel oil with low pour point and viscosity.
[0063] The present disclosure provides an additive and very low sulphur fuel oil composition containing additive that is cost-effective.
[0064] The present disclosure provides an additive and composition that is easy to prepare.
[0065] The present disclosure provides a method of preparation of additive.
[0066] The present disclosure provides a method of preparation of very low sulphur fuel oil composition.