Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents [Amendment] Rules, 2006

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION:
VALORIZATION OF PITCH FROM RESIDUE UPGRADATION UNIT TO VISCOSITY GRADE BITUMEN (30/40)

APPLICANT
NAME: HINDUSTAN PETROLEUM CORPORATION LTD
NATIONALITY: IN
ADDRESS: Green R&D Centre, KIADB Industrial Area, Tarabanahalli, Devanagundi, Hoskote Taluk Bangalore
PREAMBLE TO THE DESCRIPTION

COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
[001] The invention relates to a blend composition for blending pitch from residue upgradation facility (RUF) with VG-10 bitumen to produce higher-grade bitumen (VG-30/40). Particularly, the invention relates to a blend composition comprising RUF pitch, binder material and slop oil/heavy vacuum gas oil (HVGO). Valorization of the RUF pitch facilitates liquidation of 4-10% of the RUF pitch. The invention also relates to a process of preparation of the blend composition.

BACKGROUND OF THE INVENTION:
[002] Refineries process a wide variety of crude sources. Among these, paving grade bitumen is one of the crude sources. The Indian standard specification for paving bitumen was based on penetration, and it was formulated in 1950. Subsequent amendments were made to the specifications over the years by including various empirical test methods. The penetration-based grading had certain limitations, and to overcome the limitations viscosity-based grading was introduced in the year 2006. The latest revision of the Indian standard specifications for paving grade bitumen, i.e., IS 73 specifications classify the binders into four viscosity-based grades, and these are VG-10, VG-20, VG-30, and VG-40.

[003] Under the Visakh refinery modernization project (VRMP), a 3.55 million metric tons per annum (MMTPA) of residue up-gradation facility (RUF) has been installed. The RUF unit processes vacuum residues (VR) from crude distillation unit (CDU)/vacuum distillation unit (VDU) and clarified oil (CLO) from fluid catalytic cracking (FCC) unit and converts them into light & middle distillates, i.e., LPG, naphtha, diesel, and vacuum gas oil (VGO). It produces pitch as unconverted material. The RUF pitch is approximately 7-10 wt.% (i.e., 750-1050 tons per day) of the total feed to the RUF unit.

[004] For valorization of the RUF pitch, the inventors of the present invention considered a blend study for blending the RUF pitch in appropriate proportion with a binder material and produce higher-grade bitumen (VG-30 or VG-40). This facilitated liquidation of 4-10% of the pitch to fetch price of bitumen.

[005] Several such blend compositions are reported in literature for component blending processes to produce bitumen.

[006] RU publication 2302447C1 by Limited Liability Company "Lukoil-Permnefteorgsintez" discloses a method of producing compounded bitumen by mixing oxidized bitumen with residual petroleum non-oxidized products at elevated temperature. The blend composition comprises tar (1-5 wt.%); slop (4-20 wt.%), extract (5-25 wt.%) and oxidized bitumen (rest wt.% up to 100).

[007] Uma Chakkoth et al. relates to bitumen production using component blending. During the manufacture of blended bitumen, the proportion of the constituents, the temperature during blending, and the duration of blending are selected to meet the penetration at 25°C and the absolute viscosity at 60°C as per the Indian specifications. In the component blending process, different constituents obtained from the refinery units, such as the propane deasphalted (PDA) pitch, low viscous extract, vacuum gas oils, and vacuum tower bottom (VTB) are blended in conditioning tanks.

[008] Another publication by Uma Chakkoth et al. relates to a component blending process, wherein a highly viscous PDA pitch is blended with a less viscous flux. In this publication, two ratios of PDA pitch and flux (75:25 and 80:20) were blended in the laboratory.

[009] G.F.A. Ball et al. relates to blends of tall oil pitch (TOP) and petroleum bitumen as potential binders for road surfacing. The physical properties (i.e., viscosity, penetration, softening point) of TOP/bitumen blends (up to 30% w/w TOP) were identified to be similar to those of petroleum bitumen alone.

[0010] M. A. Poirier et al. focuses on the use of processed residues to produce roofing asphalts. Results show that 28-30 wr% of processed residue can be blended with 150-200 penetration asphalt cement to produce Type I roofing asphalt. The physical properties of the roofing asphalts were examined in terms of the composition (i.e., saturates, aromatics, resins, and asphaltenes) as well as average molecular weight of the maltenes and asphaltenes determined by gel permeation chromatography. The results are compared with two roofing asphalts obtained from petroleum refineries.

[0011] It can be observed that pitch is one of the products from RUF units and the quantity is significant. The disposal of pitch is a major concern for refineries today. With some quantity of pitch getting blended with VG-10 bitumen/vacuum residue to make higher-grade bitumen (VG-30/40), the concern of disposal of pitch will be reduced to the extent of blend portion. Therefore, the inventors of the present invention have aimed for valorization of the pitch generated to viscosity grade bitumen as per IS 73 specifications. The blend composition for blending RUF pitch to produce higher-grade bitumen (VG-30/40) comprises RUF pitch, binder material and slop oil/heavy vacuum gas oil (HVGO). This results in liquidation of 4-10% of RUF pitch to fetch price of bitumen.

SUMMARY OF THE INVENTION:
[0012] The present invention discloses a blend composition comprising RUF pitch, binder material and slop oil/heavy vacuum gas oil (HVGO). The binder material is a lower-grade bitumen, which is selected from a group consisting of vacuum tower bottom, short residue, vacuum residue, or VG-10 bitumen. The blend composition enables blending RUF pitch with lower-grade bitumen to produce higher grade bitumen (VG-30/40).

TECHNICAL ADVANTAGES OF THE INVENTION:
[0013] The present invention has the following advantages over the cited prior arts:
(i) Blending of RUF pitch with lower-grade bitumen enables liquidation of 4-10% of the RUF pitch to fetch price of bitumen.
(ii) It reduces the concern of disposal of pitch to the extent of blend portion.
(iii) Addition of pitch increases the ageing susceptibility of the binder material (i.e., lower-grade bitumen) due to the presence of higher amount of heteroatoms and metals.

OBJECTIVES OF THE INVENTION:
[0014] It is a primary objective of the present invention to provide a blend composition for blending pitch from residue upgradation unit with VG-10 bitumen to produce higher-grade bitumen (VG-30/40).

[0015] It is another objective of the present invention to provide a blend composition comprising 5-15 wt.% pitch from residue upgradation unit; 60-80 wt.% binder material; and 10-15 wt.% heavy vacuum gas oil (HVGO) or slop oil.

[0016] Yet another objective of the present invention is to provide that a weight ratio for pitch: binder material is 10: 90, for making higher-grade VG-30/40 bitumen.

ABBREVIATIONS:
RUF: residue upgradation facility
HVGO: heavy vacuum gas oil
VRMP: Visakh refinery modernization project
MMTPA: million metric tons per annum
VR: vacuum residues
CDU: crude distillation unit
VDU: vacuum distillation unit
CLO: clarified oil
FCC: fluid catalytic cracking
VGO: vacuum gas oil
PDA: propane deasphalted
VTB: vacuum tower bottom
TOP: tall oil pitch
SARA: saturates, aromatics, resins and asphaltenes
MCRT: micro carbon residue test
RTFOT: rolling thin-film oven test
rpm: revolutions per minute
mm: millimeter

DETAILED DESCRIPTION OF THE INVENTION:
[0017] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such components of the composition, features of composition, referred to or indicated in this specification, individually or collectively and any and all combinations of any or more of such components or features.

Definitions
[0018] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have their meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0019] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0020] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”.

[0021] Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.

[0022] The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.

[0023] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0024] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products and processes are clearly within the scope of the disclosure, as described herein.

[0025] The present invention relates to a blend composition for blending pitch from residue upgradation unit with VG-10 bitumen to produce higher-grade bitumen (VG-30/40) as per IS 73 specifications. The blend composition comprises: 5-15 wt.% pitch from residue upgradation unit; 60-80 wt.% binder material; and 10-15 wt.% heavy vacuum gas oil (HVGO) or slop oil. This enables valorization of pitch from residue upgradation unit to viscosity grade bitumen (VG-30/40).

[0026] In yet another embodiment, the binder material comprises lower grade bitumen, which is selected from a group consisting of vacuum tower bottom, short residue, vacuum residue, or VG-10 bitumen.

[0027] In another embodiment of the invention, the higher-grade bitumen comprises VG-30 bitumen or VG-40 bitumen.

[0028] In another embodiment of the invention, the ratio of pitch: binder material is 10:90 by weight for making higher-grade VG-30/40 bitumen. Furthermore, the blend ratio can be adjusted during actual blending based on pitch properties obtained from RUF unit.

[0029] In another embodiment, the present invention relates to blending less amount of pitch with more amount of binder material, i.e., lower grade bitumen, to produce a higher-grade bitumen.

[0030] In another embodiment of the invention, the present invention facilitates liquidation of 4-10% of the pitch to fetch price of bitumen.

[0031] In another embodiment of the invention, the blend composition is prepared under optimized blending conditions for homogenous blending of RUF Pitch, HVGO/Slop oil, and binder material in appropriate ratios. The optimized blending conditions comprise heating the binder material to a temperature present in a range of 180-220°C for 15-20 minutes; to which the HVGO/slop oil and pitch is added for homogenous blending.

[0032] In yet another embodiment of the invention, the process for preparation of blend composition comprises:
(a) grinding RUF pitch initially to a powder form;
(b) heating a binder material and adding HVGO/slop oil to the binder material while stirring for 5-10 minutes to ensure proper mixing;
(c) adding required amount of pitch from step (a) in small portions over a period of 10-15 minutes to obtain a reaction mixture; and
(d) stirring the reaction mixture for 2-3 hours based on the amount of pitch added for uniformity of the reaction mixture to obtain higher-grade bitumen.

[0033] In another embodiment, a sample of the higher-grade bitumen is collected and checked for IS 73 specifications.

[0034] In yet another embodiment, the RUF pitch in powder form in present in a size range of below 1 mm.

[0035] In another embodiment, the binder material is heated to a temperature present in a range of 180-220°C for 15-20 minutes.

[0036] In yet another embodiment, the process of stirring is performed between 250-300 revolutions per minute (rpm) using an overhead stirrer.

EXAMPLES:
[0037] Having described the basic aspects of the present invention, the following non-limiting examples illustrate specific embodiments thereof. Those skilled in the art will appreciate that many modifications may be made in the invention without changing the essence of the invention.

Example 1: Amount of saturates, aromatics, resins and asphaltenes in components of blend composition
[0038] The RUF pitch comprises approximately 50 wt.% asphaltenes. Initially, RUF pitch is ground into powder form. This RUF pitch is blended with VG-10 bitumen to prepare bitumen (VG-30/40) as per IS 73 specifications. Table 1 discloses the amount of saturates, aromatics, resins and asphaltenes (SARA) present in the components of the blend composition along with other extracts and PDA pitch, in terms of wt.%.
Fraction Saturates Aromatics Resins Asphaltenes
HVGO 20 9.6 70.4 Nil
VG 10 5.0 18.0 64.2 12.8
Slop 63.5 5.6 30.8 0.1
Extracts 150N 3 92.9 4.1 Nil
Extracts 500N 5.3 89.8 4.9 Nil
PDA Pitch 0.7 21.8 60.3 17.2
RUF Pitch Nil Nil 51-59 41-49
Table 1: Amount of saturates, aromatics, resins and asphaltenes

[0039] The powdered pitch is stabilized by adding other fractions, i.e., binder material and HVGO/slop oil, to ensure the saturates, aromatics, resins and asphaltenes (SARA) balance. The SARA balance ensures blend stability. The addition of pitch increases the ageing susceptibility of binder material due to the presence of higher amount of heteroatoms and metals.

Example 2: Comparison of different types of pitch
[0040] Four analysis were conducted by various test methods to distinguish pitch samples, i.e., RUF pitch, PDA pitch and VG-10 bitumen, as disclosed in Table 2.
Sample SARA, wt.%, IP469 MCRT, wt.%, ASTM D4530 Separability No., ASTM D7061 Sulphur wt.%, ASTM D4294 Asphaltenes, wt.%,
IP143
S A R A
RUF Pitch 0.9 51 24.6 23.5 65.3 16.7 3.8 71.7
PDA Pitch 1.1 73.4 8 17.5 26.3 5.1 6.4 18.1
VG-10 bitumen 2.6 47.4 37.1 12.9 23.3 6.4 7.4 13.6
Table 2: Comparison of different types of pitch

[0041] The results reveal that RUF pitch is much different from PDA pitch and VG-10 bitumen in terms of saturates, aromatics, resins, asphaltenes (SARA) distribution, micro carbon residue test (MCRT), separability number, sulfur content and asphaltene analysis. Also, RUF pitch is better in terms of economic aspect, as it is priced lower as compared to PDA pitch and VG-10 bitumen. Further, the value of RUF pitch is increased by mixing it with binder material and HVGO/slop oil to prepare higher-grade bitumen.

Example 3: Test analysis for different blend compositions
[0042] Table 3 discloses the test analysis for different blend compositions – VG-10 sample (VR), 10% Pitch Blended in VG-10 (binder), 10% HVGO + 10% Pitch + 80% VG-10 (binder); and 10% Slop Oil + 10% Pitch + 80% VG-10 (binder). This is compared to standard VG-10, VG-20, VG-30, and VG-40 as per IS 73 specifications.
Test Description IS 73
VG 10 IS 73
VG 20 IS 73
VG 30 IS 73
VG 40 VG 10 sample (VR) 10% Pitch Blended in VG-10 10% HVGO + 10% Pitch + 80% VG-10 10% Slop Oil + 10% Pitch + 80% VG-10
Penetration at 25°C, 0.1mm, min 80 60 45 35 74 30 114 68
Softening Point, °C min 40 45 47 50 44.2 52.8 41.6 45.7
Kinematic Viscosity @135°C cst min 200 300 350 400 286.2 514.7 240.51 335.31
Absolute Viscosity @60°C, poises 800-1200 1600-2400 2400-3600 3200-4800 856.5 3570 677.6 1563.6
After RTFOT
Viscosity Ratio at 60°C, Max 4.0 4.0 4.0 4.0 4.04 5.43 3.12 2.87
Ductility at 25°C, cm, min 75 50 40 25 >75 127 62.0 51.5
Table 3: Test Analysis for different blend compositions
*RTFOT: rolling thin-film oven test

Example 4: Test analysis for different pitch: binder ratio
[0043] Table 4 discloses the analysis of VG-30 bitumen, VG-40 bitumen, VG-10 bitumen, vacuum tower bottom (VTB), blend 1 (pitch: binder = 10:90), blend 2 (pitch: binder = 7.5:92.5) and blend 3 (pitch: binder = 6:94). The binder material consists of lower-grade bitumen.
VG 30 VG 40 VTB (Binder) 100 90 92.5 94
VG10 100 Blend 1 Blend-2 Blend-3
Pitch 10 7.5 6
45 35 Penetration at 25°C, 0.1mm, min 84 112 43 47 63
47 50 Softening Point, °C min 41.2 42 52.2 48.9 47.8
350 400 Kinematic viscosity @135°C cst min 249.9 277.6 528 499.91 402.6
2400-3600 3200-4800 Absolute Viscosity @60°C, poises 804.2 1017.38 3564.16 2982.11 2215.7
After RTFOT
Viscosity at 60°C, poises 1796.22 2157.82 13665.1 11033.81 5981.065
40 25 Ductility at 25°C, cm, min >75 >75 28 40 46
4 4 Viscosity Ratio 2.25 2.12 3.8 3.7 2.7
Table 4: Test Analysis for different bitumen specifications
*RTFOT: rolling thin-film oven test

[0044] Therefore, it is observed from Table 4 that blend 1 specification are close to VG-40 grade bitumen. With further fine tuning on blend ratios the specifications can be met comprehensively. It can be concluded that pitch blending more than 10 wt.% is not a feasible blend option to meet the VG-40 higher-grade bitumen. The ratio of pitch: binder: 10: 90 by wt.% can be considered for making VG-40 higher-grade bitumen depending on actual pitch obtained from RUF.

Example 5: Preparation of blend composition

[0045] Initially the RUF pitch is ground to a powder form in a size range of below 1 mm. 60-80 wt.% binder material is heated to a temperature present in a range of 180-220°C for 15-20 minutes. To this binder material, 10-15 wt.% of HVGO/slop oil is added while stirring for 5-10 minutes using an overhead stirrer. To this mixture, 5-15 wt.% powdered pitch is added in small portions over a period of 10-15 minutes to obtain a reaction mixture. The reaction mixture is stirred for 2-3 hours based on the amount of powdered pitch added to obtain higher-grade bitumen. Finally, a sample of the higher-grade bitumen is collected and checked for IS 73 specifications.
, Claims:We claim:

1. A blend composition for producing higher-grade bitumen, the composition comprising:
a) 5-15 wt.% pitch from residue upgradation unit;
b) 60-80 wt.% binder material; and
c) 10-15 wt.% heavy vacuum gas oil (HVGO) or slop oil.

2. The composition as claimed in claim 1, wherein the binder material consists of lower-grade bitumen.

3. The composition as claimed in claim 2, wherein the lower-grade bitumen is selected from a group consisting of vacuum tower bottom, short residue, vacuum residue, or VG-10 bitumen.

4. The composition as claimed in claim 1, wherein the higher-grade bitumen comprises VG-30 bitumen or VG-40 bitumen.

5. The composition as claimed in claim 1, wherein the ratio of pitch: binder material is 10:90 by weight.

6. A process for preparation of the blend composition as claimed in claim 1, the process comprising:
(a) grinding RUF pitch initially to a powder form;
(b) heating a binder material and adding HVGO/slop oil to the binder material while stirring for 5-10 minutes;
(c) adding required amount of pitch from step (a) in small portions over a period of 10-15 minutes to obtain a reaction mixture; and
(d) stirring the reaction mixture for 2-3 hours based on the amount of pitch added to obtain higher-grade bitumen.

7. The process as claimed in claim 6, wherein size range of the RUF pitch in the powder form is below 1 mm.

8. The process as claimed in claim 6, wherein the binder material in step (b) is heated to a temperature present in a range of 180-220°C for 15-20 minutes.

9. The process as claimed in claim 6, wherein the binder material consists of lower-grade bitumen selected from a group consisting of vacuum tower bottom, short residue, vacuum residue, or VG-10 bitumen.

10. The process as claimed in claim 6, wherein the higher-grade bitumen comprises VG-30 bitumen or VG-40 bitumen.