WO2011074003A2

WO2011074003A2 - Crumb rubber modified bitumen (crmb) compositions and process thereof

Info

Publication number: WO2011074003A2
Application number: PCT/IN2010/000808
Authority: WO
Inventors: Biswanath Saha; Sonal Maheshwari; Paramasivam Senthivel; Nettem Venkateswarlu Choudary
Original assignee: Bharat Petroleum Corporation Ltd.
Priority date: 2009-12-14
Filing date: 2010-12-14
Publication date: 2011-06-23
Also published as: WO2011074003A3

Abstract

The present invention relates to a modified bitumen composition comprising bitumen; crumb rubber; FCC spent catalyst; and optionally at least one low value polymer. The present invention also discloses a method for making a modified bitumen composition comprising heating bitumen to a temperature between about 120 degree C and about 200 degree C; adding FCC spent catalyst to the heated bitumen to obtain a mixture; optionally adding at least one low value polymer to the above mixture followed by homogenizing the mixture for about 30 minutes to about 10 hours; adding crumb rubber to the mixture; and homogenizing the resultant mixture for about 30 minutes to about 24 hours to obtain the modified bitumen.

Description

CRUMB RUBBER MODIFIED BITUMEN (CRMB) COMPOSITIONS AND

PROCESS THEREOF FIELD OF THE INVENTION

The present invention relates to a modified bitumen composition comprising of bitumen, crumb rubber, FCC spent catalyst and optionally at least one low value polymer. The invention also relates to a process for preparation of the modified bitumen composition.

The present invention is directed in a third aspect to novel method for the disposal of spent FCC catalyst and one or more low value polymers.

BACKGROUND

It is a conventional practice to incorporate scrap rubber particles into bitumen to use it as paving or sealing material. Such scrap rubber particles are referred as ground tyre rubber (GTR) or crumb rubber (C ) which h e particle size less than about 5mm and preferably have a particle size of less thas d$¾¾¾t 2 mm. The crumb rubber can include the materials obtained from grinding -slf¾sed truck tyres or automobile tyres or from any other appropriate source of ground rubber. In addition to above, rubber component- mixed with bitumen can include-sSu ^ rubber, butadiene styrene rubber, ethylene propylene rubber, etc. The bitumen base material incorporating such crumb rubber particles can be of any suitable type such as derived from petroleum refining operations and includes aliphatic, aromatic hydrocarbons and heterocyclic compounds including asphaltenes and maltenes of fairly high molecular weight.

The use of crumb rubber and polyphosphoric acid in bitumen is described in WO

04/081098. This patent application describes the properties of bitumen binder advantageously modified by combining between 0.5% by weight to 5% by weight of Polyphosphoric acid and between 0.5% by weight to 25% by weight of crumb rubber with bituminous binder.

US Patent US7335251 describes a process for enhancing the physico-chemical properties of bitumen compositions and their uses by mixing functionalized amorphous silica made by combining amorphous silica with a coupling agent with bituminous material. In US patent application number 20080015287, the use of zinc oxide claimed to facilitate the incorporation of crumb rubber into a bitumen base material at moderate temperatures.

The FCC catalyst is a coarse powder, basically contains 20-50% of an active zeolite, alumina, clay as filler and amorphous silica or silica alumina binder. It is used in the secondary processing to convert the heavy feed stocks like Vacuum Gas Oil (VGO) in to lighter valuable products. During this process, at a particular stage activity and selectivity of the catalyst is exhausted and catalyst gets contaminated with coke, sulfur, vanadium, and nickel in a manner and at a level, which makes regeneration impractical and the same is considered "spent catalyst" and it needs to be disposed. Many issues are associated with available disposal methods which are (i). use of VGO FCC spent catalyst in Residue FCC units, (ii). disposal in landfills and iii. use of demetalising technology.

The present invention also provides novel method for the disposal of spent FCC catalyst and one or more low value polymers. OBJECTIVES

An object of the present invention is to provide a viable methodology for the use of FCC spent catalyst and/or one or more low value polymers thereby resolving disposal and environment related issues. Another object of the present invention is to provide bituminous binder material with a relatively high elasticity, an acceptable rotational viscosity and that can be stored for adequate periods of time. Another object of the present invention include methods of making modified bitumen having all required properties by incorporating FCC spent catalyst and/or one or. more low value polymer materials along with crumb rubber into bitumen. SUMMARY

The present invention provides a modified bitumen composition comprising (a) 40-98% by weight of bitumen; (b) 0,5-25% by weight of crumb rubber; (c) 0.5-5% by weight of FCC spent catalyst; and .(d) optionally 0.5-20% by weight of at least one low value polymer.

There is also provided a method for preparing homogenous blend of bitumen, crumb rubber, FCC spent catalyst and /or low value polyfilm material. In carrying out the invention, bitumen base material is heated in a mixing vessel to a temperature sufficient to allow the stirring of the bitumen base material within mixing vessel. While the bitumen is stirred within the mixing vessel, a particulate crumb rubber modifier material having designated average particle size is added to the bitumen base material. In addition to the rubber component, FCC spent catalyst and /or one or more low value polymer material is added to the bitumen base material. The bitumen/crumb rubber &/or low value polyfilm mixture incorporating FCC spent catalyst is stirred for a period sufficient to provide for substantial solubilization of the crumb rubber within bitumen base material to provide a blend which has a higher homogeneity and improved modified bitumen properties.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This Summary is provided to introduce a selection of concepts in a simplified form. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a modified bitumen composition comprising (a) 40-98% by weight of bitumen; (b) 0.5-25% by weight of crumb rubber; ^'(c) 0.5-5% by weight of FCC spent catalyst; and (d) optionally 0.5-20% by weight of at least one low value polymer.

The crumb rubber used in the present invention is the pre-treated crumb rubber which is commercially available.

The low value polymers used in the present modified bitumen composition are polymers which are of low economical value such as waste plastic or discarded polymer material. These are preferably used in the invention as presses material or powdered material and can also be refered to as low value polyfilm.

An embodiment of the present invention is the modified bitumen composition, wherein the crumb rubber comprises grounded scrap truck tyres and grounded automobile tyres. The crumb rubber in the composition of the present invention also comprises natural rubber, butadiene styrene rubber or ethylene propylene rubber, or mixtures thereof, which forms another embodiment of the invention. Yet another embodiment of the present invention is the modified bitumen composition, wherein the crumb rubber has particle size distribution ranging from 10 to 2000 microns.

Still another embodiment of the present invention is the modified bitumen composition, wherein the bitumen comprises aliphatic, aromatic hydrocarbons and heterocyclic compounds, asphaltenes, maltenes, or bitumen derived from petroleum refining.

Another embodiment of the present invention is the modified bitumen composition, wherein the FCC spent catalyst has average particle size less than 100 μτη, preferably less than 75 μηι.

In another embodiment of the present invention the low value polymer in the modified bitumen composition, comprises low-density polyethylene, high-density polyethylene, polypropylene, and the co polymer thereof. The low value polymer also comprises shredded particle of size less than 5mm, preferably less than 3 mm, which is another embodiment of the invention.

Still another embodiment of the present invention is the modified bitumen composition, comprising (a) 80-98% by weight of bitumen; (b) 0.5- 15% by weight of crumb rubber; (c) 0.5-5% by weight of FCC spent catalyst; and (d) optionally 0.5-5% by weight of at least one low value poly film.

Further embodiment of the present invention is the modified bitumen composition comprising (a) 88-98% by weight of bitumen; (b) 0.5-7% by weight of crumb rubber;(c) 0.5-3% by weight of FCC spent catalyst; and (d) 0.5-3% by weight of at least one low value polymer.

An embodiment of the present invention is a method for making a modified bitumen composition, said method comprising:

a. heating bitumen to a temperature between about 120 degree C and about 200 degree C;

b. adding FCC spent catalyst to the heated bitumen to obtain a mixture; c. optionally adding at least one low value polymer to the above mixture followed by homogenizing the mixture for about 30 minutes to about 10 hours;

d. adding crumb rubber to the mixture; and e. homogenizing the resultant mixture for about 30 minutes to about 24 hours to obtain the modified bitumen.

Further . embodiment of the present invention is the method for making the modified bitumen composition, wherein homogenizing is performed to provide substantial solubilization of the crumb rubber, low value polymer within bitumen base material.

The rubber component chosen in the present invention can include natural rubber, butadiene styrene rubber, ethylene propylene rubber, etc. The invention is not limited in this regard any appropriate polymer may be used in this process of modified bitumen.

The bitumen base material incorporating such crumb rubber particles can be of any suitable type such as derived from petroleum refining operations and includes aliphatic, aromatic hydrocarbons and heterocyclic compounds including asphaltenes and maltenes of fairly high molecular weight.

In the present invention, FCC Spent catalyst and low value poly film were utilized to modify the bitumen along with the crumb rubber.

An embodiment of the present invention is the utilization of FCC spent catalyst which is usually to be disposed off, in the preparation of the bitumen composition of present invention.

Low value film materials mainly consist of plastomeric polymer like low-density polyethylene, high-density polyethylene, polypropylene, etc and their co polymer. Therefore, the invention is not limited in this regard to any particular type of polymer and included appropriate polymer of plastomeric or elastomeric or thermoset polymer type may be used in this process of modified bitumen. Preferably the low value polymer used is thermoplastic.

The present invention describes that the addition of spent FCC catalyst and/or low value polymer in Crumb Rubber Modified Bitumen (CRMB) can improve the consistency and properties of the bituminous binder at high and low temperatures. In particular, the modified bitumen of the present invention exhibit improved elastic behavior, resulting in improved performance of roads or other surfaces paved using the modified bitumen binder. Road resistance to permanent deformation, fatigue cracking and thermal cracking is enhanced by the use of modified bitumen binder. A laboratory reactor (capacity: about 2 litre) and Homogenizer (Make: IKA T50) were used for lab scale studies. Scale up studies were carried out using the pilot unit (Make: M/s ENH engineering, Denmark) equipped with a high speed colloid mill. In the first stage, bitumen (VG-30 or VG-10) is heated to temperature of about 120°C-200°C. 5 In the second stage, crumb rubber modifier, FCC spent catalyst and / or low value polyfilm were slowly added to bitumen one by one or, any two component first and thereafter third component or all together at a time and then the mixture is kept in homogenized condition by circulation for 10 min to 24 hrs. The speed of the homogenizer ranges 4000 rpm-l OOOOrpm. In the final stage, modified bitumen is taken0 out and evaluated as per IS 15462-2004 specifications and standard test methods given thereof as well as ASTM & AASHTO methods wherever applicable.

EXAMPLES

The invention will now be illustrated with working examples, which is intended5 to illustrate the working of invention and not intended to take restrictively to imply any limitations on the scope of the present invention.

Typical properties of base bitumen (VG-30 grade), crumb rubber modifier (Commercial grade) and FCC spent catalyst are given in Table 1, 2 & 3 respectively.

Table -1

s.

Characteristics VG 30 Bitumen IS-73:2006 spec

No.

1 Absolute viscosity at 60°C, Poises 2887 2400 (min)

2 Kinematic Viscosity @135°C, cSt 675 350 (min)

3 Flash Point, °C(Cleveland open cup), °C >220 220 (min)

4 Solubility in Trichloroethylene,% 99.9 99.0 (min)

5 Penetration at 25°C, 0.1 mm, lOOg, 5s 63 50-70

6 Softening Point, (R&B), °C 53 47 (min)

7 Tests on residue from thin film oven tests RTFOT

I Viscosity Ratio at 60°C 2.0 4.0 (max)

Ii Ductility at 25°C,cm, after Thin film oven test >150 75 (min) Table -2

Table -3

S. No Characteristics FCC Spent Catalyst

1. Particle Size Distribution , -105 -80 -60 -40 -20

% wt 70 43 21 7 1

2. Catalyst Components by ICP

analysis.

1. A1₂0₃ , wt% 41.1

2. Re₂0₃ ,wt% 1.6

3. Ni, wt% 0.0746

4. V, wt% 0.0460

5. Fe, wt% 0.36

6. Na, wt% 0.22

7. C, wt% 0.45

8. MgO, wt% 0.37

9. P, wt% 0.38 EXAMPLE 1

Neat bitumen VG-30 (3.6 Kg) was heated to 150°C in a mixing vessel. At this temperature, Crumb Rubber Modifier (8 wt %), and FCC Spent catalyst (2 wt %) were added together into hot bitumen. This mixture was kept under continuous circulation during the mixing process. After mixing the Crumb Rubber and Spent Catalyst, mixture was passed through a shear mill for about 30 min to make the mixture homogeneous. After this process mixture was kept in the circulation in the mixing tank for about 2-3 hrs for digestion and temperature was maintained at 150°C-160°C. At the end of the preparation, end product was taken out and evaluated as per IS 15462-2004. The product found to meet specification for CRMB 55 grade. Test results are given in Table-4.

Table 4

EXAMPLE 2

Neat bitumen VG-30 was taken in a mixing vessel of the pilot plant and heated to 150°C. After reaching the temperature, crumb rubber modifier (7 Wt %) was added slowly into the hot bitumen. Thereafter, FCC spent Catalyst (3 Wt %) was slowly added to the mix Bitumen and Crumb Rubber. Both crumb rubber and FCC spent catalyst were added in about 1 hr. The obtained mixture was kept under agitation and circulation to give uniform mixing. After sufficient mixing the modifier and spent catalyst in bitumen, it was passed through the mill to get a homogenous product. After 30 min, resultant mix was kept back in the mixing vessel for about 3 hours for digestion. After digestion, final product was evaluated as per IS 15462-2004. Product is meeting the specification for CRMB 55 grade. Test results are given in Table-5. Table 5

FRASS Breaking IS 9381

-13 -13 - point, °C

Original Binder AASTHO verification, °C T 315

69 65 - (Using Dynamic

Shear R eometer)

* Contains 8% Crumb rubber modifier EXAMPLE 3

Neat bitumen VG-10 grade heated to 150-155°C in the mixing/ heating tank of the pilot plant unit. To this hot bitumen, FCC Spent Catalyst (2 wt %) and Crumb rubber (12 wt %) was added slowly one followed by another to prepare CRMB 60. During the process of mixing, the mix was then subjected to continuous agitation and circulation to maintain the consistency. After 30 minutes period, resultant product was passed through a circulation mill to give even distribution of crumb rubber and catalyst particle into bitumen. Thereafter, the product was kept in the mixing tank for digestion. The digestion period was about 3-4 hours to get good swelling of crumb rubber particles. Finally, product was taken out and tested for its properties as per IS 15462-2004. Test results are given table in Table-6.

Table 6

S. No. Characteristics Results CRMB 60 Test

As per IS Methods 15462:2004

1 Penetration at 25°C, 0.1 mm, l OOg, 5s 40 <50 IS 1203

2 Softening Point, (R&B), °C 67 60 Min IS 1205

3 Viscosity @150°C, P(Rotational IS 1206 / Viscosity) 7.6 3-9 ASTM D- 4402

4 Elastic recovery of half thread in Annex A

54 50 in

ductilometer at 15°C, %

5 Separation difference in softening Annex B

3 4 Max

points (R&B)°C

6 TFOT

i Loss in mass on heating, %,max <1 1 Max IS 9382 ii Increase in softening point,(R&B), °C 3 5 Max IS 1205 iii Reduction in Penetration of residue at IS 1203

37 40 Max

25°C, %

iv Elastic Recovery of Half thread in 48 35 Min Annex A ductilometer at 25°C,%

Additional Tests

7 FRASS Breaking point, °C -12 - IS 9381

8 Original Binder verification, °C AASTHO

77 - (Using Dynamic Shear Rheometer) T 315

EXAMPLE 4

Bitumen VG-30 was heated to 150°C in the mixing tank. Total batch size was 5 Kg. Mixture of Crumb Rubber (10 wt %) and FCC Spent catalyst (3 wt %) were intermittently added into hot bitumen (VG-30 grade). Resultant mixture was agitated continuously at a specified speed to give uniform mixing to the product. After 30 minutes, mixture was passed through the shear mill for about 1-2 hr. The end product was evaluated for its characteristics as IS 15642-2004. It met the specifications for CRMB 60. Test results are given in Table-7.

Table 7

Elastic Recovery of Half Annex A thread in ductilometer at 71 52 35 Min iv 25°C,%

Additional Tests

7 FRASS Breaking point, °C -12 -11 IS 9381

8 Original Binder verification, AASTH °C O T 315

76 73 -

(Using Dynamic Shear

Rheometer)

* Contains 10% Crumb rubber modifier EXAMPLE 5

This example illustrates the preparation of CRMB 55 in the laboratory batch. In this batch, 340 gm of bitumen VG-10 was taken in a glass reactor which was then heated to 175-180°C. FCC spent catalyst (2 wt %) was added slowly into the bitumen once it reached reaction temperature. After complete addition of spent catalyst, shredded low value poly film (2 wt %) was added to the mixture. This mixture was kept under agitation by high torque laboratory stirrer for about 30 minutes and then temperature was reduced to 150-160°C. When temperature reached, Crumb Rubber (11 wt %) was added to the mixture. Resultant solution was then kept in agitation for 2-3 hrs for the digestion of the crumb rubber particles. At the end of the process, product was taken out and evaluated for its preliminary and critical properties as per SI 15462-2004. It met the specification for CRMB 60. Test data given in Table-8.

Table 8

S. No Characteristics Results CRMB 60 Test

As per IS Methods 15462:2004

1 Penetration at 25°C, 0.1 mm, l OOg, IS 1203

45 <50

5s

2 Softening Point, (R&B), °C 62 60 Min IS 1205

3 Viscosity @150°C, P(Rotational IS 1206 / Viscosity) 8.3 3-9 ASTM D- 4402

4 Elastic recovery of half thread in Annex A

66 50 Min

ductilometer at 15°C, %

5 Separation difference in softening Annex B

3 4 Max

points (R&B),°C

6 Thin film oven test

I Loss in mass on heating, %,max <1 1 Max IS 9382 Ii Increase in softening point,(R&B), IS 1205

5 5 Max

°C

iii Reduction in Penetration of residue IS 1203

38 40 Max

at 25°C, %

iv Elastic Recovery of Half thread in Annex A

64 35 Min

ductilometer at 25°C,%

Additional Tests

7 FRASS Breaking point, °C -13 - IS 9381

8 Original Binder verification, °C AASTHO

81 - (Using Dynamic Shear Rheometer) T315

EXAMPLE 6

This example illustrates the preparation of CRMB 55 in the laboratory scale. Batch size was planned to 500 gm. 435 gm of bitumen VG-10 was taken in a glass reactor. This was heated to 180°C, FCC Spent Catalyst (1 wt %) was added to it slowly. After catalyst addition, low value poly film (1 wt %) was added to it and mixture was kept under agitation to provide uniform mixing for about 30 min. This mixture was then cooled to 150-160°C. After cooling it to 160°C Crumb Rubber (1 1 wt %) was added to this mixture and was kept in continuous agitation for 2-3 hrs for the swelling of Crumb Rubber particles (Digestion). After digestion, product was taken out and evaluated for its preliminary and critical properties. It was found to meet the specification of CRMB 55 as per IS 15642-2004. Test data given in Table-9. Table 9

S. No Characteristics Results CRMB 60 Test Methods

As per IS

15462:2004

1 Penetration at 25°C, 0.1 IS 1203 mm, lOOg, 5s 49 <60

2 Softening Point, (R&B), IS 1205

59 55 Min

°C, min

3 Viscosity @150°C, IS 1206 / ASTM

8.0 3-9

P(Rotational Viscosity) D-4402

4 Elastic recovery of half Annex A thread in ductilometer at 66 50 Min

15°C, %

5 Separation difference in Annex B

4 4 Max

softening points (R&B),°C,

6 Thin film oven test

I Loss in mass on heating, <1 1 Max IS 9382 %,max

Ii Increase in softening IS 1205

6 6 Max

point,(R&B), °C

iii Reduction in Penetration IS 1203

39 40 Max

of residue at 25°C, %

iv Elastic Recovery of Half Annex A thread in ductilometer at 59 35 Min

25°C,%

Additional tests

7 FRASS Breaking point, °C -10 - IS 9381

8 Original Binder AASTHO T 315 verification, °C

79 - (Using Dynamic Shear

Rheometer)

Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

Claims

1. A modified bitumen composition comprising: (a) 40-98% by weight of bitumen; (b) 0.5-25% by weight of crumb rubber; (c) 0.5-5% by weight of FCC spent catalyst; and (d) optionally 0.5-20% by weight of at least one low value polymer.

2. The composition as claimed in claim 1, wherein the crumb rubber comprises grounded scrap truck tyres and grounded automobile tyres.

3. The composition as claimed in claim 1, wherein the crumb rubber comprises natural rubber, butadiene styrene rubber or ethylene propylene rubber, or mixtures thereof.

4. The composition as claimed in claim 1, wherein the crumb rubber has particle size distribution ranging from 10 to 2000 microns.

5. The composition as claimed in claim 1, wherein the bitumen comprises aliphatic, aromatic hydrocarbons and heterocyclic compounds, asphaltenes, maltenes, or bitumen derived from petroleum refining.

6. The composition as claimed in claim 1, wherein the FCC spent catalyst has average particle size less than 100 urn.

7. The composition as claimed in claim 6, wherein the average particle size of FCC Spent catalyst is preferably less than 75 μηι.

8. The composition as claimed in claim 1 , wherein low value polymer comprises low-density polyethylene, high-density polyethylene, polypropylene, and the co polymer thereof.

9. The composition as claimed in claim 1, wherein the low value polymer comprises shredded particle of size less than 5mm, preferably less than 3 mm.

10. The composition as claimed in claim 1 comprising (a) 80-98% by weight of bitumen; (b) 0.5-15% by weight of crumb rubber; (c) 0.5-5% by weight of FCC spent catalyst; and (d) optionally 0.5-5% by weight of at least one low value poly film.

11. The composition as claimed in claim 1 comprising (a) 88-98% by weight of bitumen; (b) 0.5-7% by weight of crumb rubber;(c) 0.5-3% by weight of FCC spent catalyst; and (d) 0.5-3% by weight of at least one low value polymer.

12. A method for making a modified bitumen composition comprising: a. heating bitumen to a temperature between about 120 degree C and about 200 degree C;

d. adding crumb rubber to the mixture; and

e. homogenizing the resultant mixture for about 30 minutes to about 24 hours to obtain the modified bitumen.

13. The method as claimed in claim 12, wherein homogenizing is performed to provide substantial solubilization of the crumb rubber, low value polymer within bitumen base material.