TECHNICAL FIELD OF THE INVENTION

This invention is related to the field of demulsification and more particularly a demulsifying agent and a method of using the same for demulsifying bitumen from natural asphalt.

BACKGROUND OF THE INVENTION

Bitumen is an oil-based substance diffused within natural asphalt, which consists a mixture of small stones, sand, filler and bitumen. Various methods have been used in the past to extract bitumen from natural asphalt and a large number of researches have been done in this field to maximise the recovery of bitumen using the lowest cost incurrence and to minimise emission and effluence of pollutants to the environment.

As bitumen is an oil-based substance, it has been long practiced in the field at commercial scale to recover bitumen using water. The process involves mixing the natural asphalt with either water and separating the stones, sand and fillers in the natural asphalt from the aqueous phase formed. One of the disadvantages of using water for the extraction is the requirement of large amount of process water. Another disadvantage is the issue of ensuring that bitumen is properly and effectively removed from the aqueous phase. Another method of extracting bitumen from natural asphalt is the use of nonaqueous liquid such as solvent. Similar to the use of water, solvent is also mixed with natural asphalt that eventually separates the bitumen in an aqueous phase. Although this method solves the disadvantage of using large amount of water, another disadvantage arises with the use of solvent, which is the incurrence of cost as solvents, especially organic solvents, are relatively expensive. Further, there is a requirement for means to be provided in order to recover the solvent upon completion of the extraction so that the solvent can be recycled and solvent losses and consumption can be minimized. The provision of the said means would also escalate the incurrence of cost.

US 3914132 A describes the removal of organic deposits from surfaces, particularly those deposits containing asphaltenic compounds, by the dissolution of the deposits in a solvent comprised of an aromatic hydrocarbon and an amine. US 4108681 A describes a method of dissolving asphaltic material using a liquid aromatic solvent and an additive material soluble in the liquid aromatic solvent.

Therefore, the present invention aims to provide an alternative way to demulsify bitumen from natural asphalt without the need and use of additive.

SUMMARY OF THE PRESENT INVENTION

The present invention relates to a demulsifying agent and a method of using the same for demulsifying bitumen from natural asphalt.

The demulsifying agent comprising, by weight of 52% - 75% of silicate, 27% - 42% of hydroxide salt, 1 .02% - 2.30% of sulfonic acid, and 0.60% - 1 .15% of surfactant, wherein the sodium silicate, hydroxide salt, sulfonic acid and surfactant are mixed, pressurized, cooled and solidified, and grind prior to demulsifying bitumen from natural asphalt.

The method of using a demulsifying agent for demulsifying bitumen from natural asphalt, comprising the steps of providing an amount of the said demulsifying agent, allowing the amount of demulsifying agent to react with the natural asphalt, and separating and extracting bitumen from sediments formed from the reaction, wherein the demulsifying agent comprises by weight, 52% - 75% of silicate, 27% - 42% of hydroxide salt, 1 .02% - 2.30% of sulfonic acid, and 0.60% - 1 .15% of surfactant. It is an object of the present invention to provide a demulsifying agent for demulsifying bitumen from natural asphalt without the requirement of additives. It is another object of the present invention to provide a demulsifying agent for demulsifying bitumen from natural asphalt that has a relatively low cost of production.

It is further an object of the present invention to provide method of using the demulsifying agent for demulsifying bitumen from natural asphalt that allows the recycling of water or effluence and therefore no discharge of water or effluence that could attribute pollution to the natural environment.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The above mentioned and other features and objects of this invention will become more apparent and better understood by reference to the following detailed description. It should be understood that the detailed description made known below is not intended to be exhaustive or limit the invention to the precise form disclosed as the invention may assume various alternative forms. On the contrary, the detailed description covers all the relevant modifications and alterations made to the present invention, unless the claims expressly state otherwise.

A demulsifying agent, as disclosed in the present invention, comprises, by weight of 52% - 75% of silicate, 27% - 42% of hydroxide salt, 1 .02% - 2.30% of sulfonic acid, and 0.60% - 1 .15% of surfactant, wherein the sodium silicate, hydroxide salt, sulfonic acid and surfactant are mixed, pressurized, cooled and solidified, and grind prior to demulsifying bitumen from natural asphalt. One of the embodiments of the invention discloses that the demulsifying agent is prepared by mixing, pressuring, cooling and solidifying, and grinding. Firstly, efficient amount of sodium silicate is mixed with water and then pressurized to form liquefied sodium silicate. The amount of pressure that is applied ranges from 0.4-0.6 MPa. In a preferred embodiment of the invention, the optimum pressure is 0.5 MPa, and the efficient amount of sodium silicate is 52% - 75%. Then, the liquefied sodium silicate is added and mixed with efficient amount of hydroxide salt, sulfonic acid and surfactant. In a preferred embodiment of the invention, the effective amount of hydroxide salt, sulfonic acid and surfactant is in a range of 27% - 42%, 1 .02% - 2.30% and 0.60% - 1 .15% respectively. Thereafter, the mixture undergoes cooling and solidification process. In the cooling process, the mixture is allowed to cool at room temperature of -20°C to 45°C and the mixture is cooled to a temperature ranging from 70°C to 80°C, which the mixture solidifies to an optimum hardness within this range of temperature. It is then grind to a mesh size of 0.104mm-0.149mm.

In one of the embodiments of the present invention, the silicate is sodium silicate and the sulfonic acid is dodecylbenzenesulfonic acid. The hydroxide salt is selected from any one of sodium hydroxide or potassium hydroxide. A further embodiment of the present invention discloses that the surfactant used is a non-ionic surfactant and the non-ionic surfactant is polyoxyethylene octyl phenyl ether. The said polyoxyethylene octyl phenyl ether is more industrially known as OP-10. It should be understood in the context of the present invention that other silicates, hydroxide salts, sulfonic acids and surfactants may also be used, as long as it can be used together with the other components of the demulsifying agent to demulsify bitumen from natural asphalt. Another embodiment of the present invention discloses that the demulsifying agent comprises 55wt% - 72wt% of silicate, 29wt% - 40wt% of hydroxide salt, 1 .08wt% - 2.20wt% of sulfonic acid, and 0.65wt% - 1 .10wt% of surfactant.

Further another embodiment of the present invention discloses that the demulsifying agent comprises 58wt% - 68wt% of silicate, 30wt% - 38wt% of hydroxide salt, 1 .14wt% - 2.10wt% of sulfonic acid, and 0.67wt% - 1 .05wt% of surfactant. Also disclosed in the present invention is a method of using a demulsifying agent for demulsifying bitumen from natural asphalt. The demulsifying agent mentioned herein comprises by weight, 52% - 75% of silicate, 27% - 42% of hydroxide salt, 1 .02% - 2.30% of sulfonic acid, and 0.60% - 1 .15% of surfactant.

In order to demulsify bitumen from natural asphalt, an amount of demulsifying agent is first prepared. The amount of the said demulsifying agent to be added to the natural asphalt is in the range of 6wt% to 10wt%, depending on the viscosity of the natural asphalt. The more viscous the natural asphalt is, the higher the wt% of the demulsifying agent is required. Then, the demulsifying agent is allowed to react with the natural asphalt under the temperature of 85°C to 100°C. In one of the preferred embodiment, the optimum temperature of the reaction is 95°C. As mentioned earlier, bitumen is an oil-based substance. Therefore, upon completion of the reaction, the mixture separates into three different layers, which bitumen floats and forms the top layer, water and dissolved demulsifying agent forms the middle layer and the sediments from the natural asphalt settle and form the bottom layer. Thereafter, bitumen may be extracted from the top layer and the dissolved demulsifying agent in the middle layer may be extracted from water so that both the demulsifying agent and water may be reused. Consequently, no water or demulsifying agent is discharged or disposed and therefore it does not attribute pollution to the environment. Lastly, the remaining sediments are flushed with fresh water and water is decanted from the sediments to recover the demulsifying agent from the sediments. The water and demulsifying agent is decanted from the sediment using any known means.

Upon extraction of the bitumen, the sediments are left over in processed water, which the processed water contains dissolved solvent. The sediments are removed from the processed water using known decanting methods and the processed water is recycled and reused for the subsequent demulsifying process. With the present invention, the entire demulsifying process is water- saving and solvent-saving. Further, the sediments that may be in the form of small-granulated sand may be used to produce bricks together with the application of cement and other additives and constituents. On the other hand, the extracted bitumen may be used to produce various types of products such as light oil, oil products and various types of bitumen such as heavy bitumen, construction bitumen and waterproofing bitumen.

In one of the embodiments of the method disclosed in the present invention, the silicate is sodium silicate and the sulfonic acid is dodecylbenzenesulfonic acid. The hydroxide salt is selected from any one of sodium hydroxide or potassium hydroxide. In one of the preferred embodiments, the hydroxide salt is sodium hydroxide. In another preferred embodiment, the hydroxide salt is potassium hydroxide.

A further embodiment of the method disclosed in the present invention, the surfactant used is a non-ionic surfactant. Preferably, the non-ionic surfactant is polyoxyethylene octyl phenyl ether, which is more industrially known as OP- 10. It should be understood in the context of the present invention that other silicates, hydroxide salts, sulfonic acids and surfactants may also be used, as long as it can be used together with the other components of the demulsifying agent to demulsify bitumen from natural asphalt.

Another embodiment of the method discloses that the demulsifying agent comprises 55wt% - 72wt% of silicate, 29wt% - 40wt% of hydroxide salt, 1 .08wt% - 2.20wt% of sulfonic acid, and 0.65wt% - 1 .10wt% of surfactant.

Still another embodiment of the method discloses that the demulsifying agent comprises 58wt% - 68wt% of silicate, 30wt% - 38wt% of hydroxide salt, 1 .14wt% - 2.10wt% of sulfonic acid, and 0.67wt% - 1 .05wt% of surfactant. The following examples will enable persons skilled in the art to further understand and practice the invention; however, the examples are not intended to limit the scope of this invention. Example I

Firstly, 59wt% - 72wt% of sodium silicate is mixed with water and then pressurized to form liquefied sodium silicate. The amount of pressure applied herein is 0.5 MPa. Then, the liquefied sodium silicate is added and mixed with 29wt% - 35wt% of sodium hydroxide, 1 .80wt% - 2.20wt% of sulfonic acid and 0.90wt% - 1 .10wt% of polyoxyethylene octyl phenyl ether or more industrially known as OP-10. Thereafter, the mixture undergoes cooling and solidification process. In the cooling process, the mixture is allowed to cool at room temperature of -20°C to 45°C and the mixture is cooled to a temperature ranging from 70°C to 80°C, which the mixture solidifies to an optimum hardness within this range of temperature. It is then grind to a mesh size of 0.104mm-0.149mm.

In order to demulsify bitumen from natural asphalt, an amount of demulsifying agent is first prepared. The amount of the said demulsifying agent to be added to the natural asphalt is in the range of 6wt% to 10wt%, depending on the viscosity of the natural asphalt. Then, the demulsifying agent is allowed to react with the natural asphalt under the optimum temperature of 95°C. Upon completion of the reaction, the mixture separates into three different layers, which bitumen floats and forms the top layer, water and dissolved demulsifying agent forms the middle layer and the sediments from the natural asphalt settle and form the bottom layer. Thereafter, bitumen is extracted from the top layer and the dissolved demulsifying agent in the middle layer is extracted from water so that both the demulsifying agent and water is reused. Lastly, the remaining sediments are flushed with fresh water and water is decanted from the sediments to recover the demulsifying agent from the sediments. The water and demulsifying agent is decanted from the sediment using any known means. Example II

55wt% - 67wt% of sodium silicate is mixed with water and then pressurized to form liquefied sodium silicate. The amount of pressure applied herein is 0.5 MPa. Then, the liquefied sodium silicate is added and mixed with 33wt% - 42wt% of sodium hydroxide, 1 .08wt% - 1 .32wt% of sulfonic acid, and 0.63wt% - 0.77wt% of polyoxyethylene octyl phenyl ether or more industrially known as OP-10. Thereafter, the mixture undergoes cooling and solidification process. In the cooling process, the mixture is allowed to cool at room temperature of - 20°C to 45°C and the mixture is cooled to a temperature ranging from 70°C to 80°C, which the mixture solidifies to an optimum hardness within this range of temperature. It is then grind to a mesh size of 0.104mm-0.149mm.

For the demulsification of bitumen from natural asphalt, an amount of demulsifying agent is first prepared. The amount of the said demulsifying agent to be added to the natural asphalt is in the range of 6wt% to 10wt%, depending on the viscosity of the natural asphalt. Then, the demulsifying agent is allowed to react with the natural asphalt under the temperature of 95°C. Upon completion of the reaction, the mixture separates into three different layers, which bitumen floats and forms the top layer, water and dissolved demulsifying agent forms the middle layer and the sediments from the natural asphalt settle and form the bottom layer. Thereafter, bitumen is extracted from the top layer and the dissolved demulsifying agent in the middle layer is extracted from water so that both the demulsifying agent and water is reused. Lastly, the remaining sediments are flushed with fresh water and water is decanted from the sediments to recover the demulsifying agent from the sediments. The water and demulsifying agent is decanted from the sediment using any known means. Example III

59wt% - 72wt% of sodium silicate is mixed with water and then pressurized to form liquefied sodium silicate. The amount of pressure applied herein is 0.5 MPa. Then, the liquefied sodium silicate is added and mixed with 29wt% - 35wt% of potassium hydroxide, 1 .80wt% - 2.20wt% of sulfonic acid, and 0.90wt% - 1 .10wt% of polyoxyethylene octyl phenyl ether or more industrially known as OP-10. Subsequently, the mixture undergoes cooling and solidification process. In the cooling process, the mixture is allowed to cool at room temperature of -20°C to 45°C and the mixture is cooled to a temperature ranging from 70°C to 80°C, which the mixture solidifies to an optimum hardness within this range of temperature. It is then grind to a mesh size of 0.104mm-0.149mm. In order to demulsify bitumen from natural asphalt, an amount of demulsifying agent is first prepared. The amount of the said demulsifying agent to be added to the natural asphalt is in the range of 6wt% to 10wt%, depending on the viscosity of the natural asphalt. Then, the demulsifying agent is allowed to react with the natural asphalt under the temperature of 95°C. Upon completion of the reaction, the mixture separates into three different layers, which bitumen floats and forms the top layer, water and dissolved demulsifying agent forms the middle layer and the sediments from the natural asphalt settle and form the bottom layer. Thereafter, bitumen is extracted from the top layer and the dissolved demulsifying agent in the middle layer is extracted from water so that both the demulsifying agent and water may be reused. Lastly, the remaining sediments are flushed with fresh water and water is decanted from the sediments to recover the demulsifying agent from the sediments. The water and demulsifying agent is decanted from the sediment using any known means.

The natural asphalt mentioned above should be known to the skilled addressee to be inclusive of natural occurring natural asphalt or asphaltic material, crude bitumen or the like. The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the scope of the following claims.