JPH0580249B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing an emulsion, and particularly to a method for continuously producing an emulsion for reducing the viscosity of heavy oil in pipeline transportation, ship transportation, etc. [Prior Art] Conventionally, heavy oil has high viscosity and high fluidity, so it is difficult to transport it as it is, and various methods have been used. The heavy oil referred to here refers to tar sand, bitumen, sierre oil, etc. Transportation methods include heating with a heater to lower the viscosity, dilution by adding light oil such as kerosene to lower the viscosity, and surfactants and mixing with water to create a W/O emulsion. There are methods such as water emulsion method. Although the heating method and the dilution method are practical, there are problems in terms of transportation costs. On the other hand, the technology of the water emulsion method is being actively developed because it is more economical than the previous two methods. In the water emulsion method, heavy oil and water are made into a uniform W/O emulsion with the help of surfactants.
By significantly lowering the viscosity, it can be transported by pump. As a surfactant, HLB
Nonylphenyl ether type, glycerol oxide ethylene type, etc. having a (hydrophilicity-hydrophobicity balance) value of 8 to 18 are used. Up to now, propeller-type homogenizers, grinding-type colloid mills, etc. have been used as mixing and stirring methods, but most of them employ stirring methods under certain conditions. [Problems to be solved by the invention] In the conventional water emulsion technology, as mentioned above, a stirring method under certain conditions is adopted;
When stirring highly viscous heavy oil and water, it is difficult to produce a uniform emulsion. This is because the viscosity of heavy oil and water is extremely different, resulting in either one being selectively stirred and sheared. Therefore, for example, the diameter of oil particles in an emulsion produced by such a method is wide ranging from several micrometers to several thousand micrometers, and large particles easily settle, causing separation of oil and water. Therefore, this method had a problem with the stability of the emulsion. [Means for Solving the Problems] The present invention solves the above problems by using a plurality of stirring tanks with varying stirring conditions, instead of the conventional mixing and stirring method under constant conditions. This problem can be solved by producing an emulsion using a tank with a lower stirring power, followed by a stirring tank with a higher stirring power than the previous one, and so on. [Operation] In the present invention, it is possible to form a uniform O/W type emulsion by gradually stirring a mixture of heavy oil and water. That is, since heavy oil has high viscosity, it is less likely to be sheared than water. Therefore, by performing gentle stirring at first, the heavy oil is partially sheared and an emulsion with a large particle size is formed. Next, when this partially emulsified material is further stirred with something with a strong stirring power, the material that has already been emulsified becomes even smaller particles, and the heavy oil that has not been emulsified is also reduced to smaller particles by shearing. Become. By continuing such stirring two or more times as necessary, uniform O/
It is possible to form a W-type emulsion. In this way, in the present invention, a large amount of a mixture of heavy oil and water is continuously passed through a plurality of stirring tanks with varying stirring power, thereby producing a uniform and highly stable emulsion in large quantities. can be manufactured. In addition, in the present invention, the mixing ratio of heavy oil and water is heavy oil/water (weight ratio) because if the heavy oil exceeds 75% by weight, the viscosity of the emulsion will increase extremely and transportation will be difficult. It is desirable that the ratio be 75/25 or less. Note that as the proportion of water increases, the viscosity decreases, but since there is a problem in terms of economy due to a decrease in calories, it is desirable to set an upper limit for the proportion of water in consideration of this aspect. [Example] Table 1 shows the properties of the heavy oil used. Heavy oil heated to 70℃ and distilled water at 25℃ in a weight ratio of 7:3.
Furthermore, a commercially available nonyl phenyl ether surfactant (HLB=14) was added in an amount of 0.3% by weight based on the oil-water mixture. A propeller-type homogenizer (capacity: 500 ml) was used as the stirrer in the stirring tank. The above heavy oil-water mixture was stirred by a homogenizer for a predetermined period of time at a predetermined rotation speed. The viscosity of the emulsion after stirring was measured using a double cylindrical rotational viscometer, and at the same time, the average diameter of oil particles in the emulsion was determined by observation with an optical microscope. Table 2 shows the results. As is clear from Table 2, in the case of the conventional single stirring method (RUN1-5), the viscosity of the emulsion is high and the average diameter of the oil particles is also large. This is because emulsion is insufficient and the oil layer and water layer are separated. On the other hand, it was found that in the stepwise mixing method of the present invention (RUN 6 to 8), the viscosity of the emulsion was significantly reduced and a uniform emulsion could be obtained. In addition, the average diameter of oil particles is also several
It can be seen that the oil particles are as small as 10 to 100 μm and are sufficiently sheared.

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〔Effect of the invention〕

According to the present invention, by adding water to heavy oil, which poses transportation problems due to its high viscosity, and mixing and stirring in stages, the heavy oil is dispersed in water as uniform small particles. It becomes a stable O/W type emulsion and can achieve a significant reduction in viscosity.

Claims (1)

[Claims] 1. In a method for producing an emulsion composed of heavy oil and water, a plurality of stirring tanks each having a stirrer with successively increased stirring power are provided, and a stirring tank with a stirrer with a lower stirring power is used, followed by a stirring tank with a higher stirring power. 1. A method for producing an emulsion, which comprises sequentially passing the mixture of heavy oil and water through a stirring tank equipped with a stirrer.