Process of preparing fuel in water emulsions from oil refining residues

Abstract

The present invention relates to a process for preparing fuel-in-water emulsions from oil refining residues, in both continuously or in batches, by adding an emulsifying agent to disperse the residual oil in water and facilitate its transportation. This process does not require the use of chemical substances like stabilizers or diluents for its preparation. The vacuum residue is not limited to specific characteristics and the water used, can be distilled, tap water or saltwater (seawater). The process requires low concentration of a non-ionic surfactant; and the emulsions obtained have proportions from 70 to 90% by weight of refining residues, 10 to 30% by weight of water and from 0.1 to 1% by weight of surfactant. The fuel-in-water emulsion is produced from oil refining residues, such as residues of atmospheric and vacuum distillation, heavy fuel oils and similar, and it is formed from 70 to 90% by weight of refining residues, 10 to 30% by weight of water and from 0.1 to 1% by weight of non-ionic surfactant. This fuel is efficient to its burned, because the fuel oil droplets have the best size to be completely burned into the flame, which has a favorable effect to reduce the unburned particle emissions. In addition, the emulsified fuel remains stable for an enough period for its storage and subsequent injection to the combustion equipment.

Claims

1. A method for preparing fuel-in-water emulsions from oil refining residues in a continuous process, the method comprising: (a) providing a vacuum residue, optionally from a vacuum distillation tower; (b) passing the vacuum residue to a heat exchanger; (c) adjusting the vacuum residue to a temperature of approximately 110 C. with the heat exchanger; (d) passing the vacuum residue from the heat exchanger to a storage container, and maintaining the temperature of the vacuum residue in the storage container at approximately 110 C.; (e) passing the vacuum residue from the storage container to a static mixer; (f) passing a homogenized mixture of a non-ionic surfactant and water from a container to the static mixer at a temperature between 55 and 60 C.; (g) mixing the vacuum residue with the surfactant-water mixture in the static mixer at a temperature between 70 and 110 C. to form a preliminary mixture; (h) passing the preliminary mixture to a dynamic mixer; (i) mixing the preliminary mixture at a temperature between 60 and 80 C. in the dynamic mixer to form a completed emulsion; (j) optionally passing the completed emulsion from the dynamic mixer to an emulsion storage container; wherein the completed emulsion has from 70 to 90 percent by weight refining residues, from 10 to 30 percent by weight water, and from 0.1 to 1 percent by weight surfactant, the total percent of the refining residues, water, and surfactant being 100%.

2. The method of claim 1, wherein the method does not use a chemical stabilizer for preservation of the completed emulsion.

3. The method of claim 1, wherein the method does not use a diluent.

4. The method of claim 1, wherein the water is distilled water, tap water, salt water, or a combination thereof.

5. A method for preparing fuel-in-water emulsions from oil refining residues in a batch process, the method comprising: (a) weighing a vacuum residue, a non-ionic surfactant, and water separately and adding each component to a separate container; (b) heating the vacuum residue at approximately 110 C.; (c) after heating in step (b), cooling the vacuum residue to a temperature between 80 and 90 C.; (d) providing a mixer having an impeller in an emulsion preparation vessel; (e) adding the water to the emulsion preparation vessel such that the impeller of the mixer is positioned at water level in the center of the emulsion preparation vessel; (f) maintaining the water in the emulsion preparation vessel at a temperature between 55 and 60 C.; (g) adding the non-ionic surfactant to the water in the emulsion preparation vessel to form a surfactant-water mixture; (h) mixing the surfactant-water mixture at a speed of 200 RPM; (i) after the non-ionic surfactant is incorporated into the water in the emulsion preparation vessel, adding the vacuum residue to the emulsion preparation vessel to form a preliminary mixture, keeping the vacuum residue at a temperature between 80 and 90 C., and keeping the preliminary mixture at a temperature between 55 to 60 C.; (j) during the addition of the vacuum residue in step (i), mixing the preliminary mixture at a speed of 700 RPM, to form an emulsion; (k) after all the vacuum residue is added to the emulsion preparation vessel, stopping the mixing and moving the impeller of the mixer to a height of one-third of the height of the emulsion; (l) mixing the emulsion at 700 RPM at a temperature between 55 and 60 C. to form a homogenized emulsion; (m) cooling the homogenized emulsion to form a completed emulsion; wherein the completed emulsion has from 70 to 90 percent by weight refining residues, from 10 to 30 percent by weight water, and from 0.1 to 1 percent by weight surfactant, the total percent of the refining residues, water, and surfactant being 100%.

6. The method of claim 5, wherein step (i) comprises adding the vacuum residue every 2 minutes for approximately 20 to 30 minutes.

7. The method of claim 5, wherein in step (1), the preliminary mixture is mixed for 20 minutes.

8. The method of claim 5, wherein the method does not use a chemical stabilizer for preservation of the finished emulsion.

9. The method of claim 5, wherein the method does not use a diluent.

10. The method of claim 5, wherein the vacuum residue remains fluid at least after being heated in step (b) and up to being mixed in the emulsion preparation vessel in step (i).

11. The method of claim 5, wherein the water is distilled water, tap water, salt water, or a combination thereof.

Description

BRIEF DESCRIPTION OF THE INVENTION DRAWINGS

(1) FIG. 1, is a flow chart that shows the continuous process approach of the present invention.

(2) The best-known method to prepare emulsified fuels in water from petroleum residuals, object of the present invention, is presented in the section of detailed description of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(3) From a more detailed viewpoint, the present invention relates to a process for preparing an emulsified fuel in both continuously or in batches; and the resulting fuel emulsified in water obtained with this procedure.

(4) The process to prepare an emulsified fuel in water in a continuous way, object of the present invention is carried out according to FIG. 1 and comprises the following steps:

(5) I. Conditioning of the Vacuum Residue. Conditioning through a heat exchanger (2), the temperature of the vacuum residue coming from a container (1), which may be the vacuum distillation tower or another vessel with a residual oils, whose temperature is approximately 480 C. if coming directly from the vacuum distillation tower. The vacuum residue passed through a pipe represented by line (8), from the container (1) to the heat exchanger (2), where its temperature is adjusted to approximately 110 C. The vacuum residue conditioned passes through a pipe represented by line (9), from the heat exchanger (2) to a recipient of temporary storage (3), in which it is kept at a temperature about 110 C.

(6) II. Preliminary Mixed. The vacuum residue is mixed with water and non-ionic surfactant in a static mixer (4), the vacuum residue comes from the temporary storage container (3) and goes to the static mixer (4) through a pipe represented by the line (10), at a temperature between 70 and 110 C. depending on the viscosity of the vacuum residue; since the viscosity of the vacuum residue depends of both the characteristics of the crude oil from which it is originated and the severity of the refining process. The vacuum residue conditioning and the handling temperature of the vacuum residue during the process provide the characteristic that the vacuum residue can be of any type and it is not limited to certain specifications; at the same time, not diluents are required to handle because it remains fluid. Meanwhile, the surfactant-water mixture previously homogenized and stored in a container (5), where the temperature is kept between 55 and 60 C., is dosed to the static mixer (4) at a temperature between 55 and 60 C., through a pipe represented by line (11).

(7) III. Emulsion Formation. The preliminary mixture that leaves the static mixer (4) is fed through a pipe represented by line (12) to the dynamic mixer (6), at a temperature between 60 and 80 C., where the emulsion is formed. Then the emulsion passes through a pipe represented by line (13), to a container (7) for emulsion storage. The shear stress imposes to the vacuum residue and its interaction with the water and the surfactant when passages though the interior of the dynamic mixer, together with the temperature and characteristics of the surfactant used, produces an emulsion with particle size that does not significantly change with respect to time, namely it remains stable. Because of that, it does not require additional stabilizers for its preservation. Additionally, the type of surfactant and temperature conditions used during the preparation procedure confer to the process the characteristic to use distilled water, tap water or saltwater (seawater) and low concentration of surfactant. With this process, the emulsified fuel is prepared in a continuous way, and have proportions from 70 to 90% by weight of refining residues, 10 to 30% by weight of water and from 0.1 to 1% by weight of surfactant.

(8) Another way of the novel procedure of this invention comprises a batch process, which consist of the following steps:

(9) I. Weigh the Components of the Emulsion: Weigh the vacuum residue, the non-ionic surfactant and the water (distilled, tap water or saltwater) separately and put each component in a container previously weighted.

(10) II. Heat the Vacuum Residue: Heat the vacuum residue at 110 C. approximately and homogenize, then cool and keep it at a temperature between 80 and 90 C. Heat the vacuum residue to homogenize and later keep it to a temperature between 80 and 90 C. to be handled during the process confers it the characteristic to use any type of vacuum residue and it is not limited to certain specifications. At the same time, it is not required diluents for handling because the vacuum residue remains fluid.

(11) III. Add the Water: Pour the water in the vessel where the emulsion will be prepared, heat the water, and keep its temperature between 55 and 60 C., previously the mixer has been placed in the vessel. The impeller of the mixer is positioned at water level, in the center of the vessel.

(12) IV. Add the Surfactant and the Vacuum Residue: Add the surfactant to the water and start mixing at a speed of 200 revolutions per minute (RPM); once it is incorporated in to the water, start adding the vacuum residue previously weighted and heated for handling, at this stage change the mixing speed at 700 RPM. The addition of the vacuum residue is every two minutes for about 20-30 minutes approximately. The amount added every two minutes depends on the incorporation of the vacuum residue in the emulsion. Likewise, the addition of vacuum residue continues until all the vacuum residue in the vessel has been added, keeping the temperature of the vacuum residue between 80 and 90 C.; and the emulsion that is being prepared between 55 to 60 C.

(13) V. Relocate the Mixer: Once the entire vacuum residue was added, turn off the mixer and move the impeller of the mixer, placing it in the emulsion, a third of the height of the emulsion prepared.

(14) VI. Homogenize the Emulsion: Turn on the mixer at 700 RPM for 20 minutes to homogenize the emulsion, take care that the emulsion temperature is between 55 and 60 C. The shear stress imposes to the vacuum residue with the impeller, and the procedure used to add the vacuum residue into the vessel, which contains water and surfactant, together with the temperature and characteristics of the surfactant used produces an emulsion with particle size that does not significantly change with respect to time. Namely, it remains stable, because it does not require additional stabilizers for its preservation. Additionally, the type of surfactant and temperature conditions used during the preparation procedure confer to the process the characteristic to use distilled water, tap water or saltwater (seawater) and low concentration of surfactant.

(15) VII. Turn Off the Mixer: After 20 minutes of homogenization, turn off the mixer, let cool the emulsion and weigh the container with the emulsion in it. Then hand over the emulsion prepared into a storage container and close.

(16) VIII. Weigh the Containers: Weigh the containers used for handling the vacuum residue, water, surfactant and the mixing vessel used to prepare the emulsion, to determine the weight of each of the components that remains adhered to them, and determine the final amount of each component in the prepared emulsion. With this process, the emulsified fuel is prepared in batches, and have proportions from 70 to 90% by weight of refining residues, 10 to 30% by weight of water and from 0.1 to 1% by weight of surfactant.

(17) Next, in the following 4 examples will become clear the characteristics of emulsions obtained with the process for preparing emulsions of the present invention using different surfactant concentrations, types of water (distilled, tap water and saltwater) and oil phase (vacuum residue) concentration.

EXAMPLE 1

Emulsions Prepared with Different Surfactant Concentrations

(18) According to the process for preparing emulsion fuels of the present invention, three emulsions of vacuum residue in water where obtained, with a non-ionic surfactant, and without the use of stabilizers or diluents for their preparation. The final proportions of the three emulsions are shown in Table 1. The surfactant concentration was varied from 0.24 to 1%.

(19) The droplet size of the emulsions was higher as the concentration of surfactant was reduced; on the other hand, the measurement made by laser diffraction of these emulsions showed values of mean diameter (D50) of 8.8, 9.5 and 23.2 microns respectively.

(20) TABLE-US-00001 TABLE 1 Emulsion 1 Emulsion 2 Emulsion 3 Component wt % wt % wt % Vacuum residue 72.50 72.00 71.00 Distilled water 26.50 27.50 28.76 Surfactant 1.00 0.50 0.24 Total 100.00 100.00 100.00

EXAMPLE 2

Emulsions Prepared with Different Types of Water

(21) According to the process for preparing emulsion fuels of the present invention, three emulsions of vacuum residue in water where obtained, with a non-ionic surfactant, and without the use of stabilizers or diluents for their preparation; using three different types of water: distilled, tap water and saltwater (seawater). The final proportions of the three emulsions are shown in Table 2.

(22) The droplet size of emulsions measurement by laser diffraction, showed values of mean diameter (D50) of 8.8, 8.6 and 10.0 microns respectively.

(23) TABLE-US-00002 TABLE 2 Type of water used Distilled Network Saltwater Component wt % wt % wt % Vacuum residue 72.50 73.50 73.50 Water 26.50 25.50 25.50 Surfactant 1.00 1.00 1.00 Total 100.00 100.00 100.00

EXAMPLE 3

Emulsions Prepared with High Concentration of Oily Phase

(24) According to the process for preparing emulsion fuels of the present invention, two emulsions of vacuum residue in water (tap water and distilled water) where obtained, with a non-ionic surfactant, and without the use of stabilizers or diluents for their preparation; using high concentration of oily phase, namely, vacuum residue. The final proportions of the three emulsions are shown in Table 3.

(25) The droplet size of emulsions, measurement by laser diffraction, showed values of mean diameter (D50) of 10.1 and 10.6 microns respectively.

(26) TABLE-US-00003 TABLE 3 Emulsion 1 (tap water) Emulsion 2 (Distilled water) Component wt % wt % Vacuum residue 79.00 78.00 Water 20.10 21.00 Surfactant 0.90 1.00 Total 100.00 100.00

EXAMPLE 4

Stability of the Emulsions

(27) According to the process for preparing emulsion fuels of the present invention, two emulsions of vacuum residue in distilled and tap water where obtained, with a non-ionic surfactant, and without the use of stabilizers or diluents for their preparation. Emulsions that were assessed about their temporal stability, namely the droplet size of the emulsions was measured periodically to determine its change against the time. The final proportions of the emulsions are shown in Table 4. The droplet size of the emulsions was determined by laser diffraction, and the values of mean diameter (D50) of the emulsion prepared with distilled water were 8 microns when it was prepared and 9 micron 6 months later. To the emulsion prepared with tap water, the values of the mean diameter (D50) were 8.2 and 9.2 microns, the day of his preparation and 6 months later respectively. From the results it can be seen that no significant change in the droplet size of the emulsions occurred, that is, they remained stable.

(28) TABLE-US-00004 TABLE 4 Emulsion 1 (Distilled water) Emulsion 1 (tap water) Component wt % wt % Vacuum residue 73.00 73.50 Water 26.00 25.50 Surfactant 1.00 1.00 Total 100.00 100.00