EP2340887A1

EP2340887A1 - Plant for the production of an emulsion of water in hydrocarbons

Info

Publication number: EP2340887A1
Application number: EP09425547A
Authority: EP
Inventors: Alberto Vigliotti
Original assignee: ITI Srl
Current assignee: ITI Srl
Priority date: 2009-12-30
Filing date: 2009-12-30
Publication date: 2011-07-06

Abstract

Plant for the production of an emulsion of water in hydrocarbons, comprising:
pump means (13;22) for the drawing and mixing in a first tank (16) of dosed amounts of an hydrocarbon, or of a mixture of hydrocarbons contained in a second tank (12),
with an emulsifier contained in a third tank (18);
pump means (22) for drawing and introducing dosed amounts of water, drawn from a fourth tank (6) in said mixture of hydrocarbons and emulsifier contained in said first tank (16);
pump means (22) for pressure circulating many times said mixture of water, hydrocarbons and emulsifier from said first tank (16) through an emulsifier device (E) and
from this again in said first tank (16) until obtaining a stable emulsion of water in hydrocarbons, and for transferring said emulsion from said first tank (16) until obtaining a stable emulsion of water in hydrocarbons, and for transferring said emulsion from said first tank (16) in a stocking tank (37) from which said emulsion may be drawn for the delivery to the users.

Description

The present invention has for its object the emulsions of water in hydrocarbons, like for example diesel, biodiesel, thick fuel oil (residues of the petroleum distillation, like for example HFO, IFO, BTZ) and the like.
The emulsions water/hydrocarbons constitute a modern technology for feding diesel motors and burners, can be formulated with fuels with very low content of sulphur, containing in case methylic esters of fatty acids (FAME), and are compatible with the modern emission lowering devices.
The interest displayed in recent times for the said emulsions as fuel alternative to the diesel derives from the potential capacity of the water to reduce the harmful emissions in the exhaust gases, like the nitrogen oxides and the particulate (PM), whenever injected in the motor or in the burner together with the fuel in form of a stabilised emulsion.
The emulsions water/hydrocarbons are stabilised suspensions of water and hydrocarbons, like for example diesel, biodiesel, dense fuel oil (residues of the petroleum distillation, like for example HFO, IFO, BTZ) and the like. The stabilisation is obtained by means of suitable surface-active substances which prevent for a sufficiently long period of time the separation of the two insoluble liquid phases. The average dimension of the micro drops of water which are present in the emulsion is generally minor of µm.
At present, the said emulsions are prepared in large amounts in industrial plants and are thereafter stocked also for long periods of time in suitable tanks, necessarily provided with re-circulation systems. In order to avoid that during the stocking the emulsion may be broken prematurely, with partial separation of the two liquid not-miscible phases, it is necessary to add to the emulsion surface active substances with stabilising functions.
It is therefore the main object of the present invention to provide an emulsifier device which is apt to the extemporary production of stabilised water in hydrocarbon emulsions to be used as fuels for diesel motors and burners.
It is a further object of the present invention to provide a plant for the production of a water in hydrocarbons emulsion which is apt to produce quickly in extemporary manner comparatively small amounts of emulsion so as to reduce to the minimum and to practically eliminate the stocking period of the final emulsion.
Further objects of the present invention will be better evident in the course of the following description, made with reference to the annexed drawings, in which:

Figure 1 shows diagrammatically a plant for the production of a water in hydrocarbons emulsion according to the invention.
Figure 2 is a partially in axial section schematic view of an emulsifier according to the invention.
Figure 3 is a section taken along the plane III-III of Figure 2, showing the staggering of the rows of holes of the drilled bowls of the emulsifier of Figure 2.

With reference to the drawings, and with particular reference to Figure 1, the plant shown comprises a unit 1 for demineralizing the water fed from the net line 2, through the valve 3. The demineralized water is fed, through the line 4 and the valve 5, to the tank 6 of the demineralized water. A probe 7 mounted inside of the tank 6 controls the level of the water in said tank, and transmit said data to a suitable control station (not shown).
With 8 a tank is illustrated containing an additive for improving the cetane number (for instance 2-etyl-esyl-nitrate, C₈H₁₇NO₃), which through the line 9 and the solenoid valve 10 is introduced in the line 11 of the diesel taken from the tank 12 from which the mixture of diesel- and cetane number improving additive is fed through the pump 13, the fiscal meter 14 and the solenoid valve 15 to the mixing tank 16. The addition of the cetane number improving additive to the diesel has the scope of improving the ignition performance of the produced emulsion. In the following description, by the term "hydrocarbons" all those combustibles are intended as: diesel, biodiesel (diesel + metylic esters of fatty acids), thick fuel oil (residues of the petroleum distillation, like for example HFO, IFO, BTZ) or their mixtures.
Like the tank 6, also the tank 16 is provided with a probe 17 to control the level of the products which are fed in said tank, transmitting said data to a suitable control station (not shown).
By reference numeral 18 a tank is shown containing the emulsifying additive. Like the tanks 6 and 16, also the tank 18 is provided with a probe 19 to control the level of the liquid products fed to said tank, communicating said data to a suitable control station (not shown).
From the tank 18 a line 20 departs, controlled by the solenoid valve 21, leading to the pump 22. In the line 20 flows also the line 23, controlled by the solenoid valve 24, coming from the tank 16, and the line 25, coming from the tank 6, controlled by the solenoid valve 26. From the pump 22 departs the delivery line 27 leading to the emulsifier E and from this through the high cut power mixer 28 to deliver, through the solenoid valve 30 and the line 29, the product into the tank 16. By 33 a line is shown which departs from the tank 16 and, through the pump 34, the fiscal meter 35 and the solenoid valve 36 leads to the tank 37 of the final product. Also this tank is provided with a probe 38 in order to monitor the level of liquid at its inside, transmitting it to a control station.
Finally, from the tank 37, through the line 40, the solenoid valve 39 and the pump 41, there is reached the distributor of the emulsion to the users.
Optionally, from the mixer 28 there departs also a second line 31 which, through the solenoid valve 32 can discharge directly the mixed product into the tank 37. In this case it will be necessary to insert into the line 31 a fiscal meter of the kind of the meter 35.
Having thus described the plant, we shall pass now to the description of the emulsifier E according to the invention.
With reference to the figure 2, the emulsifier E shown comprises an inlet module E1 and one (or also more) additional modules E2.
Each module E1 or E2 is formed by a cylindical tubular piece 42 carrying at its ends two flanges 43 peripherally provided with holes for the passage of securing bolts 44 (not shown). On the inside of each tubular piece 42 there are housed two opposed specularly symmetrical sets of three concentrical bowls 45, 46, 47 provided with flaring walls with a slight taper toward the outside and having a decreasing height from the most external to the most internal bowl, the whole in manner that both the side walls and the bottom walls of the three bowls 45, 46, 47 are mutually spaced. Each set of bowls 45, 46, 47 has its mouthpiece directed toward the end of the tubular piece 42, and the side walls of the bowls are perforated by a plurality of rows of bores 48 having a diameter from 0,8 to 1,4 mm, with the bores of the rows of bores of each bowl angularly offset with respect to the rows of bores of the adjacent bowl, as best schematically shown in Figure 3.
The inlet module E1, that is the module connected to the line 27, is further provided with two diametrically opposed electrodes 49, 50 connected to a 24V and between 10 and 25 A direct current source (not shown), for the purposes which will be described later.
The additional modules E2 can vary from 1 (one) to more than 1 (one), according to the requirements.
The operation of the described plant is as follows: with the pump 13 in operation, the solenoid valves 10 and 15 are opened. A certain amount of a mixture of the additive for improving the cetane number (in a concentration comprised between 0 and 1 % of the fuel utilised, and preferably between 0,1 and 0,5%) and hydrocarbons is sucked from the tanks 8 and 12 through the lines 9 and 11 by the pump 13 and sent, through the fiscal meter 14, along the line 11 to the tank 16.
As soon as the prefixed amount of the above mixture, as measured by the fiscal meter 17 is reached, the closure of the solenoid valves 10 and 15 and of the pump 13 is actuated.
At this point the opening of the solenoid valves 21, 24 and 29 and of the pump 22 is actuated. The pump 22 sucks from the tank 18 through the valve 21 and the line 20 the emulsifier additive, composed by a formulation containing one or more surface active substances, and preferably an ethoxylated surface active agent of the kind described for example in the patent application W02004/099350 , by mixing it with the mixture of hydrocarbons-additive for improving the cetane number which is present in the tank 16, which was fed through the valve 24 and the line 23 merging into the line 20, and sends the whole through the line 27 to the emulsifier E and from this through the mixer 28, the valve 30 and the line 29 back to the tank 16. The loop pump 22, line 27, emulsifier E, mixer 28, valve 30, line 29, tank 16, valve 24, line 23, line 20, pump 22 is repeated some times. Thereafter, the valve 21 is closed, and the valve 26 is opened. With the opening of said valve the demineralized water flows from the tank 6 and, through the line 25, the valve 26, the pump 22 is introduced into the loop of the line 27, emulsifier E, mixer 28, valve 30, line 29, tank 16, valve 24, line 23, line 20, line 25, pump 22. The line 25 and the valve 26 are closed as soon as the prefixed amount of water as measured by the fiscal meters 17 and 19 is reached, after which the emulsifying loop is started. Said loop is continued until the required emulsion of the water in the fuel is reached. Once completed the emulsioning cycle, the pump 22 and the mixer 28 are closed, and the pump 34 and the valve 36 are opened, thus sucking the emulsioned product from the tank 16 through the line 33, the pump 34, the fiscal meter 35 and the valve 36 and introducing it into the tank 37.
Finally, from the tank 37, through the solenoid valve 39 and the line 40, the fuel mix, so called "emulsion", is fed to the distributor 41 for the delivery to the users. Whenever the probe descends to a critical level, the cycle described is again started.
In the above described cycle, a very important function is performed by the emulsifier E. The product to be emulsified is caused to pass, at a pressure of the order of 35 bar, through the bores 48 of the bowls 45, 46, 47 following a labyrinth path which is repeated more times through the modules E1 and E2 of the emulsifier. The presence of the electrodes 49 and 50 in the inlet module E1 of the emulsifier has practically demonstrated that a better emulsion of the water in the fuel and a better stabilisation of the emulsion are obtained, thus greatly reducing the tendency to the separation of the not -miscible phases. In figure 2 the emulsifier has been shown as composed by a module E1 and a module E2. In practice, the emulsifier according to the invention is formed by 4 (four) to 8 (eight) modules in series, according to the requirements of the plant.
The bowls 45, 46, 47 have been shown and described as provided with side walls having a slight taper. Practically said taper is comprised between 2 and 10°. Of course, it would be also possible to use bowls having cylindrical side walls, instead as conical.
Just only to indicative title, it is mentioned that the percent weight ratio fuel/emulsifier is from 91,4 to the 99,9% of fuel and from the 8,6 to the 0.1 % emulsifier, and the preferred ratio is:

fuel 97.7% - emulsifier 2.3%

Similarly, the percent weight ratio fuel with emulsifier/water is approximately comprised from 70 to 95% fuel + emulsifier and from 30 to 5% of water, and preferably fuel + emulsifier 88% / water 12%.
The control station mentioned during the description (and not shown) is a computerised station provided with a suitable program by means of which the opening and/or the closure of the single solenoid valves is controlled, or are put into operation the single pumps substantially according the operational sequence described. To the said control station are also connected the probes 7, 19, 17, 38 of the different tanks, so as to furnish signals of the supply condition of the single tanks, or of the restarting of the supply operations for the preparation of a new emulsion charge.

Claims

Plant for the production of an emulsion of water in hydrocarbons, comprising:
- pump means (13;22) for drawing and mixing in a first tank (16) of dosed amounts of a hydrocarbon, or of a mixture of hydrocarbons contained in a second tank (12), with an emulsifier contained in a third tank (18);

- pump means (22) for drawing and introducing dosed amounts of water, drawn from a fourth tank (6) in said mixture of hydrocarbons and emulsifier contained in said first tank (16);

- pump means (22) for pressure circulating many times said mixture of water, hydrocarbons and emulsifier from said first tank (16) through an emulsifier device (E) and from this again in said first tank (16) until obtaining a stable emulsion of water in hydrocarbons, and for transferring said emulsion from said first tank (16) in a stocking tank (37) from which said emulsion may be drawn for the delivery to the users.
Plant according to claim 1, in which said hydrocarbon is diesel, biodiesel, thick fuel oil (residues of the petroleum distillation, like for example HFO, IFO, BTZ) or a mixture of them, and said emulsifier is a formulation containing ethoxylated surfactants.
Plant according to claim 1, in which the weight ratio of the fuel mixture + emulsifier / water is : fuel + emulsifier from 70 to 95% in weight / water from 30 to 5% in weight.
Plant according to claim 1, in which to the said fuel from 0 to 1 % and preferably from 0,1 to 0,5% of an improver of the cetane number is added, in order to raise the cetane number of the final product.
Plant according to claim 1 in which the said pump (22) is a screw or piston pump set to 35 bar for the emulsifying process, through the emulsifier (E), of the product contained in said first tank (16).
Plant according to claim 1, characterised by the fact that the emulsifier (E) comprises an inlet module (E1) and one or more additional modules (E2).
Plant according to claim 6 in which each module (E1 or E2) is formed by a cylindical tubular piece (42) on the inside of which there are housed two opposed specularly symmetrical sets of a plurality of concentrical bowls (45, 46, 47) having a decreasing height from the most external to the most internal bowl, and with their mouthpiece directed toward the end of the tubular piece (42), and the side walls of the bowls being perforated by a plurality of rows of borings (48), with the rows of bores of each bowl angularly offset with respect to the rows of bores of the adjacent bowl.
Plant according to claim 7, characterised by the fact that the inlet module (E1) is provided with two diametrically opposed electrodes (49,50) connected to a low voltage and low amperage direct current source, and for example to a source of direct current at 24V and from 10 to 25 A.
Plant according to any one of the preceding claims, characterised by the fact that it comprises a computerised station to which the single probes (7, 17, 19, 38) for monitoring the liquid level in the respective tanks are connected, the said station being provided with a suitable program by means of which the opening and/or the closure of the single solenoid valves (3, 5, 10, 15, 21, 24, 26, 30, 36, 39) is controlled or the single pumps (13, 22, 34) are put into operation.