Static laminar flow emulsifier. A new method, developed from research and development work, consists of achieving the emulsion of fuels in a laminar current regime, which allows greater uniformity of the droplet diameters and close to the average value. This guarantees the stability and quality of the emulsion.
Summary
[ hide ]
- 1 Description of the method.
- 2 Hypothesis according to criteria
- 3 Description of the emulsifier
- 4 Principle of operation
- 5 Case study.
- 6
Description of the method.
Liquid fuels emulsion is a solution that is used worldwide to save fuel and reduce environmental pollution. The most widely used method is the turbulent current regime, but the cost of the facilities is very high, which does not favor the development of this technology. This method was achieved through the static laminar flow emulsifier and constitutes a technological innovation ; it is simple, compact, small and cheap. Both method and technology are Cuban, from the author of this article. It has been successfully applied in Cuba , since fuel saving values of 10% have been obtained, with the reduction of polluting gases, such as CO , NOX andSO2 , and combustion is improved. With the fuel emulsion you get savings, better efficiency and energy management. The design of this device allows the emulsion of any liquid fluid with water, or other substance. The main objective of the invention is to supply water to a liquid fuel emulsifier that does not have a moving part, nor does it consume additional electrical energy. The achievement of the emulsion is performed under the novel principle of laminar flow current regime. Another objective was to achieve a type of emulsifier capable of obtaining water droplets of very small and more uniform sizes. The advantages of supplying small and uniform drops of water in each fuel cell, is that a secondary atomization can be carried out in the combustion, which is responsible for greatly reducing the production of soot, taking full advantage of the fuel, increasing the heat transfer between the combustion gases and the feed water, noticeably improving the efficiency of the boiler and as a consequence of good combustion; In addition, it reduces the pollution of gases to the atmosphere. The emulsion not only helps to saveenergy , but also directly and visibly rewards the heating system with a substantial reduction in annual fuel costs; It also enables long intervals to occur between cleaning periods. As soot production was reduced, it is possible to use cheaper fuel and still maintain environmental standards for particulate emissions from furnace combustion.
Hypothesis according to criteria
National crude oil can be emulsified with this technology, with the consequent decrease in environmental pollution
For the design of the static laminar flow emulsifier it was important to choose a flow current criterion, in this case that of laminar flow current. The method used to facilitate the emulsion is a simple apparatus, without a moving part.
- To obtain an excellent emulsion, a laminar regime in the reduced diameter area of the central chamber must be achieved in the fluid flow, for which Re <600.
- The pressure of the fluid used and the pressure of the water at the inlet of the emulsifier should be the same, although a slightly higher water pressure can be admitted.
- The total area of all the holes through which the water is injected is 0.11-0.16 times the total area of the neck of the emulsifier chamber.
- The flow of the water for the emulsion will be the flow of the fluid multiplied by 0.05; 0.08; 0.10; 0.15; 0.20; 0.25; etc. In the case of fuel oil, the optimum is 0.08; for diesel-fuel oil blends, it is 0.10; for boilers and furnaces the mixture of diesel-fuel and diesel-fuel for transport engines is 0.25.
- The central chamber must have 8; 18 or 36 agate injection holes for the emulsion, depending on the type of fuel consumed.
- The speed of the fuel is greater than that of the injected water.
- The viscosity of the fluid to be used, as well as the consumption per hour, define the diameter of the reduced area of the chamber .
A disadvantage of “turbulent” fuel flow is that such flow can sometimes, for just an instant, develop a very low speed or reach zero on the wall where the water flow enters the neck of the central chamber; therefore, a small percentage of water droplets will be larger and will not maintain the standard size they should be. This indicates that it is more useful to have water droplets with a more uniform size, in order to obtain an optimal result. The term “laminar flow” means that their velocities are “free of microscopic fluctuations”, that is, that the flow is substantially free of turbulence, characterized by counterflow, with the exception of micro-turbulence, which occurs in the injection lines of neighboring water and the induced turbulence of water in neighboring bubbles, or in sediments or water flows. In the static laminar flow emulsifier, the emulsion process is carried out by suction or dragging, and by the cut of the water droplets that have formed and organized inside the holes or channels when the fuel flow passes in the area. small diameter of the central chamber. The fuel flow when colliding with the directional device passes through the grooves that are close to the cone wall of the central chamber, organizing itself in the form of a film on the wall of the cone and the neck of said chamber. As the pressure of the water is equal to the pressure of the fuel in the neck area, this allows the entry of the flattened ellipsoid with a diameter smaller than the diameter of the hole. When the water droplet comes out of its channels it is cut by the fuel film that comes from the wall of the cone and the neck (droplet that originated within their respective channels and has smaller diameters than this). As the water droplets are cut by the fuel film, they are divided into several droplets of smaller diameters. These droplets are then brought to the center of the chamber neck, where there is a region of microtur-bulence, and are again cut by the fuel molecules that move with greater speed. Finally, leaving the emulsifier as the flow of emulsified fuel passes into and into the pump, the water droplets reach the smallest diameter values. These are divided into several droplets of smaller diameters. These droplets are then taken to the center of the chamber neck, where there is a region of microtur-bulence, and are again cut by the fuel molecules that move with greater speed. Finally, leaving the emulsifier as the flow of emulsified fuel passes into and into the pump, the water droplets reach the smallest diameter values. These are divided into several droplets of smaller diameters. These droplets are then taken to the center of the chamber neck, where there is a region of microtur-bulence, and are again cut by the fuel molecules that move with greater speed. Finally, leaving the emulsifier as the flow of emulsified fuel passes into and into the pump, the water droplets reach the smallest diameter values.
- Population, uniformity and distribution of the water droplet in the emulsion. Case a: correct; case b: incorrect.
It is important to recognize that the merit of the laminar flow current regime is that when cutting the water droplets, it does so in such a way that the fragmentation of these allows each of them to have the most uniform diameter, one with other; This occurs in the first cut of the water droplets, which ensures that the largest diameter that some droplets may have is close to the average value between them. When the droplets are accelerated, or retarded, the resistance to movement apparently changes by an amount described in terms of “transported mass,” varying from one-half to twice the mass of the displaced fluid. Finally, the emulsion has performed satisfactorily if it is “well divided”, if it is “reasonably uniform” and if more than 95% of its droplets have a diameter of 2 to 5 ìm.
Emulsifier Description
The static laminar flow emulsifier is composed of a body of cylindrical shape and with a longitudinal slit; its function is to protect the emulsifier from shocks. In addition, it makes it compact and avoids leaks. The central chamber is inside the body butt and is made up of two cones, which has an area of reduced diameter or neck in its center. In it there are perforations to allow the entry of water in the form of a drop into the interior. The directional device is in charge of distributing the fluid at the inlet of the emulsifier through the walls of the cone of the central chamber towards the area of reduced diameter, to achieve the emulsion. Two-way stoppers guarantee the entry and exit of the fluid before and after the emulsion and help to compact and seal the emulsifier.
Operating principle
The emulsion process is carried out by suction or drag and cut of the water droplets that have formed inside the holes, as the fuel flow passes in the reduced diameter area of the central chamber. The fuel flow when colliding with the directional device, is introduced through the grooves that are close to the cone wall of the central chamber, organizing itself in the form of a film in the neck of said chamber. A vacuum is produced in the center of the cone of the central chamber after the device.
Static emulsifier
- Exploded view of the static laminar flow emulsifier.
The water pressure is slightly higher than that of the fuel in the neck area, allowing the entry of the flattened ellipsoid with a diameter smaller than that of the orifice. The fuel in this reduced zone increases its speed, creating a suction or entrainment of the water droplet, which is cut by the fuel film formed on the cone wall. As the droplet is cut, it divides into several smaller sizes. Later they are taken to the center of the neck of the central chamber where there is a region of micro-turbulence and they are cut again by the fuel molecules that move with greater speed, because as the molecules move away from the wall they increase their speed.
Table 1. Average values in a medium boiler with a wall of water pipes.
Legend:
- VN: Regulatory value (conceived by the manufacturer).
- VR: Real value.
- VRE: Real value of the emulsion.
- Tg: Temperature of the exhaust gases from the boiler.
- Tll: Boiler burner flame temperature.
Table 2. Average values in small fire tube boiler.
Case study.
Tests were carried out on four medium-sized boilers with water tube walls and on more than twenty small boilers with fire tubes. Tables 1 and 2 show the average values of the parameters measured in a medium boiler and in a small boiler. As can be seen in Tables 1 and 2, the CO, SO2 and SO3 values decrease, as does the flame temperature, so the NOX value also decreases. The total values of the polluting gases that decrease with the application of the emulsified fuel were 2.29% with respect to the normative value, and 3.89% with respect to the real value, as an average value, according to measurements made during the tests.
