Patent Application
20180369441
The present invention relates to a system, method and apparatus for transferring vapor molecules from a liquid to a gas stream. Particularly, it refers to a system and apparatus for increasing humidification and filtration of air and water pollutants, and solutes dissolved in water. Specifically, a system and apparatus for transferring an aqueous mass to a specific air stream, having solid surfaces and/or aqueous membranes is described.
The present invention will be described as a system for enhancing mass transfer, wherein liquid (water) molecules are transferred by means of mass transfer to a gas stream (air), in contact with the liquid and said solid surfaces.
Liquids have a physicochemical property called vapor pressure. Such property determines the equilibrium between the liquid-vapor phases of a liquid. By such property, a liquid will always tend to establish equilibrium between the liquid and vapor phases.
The evaporation phenomenon takes place when vapor is generated as a result of the equilibrium between the liquid-vapor phases. If a gas stream absorbs vapor in equilibrium with the liquid phase, fresh vapor will be generated to re-establish the liquid-vapor equilibrium.
Mass transfer is a phenomenon that has many applications, as in the desalination plants or environmental control systems, to name just a couple of examples.
In the case of desalination plants, the objective is to separate and remove salt from seawater to obtain drinking water. Seawater contains mineral salts dissolved therein, which is not potable for human consumption. Even, drinking large quantities of seawater can cause death. About 97.5% of the planet's water is salty, and only an amount below 1% is suitable for human consumption, therefore making seawater potable is one of a number of possible solutions to drinking water shortage. Since some time now, and particularly in Middle East countries desalination plants have been implemented to produce drinking water, however, the process is costly, and it is relatively seldom used. Currently there is a production of over 24 million cubic meters per day of desalinated water all over the world. The main disadvantage of the current desalination plants is that during the process of salt extraction from water, saline residues and polluting substances that endanger flora and fauna are produced. However, the main problem of such desalination process is the high-energy consumption cost, either through a reverse osmosis, distillation, freezing, flash evaporation, hydrates formation or electrodialysis process. It is known that the average cost of the most efficient desalination process per cubic meter of drinking water is about 5 to 15 dollars.
In this respect, there is a plurality of patents related to desalination processes and plants. For example, the Chinese patent application describes to an electrodialysis seawater desalination apparatus using a means of electromagnetic separation having upper and lower electrodes connected with a magnetic pole and a vertical outlet connection tube allowing water to flow through the pipe.
On the other hand, the Chinese utility model CN203922783U relates to a salt removal electromagnetic device, having an evaporation tank provided with a reservoir body provided with a vapor outlet port, and a controller connected to the reservoir body, wherein outlet vapor port ends are connected to two pipeline units. The disadvantage of said documents is that the evaporation process does not take advantage of the potential of applying mass transfer to that purpose.
In the mass transfer process, an airstream encounters the vapor in equilibrium with the liquid phase, the equilibrium is broken, and new vapor is generated to restore said equilibrium, where the air generated is humid air.
Said mass transfer process is applied to some evaporation humidifiers.
However, some humidifiers make use of other processes using a humidified material, which has the disadvantage that said material can be a source for the creation of fungus, algae and aerobic germs.
The U.S. Pat. No. 5,945,038 relates to an evaporative humidifier comprising an absorbent material where a portion of the humidification material is submerged, and the upper portion is exposed to air, in said patent the use of a float valve to control the water supply is also described.
Boiling humidifiers mix an air stream with a steam stream obtained from boiling water.
Said evaporators has the advantage of eliminating all kind of microorganisms, however they generate a “white powder” consisting of insoluble salts and minerals from water that are entrained by such steam streams. On the other hand, evaporation humidifiers have the disadvantage of consuming a great deal of energy to boil water. Moreover, said humidifiers do not provide means for eliminating pollutants contained in the air stream.
Warm mist humidifiers operate with steam near dew point. Steam is cooled down just before contacting the air stream, in such a way that a gas mixture of steam, small water droplets and air is obtained. Therefore, such equipment has the disadvantage of retaining air pollutants. Also, said mist humidifiers are not provided with means to remove pollutants present in the air stream.
In cold mist humidifiers, water or an aqueous liquid is sprayed and then mixed with air. Said equipment has the disadvantage of retaining pollutants and microorganisms in the humid air stream.
Such humidifiers are also not provided with means to remove pollutants contained in the air stream.
Ultrasonic humidifiers use high frequency vibrations to spray and evaporate water. Nevertheless, they have the disadvantage of requiring costly maintenance. Furthermore, such humidifiers are also not provided with means to remove pollutants contained in the air stream.
As indicated above, the boiling, the warm mist, the cold mist, and ultrasonic humidifiers do not remove the pollutants contained in air streams so that in such humidifiers, the pollutants are entrained along with the humidified air stream.
On the other hand, in the case of evaporation vaporizers, even when dust in the humidified material is removed by filtration, said dust in contact with the humidified material results in the occurrence of fungus, algae and aerobic germs. Also, over time, the dust accumulated on the humidified material has a tendency to block air circulation through the humidified material, thus affecting transfer of water to the vapor stream.
In order to remove dust, different types of filters are known. Also, the use of foam to control dust content in mine environments is known, for example in coal mines. Said foam is generated by ejectors, where it is mixed with an air stream and water stream at high velocity.
U.S. Pat. No. 4,000,992 and U.S. Pat. No. 4,400,220 of Jan. 4, 1977 and Aug. 23, 1983, describe a system for removing dust by using bubbles in a cyclone.
Finally, Mexican Patent 264635, developed by the present applicant, refers to a system and apparatus for transferring a mass from the liquid phase to the gas phase while removing pollutants characterized by comprising a plurality of liquid membrane generating cells, where said liquid membranes are collapsed by contact with a gas stream, the collapsed liquid material covers the suspended particles and removes them via decantation, where the membrane cells also increase the speed of the gas stream and cause said stream to impinge on the surface of the liquid at an angle of 45°. However, said evaporator has some disadvantages regarding an upper threshold in mass transfer.
Nevertheless, said systems suffers from cooling on the contact surfaces, as well as in the water mirror (tank, reservoir, container of liquid) that feeds the solid surfaces in contact with the airflow that absorbs humidity through said systems; this is due to a phenomenon called “wet bulb”, where, as the liquid is cooled down, its aqueous molecules tend to compact themselves by a natural temperature phenomenon (with the extreme being the formation of ice, where it becomes totally solidified); this cooling of the aqueous molecules reduces dramatically the evaporation capabilities of all the known cold evaporation systems using contact surfaces.
The present invention seeks to provide a high-efficiency system and apparatus for transferring vapor molecules from a liquid to a gas stream, for use in eliminating particles such as dust and pollutants from a humidified air stream and, additionally, removing metals, particles and salts in the liquid (water), thus substantially overcoming the problems associated with the abovementioned systems and apparatuses. The increase in efficiency is achieved by inhibiting the “wet bulb” phenomenon in the liquid mirror (water), wherein said system, method and apparatus of the present invention is based on one or several elements allowing for increasing the liquid temperature by using contact surfaces, thus increasing humidification up to 1000%.
For carrying out the present invention the characteristics of aqueous membrane cells (bubbles) generated by using a disk were studied, where the effect of temperature on said disk and liquid was studied and verified, as well as the characteristics of the aqueous membrane cells (bubbles) generated by using a disk, considering the airflow velocity and particularly the size of the holes on the disk (membrane cells). The results showed that the efficiency in transferring liquid molecules (water) in a gas flow (air) increases according to the increase in temperature of the membrane cell on the disk, and the liquid. Wherein, the air bubble column achieves the highest efficiency in comparison to a conventional humidifier.
According to the present invention, the main object is to provide a high-efficiency system and apparatus for transferring vapor molecules from a liquid to a gas stream.
A second object being the invention of a high-efficiency mass transfer system and apparatus allowing for controlling the temperature by means of solid surfaces that are humidified and subjected to an airflow, avoiding the wet bulb phenomenon.
A third object of the invention is a high efficiency mass transfer system and apparatus that eliminates dust and pollutants from a humidified air stream without generating fungus, algae and aerobic germs.
A fourth object of the invention is a high-efficiency mass transfer system and apparatus that eliminates solutes dissolved in water such as salts, metals or any other particle in the water.
For a detailed description of the invention, in the following, reference will be made to the accompanying drawings, in which:
As it is well known, the cold evaporation equipment using contact surfaces passes water (evaporative liquid) through solid or semi-solid surfaces, which are subjected to an airflow with the capability of absorbing humidity, that means that its relative humidity is less than 100%, and while exchanging humidity on the humid surfaces, it absorbs part of said humidity, generating evaporation (an increase in relative humidity of the dry air that passes through the system).
In the already known systems, the contact surfaces and the liquid are subjected to an air flow, then cooled down by the “wet bulb” phenomenon, and when they are cooled down due to said phenomenon efficiency is lost, because molecules agglomerates together due to a reduction in temperature.
Particularly, the present invention relates to a method, apparatus and system, by means of which the temperature of a liquid can be controlled, via solid surfaces which are humidified and subjected to an airflow, which becomes humid by contacting a water source; said water source, as well as said surfaces, tend to warm up, and when this happens, its efficiency increases because a change in temperature of the contact surfaces, as well as in the liquid involved in the humidification process is inhibited.
According to
Each disk (110) has a hollow center (114) comprising a plurality of grooves (111) disposed on the perimeter thereof, a solid surface (115) having a plurality of holes (112) arranged with equidistant spacing from each other. Particularly, each hole (112) has a perimeter (113) by which aqueous membranes are generated, in the present description said perimeter will be referred to as membrane cells.
As illustrated in
In reference to
The liquid diffuses through the membranes with a gas stream (mass transfer), causing the outlet air to become modified, wherein the liquid diffusion depends on the membrane diameter within the holes (112), the velocity of the aqueous membrane (membrane-liquid ratio in a volume of air), the water temperature, the temperature of the disk (110), which leads to an increase in the mass transfer coefficient.
Turning to
The heat generation means (116) are electrically energized by a control element controlling the current flow through the conducting element. By using a control means and temperature sensors, the temperature of the electrical resistors forming said conducting element is controlled, whose objective is to increase the point temperature within the mass transfer zone in order to increase the efficiency of the device.
Thus, the temperature of disks (110) is controlled by using the heat generation means (116) on their solid surfaces (115) which become humid and then are subjected to an airflow, which in turn becomes humid by being in contact with a liquid source; where said disks (110) will transmit heat to the liquid source. Temperature is kept and controlled in the system in such a way that, the “wet bulb” phenomenon is inhibited in the liquid source mirror, leading to an increase in the mass transfer efficiency and performance of up to 1000%.
The assembly plate shown in
As will be evident to one skilled in the art, said disks (110) can have any shape, for example, a polygonal shape.
With reference to
The membrane cells (118) are formed in the spaces between the solid surfaces (115) of said disks (110) and the assembly plate (120). Said cells have the shape of an irregular cube with one a widened face. The plurality of disks (110) is made of any metallic material that allows heat transmission as well as formation of an aqueous membrane.
The heat generation means (116) heat up the disk (110) to a predetermined temperature thus evaporating the liquid impregnated on the solid surface (115) and allowing rupture of the aqueous membranes between the disks (110) and the membrane cells (112) that are formed between said disks (110) by means of an injected gas flow.
According to
The air convection means (404) comprise any means to force air or gas convection inside the system. According to
A motor (406) is mounted on the base (407), generating a rotary motion and transmitting it to the membrane generation means (100) through the mechanical coupling to a toothed wheel or gear (408).
According to
Furthermore, the heat generation means (116) heats the liquid (500) contained in the base (401) of the high efficiency apparatus for transferring vapor molecules from a liquid to a gas stream (501).
The disks (110) rotate continuously or intermittently, so that the membrane generation means (100) is immersed in and emerged from the liquid (500), forming liquid membranes within the holes (112) of each disk (110) that constitutes the membrane generation means (100), additionally liquid membranes are formed between the space between each disk (110).
Therefore, once the air injected by the air convection means (404) passes through the disks (110), a portion of the air is deflected due to the geometry of the membrane generation means (100) and location of the comb-like assembly plates (120), causing deviation of air. The air pressures inside the membrane generation means (100) zone are homogeneous.
The vortices generated in the assembly plate (120) zone, cause the air to recirculate in those spots, this can be beneficial as it is a requirement that the flow passing through the disks (110) must be turbulent; and what the vortex values mean is a turbulent flow with spiral rotation. The injected air forms a plurality of vectors where the air flows directly towards the disks (110) and the assembly plates (300) with the aid of a deflector additionally installed (not shown in the figure). Therefore, the criterion of a greater pressure exerted on the disks (110) will be fulfilled and rupture of the membranes ensured.
The disks (110) are heated to a predetermined temperature through the heat generating means (126), which are partially immersed in the base (401) containing a liquid (500) up to a certain level of liquid. The disks (110) of the membrane generation means (100) transfer a portion of the heat generated to the liquid (500). As illustrated in
Thereafter, the disk (110) rotates to position B, where half of the membrane holes (112) that were immersed now emerge, and part of the liquid (500) drains back to the container (401). However, due to the surface tension of the liquid, aqueous membranes are generated in each hole (112) emerging from the liquid surface of the base (401).
At least one aqueous membrane is formed from the liquid in the membrane generation means (100), and it is impinged with the airflow injected by the air convection means (404). The membrane collapses spraying itself into thousands of particles. Particles suspended on air are trapped by the membrane spray and decanted.
The disk arrangement (110) of said membrane generation means (100) provides to the system and apparatus of the present invention, means for channeling, space and time to allow for the humidified particles still dispersed in the gas, to precipitate and agglutinate.
The airflow (501) directly impinges on the aqueous membranes of the membrane generation means (100), which collapse when they receive the airflow, spaying themselves into thousands of small liquid particles that were part of each membrane.
The solid particles and pollutants accompanying the gas stream are decanted as a result of the saturation they were subjected to at the time of the rupture of said membranes. This effect captures suspended particles, causing a change in their weight and the precipitation thereof.
The liquid membranes described in the present disclosure are collapsed upon contact with small particles of material, such as dust, and the portions of the collapsed membrane are capable of wetting particles of the size of one micron. In this way, particles in the air are collected and agglutinated.
Simultaneously, the liquid particles of the collapsed membrane are transferred to the air stream humidifying the same. Fragrances that alternatively can be added are also transferred to the air stream by aromatizing it. The resulting airflow from the process exits completely clean, humidifying and scenting the environment.
Spraying of the liquid by rupturing the membranes, promotes the transfer of liquid into the gas stream, furthermore by controlling the temperature of the liquid (500) the “wet bulb” phenomenon in the liquid is inhibited and mass transfer efficiency is increased. As the liquid cools down, its water molecules tend to compact themselves by a natural temperature phenomenon (with the extreme being the formation of ice, where it becomes totally solidified);
this cooling of the aqueous molecules reduces dramatically the evaporation capabilities.
The membrane generation means (100), in the preferred embodiment of the invention, has been illustrated as a plurality of disks (110) forming the membrane cells in a cylinder arrangement. However, it is not limited to said form or to the number of cells, as will be evident to one skilled in the art, that said arrangement can be changed. For example, they can be arranged as a block of cells through which air circulates, with the provision that the supplying liquid means must flood or wet said block of cells. A block membrane generation cells is considered as included within the scope of the present invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2015/059704 | 12/17/2015 | WO | 00 |
