DE4440319A1 - Process for improving the efficiency of an evaporation process - Google Patents

Abstract

If in evaporation processes the boiling temperature cannot or may not be achieved, a liquid evaporates only at its surface as a function of the partial pressures. Two known possible methods for accelerating this process are: Generating reduced pressure and Removing the layer of saturated steam forming at the surface which functions as an insulating layer. However, in both cases the surface of this liquid is the decisive parameter. The process which is the subject matter of the present application achieves by simple means an enlargement of the active surface area - exchange surface area - by simulating a boiling process and additionally utilises the abovementioned two possible methods. This improvement is achieved by injecting dry unsaturated air at the bottom of the liquid column, which air is then removed by suction, cooled and after partial yielding of its water content is injected dry. By parametrisation of the rate of ascent by the injection pressure and/or the height of the liquid column, an enlargement of the evaporation surface area by approximately 6-fold can be achieved by this means.

Description

The present invention has been made in connection with the problem of desalination of develops brackish or pure salt water, as it results when you primarily wants to use renewable energy sources - solar radiation, wind power - whose Efficiency strongly depends on the weather conditions.

There are basically two methods for obtaining pure water:
The method of reverse osmosis and
The method of evaporation.

After the first, the water to be treated with high pressures - approx. 650 m Water column - pressed by special membrane, but after the second this is Water evaporates by adding heat and then it is cooled siert. It is a real distillation process. The aftercare the water obtained by the first or second method is not an object this registration.

The purpose of the present invention is to control the evaporation process of the second Accelerate method and thereby increase the efficiency and efficiency of this Process.

The processes related to evaporation are intended to improve ver briefly explained.

Every liquid evaporates on its surface at different speeds Dependence on their temperature and the partial prevailing on their surface print. By applying heat, a specific point for each liquid is Boiling point - reached, at which the evaporation from the whole mass of this me diums takes place. This process is called boiling or boiling.

However, it can prove to be useful to have this process below the To carry out the boiling point of this liquid, either because of the power of the heat source cannot reach this point, or also because the implementation of this Distillation process below the boiling point u. a. better purity can be expected. The former case can e.g. B. occur when, as mentioned at the beginning, as Heat source solar panels are used, the performance of which is not only dependent on the Time of day, but also depends on general weather conditions. Of the second case is z. B. not only in petrochemical processes, but also in  Processing of e.g. B. natural juices conceivable. You want the water and juice there withdraw, but without overheating, the otherwise existing, more valuable substances e.g. B. to destroy vitamins.

The cooking or boiling process should thus be simulated and the evaporation process are accelerated by the fact that now also at temperatures below the boiling point point of evaporation not only on the surface, but from the whole mass of the medium.

According to the invention by means of a suitable construction, for. B. a nozzle ring, Air in bubble form is pressed in at the bottom of the liquid column to be evaporated and vacuumed on their surface.

Depending on the rate of climb of these bubbles, it can be achieved that this air blown in unsaturated, dry state on the surface of the Medium emerges saturated.

This means that the full-volume evaporation that can otherwise only be achieved at the boiling point of the medium not only accelerates, but especially at lower temperatures than that of the boiling point.

Rough calculations are expected to be the result of evaporation decisive area - active area - compared to a conventional system Multiples can be increased up to a factor of 6.

For better understanding, please refer to the two diagrams below are explained. It should be noted that this schematic representation, as otherwise usual, has hardly any resemblance to the installation occurring in practice and only serves the basic understanding.

Scheme 1 shows the usual evaporation process.

In the left vessel, the liquid to be processed is evaporated by heating brought and then passed into the right vessel, in which they by cooling to Distillate condenses. The steam can be fed into the right vessel either by means of a suction device, or freely - freely - through the prevail the differential pressures between a warmer and a colder environment.

Scheme 2 shows the modification registered here.

According to the invention, air is drawn off from the right container and approximately in the base of the left container with the help of the mentioned wreath, in the form of air bubbles presses. This air, which is dry by comparison, passes through a parameterizable speed  liquid and reaches its surface in a saturated state in order to finally cooled in the second container and thereby dried, releasing the amount of liquid absorbed.

It is readily apparent that the evaporation is not only at the top area, but from the entire volume of the liquid to be treated; a Fact, which, as noted above, an increase in that for evaporation relevant area by up to a factor of 6. The full volume evaporation, Cooking, which is at water at sea level at a temperature of 100 ° C, can now be used with this method even at lower Execute temperatures.

Claims (1)

Method for improving the efficiency of an evaporation process, characterized in that

• 1. by introducing a suitably prepared medium, in the present case dry air, by means of the mass to be evaporated, this process is accelerated by increasing the active (exchange) area,
• 2. irrespective of whether the necessary preparation consists solely of drying this medium or also of enriching it with appropriately determined additives,
• 3. depending on the purpose to be achieved and the nature of the medium to be evaporated, other means of transport, in the present case air, depending on the decisive mutual solubility can be used.