DE20301711U1 - Assembly with conical cover evaporates salt water, brackish water for condensation and recovery of drinking water - Google Patents

Abstract

An assembly evaporates salt water, brackish water for condensation and recovery of drinking water. The water is heated to evaporation temperature and water vapour impinges on a cooled surface, condensing and collecting in grooves to tubes and another container. The heat energy is supplied by combustion of fossil fuel, or electrical energy from public supplies or solar power. The water evaporation chamber has an approx. conical top cover which acts as the condensation surface and is covered by a dark-coloured textured collector surface which warms when exposed to sunlight. The condensed water collector groove runs around the inner lower face of the conical section and discharges via a tube through the wall.

Description

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The invention relates to a thermal evaporation system for drinking water treatment from seawater, brackish water or wastewater and/or for desalination of seawater.

Known processes for desalinating seawater include osmosis and reverse osmosis, which are based on the principle of filtering seawater through synthetic membranes. The medium to be treated is pressed through the pores of the membranes. The pressures required for this are up to 60 bar, so the corresponding energy expenditure is very high. When considering the aspects of economic efficiency and environmental compatibility, the raw materials and energy required to produce such membranes and the environmentally harmful waste materials generated during production must not be ignored. In thermal seawater desalination and the treatment of brackish water or waste water, energy is supplied to the medium to be treated in thermal form. The medium changes from a liquid state to a boiling state and then into a gaseous state. If the transition from the liquid to the gaseous state takes place at temperatures below the boiling point, this is called evaporation, whereby significantly smaller quantities per unit of time pass into the gaseous state during evaporation than during vaporization. While evaporation takes place on the surface of the medium, vaporization occurs through the formation of gas inside the liquid, which shows that large surfaces are necessary for evaporation. If a contaminated medium is caused to evaporate in this way, water vapor is created, which can be collected as condensate. Such devices are called distillers. With the appropriate evaporation rate, the resulting distillate is pure water without any contaminated residues such as salts or other contaminated substances. At constant pressure, the boiling temperature and condensation temperature are the same, i.e. during condensation, the heat supplied for evaporation is released again in the form of condensation heat. With a pure distillate, care should be taken to ensure that evaporation takes place under normal pressure at a maximum boiling temperature. To prevent contamination through cohesion, boiling of the surface of the liquid medium should be avoided as far as possible. Working temperatures of approx. 80° to a maximum of 90 ⁰ C are therefore recommended, with energy consumption of approx. 150 kW/h to 180 kW/h per m ³ of condensed water. For the above-mentioned reasons of the purity of the required distillate, higher temperatures in the pressure system are not recommended; theoretically 12O ⁰ C is possible. The waste product during and after the evaporation process is water as pure distillate for further use and solids separated in the still.

Other waste and residues depend on the primary energy source used, which is converted into thermal energy and sets the evaporation process in motion. Renewable forms of energy in thermal form from solar radiation, in electrical form from solar cells, in electrical form from wind turbines and in geothermal form by exploiting high ground temperatures can be considered as primary energy. Fossil energy sources in the form of gas, oil, coal, but also wood and/or other carbon-containing organic fuels can be used.

A system according to the invention comprises, among other things, a boiler (1) containing water (12) to be treated. This is designed in such a way that it can be heated from below by firing (2) or, depending on the variant, the water (12) can be heated by heating elements (3) inside the boiler (1). Water evaporating on the surface of the water level rises and condenses on the upper end of this boiler (1), which is designed as a condenser surface (4), and which is approximately conical (with the tip pointing upwards). At the upper end of the approximately cylindrical boiler shell, a condensate collecting channel (14) is attached all the way around the inside, which has a lowest point at one point on the circumference of the boiler shell with a drain pipe (5) through which condensate can flow out. Above the upper, roughly conical container end, there is another, roughly conical cover, roughly equidistant from it, which, together with the cylinder jacket that continues upwards around the circumference of the vessel, forms a housing for the condenser cooling air. Cutouts (6) are made in the cylinder jacket of this housing, which enable a condenser cooling air flow from the outside, centrally, inwards and upwards. Cooling surfaces (9) running in a radial direction on the outside of the condenser surface (4) support the heat dissipation from the condenser surface (4) to the cooling air flow. In the area of the cone tip of the upper condenser cooling air housing wall, the cooling air is discharged upwards through a pipe (7). A fan to support the cooling air flow can be installed in this pipe (7) as required. In addition, solar collectors (8) are attached to the circumference of the upwardly leading pipe (7), which transfer heat to the pipe jacket surface, further heat the air flowing upwards in it and thus increase the condenser cooling air flow. The medium to be treated is supplied through a pipe (10) leading into the boiler from the outside, which is installed below the surrounding condensate collecting channel (14). A pipe (11) is positioned on the boiler shell near the lower boiler floor, through which dirty water can flow out.

If several units of the system described above are connected together, this makes it possible to switch off one or more individual systems, e.g. for maintenance or cleaning, without having to switch off the entire system.

The resulting concept of thermal stills heated as regeneratively as possible via collectors, component construction, consideration of architecture and construction planning in the form of storage basins, etc. enables not only inexpensive but highly effective seawater desalination plants. By choosing the components sensibly and designing and planning accordingly, almost maintenance-free systems are created, with maintenance intervals of more than 6 months. Depending on the design, the parts of such a system that require maintenance are particle protection or coarse filters, the function of the main pumps, the main system components, the fill level of the heat transfer media in the heat exchange systems, leaks and the like. More costly maintenance and the replacement of expensive membranes are no longer necessary. The functional principle described thus results in a highly effective and safe seawater desalination system, which, unlike other systems, can be expanded as required and without great effort. Even if individual components are damaged, a large system complex is able to maintain operation.

Water treatment plant Thermal evaporation system

Legend to Fig. 1 Warm exhaust air 1 Collector surfaces heated by the sun 2 Cooling fins 3 Side inlet for cold air 4 Drain channel for condensate 5 Condensate outlet 6 Waste water inlet 7 Wastewater 8th Convection roller from moist air 9 Thermal insulation 10 Waste water outlet 11 Direct heating e.g. electric 12 Sloping floor sloping forward 13 Fire opening for external heating 14

Claims (12)

1. Thermal evaporation system for the treatment of drinking water from sea, brackish or waste water and/or for the desalination of sea water, characterized in that the water to be treated is heated to evaporation temperature, the evaporated water portion condenses on condensers and is led into another container in collecting channels and drain pipes provided for this purpose, the energy required for heating the water being provided by burning fossil fuels and/or with electrical energy taken from the power grid or generated by solar energy. 2. Thermal evaporation system according to claim 1, characterized in that the water to be treated is heated in a container above which there is an evaporation chamber with an approximately conical upper end which acts as a condenser surface. 3. Thermal evaporation system according to claim 1, characterized in that a collector surface is located above the condenser surface, which collector surface heats up when exposed to light due to the dark color and the surface texture of the upper side. 4. Thermal evaporation system according to claim 1, characterized in that a collecting channel is located around the lower cone circumference of the upper water tank end, which collects condensate flowing off the inside of the cone surface. 5. Thermal evaporation system according to claim 1, characterized in that the condensate collected on the inside of the container in the circumferential collecting channel can flow outwards through a drain pipe in the container wall. 6. Thermal evaporation system according to claim 1, characterized in that above the approximately conical condenser surface there is a housing design such that, starting from the lower cone circumference, an approximately central air flow towards the cone tip can occur. 7. Thermal evaporation system according to claim 1, characterized in that the upper cover of the air flow space is designed on the outer surface as a collector surface. 8. Thermal evaporation system according to claim 1, characterized in that the central air flow is discharged upwards in a tube above the approximately conical condenser surface. 9. Thermal evaporation system according to claim 1, characterized in that the tube in which the air flow is discharged over the tip of the condenser surface is provided with collector surfaces on the outside of the circumference. 10. Thermal evaporation system according to claim 1, characterized in that the cooling air flow for the condenser surface is supported by a fan. 11. Thermal evaporation system according to claim 1, characterized in that the bottom surface of the water tank in which the treatment process takes place has a lowest point in the middle. 12. Thermal evaporation system according to claim 1, characterized in that a pipe is positioned through the container wall of the water container in which the treatment process takes place, above the container bottom, approximately tangentially to the approximately circular container bottom.