AT509864B1 - nucleating - Google Patents

Description

Austrian Patent Office AT509 864B1 2011-12-15

Description: [0001] The invention relates to a nucleating agent, as can be used for producing artificial snow (= technical snow = machine snow).

The increasing climate change, in particular global warming, requires intensive work on methods for artificial or technical influencing of the atmospheric water vapor condensation processes and in particular snow production.

One of the consequences of global warming increasingly causes negative effects, on the one hand on tangible and agricultural goods in hail and on the other hand on tourism, especially due to insufficient amounts of snow.

Methods using nucleating agents (= additives) in technical / artificial processes to bring rain or fend off hail and to optimize artificial snow production are particularly critical because they may have adverse effects on the environment (limited environmental impact) and long-term effects ., the energy needs are taken into account.

When producing artificial snow, freezing cores are used as additives (= nucleating agents). Alternatively, condensation nuclei in water vapor saturated cloud formations are used to fend off hail or to cause clouds to deliberately rain down.

Freezing nuclei are known as nucleating agents based on, for example, freeze-dried bacteria "pseudomonas syringae", which due to special proteins are able to raise the nucleation temperature of water. If this nucleating agent (= additive), ie the dried bacterium "pseudomonas syringae", is used in the snow water, effective artificial snowmaking can be carried out at higher wet bulb temperatures, which is possible at higher temperatures than for snow water without the addition of nucleating agents. A disadvantage of this process, in which freeze-dried bacteria are added as nucleating agent (= additive) when producing technical snow, is that this nucleating agent is not permitted in all countries due to its biological origin.

It is further known that natural minerals in the dust form are atmospheric nucleators for forming droplets / ice crystals in clouds, and that contaminants in the form of particles of mineral origin (e.g., glacial cut) in the snowwater promote the formation of artificial snow at higher temperatures.

As condensation nuclei for inoculating clouds usually silver iodide is used in water vapor saturated cloud formations, these condensation nuclei are brought from aircraft or with the help of hailstorm missiles in the clouds. A disadvantage of the use of silver iodide for vaccinating clouds is a possible negative impact on health and safety as well as a possible adverse effect on the vegetation.

From DE 694 20 522 T2 it is known to use the juice of the seabuckthorn plants in the ice cream preparation to allow higher production temperatures.

It is known from the prior art that minerals, including calcium carbonate-containing minerals, can serve as nucleating agents for forming ice (F. Zimmermann, M. Ebert, St. Weinbruchl and L. Schütz. &Quot; ice-nucleating "The European Aerosol Conference, 2007 Sept. 9th-14th, Salzburg, Special Session: UT / LS Aerosols and Clouds - Measurements and Modeling, Abstract T13A034; Zimmermann, F., S. Weinbruch , L. Schütz, H. Hofmann, M. Ebert, K. Kandier, and A. Worringen (2008), Ice Nucleation properties of the most abundant mineral dust phases, J. Geo-phys. Res., D23204, doi: 10.1029 / 2008JD010655; Eastwood, ML, S. Cremel, C. Gehrke, E. Girard, and AK Bertram (2008), Ice nucleation on mineral dust particles: Onset conditions, 1/5 Austrian Patent Office AT509 864B1 2011-12-15 nucleation rates and contact angles, J. Geophys. Res., 113, D22203, doi: 10.1029 / 2008JD010639 and US 6,151,902A). LF Evans. " Ice Nucleation by Amino Acids ". Journal of the Atmospheric Sciences November 1966, Vol. 23, page 751-2 describes amino acids such as L-leucine as a nucleating agent for ice formation.

The invention has for its object to propose nucleating agents (= additives), which rely exclusively on substances that occur in nature frequently and in appropriate amounts occurrences.

This object is achieved with a nucleating agent having the features of claim 1.

Preferred and advantageous embodiments of the nucleation agent according to the invention are the subject matter of the subclaims.

The invention is based on the finding that basically all naturally occurring minerals or synthetically producible (for example with the aid of precipitation reactions) can be used as additives (= nucleating agents) for the purposes of the invention.

Advantage of the additive according to the invention (= nucleating agent) is that this can be adapted exactly in size, quantity and condition and in its shape to the circumstances. This applies with regard to size, quantity and condition for naturally occurring and for synthetically produced nucleating agents of the invention, wherein the morphology, ie the shape, especially in artificially produced nucleating agents can be adapted to the circumstances.

So nucleating agents are provided with the invention, which can be selected specifically in terms of chemical composition, grain size, particle size distribution, concentration and morphology. The nucleating agents according to the invention can be produced by milling or precipitation method exactly with the parameters that make them suitable for use as an additive (= nucleating agent).

In the present case, a mineral is understood as meaning a naturally occurring, mostly crystalline solid having a uniform chemical composition and a uniform structure at the microscopic level. According to the invention, minerals according to the invention can also be produced synthetically with the same chemical composition as the naturally occurring mineral.

In particular, the following minerals or mixtures thereof are considered within the scope of the invention: Carbonates: calcium carbonate

Calcium magnesium carbonate (dolomite)

barium carbonate

potassium carbonate

sodium

magnesium carbonate

Strontium carbonate Sulfates: calcium sulfate

barium sulfate

Strontium sulfate silicates: kaolin

talc

Quartz sand (SiO 2) In the context of the invention, the whitening agents used (= additive) are Austrian Patent Office AT509 864B1 2011-12-15

Minerals are either crushed mechanically to a particle size of 0.05 to 5 gm or they are, if they are produced by precipitation, by maintaining defined boundary conditions, precipitated so that they are in the particle size range 0.05 to 5 pm.

Especially considered in the context of the present invention, not least due to its availability ground calcium carbonate on the one hand and precipitated calcium carbonate on the other.

Ground calcium carbonate may e.g. be present as chalk, limestone or marble and is mechanically comminuted after mining mining in several stages dry and / or wet on the invention considered grain size between 0.05 and 5 pm. The crushed calcium carbonate (crushed grain) has an amorphous structure, and the shape has not been significantly affected by the grinding process.

Precipitated calcium carbonate, which is also preferred in the context of the invention as a nucleating agent (= additive), has the advantage over ground calcium carbonate that it can be prepared in different morphologies and in a very narrow particle size band with high purity. Precipitated calcium carbonate also has the advantage that it can be produced without contamination by organic substances, especially when burnt lime is used as the starting product before the precipitation process. Depending on the precipitation conditions, one of the following morphologies can be achieved in precipitated calcium carbonate: - Scalenohedron - rhombohedron - aragonite - vaterite The crystals can be used discretely as a nucleating agent according to the invention (= additive) or in the form of agglomerates become. The single crystal sizes are in a preferred range in the invention of about 0.05 to 5 pm.

When used, the nucleating agents according to the invention can be sprayed with the aid of pyrotechnic aids or used as a suspension by means of a targeted liquid metering in the snow / feed water of snow guns.

When producing artificial snow (= technical snow), the number of Nukleationskeime per water droplet can be precisely defined with the help of a dosage of nucleating agent (= additive) in the form of a suspension and thus a continuous, adapted to the requirements amount can be selected , which is adjustable to the given conditions. Thus, the consumption of nucleating agent can be optimized according to the invention.

In the case of producing artificial snow (= technical snow) nucleating agent according to the invention can be used in all snow-making equipment, such as snow lances or propeller machines.

As naturally occurring minerals are used in the invention (even if they have been produced synthetically), a risk or negative impact on flora and fauna is excluded.

In the context of the invention, the effect of the nucleating agent is increased as nucleation nuclei, since they are used with a coating with L-leucine.

A considerable advantage of the nucleating agent according to the invention for the production of artificial snow is still that the snow volume can be increased, the artificial snow quality improved and / or the water / energy consumption can be reduced.

Experiments with a propeller snow gun in which precipitated calcium carbonate coated with L-leucine (in powder form) was used as the nucleating agent have shown that about 1.5 ° C higher wet bulb temperature even technical snow can be produced compared to standard conditions without inventive nucleating agent.

An exemplary embodiment is reproduced below:

Test date: Place: Machine type: Additive: Average particle size: Morphology: Specific surface area: Coating: Dosage point: Nucleation nuclei: 10.12.2009 Villach (AT)

Areco / Sufag standard propeller machine PCC (precipitated calcium carbonate) 100 nanometers (= 0.1 pm) rhombohedral approx. 17m2 / gr L-leucine (amino acid) cooling tower basin = suction point for supply pump approx. 70 (assuming droplet diameter of 0.75 mm)

Additive Dosing Wet bulb Temperature Water temperature Result No -2.2 ° C approx. 2 ° C No snow No -3.7 ° C approx. 2 ° C Wet snow Yes -2.2 ° C approx. 2 ° C Wet snow The Nucleating agents according to the invention of ground, coated minerals, in particular calcium carbonate as precipitated or ground calcium carbonate, can be used in the production of artificial snow (= technical snow = machine snow) with a coating / treatment agent of proteinaceous and lipidic components of the sea-buckthorn plant (Hippophae) and / or of amino acids, such as L-leucine, persist.

The nucleating agents according to the invention can, apart from the production of artificial snow (technical snow or machine snow), for accelerated condensation of water in the atmosphere, in particular as a hailstorm measure, are used. In this context, the accelerating condensation and dripping of water in the atmosphere of importance.

In summary, an embodiment of the invention may be described as follows: As an additive / nucleating agent for causing condensation of water in clouds to cause rain and / or to produce artificial snow, naturally occurring, mechanically processed minerals or minerals are used synthetically produced minerals with the same chemical composition, or a mixture of both types used in a particle size between 0.05 and 5 pm. Particularly contemplated are nucleating agents in the form of mineral carbonates, sulfates or silicates, with calcium carbonate being particularly preferred. The nucleating agents are provided with a coating of L-leucine, which acts as a nucleation promoter. 4.5