WO2014114508A1 - Procédé destiné à améliorer des compositions de sels de nitrate, au moyen d'acide nitrique, au cours de leur utilisation en tant que milieu caloporteur ou milieu accumulateur de chaleur - Google Patents

Procédé destiné à améliorer des compositions de sels de nitrate, au moyen d'acide nitrique, au cours de leur utilisation en tant que milieu caloporteur ou milieu accumulateur de chaleur Download PDF

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Publication number
WO2014114508A1
WO2014114508A1 PCT/EP2014/050424 EP2014050424W WO2014114508A1 WO 2014114508 A1 WO2014114508 A1 WO 2014114508A1 EP 2014050424 W EP2014050424 W EP 2014050424W WO 2014114508 A1 WO2014114508 A1 WO 2014114508A1
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Prior art keywords
nitrate salt
salt composition
nitrate
heat transfer
heat
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PCT/EP2014/050424
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German (de)
English (en)
Inventor
Jürgen WORTMANN
Michael Lutz
Johan Ter Maat
Kerstin Schierle-Arndt
Stephan Maurer
Michael LADENBERGER
Florian Garlichs
Katharina Kaleta
Original Assignee
Basf Se
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Basf Se filed Critical Basf Se
Priority to EP14700358.6A priority Critical patent/EP2948518A1/fr
Priority to MA38312A priority patent/MA38312B2/fr
Priority to AU2014210130A priority patent/AU2014210130B2/en
Priority to CN201480017351.1A priority patent/CN105051147A/zh
Publication of WO2014114508A1 publication Critical patent/WO2014114508A1/fr
Priority to IL240113A priority patent/IL240113B/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/08—Materials not undergoing a change of physical state when used
    • C09K5/10—Liquid materials
    • C09K5/12—Molten materials, i.e. materials solid at room temperature, e.g. metals or salts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S80/00—Details, accessories or component parts of solar heat collectors not provided for in groups F24S10/00-F24S70/00
    • F24S80/20—Working fluids specially adapted for solar heat collectors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/40—Solar thermal energy, e.g. solar towers

Definitions

  • the present invention relates to a method for maintaining or expanding the long-term operating temperature range of a heat transfer medium and / or heat storage medium as defined in the claims, a corresponding process engineering system as defined in the claims, the use of an additive for maintaining or expanding the long-term operating temperature range of a heat transfer medium. and / or heat storage medium as defined in the claims and a method for generating electrical energy in a solar thermal power plant as defined in the claims.
  • Heat transfer mediums or heat storage media based on inorganic solids, in particular salts are known both in chemical technology and in power plant technology. They are usually used at high temperatures, for example, beyond 100 ° C, ergo beyond the boiling point of water at atmospheric pressure.
  • so-called Salzbadreaktoren be used at temperatures of about 200 to 500 ° C in chemical plants for large-scale production of various chemicals.
  • Heat transfer media are media that are heated by a heat source, such as the sun in solar thermal power plants, and transport the amount of heat contained in them over a certain distance. You can then transfer this heat to another medium, such as water or a gas, preferably via heat exchangers (also called heat exchanger), this other medium then, for example, can drive a turbine. Heat transfer media can continue to heat in chemical engineering reactors (for example Salzbadreaktoren) to the desired temperature, or cool.
  • a heat source such as the sun in solar thermal power plants
  • heat transfer media can also transfer the amount of heat contained in them to another, located in a reservoir medium (for example, molten salt) and thus pass the heat for storage. Heat transfer media can also be fed into a reservoir and remain there. You are then both heat transfer media and heat storage media.
  • a reservoir medium for example, molten salt
  • Heat accumulators contain heat storage media, usually material compositions, for example the mixtures according to the invention, which can store a quantity of heat over a certain period of time.
  • Heat storage for fluid, preferably liquid, heat storage media are usually formed by a solid, preferably insulated against heat loss, container.
  • a relatively recent application of heat transfer media or heat storage media are solar thermal power plants (herein and in the art also called solar thermal power plants) for generating electrical energy.
  • An example of a solar thermal power plant is shown schematically in FIG.
  • concentrated solar radiation (1) heats up a heat carrier medium, usually in a receiver system (2), which usually consists of a combination of tubular “receivers.”
  • the heat transfer medium usually flows into a pump, usually driven by pumps
  • Heat storage system (5a) flows via the line (6) from there on to a heat exchanger (8) (colloquially also referred to as “heat exchanger"), where it gives off its heat to water, thus generating steam (9), the turbine (1 1), which eventually, as in a conventional power plant, drives a generator for generating electrical energy.
  • the steam loses heat (13) then flows back as a condensate (10) usually in the heat exchanger (8).
  • the cooled heat transfer medium flows from the heat exchanger (8) usually over the cold area (5b) of a heat storage system to the receiver system (2) back, in which it is heated again by the solar radiation and creates a cycle.
  • the storage system can consist of a hot (5a) and a cold (5b) tank, for example as two separate vessels.
  • An alternative construction of a suitable storage system is for example a stratified storage with a hot area (5a) and a cold area (5b), for example in a vessel. More about solar thermal power plants is described for example in Schm dertician, 3, 2009 pages 82 to 99 and in the following.
  • the parabolic trough power plant, the Fresnel power plant and the tower power plant are The parabolic trough power plant, the Fresnel power plant and the tower power plant.
  • the solar radiation is focused via parabolic shaped troughs into the focal line of the mirrors.
  • a pipe usually called a "receiver”
  • the heat transfer medium is heated by the solar radiation and flows to the heat exchanger, where it gives off its heat as described above, to generate steam can reach more than 100 kilometers in current solar thermal power plants.
  • the solar radiation is focused into a focal line with generally flat mirrors.
  • a pipe usually referred to as "receiver”
  • the mirror and the tube are not tracked together the sun, but the position of the mirror is adjusted relative to the permanently installed pipe. The mirror position follows the position of the sun so that the fixed pipeline is always in the focal line of the mirrors, and even in Fresnel power plants, molten salt can be used as heat carrier.
  • Fresnel power plants are currently still largely in development.
  • the steam generation, or the generation of electrical energy takes place in the salt Fresnel power plant analogous to the parabolic trough power plant.
  • a tower surrounded by mirrors, in the professional world also referred to as "heliostats”, which radiate the solar radiation to a so-called central receiver in the upper part of the tower bundled in the receiver Pipe bundles is constructed, a heat transfer medium is heated, which produces analogous to the parabolic trough power plant or Fresnel power plant via heat exchanger steam for generating electrical energy.
  • Heat transfer media or heat storage media based on inorganic salts have long been known. They are usually used at such high temperatures, in which water is already vaporous, that is usually at 100 ° C and more.
  • Examples are the products of the Coastal Chemical Company LLC Hitec® Solar Salt (potassium nitrate: sodium nitrate 40 wt%: 60 wt%), Hitec® (eutectic mixture of potassium nitrate, sodium nitrate and sodium nitrite).
  • Hitec® eutectic mixture of potassium nitrate, sodium nitrate and sodium nitrite.
  • nitrate salts usually those of the alkali metal lithium, sodium, potassium, optionally additionally with nitrite salts, usually those of the alkali metals lithium, sodium, potassium or the alkaline earth metal calcium
  • nitrite salts usually those of the alkali metals lithium, sodium, potassium or the alkaline earth metal calcium
  • alkali metal, lithium, sodium, potassium, rubidium, cesium, preferably lithium, sodium, potassium, particularly preferably sodium is to be understood as meaning potassium unless expressly stated otherwise.
  • alkaline earth metal beryllium, magnesium, calcium, strontium, barium, preferably calcium, strontium, barium, more preferably calcium and barium, unless otherwise specified.
  • the aim is still to develop a heat transfer medium or heat storage medium, which solidifies at relatively low temperature (solidifies) ergo a lower melting point but a high maximum long-term operating temperature (analog: high decomposition temperature) has.
  • the maximum long-term operating temperature is herein understood to mean the highest operating temperature of the heat transfer medium or heat storage medium, in which its properties, for example viscosity, melting temperature, corrosion behavior do not change significantly over a long period of time, generally 10 to 30 years, compared to the initial value.
  • mixtures of sodium nitrate or potassium nitrate are used at relatively high temperatures.
  • a typical long-term operating temperature range is 290 to 565 ° C.
  • Such mixtures are characterized by a relatively high melting point.
  • Mixtures of alkali metal nitrate and alkali metal nitrite usually have a lower melting point than the nitrate mixtures mentioned above, but also a lower decomposition temperature. Mixtures of alkali metal nitrate and alkali metal nitrite are usually used in the temperature range of 150 ° C to 450 ° C.
  • nitrate salt mixtures or nitrate / nitrite salt mixtures can change negatively in several ways, for example, if the mixtures mentioned, in particular over a long time, comparatively high temperatures, for example more than 565 ° C for Nitratsalzmischungen, and more than 450 ° C for nitrate / nitrite salt mixtures are exposed. They then generally decompose into various degradation products.
  • Nitratsalzmischungen or nitrate / Nitritsalzmischungen and thus, for example, their long-term operating temperature range in solar thermal power plants by recording traces or even relatively large amounts of water or carbon dioxide can change negative, for example by a leak in the heat transfer medium / steam Heat exchanger or by the so-called open operation, in which the heat transfer or heat storage media contact the humidity of the outside air.
  • Nitratsalzmischungen or nitrate / Nitritsalzmischungen can thereby worsen so far that they are unsuitable as a heat transfer medium or heat storage medium and usually have to be replaced with fresh mixtures, resulting in the huge amounts, for example, in the tube and storage system of a Solar thermal power plant with thermal Mehrpen arrivedn are included, technically and economically Häturban or practically impossible.
  • the object of the present invention was to find a method which avoids or reverses the deterioration of a heat transfer medium or heat storage medium based on a nitrate salt mixture or nitrate / nitrite salt mixture or extends the long-term operating temperature range of such mixtures.
  • nitrate salt compositions defined in the description and in the claims, in particular their preferred and particularly preferred embodiments, are also referred to below as "nitrate salt composition according to the invention".
  • the nitrate salt composition of the present invention is selected from the group consisting of alkali metal nitrate and alkaline earth metal nitrate and optionally alkali metal nitrite and alkaline earth metal nitrite as essential components.
  • a highly suitable embodiment of the nitrate salt composition according to the invention contains as essential constituents an alkali metal nitrate or an alkaline earth metal nitrate or a mixture of alkali metal nitrate and alkaline earth metal nitrate and in each case optionally an alkali metal nitrite and / or alkaline earth metal nitrite.
  • the alkali metal nitrate is herein a nitrate, preferably practically anhydrous, more preferably anhydrous, nitrate of the metals lithium, sodium, potassium, rubidium or cesium, preferably lithium, sodium, potassium, more preferably sodium, potassium, generally described as MetNC "3, where Met
  • the term alkali metal nitrate includes both a single nitrate and mixtures of the nitrates of these metals, for example, potassium nitrate plus sodium nitrate
  • the alkaline earth metal nitrate herein is a nitrate, preferably practically anhydrous, more preferably anhydrous, nitrate of the metals, magnesium, Calcium, strontium, barium, preferably calcium, strontium, barium, more preferably calcium and barium, generally described as Met (NC "3) 2, where Met is the alkaline earth metals described above, the term alkaline earth metal nitrate both a single nitrate and mixtures ofnitrates of these
  • the alkali metal nitrite is herein a nitrite, preferably practically anhydrous, more preferably anhydrous, nitrite of the alkali metals lithium, sodium, potassium, rubidium and cesium, preferably lithium, sodium, potassium, more preferably sodium, potassium, generally described as MetNC "2, where Met
  • the alkali metal nitrite may be present as a single compound but also as a mixture of different alkali metal nitrites, for example sodium nitrite plus potassium nitrite.
  • the alkaline earth metal nitrite is herein a nitrite, preferably practically anhydrous, more preferably anhydrous, nitrite of the metals magnesium, calcium, strontium, barium, preferably calcium, strontium, barium, more preferably calcium and barium, generally described as Met (NC "2) 2, where Met means the above-described alkaline earth metals, where the term alkaline earth metal nitrite includes both a single nitrite and mixtures of the nitrites of these metals, for example calcium nitrite plus magnesium nitrite.
  • Nitrate salt composition according to the invention containing as essential constituents an alkali metal nitrate and / or alkaline earth metal nitrate and in each case optionally an alkali metal nitrite and / or alkaline earth metal nitrite; Nitrate salt composition according to the invention containing as essential constituents an alkali metal nitrate selected from sodium nitrate and / or potassium nitrate and in each case optionally an alkali metal nitrite and / or alkaline earth metal nitrite;
  • Nitrate salt composition containing as essential constituents an alkali metal nitrate and optionally an alkali metal nitrite;
  • Nitrate salt composition containing as essential constituents an alkali metal nitrate and optionally an alkali metal nitrite selected from sodium nitrite and / or potassium nitrite;
  • Nitrate salt composition containing as essential constituents an alkali metal nitrate selected from sodium nitrate and / or potassium nitrate and in each case optionally an alkali metal nitrite selected from sodium nitrite and / or potassium nitrite and / or alkaline earth metal nitrite selected from calcium nitrite and / or barium nitrite;
  • Nitrate salt composition containing as essential constituents an alkali metal nitrate and / or alkaline earth metal nitrate;
  • Nitrate salt composition comprising as essential constituents an alkali metal nitrate selected from sodium nitrate and / or potassium nitrate and / or alkaline earth metal nitrate selected from calcium nitrate and / or barium nitrate;
  • a nitrate salt composition of the present invention containing as an essential ingredient an alkali metal nitrate;
  • Nitrate salt composition according to the invention containing as essential constituents an alkali metal nitrate selected from sodium nitrate and / or potassium nitrate.
  • nitrate salt compositions according to the invention containing as essential components an alkali metal nitrate selected from sodium nitrate and / or potassium nitrate are, for example, the following: Potassium nitrate in an amount ranging from 20 to 55% by weight, and
  • Sodium nitrate in an amount ranging from 45 to 80% by weight, based in each case on the mixture; Potassium nitrate in an amount in the range of 35 to 45 wt .-%, preferably 40 wt .-% and sodium nitrate in an amount ranging from 55 to 65 wt .-%, preferably 60 wt .-%, each based on the mixture.
  • nitrate salt compositions according to the invention comprising as essential constituents an alkali metal nitrate and optionally an alkali metal nitrite selected from sodium nitrite and / or potassium nitrite are, for example, the following:
  • Potassium nitrate in an amount ranging from 30 to 70% by weight, preferably 50 to 60% by weight and sodium nitrate in an amount ranging from 3 to 30% by weight, preferably 5 to 10% by weight and sodium nitrite an amount in the range of 20 to 60 wt .-%, preferably 35 to 45 wt .-% each based on the mixture.
  • a mixture of potassium nitrate, sodium nitrate and sodium nitrite is also commercially available, also as product Hitec® from Coastal Chemical Company LLC.
  • the nitrate salt composition according to the invention may also contain traces of further constituents, for example oxides, chlorides, sulfates, carbonates, hydroxides, silicates of the alkali metals and / or alkaline earth metals, silicon dioxide, iron oxide, aluminum oxide or water.
  • traces of further constituents for example oxides, chlorides, sulfates, carbonates, hydroxides, silicates of the alkali metals and / or alkaline earth metals, silicon dioxide, iron oxide, aluminum oxide or water.
  • the sum of these constituents is generally not more than 1% by weight, based on the novel nitrate salt composition.
  • the nitrate salt composition according to the invention passes into the molten and usually pumpable form at a temperature above about 100 to 300 ° C., inter alia, depending on the nitrite content and the ratio of the cations forming the mixture.
  • the nitrate salt composition according to the invention preferably in molten form, for example as a pumpable liquid, is used as heat transfer medium and / or heat storage medium, preferably in power plants for the production of heat and / or electrical energy, in chemical engineering, for example in salt bath reactors and in metal hardening plants.
  • Examples of power plants for the production of heat and / or electrical energy are solar thermal power plants such as parabolic trough power plants, Fresnel power plants, tower power plants.
  • the nitrate salt compositions according to the invention preferably in the molten state, for example as a pumpable liquid, both as a heat transfer medium and as a heat storage medium in the solar thermal power plants, such as parabolic trough power plants, tower power plants or Fresnel power plants.
  • the nitrate salt compositions according to the invention preferably in the molten state, for example as a pumpable liquid, either as a heat transfer medium or as a heat storage medium in the solar thermal power plants, such as parabolic trough power plants, the tower power plants, the Fresnel power plants.
  • the nitrate salt compositions according to the invention are preferably used in the molten state, for example as a pumpable liquid, in tower power plants as the heat transfer medium and / or as a heat storage medium, particularly preferably as a heat transfer medium.
  • the Nitratsalzzusammen stuen invention preferably in the molten state, for example as a pumpable liquid, as a heat transfer medium in solar thermal power plants, such as parabolic trough power plants, the tower power plants, the Fresnel power plants, the heat transfer media are guided through solar heated pipes. They usually carry the heat produced there to a heat storage or to the heat exchanger of the steam heater of a power plant.
  • the heat store comprises a plurality of usually two large containers, generally a cold and a hot container (also referred to as "two-tank store”) .
  • the nitrate salt composition according to the invention preferably in the molten state, for example as pumpable Liquid, which is usually taken from the cold tank of the solar system and heated in the solar field of a parabolic trough plant or a tower elevator, is heated in the hot container and kept there until there is a need to generate electrical energy
  • a heat accumulator the so-called “thermocline storage” consists of a tank in which the heat storage medium is stored in layers at different temperatures, this variant also being called “stratified storage”. When storing material is removed from its cold area. The material is heated and stored back in its hot area.
  • the thermokline memory is thus used largely analogously to a two-tank memory.
  • the hot nitrate salt compositions according to the invention in the molten state are usually taken from the hot tank or the hot zone of the stratified storage tank and pumped to the steam generator of a steam power plant.
  • the steam generated there which is stretched to over 100 bar, usually drives a turbine and a generator, which supplies electrical energy to the electricity grid.
  • the nitrate salt composition according to the invention in the molten state, for example as a pumpable liquid, usually cooled to about 290 ° C and usually fed back into the cold tank or the cold part of the stratified storage.
  • the nitrate salt composition of the present invention operates in molten form as a heat transfer medium. Filled in the heat storage tank, the same nitrate salt composition according to the invention works as a heat storage medium, for example, to enable on-demand generation of electrical energy.
  • the nitrate salt composition according to the invention preferably in molten form, is also used as a heat transfer medium and / or heat storage medium, preferably heat transfer medium, in chemical engineering, for example for heating reaction apparatuses of chemical production plants, where as a rule a very high heat flow at very high temperatures narrow fluctuation ranges must be transferred.
  • heat transfer medium preferably heat transfer medium
  • Examples are salt bath reactors.
  • Examples of the said production plants are acrylic acid plants or plants for the production of melamine.
  • GB 545,590 describes on page 7, lines 90 to 1 12 that from 1, 5 million “pounds” of a mixture, the 54 wt .-% potassium nitrate (KNO3) and 46 wt .-% sodium nitrite (NaNO ⁇ ) and 0.8 % "Alkali” contains 40,000 "pound” per week to be withdrawn into a tower, mixed with nitric acid of concentration 91.4% and the salt mixture so treated returned to the "system".
  • KNO3 potassium nitrate
  • NaNO ⁇ sodium nitrite
  • Alkali contains 40,000 "pound” per week to be withdrawn into a tower, mixed with nitric acid of concentration 91.4% and the salt mixture so treated returned to the "system".
  • GB 545,590 on page 8, lines 17 to 65 describes that in vessels in which "salt" is stored an atmosphere with less oxygen partial pressure than in air is to be used with an additive containing the components nitric acid and / or nitrous acid and oxygen-containing gas with an oxygen partial pressure equal to or greater than those in air and / or oxygen generating compounds and optionally nitrogen oxides and / or other nitrogen oxide generating compounds disclosed GB 545,590 not.
  • the nitrate salt composition according to the invention is used with an additive containing the components nitric acid and / or nitrous acid, and oxygen-containing gas having an oxygen partial pressure equal to or greater than those in air and / or oxygen-generating compounds and optionally nitrogen oxides and / or other nitrogen oxide-generating compounds brought into contact.
  • This additive is also referred to below as "inventive additive”.
  • oxygen-containing gas herein is meant pure elemental oxygen or oxygen-containing gas mixtures having an oxygen partial pressure equal to or greater than that in air.
  • Oxygen-containing gas is (i) air, (ii) mixtures of oxygen with other gases such as nitrogen or noble gases, wherein in each case the oxygen content, based on the gas mixture and measured at 1013.25 hPa and 20 ° C, in the range of 22 to 99.9 vol.% And (iii) pure elemental oxygen (O2).
  • oxygen contents in the oxygen-containing gas are preferred:
  • the oxygen content in the oxygen-containing gas is preferably in the range of 60 to 99.9 vol.%, Particularly preferably in the range of 80 to 99.9 vol.% Or the oxygen-containing gas is pure elemental oxygen.
  • the oxygen content in the oxygen-containing gas is preferably in the range of 22 to 40% by volume.
  • the respective acids nitric acid or nitrous acid are usually present as a solution in water of different concentrations.
  • the nitrate salt composition according to the invention is generally present in liquid, pumpable, generally molten form.
  • the concentration of nitric acid HNO 3 is usually in the range of 1 to 100% by weight, preferably 50 to 100% by weight, particularly preferably 60 to 90% by weight of HNO 3 in water.
  • the concentration of nitrous acid HNO2 is usually in the range of 1 to 40
  • Nitric acid and nitrous acid can be used both individually and in mixtures, the mixing ratio not being considered critical.
  • oxygen-containing gas having an oxygen partial pressure equal to or greater than that used in air and / or oxygen-generating compounds and optionally nitrogen oxides and / or nitrogen oxides generating compounds.
  • nitrogen oxides are present depends on the boundary conditions, such as pressure, temperature, presence or absence of oxygen.
  • Oxygen generating compounds are all those which release elemental oxygen, for example as atomic oxygen, dioxygen or ozone, under the conditions at the site of additive addition.
  • Such compounds are, for example, inorganic or organic peroxides, for example sodium peroxide, potassium superoxide, dibenzoyl peroxide.
  • Nitrogen oxides generating compounds are all those which release nitrogen oxides, for example dinitrogen monoxide, nitrogen monoxide, nitrogen dioxide, dinitrogen tetroxide, under the conditions at the site of the additive addition
  • Preferred further components of the additives according to the invention - in addition to the nitric acid and / or nitrous acid - are oxygen-containing gas having an oxygen partial pressure equal to or greater than that in air and / or oxygen-generating compounds and optionally the nitrogen oxides nitrous oxide, nitrogen monoxide, nitrogen dioxide, dinitrogen tetroxide and these nitrogen oxides generating compounds.
  • additives according to the invention in addition to the nitric acid and / or nitrous acid - are oxygen-containing gas having an oxygen partial pressure equal to or greater than that in air and optionally the nitrogen oxides nitrogen monoxide, nitrogen dioxide.
  • Particularly preferred further components of the additives according to the invention - in addition to the nitric acid and / or nitrous acid - are combinations of air or virtually pure elemental oxygen and nitrogen oxides, preferably nitrogen monoxide.
  • a particularly preferred additive according to the invention contains nitric acid and an oxygen-containing gas having an oxygen partial pressure equal to or greater than that in air, preferably air or virtually pure elemental oxygen and nitrogen oxides, preferably nitrogen dioxide and / or nitrogen monoxide.
  • Another particularly preferred additive of the present invention contains nitric acid and an oxygen-containing gas having an oxygen partial pressure equal to or greater than that in air, preferably air or substantially pure elemental oxygen, but substantially no nitrogen oxides.
  • Contacting the additive of the present invention with the nitrate salt composition of the present invention is generally accomplished by feeding the additive of the invention above or preferably below the surface of the nitrate salt composition of the present invention, which is usually in liquid, pumpable, generally molten form.
  • the additive according to the invention When contacting the additive according to the invention with the nitrate salt composition according to the invention, it is preferred to distribute the nitric acid uniformly, which can be achieved for example by stirring or a longer mixing distance.
  • the contacting of the nitrate salt composition of the invention with the additive of the invention generally takes place in a suitable apparatus.
  • a suitable apparatus This may be a container and / or a conduit through which the nitrate composition according to the invention flows or is at rest or a partial volume of a container or a pipeline.
  • the container or the pipe are preferably made of a material which is technically resistant to nitric acid or nitrous acid.
  • nitrate salt composition of the present invention Contacting the nitrate salt composition of the present invention with the additive of the present invention generally occurs at a temperature just above, for example, 50 ° C above, the melting temperature of the nitrate salt composition of the invention, usually in the range of 150 ° C to 650 ° C, preferably at one temperature in which a possible formation of nitrous oxide (N2O) is reduced or virtually completely suppressed.
  • the additive according to the invention can be added as a complete mixture to the nitrate salt composition according to the invention or in the form of the individual components or groups of individual components, for example in the last two cases, successively.
  • the following variants of contacting the nitrate salt composition according to the invention with the additive according to the invention are preferred: If the nitrate salt composition according to the invention contains a proportion of total
  • the oxygen content in the oxygen-containing gas is preferably in the range of 60 to 99.9 vol.%, Particularly preferably in the range of 80 to 99, 9 vol.%
  • the oxygen-containing gas is pure elemental oxygen
  • the above-described oxygen-containing gas or the oxygen-containing gas in the form of pure elemental oxygen is added to the above-described nitrate salt composition at a temperature in the range of 450 to 650 ° C and before and / or thereafter, the nitric acid and / or nitrous acid is added at a temperature in the range of 150 to 350 ° C to the above-described nitrate salt composition.
  • the oxygen content in the oxygen-containing gas is preferably in the range from 22 to 40% by volume, with the additive according to the invention in the temperature range of 150 to 350 ° C, preferably as a complete mixture, is added to the above-described Nitratsalzzusammen stuct. More preferably, after the additive of the invention has been added to the nitrate salt composition described above, oxygen is removed from the system again, for example by metering in inert gas, such as nitrogen, noble gases in or over the nitrate salt composition described above.
  • inert gas such as nitrogen, noble gases in or over the nitrate salt composition described above.
  • the contacting of the nitrate salt composition according to the invention with the additive according to the invention is generally carried out at a pressure which is so high that it does not lead to significant outgassing of, for example. Nitrous oxides and / or water vapor and / or other gaseous components comes. Corresponding pressures can be taken from the relevant tables, for example for nitric acid or water.
  • the contacting of the nitrate salt composition according to the invention with the additive according to the invention can be carried out continuously or batchwise. Continuous operation not only means that the contact is done without interruption, but also includes intermittent interruption. Batch mode of operation is present, for example, when a portion of the nitrate salt composition according to the invention is introduced into a container where it is brought into contact with the additive, if appropriate degassed and thus, for example, water is substantially completely or partially removed, and then the nitrate salt composition according to the invention is recycled to the system becomes.
  • nitrate salt composition according to the invention in contact with the additive according to the invention, inter alia water is introduced into the nitrate salt composition according to the invention and / or water is also formed.
  • This incorporated and / or formed water is removed in one embodiment of the invention, optionally in addition to other volatile compounds virtually completely or in part from the additized nitrate salt composition according to the invention.
  • at least 99% by weight of the water formed from the additized nitrate salt composition of the present invention is removed at least to the extent that the water content of the nitrated salt additive composition of the present invention is not greater than that of the nitrate salt composition of the present invention immediately prior to Contact with the additive of the invention.
  • the removal of the formed and / or introduced water is preferably carried out at a, compared with the bringing into contact with the additive according to the invention, reduced pressure and elevated temperature.
  • the pressure usually corresponds to the system pressure of the plant in which the nitrate salt composition according to the invention is in the form of heat transfer medium and / or heat storage medium, for example 1 to 2 bar abs.
  • the temperature is usually at the maximum operating temperature of the plant in which the nitrate salt composition according to the invention is as a heat transfer and / or heat storage medium, for example at a temperature in the range of 500 to 650 ° C.
  • the removal of the formed and / or introduced water or optionally further volatile compounds in a separate phase separator, for example, a downstream container is performed.
  • the nitrate salt composition according to the invention treated by removal of the formed and / or introduced water or optionally further volatile compounds is usually recycled to the system in which the majority of the nitrate salt composition according to the invention is present as heat carrier and / or heat storage medium.
  • the water vapor, optionally with nitrogen oxides, is condensed and removed from the system.
  • the additive according to the invention is fed into a vessel which is in molten form, in addition to the main amount of the nitrate salt composition according to the invention, in molten form, for example a mixture of sodium nitrate and potassium nitrate in molten form
  • a vessel which is in molten form, in addition to the main amount of the nitrate salt composition according to the invention, in molten form, for example a mixture of sodium nitrate and potassium nitrate in molten form
  • All of the embodiments described in the preceding passages for contacting the additive according to the invention with the nitrate salt composition according to the invention expressly refer to the "shunt” embodiment described here ".
  • the nitrate salt composition according to the invention can be prepared from the deepest possible location of the system in which the main amount of the nitrate salt composition according to the invention is used as heat carrier and / or heat carrier.
  • the feed of the additive according to the invention into a bypass to the main stream of the flowing nitrate salt composition according to the invention has the advantage that, independently of the respective operating pressure of the main stream in the container, another - advantageously higher - pressure and / or a different temperature can be selected, which usually has a faster Reaction and thereby a higher rate of regeneration of the nitrate salt mixture according to the invention has resulted.
  • the nitrate salt composition according to the invention thus treated can subsequently be freed of interfering disperse components, for example metal oxides, by filtration and is then returned to the heat transfer circuit.
  • FIG. 2 Two variants are outlined, for example, in FIG. 2, how a contacting of the nitrate salt mixture according to the invention with the additive according to the invention for a solar thermal power plant (see FIG. Common to all variants is a receiver system (2) which exchanges a heat carrier / storage medium via lines (3) and (4) with a heat storage system (1).
  • the heat storage system (1) has a hot (5a) and a cold (5b) area.
  • the partial flow take-off takes place from an average temperature range of the heat storage system. Removal from the cold area of the storage system is also possible.
  • FIG. 2b In the second variant (FIG. 2b), removal takes place from the cold main flow (4) of the heat transfer medium.
  • the Molstroma notede is carried out for example by pumping. After removal, contact with the additive according to the invention takes place in a separate reaction vessel. In the reaction vessel, turbulence can be achieved by stirring or various internals to improve the mixing of the additive with the nitrate salt composition.
  • the reaction vessel can be adjusted by customary means to another, preferably higher, pressure and / or a temperature which is changed with respect to the removal temperature in order, for example, to achieve a higher regeneration rate of the nitrate salt mixture according to the invention.
  • the amount of the additive according to the invention which is brought into contact with the nitrate salt composition according to the invention depends on the technical problem to be solved and can be determined by the person skilled in the art by customary methods for determining the composition of the nitrate salt composition which is to be brought into contact with the additive according to the invention become.
  • Examples of these methods are analytical methods such as the determination of the basicity, determination of the nitrite and / or nitrate content of the nitrate salt composition which is to be brought into contact with the additive according to the invention.
  • the basicity of the inventive nitrate salt composition to be brought into contact with the additive according to the invention for example, determined by acid-base titration or potentiometric. This determination can be made inline, online or offline. Based on the basicity value thus determined, the amount of the additive according to the invention is determined and metered, which leads to complete neutralization of the nitrate salt composition according to the invention.
  • the nitrate salt composition according to the invention thereby obtains a low residual basicity, as defined below.
  • alkalinity basic or offline
  • it may be 0.001 to 5%, preferably 0.005 to 1% and particularly preferably 0.01 to 0.5%
  • a replacement sensor size Parameter (spectrum) ua instead of measuring the alkalinity by means of titration, it is also possible, after suitable adjustment, to apply a replacement sensor size Parameter (spectrum) ua.
  • the subject of the present application is also a process engineering system as defined in the claims.
  • This is understood to be containers connected by pipelines, for example storage vessels such as tanks, in particular heat storage tanks and / or devices, for example devices for conveying fluids (for example molten salts), such as pumps, which transport or / and store thermal energy by means of heat transfer media
  • Heat storage media ensure, for example, the primary circuit for heat transfer media and / or heat storage media in solar thermal power plants.
  • pipelines are those which are located in solar thermal power plants in the focal line of the parabolic trough or Fresnel mirrors, and / or the Receiverroh- re or Receiverrohrbündel in solar thermal tower power plants and / or those who, for example, in solar thermal power plants, certain devices together connect without having a sunbeam collection function.
  • the present application also relates to the use of the additive as defined in the claims for maintaining or expanding the long-term operating temperature range of a heat transfer and / or heat storage medium containing a nitrate salt composition as defined in the claims.
  • the nitrate salt composition here is to be understood as meaning what has been described in more detail above and is also described herein as the nitrate salt composition according to the invention, including all preferred embodiments.
  • the above-mentioned use preferably relates to a heat transfer and / or heat storage medium in a) power plants for generating heat and / or electricity, more preferably solar thermal power plants, in particular those of the type parabolic turbine power plant, Fresnel power plant or tower power plant, b) in chemical engineering, particularly preferably Salzbadreaktoren, or c) in metal hardening plants.
  • the subject matter of the present application is also a process for producing electrical energy in a solar thermal power plant having a nitrate salt composition as defined in the claims as a heat transfer and / or heat storage medium, wherein the nitrate salt composition is in contact with an additive as defined in the claims is brought.
  • an additive is here to understand what is described in more detail above and herein also described as inventive additive, including all preferred embodiments.
  • the nitrate salt composition here is to be understood as meaning what has been described in more detail above and is also described herein as the nitrate salt composition according to the invention, including all preferred embodiments.
  • the above-mentioned method preferably relates to a heat transfer and / or heat storage medium in solar thermal power plants of the parabolic trough power plant, Fresnel power plant or tower power plant.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Sustainable Energy (AREA)
  • Sustainable Development (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Anti-Oxidant Or Stabilizer Compositions (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

L'invention concerne un procédé pour le maintien ou l'extension de la plage de température d'exploitation à long terme, d'un milieu caloporteur et/ou d'un milieu accumulateur de chaleur, renfermant une composition de sel de nitrate, choisie dans le groupe constitué par un nitrate de métal alcalin et un nitrate de métal alcalinoterreux et, éventuellement, par un nitrite de métal alcalin et un nitrite de métal alcalinoterreux, caractérisé en ce que la composition de sel de nitrate est mise en contact avec un additif renfermant les composants acide nitrique et/ou acide nitreux, et un gaz oxygéné ayant une pression partielle d'oxygène qui est égale ou supérieure à celle dans l'air, et/ou des composés générant de l'oxygène, et, éventuellement, des oxydes d'azote et/ou d'autres composés générant de l'oxyde d'azote.
PCT/EP2014/050424 2013-01-23 2014-01-13 Procédé destiné à améliorer des compositions de sels de nitrate, au moyen d'acide nitrique, au cours de leur utilisation en tant que milieu caloporteur ou milieu accumulateur de chaleur WO2014114508A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
EP14700358.6A EP2948518A1 (fr) 2013-01-23 2014-01-13 Procédé destiné à améliorer des compositions de sels de nitrate, au moyen d'acide nitrique, au cours de leur utilisation en tant que milieu caloporteur ou milieu accumulateur de chaleur
MA38312A MA38312B2 (fr) 2013-01-23 2014-01-13 Procédé destiné à améliorer des compositions de sels de nitrate, au moyen d'acide nitrique, au cours de leur utilisation en tant que milieu caloporteur ou milieu accumulateur de chaleur
AU2014210130A AU2014210130B2 (en) 2013-01-23 2014-01-13 Method for improving nitrate salt compositions by means of nitric acid in the use thereof as a thermal transfer medium or as a thermal accumulator medium
CN201480017351.1A CN105051147A (zh) 2013-01-23 2014-01-13 借助硝酸改进硝酸盐组合物用作传热介质或储热介质的方法
IL240113A IL240113B (en) 2013-01-23 2015-07-23 A method for improving the compositions of nitrate salt using nitric acid used as a thermal transfer agent as a thermal accumulation agent

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EP13152308.6 2013-01-23
EP13152308 2013-01-23

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EP (1) EP2948518A1 (fr)
CN (1) CN105051147A (fr)
AU (1) AU2014210130B2 (fr)
CL (1) CL2015002065A1 (fr)
IL (1) IL240113B (fr)
MA (1) MA38312B2 (fr)
WO (1) WO2014114508A1 (fr)

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WO2016184961A1 (fr) 2015-05-21 2016-11-24 Basf Se Réservoir pour stocker un liquide et son utilisation
DE102015212057A1 (de) 2015-06-29 2016-12-29 Deutsches Zentrum für Luft- und Raumfahrt e.V. Verfahren zur Reduktion korrosiver Eigenschaften von Nitratsalzmischungen
US11150031B2 (en) * 2016-04-28 2021-10-19 Basf Se Use of a nitrate salt composition as a heat transfer or heat storage medium for first operation of an apparatus containing these media

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GB545590A (en) 1940-02-17 1942-06-03 Houdry Process Corp Improvements relating to the use of molten salts in heat exchange circulating systems
US3793208A (en) * 1973-01-04 1974-02-19 Park Chem Co Method of rectifying commercial salt baths

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016184961A1 (fr) 2015-05-21 2016-11-24 Basf Se Réservoir pour stocker un liquide et son utilisation
DE102015212057A1 (de) 2015-06-29 2016-12-29 Deutsches Zentrum für Luft- und Raumfahrt e.V. Verfahren zur Reduktion korrosiver Eigenschaften von Nitratsalzmischungen
US11150031B2 (en) * 2016-04-28 2021-10-19 Basf Se Use of a nitrate salt composition as a heat transfer or heat storage medium for first operation of an apparatus containing these media

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EP2948518A1 (fr) 2015-12-02
MA20150379A1 (fr) 2015-10-30
CN105051147A (zh) 2015-11-11
AU2014210130A1 (en) 2015-08-20
AU2014210130B2 (en) 2017-08-31
IL240113A0 (en) 2015-09-24
CL2015002065A1 (es) 2016-01-08
IL240113B (en) 2018-03-29
MA38312B2 (fr) 2017-12-29

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