Heat-retaining composition

FIELD: chemistry.

SUBSTANCE: heat-retaining composition contains 2.3-2.7 wt % strontium fluoride, 65.9-66.4 wt % strontium chloride, 22.3-22.8 wt % sodium chloride and 8.5-9.0 wt % strontium tungstate.

EFFECT: high enthalpy of fusion, density and electroconductivity.

1 cl, 2 tbl, 4 dwg, 1 ex

 

The invention relates to applied chemistry, more specifically to a heat storage compositions, and can be used in various thermal battery (TA).

Known compositions containing as the basis of the strontium fluoride, strontium chloride and sodium chloride is used or recommended as working bodies of heat accumulators. In the literary sources of quantitative and phase relations of the components of the compositions of salts, receiving and pre-emptive scope (Reference the fusibility of anhydrous inorganic salts. System triple and more complex / Under. General Ed. Nccessarily. - M. - L.: an SSSR, 1961. - Vol.2. - P.586; Buhalova GA System Na, Sr // F, Cl. - M.: SFHA, 1955. - T. - VIP. - S-477; Asanaliev A.M. Hamatova BY System of fluorides and chlorides of sodium, strontium and barium, Zh. norgan. chemistry, 1980. - V.25. - Vol.5. - S-1381).

The disadvantages of these compounds are low enthalpy of fusion, density, and electrical conductivity.

Known heat storage compositions, which are promising for use as working fluids in thermal batteries.

The ingredients and their physico-chemical properties similar to the claimed salt composition, the composition that contains the specified ingredients in the following amounts, wt.%:

fluoride strontium - 5,0

strontium chloride 70,0

sodium chloride - 25,0

(Handbook of fusibility of anhydrous inorganic salts. System triple and more complex / Under. General Ed. Nccessarily. - M. - L.: an SSSR, 1961. - Vol.2. - P.586).

The disadvantages of this structure are low physico-chemical characteristics, such as melting point, specific enthalpy of fusion, density, electrical conductivity.

This heat storage composition selected by the authors as a prototype.

The technical result is to increase the enthalpy of fusion, density and conductivity, due to the input of the component having a higher density and electrical conductivity.

The technical result is achieved by the fact that the composition containing strontium fluoride, strontium chloride and sodium chloride, additionally introduced strontium tungstate in the following ratio, wt.%:

fluoride strontium 2,3-2,7

strontium chloride 65,9-66,4

sodium chloride 22,3-22,8

the strontium tungstate 8,5-9,0

The inventive composition obtained in the study of stable single phase unit (Phoebe) SrF2·SrCl2- SrCl2- (NaCl)2- SrWO4obtained by differentiation of Quaternary reciprocal system Na, Sr || F, Cl, WO4method graph.

To perform technical tasks in FEBE defined characteristics of the Quaternary eutectic, as eutectic status is to improve convective heat transfer.

For the experimental study of PHOEBUS presents the right tetrahedron.

All data structures are expressed in equivalent percent, the temperature - °C.

Experimental studies conducted by differential thermal and partly visual-polythermal methods of physicochemical analysis (Wendlandt Conventional Thermal methods of analysis. - M.: Mir, 1978. - 528 S.).

For recording curves of heating (cooling) differential thermal analysis used a potentiometer APPS, as thermoelectric power amplifier differential thermocouple applied photoshotel f 116/1. Research conducted in platinum microtesla using a platinum-rhodium thermocouples (Pt/Pt-Rh).

Table 1
Features triple nonvariant points stable complex SrCl2- SrWO4- (NaCl)2- SrF2·SrCl2Quaternary reciprocal system Na, Sr || F, Cl, WO4
Character pointsThe designation of the pointt, °CComposition, EQ. share in %Solid equilibrium phases
(NaCl)2 SrWO4SrCl2SrF2·SrCl2
EutecticE149933,55,261,3SrWO4, SrCl2NaCl
EutecticE254528,3-61,6the 10.1NaCl, SrCl2, SrF2·SrCl2
EutecticE376968,48,3-23,3SrWO4, NaCl, SrF2·SrCl2
EutecticE4761-5,887,56,7SrCl2, SrWO4, SrF2·SrCl2

Visual-polythermal analysis conducted with the use of the furnace SCHOOL, Pt/Pt-Rh thermocouple, mV M 1109 mirrored reference. The cold junctions of thermocouples were thermostatically at 0°C in the Dewar vessel with melting ice.

X-ray phase analysis of the eutectic performed on the diffractometer DRON -2,0 (CuK radiationα, λ=0,539 Å, usually β-filter). Samples for XRD were annealed in order 9-10 hours and then were quenched by immersion of the crucible in the melting ice.

The density of the melt of the eutectic measured by the method of hydrostatic weighing platinum ball on the scales VLR. The temperature of the molten mixture measured with a calibrated platinum-rhodium thermocouple.

For measuring conductivity used AC bridge P 5021.

Qualification salts "chemically pure".

To achieve the objective of the present invention driven theoretical and experimental studies to determine the characteristics of the Quaternary eutectic E 495°C, proposed as a thermal storage composition for THE same.

Figure 1 shows the topology ohranyaemih elements of the tetrahedron SrCl2-SrWO4- (NaCl)2- SrF2·SrCl2system Na, Sr ||F, Cl, WO4,

figure 2 - two-dimensional cross-section ABC tetrahedron SrCl2- SrWO4- (NaCl)2- SrF2·SrCl2Quaternary reciprocal system Na, Sr || F, Cl, WO4,

figure 3 is a state diagram of one-dimensional polythermal section MN slashing the Oia ABC tetrahedron SrCl 2- SrWO4- (NaCl)2- SrF2·SrCl2volume crystallization of strontium tungstate,

figure 4 - composition of the Quaternary eutectic495 tetrahedron SrCl2- SrWO4- (NaCl)2- SrF2·SrCl2system Na, Sr || F, Cl, WO4.

Research conducted projection-thermal method (Vasilchenko L.M. Rational approaches to the study of multicomponent salt systems and their implementation. Dis ... laboratory - Samara, 2000. - 245 S. Vasilchenko L.M., Trunin A.S. study of the Quaternary reciprocal system Na, K || F, Cl, WO4conversion and projection-thermographic methods // Ukr. neorg. chemistry. - 1980. - So XXV. - Issue 3. - S-832).

Based on the analysis of the four ternary systems terminated tetrahedron SrCl2- SrWO4- (NaCl)2- SrF2·SrCl2(1) selected for study two-dimensional cross-section of the FAA in the amount of crystallization of strontium tungstate with his constant content equal to 15 EQ. % (1, 2). On a side sectional ABC inflicted Central projection triple nonvariant points items terminated tetrahedron. Given the location nonvariant points selected for the experimental study, the most rational one-dimensional polythermal incision MN (figure 2). The chart is cut MN (figure 3) allows you to define a Central projection quadruple avtec the IKI 495 to section ABC geometric build - the intersection of two sections passing through points 3 and 9, respectively, the vertices b and C (figure 2, 3). At 3 and 9 (figure 3) for co-crystallization of two phases occurs nonvariant balance495.

The composition of the Quaternary eutectic determined from a chart (figure 3) status of the one-dimensional cut through the Central projection495 section ABC and the top of strontium tungstate.

Thus, the study only two-dimensional sections, not three, to determine the composition of the Quaternary eutectic495 (figure 4), in which EQ. %: 6,00 SrF2·SrCl2; 60,52 SrCl2; 29,48 (NaCl)2; 4,0 SrWO4.

Differential thermal analysis determined the enthalpy of melting component 315 kJ·kg-1(Vasilchenko L.M., Chertykovzeva NV Using differential thermal analysis for the rational study phase systems and determine the enthalpies of melting. - Samara: Samara state Academy of construction and architecture, Proc. of the XIII national. proc. on therm. analysis. - 2003. - P80-84).

The resulting POLITERM density of three low-melting compounds. From the analysis of POLITERM follows that with increasing temperature from 500 to 800°C, the density varies linearly reduced by 5-8%, sootvetstvenno.lechenie the volume of the melt. At a temperature of 505°C, the density is 3.6·103kg·m-3.

Temperature dependence of the conductivity is close to exponential. At a temperature of 505°C is 200 Ω-1·m-1. Conductivity allows to judge about the structure of the melt, the nature of the particles that carry the current, and the assessment of their mobility.

Low-melting compounds studied single block SrCl2-SrWO4-(NaCl)2-SrF2·SrCl2with the enthalpy of melting 315 kJ·kg-1density of 3.6·103kg·m-3and electrical conductivity 200 Ω-1·m-1are promising fotoperiodismo materials for heat storage in the temperature range 500-800°C and can be used in various thermal battery.

As can be seen from table 2, the physico-chemical characteristics, and, namely, enthalpy of fusion, density, and conductivity increased, significantly higher than the same values in the known composition. The claimed composition is a eutectic495°C. Optimum addition of strontium tungstate is 8.5, and 9.0 wt.%.

Here is 3 examples of experimental studies of the three compounds at the middle and edge (upper and lower) proportions of ingredients. To do this in an electric furnace shaft type smelting in a platinum crucible betwo the major salt qualification "hç:". The compositions of samples containing components (wt.%):

Example 1 (with an average quantitative ratios of ingredients): 0,352 g (8.8 wt.%) strontium tungstate+0,904 g (22,6 wt.%) sodium chloride + 0.1 g (2.5 wt.%) fluoride strontium+2,644 g (66,1 wt.%) chloride of strontium.

The melting point of a mixture of 495°C. the Specific enthalpy of melting 315 kJ·kg-1. The density of the melt 3,6·103kg·m-3. The electrical conductivity of the melt 2,0·102Ω-1·m-1.

Example 2 (lower bound on the ratio of ingredients): 0,343 g (8.5 wt.%) strontium tungstate + 0.9 g (22.3 wt.%) sodium chloride + 0.09 g (2.3 wt.%) fluoride strontium + 2,60 g (65,9 wt.%) chloride of strontium.

The melting point of a mixture of 494°C. the Specific enthalpy of melting 314 kJ·kg-1. The density of the melt of 3.5·103kg·m-3. The electrical conductivity of the melt is 1.8·102Ω-1·m-1.

Example 3 (with the upper boundary ratio of ingredients): 0,357 g (9,0 wt.%) strontium tungstate + 0,904 g (of 22.8 wt.%) sodium chloride + to 0.108 g (2.7 wt.%) fluoride strontium + 2,63 g (66,4 wt.%) chloride of strontium.

The melting point of a mixture of 496°C. the Specific enthalpy of melting 318 kJ·kg-1. The density of the melt 3,7·103kg·m-3. The electrical conductivity of the melt 2.4 x 102Ω-1·m-1.

The proposed thermal storage composition ensures the operability of thermal battery is in the temperature range 494-496°C; it has a specific enthalpy of melting 315 kJ·kg-1the density of 3.6·103kg·m-3the conductivity is 2.0·102Ω-1·m-1and has a higher convective heat transfer due to the homogeneity of the eutectic composition.

Physico-chemical characteristics (enthalpy of fusion, density, and electrical conductivity) of the prototype low, which has an experimental research applicants thermal storage composition. Enthalpy of fusion, density, and electrical conductivity are the main criteria for the choice of heat-retaining structures. Low density leads to decrease of the specific heat, and consequently, the amount of accumulated heat in the material volume.

Proposed by the authors, the composition of thermal storage material allows more compact material. The composition has a higher electrical conductivity, which increases the heat transfer to the coolant and has a higher convective heat transfer due to the homogeneity of the eutectic composition.

The heat storage composition containing strontium fluoride, strontium chloride and sodium chloride, characterized in that it additionally introduced strontium tungstate, wt.%:

fluoride strontium 2,3-2,7
strontium chloride65,9-66,4
sodium chloride22,3 and 22.8
the strontium tungstate8,5-9,0



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to a heat-retaining composition which contains lithium bromide 51.13-53.27 wt %, lithium sulphate 30.21-32.33 wt % and lithium chloride 16.6-17.47 wt %.

EFFECT: higher specific enthalpy of fusion.

1 cl, 1 tbl, 4 ex

FIELD: heating.

SUBSTANCE: proposed heat-retaining compound consists of n-undecane (90.3-91.75 wt %) and n-pentadecane (8.3-9.7 wt %). Provision for thermal accumulator efficient operation of under low temperatures within the range of -29.5÷-28.5°C, thermal effect accompanying the α/β-n-C11H24 transition ensures operability at a temperature of -36.6°C.

EFFECT: accumulator efficiency and operational capacity enhancement.

1 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the heat-retaining composition including lithium fluoride 7.1...7.8 % weight ratio, lithium sulphate 24.8...26.8 % weight ratio and lithium bromide 66.0...68.1 % weight ratio.

EFFECT: working capacity of hear-retaining composition at very high temperature.

1 cl, 1 tbl, 4 ex

FIELD: heating engineering .

SUBSTANCE: invention provides material that can be used for thermostatically controlling object under cooling conditions or outside heating, in particular, in medicine for storage and transportation of living tissues and organs and in instrumentation engineering when manufacturing phase-transfer executing sensors operated ay low temperatures. Phase-transfer contains 52.5-54.1% octane, 43.9-45.5% nonane, and tetradecane in balancing amount.

EFFECT: lowered allowed working temperature of material.

2 tbl, 3 ex

FIELD: heat-and-power engineering.

SUBSTANCE: invention is dealing with heat- retaining substances based on saturated hydrocarbons and provides heat carrier containing 88.0-90.5% n-heptadecane and 12.0-9.5% n-tricosane. Advantages of such composition compared to known one reside in that melting point of the substance is by 3.5-5.0°C below, which expands temperature application range, in particular enables use in heat accumulators to provide heat generation in thermoregulation and heat-supply systems at 17-18.5°C.

EFFECT: extended application area.

3 ex

FIELD: heat-storage materials.

SUBSTANCE: invention relates to mixtures capable of accumulating heat energy and relevant solar energy transformers. Heat-storage material according to invention contains silicon dioxide, 3-5% of liquid soda glass, and 50-82% of VO2+x wherein x=0-0.5. Material is prepared by compacting mixture of vanadium dioxide VO2+x and silica in presence of liquid soda glass as binder followed by solidification at 150-200°C. Summary heat when using combined transformer including phase transformation heat (α-VO2 ↔ β-VO2) and oxygen adsorption-desorption heat of mechano-chemically treated VO2+x may reach 250 J/g.

EFFECT: increased heat-storage capacity.

8 cl, 1 tbl

FIELD: special-destination materials.

SUBSTANCE: invention relates to development of heat-storage compositions including alkali metal halides, metavanadates, and molybdates. In particular, composition contains 6.1-6.2% lithium fluoride, 23.4-24.3% lithium chloride, 24.8-27.6% lithium metavanadate, 27.1-27.6% lithium molybdate, and 17.3-17.8% lithium sulfate. Composition has considerable advantages over prototype: ensures working capacity within temperature range 360-363°C and by 56-69 J/g exceeds specific melting enthalpy.

EFFECT: improved performance characteristics.

1 tbl, 4 ex

FIELD: special-destination materials.

SUBSTANCE: invention relates to development of heat-storage compositions including alkali metal fluorides, chlorides, and molybdates for use as heat-storage substances in heat accumulators and devices serving to maintain constant temperatures in heating engineering. In particular, composition contains 5.8-6.2% lithium fluoride, 28.0-32.1% lithium chloride, 39.0-41.3% lithium molybdate, and 23.1-24.5% lithium sulfate.

EFFECT: achieved heat storage capacity within 402-404°C temperature range.

1 tbl, 4 ex

FIELD: heat-accumulating compositions.

SUBSTANCE: the invention is dealt with substances used for a heat transportation at the expense of a change of a phase state of heat-accumulating composition in the devices receiving the heat at its irregular delivery or consumption, in particular, in the system of a pre-starting preparation of transportation means and their power installations. The heat-accumulating composition contains (in mass %): 99 - 99.5 of octohydrate of barium hydroxide, 0.5-1.0 of sodium sulfite. Use of the composition decreases action of corrosion and considerably improves operational characteristics of the heat accumulator.

EFFECT: the invention ensures reduction of action of corrosion and considerable improvement of operational characteristics of the heat accumulator.

1 cl, 1 ex, 1 tbl

FIELD: heating engineering.

SUBSTANCE: invention proposes employment of anhydrous C1-C18-carboxylic acid alkali or alkali-earth metal salt(s) as medium for accumulation of heat and using heat energy. Method of improving heat-exchange properties and heat capacity of liquid comprises dispersing above-indicated salts therein. Invention allows selection of combinations of heat-accumulating salts, which are less toxic, less environmentally harmful, and less corrosive for metals and materials used in heat-accumulation and heat-transmission equipment.

EFFECT: improved heat-exchange characteristics of heat-accumulation materials.

7 cl, 17 dwg, 13 ex

FIELD: heating engineering.

SUBSTANCE: invention proposes employment of anhydrous C1-C18-carboxylic acid alkali or alkali-earth metal salt(s) as medium for accumulation of heat and using heat energy. Method of improving heat-exchange properties and heat capacity of liquid comprises dispersing above-indicated salts therein. Invention allows selection of combinations of heat-accumulating salts, which are less toxic, less environmentally harmful, and less corrosive for metals and materials used in heat-accumulation and heat-transmission equipment.

EFFECT: improved heat-exchange characteristics of heat-accumulation materials.

7 cl, 17 dwg, 13 ex

FIELD: heat-accumulating compositions.

SUBSTANCE: the invention is dealt with substances used for a heat transportation at the expense of a change of a phase state of heat-accumulating composition in the devices receiving the heat at its irregular delivery or consumption, in particular, in the system of a pre-starting preparation of transportation means and their power installations. The heat-accumulating composition contains (in mass %): 99 - 99.5 of octohydrate of barium hydroxide, 0.5-1.0 of sodium sulfite. Use of the composition decreases action of corrosion and considerably improves operational characteristics of the heat accumulator.

EFFECT: the invention ensures reduction of action of corrosion and considerable improvement of operational characteristics of the heat accumulator.

1 cl, 1 ex, 1 tbl

FIELD: special-destination materials.

SUBSTANCE: invention relates to development of heat-storage compositions including alkali metal fluorides, chlorides, and molybdates for use as heat-storage substances in heat accumulators and devices serving to maintain constant temperatures in heating engineering. In particular, composition contains 5.8-6.2% lithium fluoride, 28.0-32.1% lithium chloride, 39.0-41.3% lithium molybdate, and 23.1-24.5% lithium sulfate.

EFFECT: achieved heat storage capacity within 402-404°C temperature range.

1 tbl, 4 ex

FIELD: special-destination materials.

SUBSTANCE: invention relates to development of heat-storage compositions including alkali metal halides, metavanadates, and molybdates. In particular, composition contains 6.1-6.2% lithium fluoride, 23.4-24.3% lithium chloride, 24.8-27.6% lithium metavanadate, 27.1-27.6% lithium molybdate, and 17.3-17.8% lithium sulfate. Composition has considerable advantages over prototype: ensures working capacity within temperature range 360-363°C and by 56-69 J/g exceeds specific melting enthalpy.

EFFECT: improved performance characteristics.

1 tbl, 4 ex

FIELD: heat-storage materials.

SUBSTANCE: invention relates to mixtures capable of accumulating heat energy and relevant solar energy transformers. Heat-storage material according to invention contains silicon dioxide, 3-5% of liquid soda glass, and 50-82% of VO2+x wherein x=0-0.5. Material is prepared by compacting mixture of vanadium dioxide VO2+x and silica in presence of liquid soda glass as binder followed by solidification at 150-200°C. Summary heat when using combined transformer including phase transformation heat (α-VO2 ↔ β-VO2) and oxygen adsorption-desorption heat of mechano-chemically treated VO2+x may reach 250 J/g.

EFFECT: increased heat-storage capacity.

8 cl, 1 tbl

FIELD: heat-and-power engineering.

SUBSTANCE: invention is dealing with heat- retaining substances based on saturated hydrocarbons and provides heat carrier containing 88.0-90.5% n-heptadecane and 12.0-9.5% n-tricosane. Advantages of such composition compared to known one reside in that melting point of the substance is by 3.5-5.0°C below, which expands temperature application range, in particular enables use in heat accumulators to provide heat generation in thermoregulation and heat-supply systems at 17-18.5°C.

EFFECT: extended application area.

3 ex

FIELD: heating engineering .

SUBSTANCE: invention provides material that can be used for thermostatically controlling object under cooling conditions or outside heating, in particular, in medicine for storage and transportation of living tissues and organs and in instrumentation engineering when manufacturing phase-transfer executing sensors operated ay low temperatures. Phase-transfer contains 52.5-54.1% octane, 43.9-45.5% nonane, and tetradecane in balancing amount.

EFFECT: lowered allowed working temperature of material.

2 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the heat-retaining composition including lithium fluoride 7.1...7.8 % weight ratio, lithium sulphate 24.8...26.8 % weight ratio and lithium bromide 66.0...68.1 % weight ratio.

EFFECT: working capacity of hear-retaining composition at very high temperature.

1 cl, 1 tbl, 4 ex

FIELD: heating.

SUBSTANCE: proposed heat-retaining compound consists of n-undecane (90.3-91.75 wt %) and n-pentadecane (8.3-9.7 wt %). Provision for thermal accumulator efficient operation of under low temperatures within the range of -29.5÷-28.5°C, thermal effect accompanying the α/β-n-C11H24 transition ensures operability at a temperature of -36.6°C.

EFFECT: accumulator efficiency and operational capacity enhancement.

1 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a heat-retaining composition which contains lithium bromide 51.13-53.27 wt %, lithium sulphate 30.21-32.33 wt % and lithium chloride 16.6-17.47 wt %.

EFFECT: higher specific enthalpy of fusion.

1 cl, 1 tbl, 4 ex

Up!