Quartz sand composite multi-component nitric acid Molten Salt Heat Transfer heat storage medium and preparation method
Technical field
The present invention relates to the heat-accumulating heat-transfer complex medias for solar light-heat power-generation, multiple more particularly to a kind of quartz sand
Close polynary nitric acid Molten Salt Heat Transfer heat storage medium and preparation method.
Background technique
In industrial accumulation of energy and solar light-heat power-generation technology, heat-accumulating heat-transfer medium used at present be mainly free gas and water,
The metals such as conduction oil, fuse salt, sodium and aluminium.Fused salt because have extensive use temperature range, low-steam pressure, low viscosity, well
Stability, many characteristics such as low cost have become the heat transfer heat storage medium that potentiality are had much in solar light-heat power-generation technology, at
To apply more, more mature heat transfer heat storage medium at present.High-temperature fusion salt mainly has nitrate, carbonate, sulfate, fluorine
Compound, chloride, oxide etc..
The raw material sources of nitric acid molten salt system are extensive, cheap, corrosivity is small, therefore compared with other fused salts, nitric acid
Fused salt has very big advantage.Polynary nitric acid fused salt fusing point therein is low, but the upper limit is low using temperature.
Chinese patent application 00111406.9 discloses a kind of LiNO3-KNO3-NaNO3-NaNO2Polynary nitric acid molten salt body
System, operating temperature range are 250 °C -550 °C, and the maximum working temperature of this system is higher than ternary nitric acid salt system, reaches
550 °C, but its lower working temperature is also enhanced, and causes maintenance cost when obnubilation to increase, and LiNO3Addition so that it is rotten
Corrosion increases, and cost increases.
United States Patent (USP) US007588694B1 discloses a kind of LiNO3-KNO3-NaNO3- Ca(NO3)2Polynary nitric acid molten salt body
System, fusing point are lower than 100 °C, and the upper limit uses temperature higher than 500 °C, but LiNO3Addition so that system to hold over system
Corrosivity increases, and industrial cost increases.
The unique molecular chain structure of quartz sand, crystal shape and lattice variations rule, make it have high temperature resistant, it is anti-oxidant,
Many characteristics such as thermal expansion coefficient is small, high-insulation, unique physics, the chemistry such as corrosion-resistant, send out in many high-tech products
Increasingly important role is waved, manufacture glass, refractory material, smelting duriron, flux for metallurgy, ceramic grinding material are often used as
Material, the raw material cast.
So far, it does not see and quartz sand is added in polynary nitric acid fused salt as industrial accumulation of energy and solar energy high temperature
The report of the heat transfer heat storage medium in heat utilization field.
Summary of the invention
The purpose of the present invention is to provide a kind of quartz sand composite multi-component nitric acid Molten Salt Heat Transfer heat storage medium and preparation method,
The addition of quartz sand improves the maximum working temperature of system, and freezing point (fusing point that DSC Differential Scanning Calorimeter is measured) does not have substantially
It changes, therefore has widened the operating temperature range of polynary nitric acid molten salt system, can be widely used for industrial accumulation of energy and solar energy optical-thermal
Technical field of power generation, and since quartz sand is cheap, so that fused salt production cost is greatly lowered.
To achieve the above object, technical scheme is as follows:
A kind of quartz sand composite multi-component nitric acid Molten Salt Heat Transfer heat storage medium, it is characterised in that: the heat transfer heat storage medium is
Quartz sand is added in polynary nitric acid molten salt system to be combined.
The polynary nitric acid molten salt system accounts for the 50 ~ 99% of heat transfer heat storage medium total weight, and quartz sand accounts for 1 ~ 50%.
The polynary nitric acid molten salt system accounts for the 50 ~ 90% of heat transfer heat storage medium total weight, and quartz sand accounts for 10 ~ 50%.
The polynary nitric acid molten salt system is KNO3-NaNO3-NaNO2-CsNO3System,
KNO3-NaNO3-NaNO2-Ca(NO3)2System,
KNO3-NaNO3-NaNO2-LiNO3System,
KNO3-NaNO3-CsNO3-Ca(NO3)2System,
KNO3-NaNO3-LiNO3-CsNO3System or KNO3-NaNO3-NaNO2-CsNO3-Ca(NO3)2System.
The KNO3-NaNO3-NaNO2-CsNO3The components by weight percent of system is as follows: 40 parts -80 parts of potassium nitrate, sodium nitrate 5
- 15 parts, 20-50 parts of sodium nitrite, 1 part -10 parts of cesium nitrate of part;
The KNO3-NaNO3-NaNO2-Ca(NO3)2The component of system is as follows: 40 parts -80 parts of potassium nitrate, 5 parts of sodium nitrate -
15 parts,;20 parts -50 parts of sodium nitrite, 1 part -10 parts of calcium nitrate;
The KNO3-NaNO3-NaNO2-LiNO3The component of system is as follows: 40 parts -80 parts of potassium nitrate, 5 part -15 of sodium nitrate
Part, 20 parts -50 parts of sodium nitrite;1 part -10 parts of lithium nitrate;
The KNO3-NaNO3-CsNO3-Ca(NO3)2The component of system is as follows: 40 parts -80 parts of potassium nitrate, 5 parts of sodium nitrate -
15 parts, 20 parts -50 parts of cesium nitrate, 1 part -10 parts of calcium nitrate;
The KNO3-NaNO3-LiNO3-CsNO3The component of system is as follows: 40 parts -80 parts of potassium nitrate, 5 part -15 of sodium nitrate
Part, 20 parts -50 parts of lithium nitrate, 1 part -10 parts of cesium nitrate;
The KNO3-NaNO3-NaNO2-CsNO3-Ca(NO3)2Component it is as follows: 40 parts -80 parts of potassium nitrate, sodium nitrate 5
- 15 parts, 10 parts -50 parts of sodium nitrite, 10 parts -30 parts of cesium nitrate, 10 parts -30 parts of calcium nitrate of part.
Purposes of any of the above-described heat transfer heat storage medium in industrial accumulation of energy or solar light-heat power-generation.
Any of the above-described preparation method for stating heat transfer heat storage medium, its step are as follows:
(1) the polynary nitric acid molten salt system is formed, is put into reaction kettle, heating stirring makes fused salt completely at melting, so
After keep the temperature 0.5-1h,
(2) under stirring condition, quartz sand is distributed in high-temperature fusion salt, continues to stir 1-2h, mixture agglutination shape
State,
(3) cooling, packaging.
The heating stirring makes fused salt melt the phase transition temperature of the temperature polynary nitric acid fused salt of use or more completely
80-120℃。
The present invention selects quartz sand as the composite material of nitric acid fused salt for the first time, and quartz sand is a kind of hard, wear-resisting, chemical
The stable silicate mineral of performance, main component are SiO2, a small amount of impurity component such as Fe is often contained in mineral2O3、Al3O2、
CaO, MgO, NaO etc..About 1723 DEG C of fusing point, about 2230 DEG C of boiling point, there is higher fire resistance.It is adopted for quartz sand of the invention
It is greater than 75% common quartz sand with dioxide-containing silica.It is demonstrated experimentally that quartz sand is added in polynary nitric acid molten salt system
Prepare resulting heat transfer heat storage medium, industrial cost is low, little to hold over system corrosivity, and with former polynary nitric acid molten salt system
Compared to having the following advantages and good effect:
Composite fused salt heat transfer heat storage medium prepared by the present invention had not only had the heat transfer property of nitric acid fused salt, but also improved hot steady
The qualitative and upper limit uses temperature.
Quartz sand is added and does not change the fusing point of former polynary nitric acid molten salt system substantially, but increases latent heat of phase change,
I.e. energy storage density is high, this can reduce the requirement to hold over system size and energy.
The quartz sand that the present invention is added in polynary nitric acid molten salt system, the granularity the thin more is conducive to the conductivity of heat of system
Energy.
In the preferred embodiments of the invention, quartz sand accounts for 1 ~ 50%, and quartz sand content is higher, reduces cost and is more obvious;This
Not only it can guarantee that the ceiling temperature of polynary nitric acid fused salt improved in a range, but also can guarantee that fusing point does not increase.
Specific embodiment
The present invention will be described in detail combined with specific embodiments below.
Experimental material:
Common quartz sand (dioxide-containing silica is greater than 75%), 100 mesh are purchased from Shandong Hong Tai quartz sand factory.
Potassium nitrate, sodium nitrate, sodium nitrite, cesium nitrate, calcium nitrate, lithium nitrate: technical pure grade, general chemical article company
It is commercially available.
Polynary nitrate system formulation such as table 1.
Polynary nitric acid system formula in each embodiment of table 1.
More than 1 ~ 3. yuan of nitric acid salt system KNO of embodiment3-NaNO3-NaNO2-CsNO3Middle addition quartz sand prepares heat-accumulating heat-transfer
Medium
The preparation of step 1. quartz sand composite multi-component nitric acid fused salt product 1 ~ 3:
Prepare the material of the polynary nitric acid molten salt system of composition by formula listed by table 1, quartz is uniformly added in heating stirring afterwards
Sand is continued heating stirring, is removed water with degasification, and heating temperature is above 80-120 °C of fused salt phase transition temperature.
Quartz sand (100 mesh) is distributed in the polynary nitric acid molten salt system of melting, molten mixture 1-2h is stirred, obtains
Quartz sand composite multi-component nitric acid Molten Salt Heat Transfer heat storage medium.Quartz sand accounts for 1%, 20%, 50% respectively in product 1 ~ 3.
The heat stability testing of step 2. product 1 ~ 3
Heat stability testing is carried out to the heat transfer heat storage medium and the polynary nitric acid fused salt of control that are prepared.
Test is carried out using gravimetric method: 1 ~ 3 resulting 3 kind of fuse salt of embodiment being respectively charged into the crucible of nickel, is put
Enter in temperature controlling stove and heated, tested since room temperature, takes out experiment crucible at regular intervals and weighed with assay balance.
If the weight of sample is no longer reduced in a certain temperature section, then improves the temperature of temperature controlling stove.Then it takes at regular intervals again
Experiment crucible is weighed out, then is further continued for heating up later to another stable state.
As the result is shown:
120 hours are kept the temperature under 600 °C of fused salt of product 1 ~ 3, loss late is less than 1;
30 hours are kept the temperature under 700 °C, the loss late of three products respectively may be about 20%, 3%, 1%.
Control is three kinds of polynary nitric acid system fused salts (the corresponding system of 1 embodiment number of table 1 ~ 3) for not adding quartz sand,
It is about 8% that 30 hourly loss rates can be run under 600 °C, but occurs apparent loss under 700 °C, is run to 30 hours, loss
Rate is up to 25%
Illustrate that quartz sand, which is added, can effectively improve the stability and raising SC service ceiling of nitric acid molten salt system at high temperature
Temperature.
The latent heat of phase change test and fusing point test of step 3. product 1 ~ 3.
(being scanned under normal pressure) is carried out using general Differential Scanning Calorimeter DSC.
Test result shows that compared with the control, latent heat of phase change all significantly increases;The fusing point of product 1,2 is basically unchanged, product
3 fusing point slightly increases.
More than 4 ~ 6 yuan of nitric acid salt system KNO of embodiment3-NaNO3-NaNO2-Ca(NO3)2Middle addition quartz sand preparation accumulation of heat passes
Thermal medium
Prepare the material of the polynary nitric acid molten salt system of composition by formula listed by table 1.
For the preparation method and detection method of product 4 ~ 6 completely with embodiment 1 ~ 3, quartz sand (100 mesh) accounts for 10% respectively,
25%, 40%;Control is free of quartz sand, is the corresponding system of embodiment 4 ~ 6 in table 1.
Thermal stability determination result is similar to embodiment 1 ~ 3, and after keeping the temperature 30 hours under 700 °C, the present invention is prepared
Three kinds of products loss late successively about 10%, 3%, 1%, hence it is evident that lower than the highest 28% of control.
(being scanned under normal pressure) is carried out using general Differential Scanning Calorimeter DSC.Test result shows, and to photograph
Than latent heat of phase change all significantly increases;Fusing point is basically unchanged.
More than 7 ~ 9. yuan of nitric acid salt system KNO of embodiment3-NaNO3-NaNO2-LiNO3Middle addition quartz sand prepares heat-accumulating heat-transfer
Medium
Prepare the material of the polynary nitric acid molten salt system of composition by formula listed by table 1
Preparation method and detection method are completely the same as embodiment 1 ~ 3.
Quartz sand added by embodiment 7 ~ 9 (100 mesh) accounts for 15%, 30%, 45%
Thermal stability determination result is similar to embodiment 1 ~ 3, and after keeping the temperature 30 hours under 700 °C, the present invention is prepared
Three kinds of products loss late highest 12%, 4%, 2%, hence it is evident that lower than the 30% of control.
(being scanned under normal pressure) is carried out using general Differential Scanning Calorimeter DSC.Test result shows, and to photograph
Than the fusing point of product 7 ~ 9 is basically unchanged, and latent heat of phase change is increased.
More than 10 ~ 12. yuan of nitric acid salt system KNO of embodiment3-NaNO3-CsNO3-Ca(NO3)2Middle addition quartz sand prepares accumulation of heat
Heat transfer medium
Completely with embodiment 10 ~ 12, quartz sand (100 mesh) accounts for the preparation method and detection method of product 10 ~ 12 respectively
10%, 25%, 45%;Control is free of quartz sand, is the corresponding system of embodiment 10 ~ 12 in table 1.
Thermal stability determination result and embodiment 7 ~ 9 are closely similar, after keeping the temperature 30 hours under 700 °C, present invention preparation
The loss late highest 12% of three kinds of obtained products, 3%, 2%, hence it is evident that lower than the 30% of control.
(being scanned under normal pressure) is carried out using general Differential Scanning Calorimeter DSC.Test result shows, and to photograph
Than latent heat of phase change is increased, and the fusing point of product 10 ~ 11 is substantially unchanged, and the fusing point of product 12 slightly increases.
Quartz sand is added in the other polynary nitric acid salt systems of embodiment 13 ~ 18 and prepares heat-accumulating heat-transfer medium
The preparation method and detection method of product 13 ~ 18 completely with embodiment 13 ~ 18, every kind of polynary nitric acid molten salt system
Three kinds of matched quartz sand (100 mesh) ratios of formula are respectively as follows: 15%, 25%, 40%;Control is free of quartz sand, is real in table 1
Apply the corresponding system of example 13 ~ 18.
After thermal stability determination is as a result, keep the temperature 30 hours at 700 DEG C, the loss for 6 kinds of products that the present invention is prepared
Rate highest 11%, 2.5%, 1%, hence it is evident that lower than the 30% of control.
(being scanned under normal pressure) is carried out using general Differential Scanning Calorimeter DSC.Test result shows, and to photograph
Than the fusing point of product 13 ~ 18 is basically unchanged, and latent heat of phase change is increased.Above-mentioned experimental result explanation: the present invention is in polynary nitric acid
Quartz sand is added in molten salt system and prepare resulting heat transfer heat storage medium, it is little to hold over system corrosivity, and with the polynary nitre of original
Sour molten salt system is compared and brings the progress of following several respects:
The heat transfer property of existing nitric acid fused salt, but the upper limit for improving polynary nitric acid fused salt uses temperature;Use temperature model
Enclose wider, thermal stability is good.
Latent heat of phase change is big, and energy storage density is high, reduces the requirement to hold over system size and energy, and capacity usage ratio is high,
Energy-saving effect is good.
Molten Salt Heat Transfer heat storage medium heating conduction prepared by the present invention greatly increases, and overcomes nitric acid fused salt heating conduction
The shortcomings that difference, easy hot-spot, can be widely used for solar light-heat power-generation technical field.