Densities of component salts in low-temperature eutectic region

doi:10.11949/0438-1157.20190596

Abstract

Abstract:

By establishing a theoretical model, the density of the molten salt is calculated and compared with the experimental data. The error analysis shows that the quadratic polynomial model is the best calculation method. Low-temperature eutectic region (LTER) of mixed molten salts is defined as the temperature range between the melting temperature of mixed salts and the highest melting temperature of component salts. The molten salt is a solid-liquid coexistence state in LTER, and the thermal properties cannot be directly measured. It must be obtained by a combination of theoretical research and experimental verification. Using the quadratic polynomial model,the density of the mixed molten salts in LTER is calculated by extrapolation method. The density in the whole temperature range is obtained with little error, which proves that the theoretical calculation method is feasible. In order to reduce the error in the molten salt density, the experimental data are from the same literature or the same research group.

Key words: mixing, model, binary mixture, molten salts, density, low-temperature eutectic region

摘要：

通过建立理论模型，计算熔融盐的密度并与实验数据做比较，进行误差分析得出二次多项式模型是最佳的计算方法。混合熔融盐熔点到各组分盐熔点之间的温度区域,称之为“低温共熔区”。其熔融盐是固液共存状态，热物性无法直接测量，必须采用理论研究与实验验证相结合的方法来获取。采用二次多项式模型，利用外插法对混合熔融盐低温共熔区的密度进行计算，得到了全温度范围内的密度并且误差很小，证明此理论计算方法是可行的。在研究混合熔融盐密度时，为了减小误差，实验数据均来自同一文献或者同一研究组。

关键词: 混合, 模型, 二元混合物, 熔融盐, 密度, 低温共熔区

CLC Number:

TK 124

Qingguo ZHAO,Jianru FENG,Yuting WU,Hang GUO. Densities of component salts in low-temperature eutectic region[J]. CIESC Journal, 2019, 70(S2): 37-43.

赵庆国,冯建茹,吴玉庭,郭航. 混合熔融盐低温共熔区的密度计算[J]. 化工学报, 2019, 70(S2): 37-43.

Figures/Tables 10

References 32

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熔融盐	温度/℃	密度/(kg/m³)	三种关系模型	误差/%			文献
熔融盐	温度/℃	密度/(kg/m³)	三种关系模型	线性关系	二次多项式	指数关系	文献
NaNO₃	318	1904	ρ=2118.037-0.6722464t ρ=2109.104- 0.6255731t-0.00006018318t ² ρ=1910.156exp(-0.0003620212(t-310))	0.0138	0.00452	0.0332	[27]
	344	18877		-0.0115	-0.0114	-0.0112
	360	1876		0.00150	0.00520	-0.00580
	378	1864		-0.0039	0.0021	-0.0157
	402	1848		-0.0111	-0.0055	-0.0225
	415	1839		0.00300	0.00690	-0.00490
	458	1810		0.00820	-0.00180	0.0279
最大相对误差				0.0138	0.0114	0.0332
NaNO₃	342	1893	ρ=2133.843-0.7040474t ρ=2173.215-0.8966219+0.0002319207t ² ρ=1916.719exp(-0.0003821566(t-310))	-0.019	0.0134	-0.000646	[5]
	400	1852		-0.018	-0.0480	-0.0351
	433	1828		0.0311	0.00230	0.0158
	452	1814		0.0734	0.0578	0.0661
	491	1789		-0.0670	-0.0250	-0.0403
最大相对误差				0.0734	0.0578	0.0661
NaNO₃	324	1903	ρ=2108.804-0.6316582t ρ=1872.441+0.6904648t-0.001837628t ² ρ=1913.176exp(-0.0003358244(t-310))	0.0603	0.0128	0.0632	[7]
	333	1899		-0.028	-0.021	-0.0287
	353	1887		-0.062	0.0101	-0.0664
	393	1860		0.0302	-0.001	0.0315
最大相对误差				0.0302	-0.001	0.0315

熔融盐	温度/℃	密度/(kg/m³)	三种关系模型	误差/%			文献
熔融盐	温度/℃	密度/(kg/m³)	三种关系模型	线性关系	二次多项式	指数关系	文献
NaNO₃	318	1904	ρ=2118.037-0.6722464t ρ=2109.104- 0.6255731t-0.00006018318t ² ρ=1910.156exp(-0.0003620212(t-310))	0.0138	0.00452	0.0332	[27]
	344	18877		-0.0115	-0.0114	-0.0112
	360	1876		0.00150	0.00520	-0.00580
	378	1864		-0.0039	0.0021	-0.0157
	402	1848		-0.0111	-0.0055	-0.0225
	415	1839		0.00300	0.00690	-0.00490
	458	1810		0.00820	-0.00180	0.0279
最大相对误差				0.0138	0.0114	0.0332
NaNO₃	342	1893	ρ=2133.843-0.7040474t ρ=2173.215-0.8966219+0.0002319207t ² ρ=1916.719exp(-0.0003821566(t-310))	-0.019	0.0134	-0.000646	[5]
	400	1852		-0.018	-0.0480	-0.0351
	433	1828		0.0311	0.00230	0.0158
	452	1814		0.0734	0.0578	0.0661
	491	1789		-0.0670	-0.0250	-0.0403
最大相对误差				0.0734	0.0578	0.0661
NaNO₃	324	1903	ρ=2108.804-0.6316582t ρ=1872.441+0.6904648t-0.001837628t ² ρ=1913.176exp(-0.0003358244(t-310))	0.0603	0.0128	0.0632	[7]
	333	1899		-0.028	-0.021	-0.0287
	353	1887		-0.062	0.0101	-0.0664
	393	1860		0.0302	-0.001	0.0315
最大相对误差				0.0302	-0.001	0.0315

熔融盐	温度范围/℃	三种关系模型	误差/%			文献
熔融盐	温度范围/℃	三种关系模型	线性关系	二次多项式关系	指数关系	文献
NaNO₃	318～492	ρ=2125.627- 0.6867394t ρ=2114.155- 0.6281429t- 0.00007355967t ² ρ=1913.406exp(- 0.0003709027(t- 310))	0.229	0.219	0.247	[5,7,27]
KNO₃	344～612	ρ=2117.172- 0.7295381t ρ=2118.253- 0.7343305t+5.177395×10- 6t ² ρ=1871.359exp(- 4.101913×10^{- 4}(t- 339))	0.297	0.298	0.325	[5,7,27,28,29]
NaCl	876～139	ρ=1922.625- 0.4693520t ρ=1953.603- 0.5265682t+0.00002569246t ² ρ=1550.341exp(- 0.0003357776(t- 804))	0.298	0.261	0.271	[30]
KBr	740～930	ρ=2737.040- 0.8297332t ρ=2811.161- 1.007957t+0.0001065906t ² ρ=2129.187exp(- 0.0004061447(t- 734))	0.035	0.018	0.022	[18]
NaBr	735～945	ρ=2951.834- 0.8168944t ρ=2998.893- 0.9286811t+0.00006601913t ² ρ=2342.509exp(- 0.0003614983(t- 747))	0.023	0.021	0.025	[18]
CsBr	637～860	ρ=3910.889- 1.223433t ρ=3925.138- 1.261939t+0.00002578241t ² ρ=3134.661exp(- 0.0004083698(t- 636))	0.020	0.019	0.074	[18]
KI	682～903	ρ=3098.547- 0.9557355t ρ=3123.435- 1.018949t+0.00003990059t ² ρ=2449.417exp(- 0.0004083295(t- 681))	0.028	0.022	0.074	[8]

熔融盐	温度范围/℃	三种关系模型	误差/%			文献
熔融盐	温度范围/℃	三种关系模型	线性关系	二次多项式关系	指数关系	文献
NaNO₃	318～492	ρ=2125.627- 0.6867394t ρ=2114.155- 0.6281429t- 0.00007355967t ² ρ=1913.406exp(- 0.0003709027(t- 310))	0.229	0.219	0.247	[5,7,27]
KNO₃	344～612	ρ=2117.172- 0.7295381t ρ=2118.253- 0.7343305t+5.177395×10- 6t ² ρ=1871.359exp(- 4.101913×10^{- 4}(t- 339))	0.297	0.298	0.325	[5,7,27,28,29]
NaCl	876～139	ρ=1922.625- 0.4693520t ρ=1953.603- 0.5265682t+0.00002569246t ² ρ=1550.341exp(- 0.0003357776(t- 804))	0.298	0.261	0.271	[30]
KBr	740～930	ρ=2737.040- 0.8297332t ρ=2811.161- 1.007957t+0.0001065906t ² ρ=2129.187exp(- 0.0004061447(t- 734))	0.035	0.018	0.022	[18]
NaBr	735～945	ρ=2951.834- 0.8168944t ρ=2998.893- 0.9286811t+0.00006601913t ² ρ=2342.509exp(- 0.0003614983(t- 747))	0.023	0.021	0.025	[18]
CsBr	637～860	ρ=3910.889- 1.223433t ρ=3925.138- 1.261939t+0.00002578241t ² ρ=3134.661exp(- 0.0004083698(t- 636))	0.020	0.019	0.074	[18]
KI	682～903	ρ=3098.547- 0.9557355t ρ=3123.435- 1.018949t+0.00003990059t ² ρ=2449.417exp(- 0.0004083295(t- 681))	0.028	0.022	0.074	[8]

混合熔融盐	纯质盐最大相对误差/%		混合熔融盐最大相对误差/%	文献
45.15%KCl-54.85%KI	KCl	0.0571	0.60	[8]
45.15%KCl-54.85%KI	KI	0.0224	0.60	[8]
50%NaNO₃-50%KNO₃	NaNO₃	0.236	0.24	[28]
50%NaNO₃-50%KNO₃	KNO₃	0.159	0.24	[28]
41.2%KCl-58.8%LiCl	KCl	0.0571	0.11	[32]
41.2%KCl-58.8%LiCl	LiCl	0.0153	0.11	[32]