粉煤灰-硅藻土复合相变储能材料制备及导热强化

固废资源化利用是实现节能减排的重要途径,以月桂酸为相变工作介质,以粉煤灰-硅藻土二元载体为封装材料,碳纳米管为导热剂,采用直接熔融共混法制备出月桂酸/粉煤灰-硅藻土/碳纳米管复合相变储能材料。采用热扩散渗透测试、傅里叶红外光谱仪(FTIR)、差示扫描量热仪(DSC)、热重分析仪(TGA)、无纸记录仪等分别考察了定形复合相变储能材料的承载性能、微观结构和热物性。结果表明:粉煤灰-硅藻土二元载体可有效防止月桂酸的泄漏,当二元载体中月桂酸的质量分数为28%时可制得无泄漏复合相变储能材料,且原样粉煤灰利用率为55%;FTIR结果表明复合材料中各组分之间相容性好;DSC测得其熔化相变温度为45.79℃,相变潜热为51.06 J/g;TGA分析显示月桂酸/粉煤灰-硅藻土/碳纳米管热稳定性较好;储/放热性能曲线显示加入质量分数为5%的碳纳米管时,复合相变储能材料的熔化与凝固时间分别减少60%和62.5%,传热效率得到显著改善。

Preparation and thermal conductivity enhancement of fly ash-diatomite-based composite phase change materials

The resource utilization of solid waste is an important way to achieve energy saving and emission reduction.A lauric acid(LA)/raw fly ash(RFA)-diatomite(DT)/carbon nanotubes(CNT)composite form-stable phase change materials(FSPCM)for thermal energy storage were prepared via simple direct impregnation method,in which LA,RFA-DT binary matrix and CNT were employed as phase change materials(PCMs),the supporting material,and thermal conductive additive,respectively.The loading capacity,structure and thermal properties of FSCPCM were investigated through the diffusion-oozing testing,Fourier transform infrared spectrometer(FTIR),differential scanning calorimetry(DSC),thermo gravimetry analysis(TGA)and paperless recorder,respectively.The results show that the RFA-DT binary material can effectively prevent the leakage of LA.When the mass fraction of LA in composite is 28%,the FSPCM without leakage can be obtained.What’s more,the utilization rate of RFA reaches 55%.The FTIR demonstrates that FSPCM has good compatibility between its four components,LA,RFA-DT,and CNT.The melting onset temperature of FSPCM is 45.79℃measured by DSC,and the corresponding latent heat of FSPCM is determined as 51.06 J/g.TGA analysis shows LA/RFA-DT has good thermal stability.The storage/release performance curve indicates that when mass fraction of CNT is added with 5%,the melting and solidification time of LA/RFA-DT/CNT are decreased by 60%and 62.5%,respectively,indicating that the heat transfer performance is remarkably improved.