球形粉煤灰基高温定形复合相变蓄热材料的制备与性能  

Preparation and Properties of Spherical Fly Ash Based Form-stable Composite Phase Change Material for High Temperature Thermal Storage

作　　者：朱桂花[1] 吕硕[1] 韩金鹏 欧阳群勇 

机构地区：[1]北方民族大学化学与化学工程学院,银川教授750021

出　　处：《煤炭转化》2018年第2期73-79,共7页Coal Conversion

基　　金：国家自然科学基金资助项目(51666001);国家民委化工技术重点实验室项目(2015HG02);北方民族大学重点科研项目(2015KJ32)

摘　　要：研究了干压成型法制备球形高温定形复合相变蓄热材料的工艺.采用粉煤灰为陶瓷基体材料、金属铝为相变介质,以PVA作黏合剂,通过球形模具干压成型后,在室温至1 000℃程序控温及无保护气的条件下进行无压烧结,得到直径D为7.5mm的近球形高温定形相变材料,有望在高温球形堆积床蓄热器中加以应用.研究表明:相变介质含量、坯料量和素坯成型压力对材料的球形度及烧结稳定性有明显影响,烧结后相变介质由最初的单质铝转变为Al-Si共晶合金.当坯料量为0.35g、成型压力为0.6 MPa时,制备的D7.5mm球形材料铝含量可达57%(质量分数),球形度为0.92,密度为1.60g/cm^3,经20次热震后相变潜热为62.49J/g,相变温度峰值为577.33℃.The preparation process of spherical form-stable composite phase change material for high temperature thermal storage by the use of dry pressing is researched.The nearly spherical form-stable phase change material with 7.5 mm in diameter,which is expected to be adopted in high temperature thermal storage with spherical capsule packed bed,is obtained by the way of utilizing fly ash as the ceramic matrix,aluminum as the phase change medium and PVA as adhesive.Non-pressurized sintering without protective gas with the help of program temperature controlling from room temperature to 1 000 ℃ was employed to process the green sample after dry pressing.The results show that the content of phase change medium,the amount of blank and the pressure of blank shaping affect the sphericity and sintering stability of materials significantly.The phase change material pure aluminum combines the silicon in the fly ash,forming Al-Si eutectic alloy after sintering.On the prerequisite of 0.35 g in the amount of green sample and0.6 MPa in forming pressure,the aluminum content,sphericity,density and phase change temperature of spherical material with 7.5 mm in diameter could be 57%,0.92,1.60 g/cm^3 and 577.33 ℃,respectively.The latent heat is 62.49 J/g after 20 times of thermal shock.

关 键 词：粉煤灰 铝 球形 高温 定形复合相变材料 

分 类 号：TQ536.4[化学工程—煤化学工程] TB333[一般工业技术—材料科学与工程]