Modification of fly ash as a carrier of paraffin wax based phase change energy storage material for waste heat recovery

doi:10.3969/j.issn.2095-4239.2013.06.006

Abstract

Abstract: The work reported in this paper concerns preparation of paraffin wax based composite phase change materials (PCMs) for waste heat recovery. Surface modified fly ash was used as the PCM carrier and water-free ethanol as the solvent and the solution intercalation was used to prepare the composite materials. The fly ash modification was done by using citric acid, which did not affect the structure of the fly ash. The modification process was found to be able to remove impurities of fly ash and improve the adsorption capacity of PCMs. A series of experiments were conducted to characterize the prepared composite materials using DSC, FT-IR and SEM. The DSC results showed that the best composite material had a melting latent heat of 84.23 kJ/kg with the melting temperature of 53.63 ℃. The FT-IR analyses showed good chemical stability of composites, and the leakage of melted paraffin from the composites could be prevented through the capillary force and surface tension between paraffin and fly ash. By using a heat exchanger, the PCMs were tested for the recovery of industrial waste heat. It was shown that the outlet water temperature of the heat exchanger could be maintained approximately constant for a few hours.

Key words: phase change energy storage materials, fly ash, paraffin, waste heat recovery, heat exchanger

CLC Number:

TK531.5

ZHAO Liang, WANG Haiyang, FANG Xiangchen, WANG Gang, XU Hong. Modification of fly ash as a carrier of paraffin wax based phase change energy storage material for waste heat recovery[J]. Energy Storage Science and Technology, 2013, 2(6): 598-602.

References

[1] Zhang Renyuan(张仁元), et al . 相变材料与相变储能技术[M]．Beijing:Science Press,2009:10-24．
[2] Huang Jin(黄金),Ke Xiufang(柯秀芳). Research and development of Na 2 SO 4 ∙10H 2 O as phase change materials[J]. Materials Review (材料导报),2008,22(3):63-67.
[3] Cho K,Choi S H. Thermal characteristics of paraffin in a spherical capsule during freezing and melting processes[J]. Inter. J. of Heat and Mass Transfer ,2000,43(24):3183-3196.
[4] He B,Setterwall F. Technical grade paraffin waxes as phase change materials for cool thermal storage and cool storage systems capital cost estimation[J]. Energy Conversion and Management ,2002,43(13):1709-1723.
[5] Trp A. An experimental and numerical investigation of heat transfer during technical grade paraffin melting and solidification in a shell-and-tube latent thermal energy storage unit[J]. Sol. Energy ,2005,79(6):648-660.
[6] Hittle D C,Lee A S. Tile structures having phase change material (PCM) component for use in floorings and ceilings:US,20090223160[P]. [2013-04-20].
[7] Zhang Baoping(张宝平),Chen Yunlin(陈云琳),Wei Lin(魏琳),Zu Zhinan(祖志楠). Study on the modification and adsorption capacity of coal fly ash[J]. Bulletin of the Chinese Ceramic Society (硅酸盐通报),2012,31(3):675-678.
[8] Wang Shuqin(王淑勤),Fan Xuejuan(樊学娟)．Experimental study on indoor air pollution with activated fly ash treatment[J]. Journal of North China Electric Power University (华北电力大学学报),2005,32(6):89-91．
[9] Zhang Baozhu(张保柱). Study on adsorption of Rhodamine B waste water by acid-modified fly ash[J]． Applied Chemical Industry (应用化工),2012,41(10):1767-1773.
[10] Zhao L,Ma R Y,Meng X L, et al . Characterization and preparation of paraffin/modified inorganic porous materials composites as building energy storage materials[J]. Advanced Materials Research ,2012,450-451:1419-1424.
[11] Zhao Liang(赵亮),Ma Ruiying(马蕊英),Meng Xianglan(孟祥兰), et al . Characterization and preparation of paraffin/γ-Al 2 O 3 composites as phase change energy storage materials[J]. Chemical Industry and Engineering Progress (化工进展),2011,30(s1):759-761.
[12] Dong Xiangmei(董香梅),Liu Min(刘民),Shi Jinliang(施金亮), et al . Effects of acidity and crystal size of Hβ catalysts on the dehydration and ring-closure reaction of 2-(4 ' -ethylbenzoyl) benzoic acid[J]. Acta Petrolei Sinica : Petroleum Processing Section (石油学报:石油加工),2008,24(3):288-292.
[13] Zhai Lingjuan(翟玲娟),Liu Min(刘民),Dong Xiangmei(董香梅), et al . Dehydration of 2-(4 ' -ethylbenzoyl)-benzoic acid to 2-ethylanthraquinone over Hβ zeolite modified with organic acids[J]. Chinese Journal of Catalysis (催化学报),2009,30(1):9-13.
[14] Ma Bingqian(马炳倩),Li Jianqiang(李建强),Peng Zhijian(彭志坚),Ding Yulong(丁玉龙). Paraffin based composite phase change materials for thermal energy storage:Thermal conductivity enhancement[J]. Energy Storage Science and Technology (储能科学与技术),2012,1(2):131-138.
[15] Chen Z,Shan F,Cao L, et al . Synthesis and thermal properties of shape-stabilized lauric acid/activated carbon composites as phase change materials for thermal energy stoarge[J]. Sol. Energy Mater. and Sol. Cells ,2012,102:131-136.
[16] Fang G Y,Li H,Liu X. Preparation and properties of lauric acid/silicon dioxide composites as form-stable phase change materials for thermal energy storage[J]. Materials Chemistry and Physics ,2010,122(2-3): 533-536.