Articles & Issues

Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

All issues

화학열펌프용 열전도성 블록의 제조 및 특성

Manufacture and Characteristics of Heat Conductive Blocks for Chemical Heat Pump

한종훈 조길원 이건홍

Han JH Cho KW Lee KH

HWAHAK KONGHAK, December 1996, 34(6), 757-764(8), NONE

Download PDF

Abstract

황산이 함유된 천연 흑연을 열처리하여 팽창흑연분말을 준비하였다. 이 팽창흑연을 압축, 성형하여 흑연지지체를 제조하였으며, 성형된 지지체에 20% CaCl₂ 용액을 이용하여 진공기법으로 염을 함침하고, 200℃, 20kPa의 조건에서 건조과정을 거쳐 전도성 블록을 제조하였다. 흑연지지체의 특성분석으로서 기체투과도는 Darcy’s law를 적용하고, 열전도도 측정은 전이 헬륨침투법과 수은침투법을 이용하였다. 반응기내 전도성 블록의 크기변화 및 온도분포를 조사하기 위하여 기본적인 열펌프 시스템을 구성하였다. 흑연지지체의 기체투과도는 0.01-1.0Darcy의 범위에 있었으며 열전도도는 흑연지지체의 겉보기 밀도가 P_b=100-400㎏/㎥의 경우 4.4-21.6W/mK의 범위에 있엇다. 블록내 염은 균일하게 분산되어 있었으며, 기공률은 제조조건에 따라 0.4-0.83의 범위에 있었다. 전도성 블록이 암모니아와 반응시 크기변화는 겉보기 밀도가 증가할수록 안정되어 있었으며 반응기내에 온도분포는 초기에 반응의 kinetics가 내부온도를 지배하였으나, 시간이 경과할수록 외부열전달에 의해 외부온도롤 진행됨을 알 수 있었다.

Expanded graphite powders were prepared by heating natural flake graphites intercalated with sulfuric acid. Graphite matrices were fabricated by pressing expanded graphite powders. Impregnation of salts into the graphite matrices were done using vacuum filtration with 20 wt% CaCl₂ solution followed by vacuum drying at 200℃ and 20kPa. Techniques used to examine the properties of blocks include EDAX and EPMA for amount and distribution of salts in the block, Hepycnometer for porosity, permporometer for gas permeability and transient 1-dimensional heat flow technique for thermal conductivity measurement. Basic chemical heat pump system is used to examine the dimensional stability and temperature distribution for blocks in the reactor. Results showed that Darcy’s permeability constants of graphite matrices were in 0.01-1.0 Darcy at △P=0.8bar. for graphite matrices with P_b= 100-400kg/㎥, thermal conductivites were in the range of 4-22 W/mK. CaCl₂ was uniformly dispersed on the surface of expanded graphites in the block. The porosities of blocks were in the range of 0.4-0.83. The dimension of blocks was found to be more stabilized as bulk density increases. Temperature profile was govened by the reaction kinetics at the initial stage and by the external heat transfer in the long run.

Keywords

Expanded Graphite Chemical Heat Pump Heat Conductive Block

References

이철수, 상자부 보고서 (1993)
Kim JW, Sim KS, Son YM, Myung KS, Kim YS, Energy R&D, 15(2), 172 (1993)
Neveu P, Castaing J, Heat Recov. Syst. CHP, 13, 233 (1993)
Spinner B, Heat Recov. Syst. CHP, 13(4), 301 (1993)
Goetz V, Elie P, Spinner B, Heat Recov. Syst. CHP, 13, 79 (1993)
Mazet N, Meyer P, Neveu P, Spinner B, Int. Absorp. Heat Pump Conference, 31, 407 (1993)
Bougard J, Jadot R, Poulain V, Int. Absorp. Heat Pump Conference, 31, 413 (1993)
Mazet N, Amouroux M, Chem. Eng. Commun., 99, 175 (1992)
Mazet N, Amouroux M, Spinner B, Chem. Eng. Commun., 99, 155 (1991)
Crozat G, Mazet N, Spinner B, Arnaud G, J. Chem. E. Symp., 87, 377 (1989)
Lebrun M, Chem. Eng. Prog., 28, 67 (1990)
Dufour LC, Hartoulari R, React. Solids, 5, 205 (1988)
Log T, Rev. Sci. Instrum., 64(7), 1956 (1993)
Marsh H, "Introduction to Carbon Science," Butterworth & Co., Ltd. (1989)
Kinoshita K, "Carbon-Electrochemical and Physicochemical Properties," J. Wiley (1988)
Mauran S, Lebrun M, Prades P, Moreau M, Spinner B, Drapier C, U.S. Patent, 5,283,219 (1994)
Mcketta JJ, "Inorganic Chemicals Handbook," 1 (1993)
이종호, "가역 화학반응열 적용기술 개발," 한국에너지기술연구소 (1992)
Balat M, Roca A, Spinner B, U.S. Patent, 4,906,258 (1990)
Camille C, U.S. Patent, 4,585,774 (1986)