Journal of the Ceramic Society of Japan 115 [8]491 497 (2007) Paper º Ý Li 4 SiO 4 CO 2 ~ u Å 112 8551 o vt 1 13 27 `l O ^Äëçêéíáçå oé~åíáçå çñ iá Q pál Q ëíìçáéç Äó íüé o~íé qüéçêó ìëáåö qüéêãçöê~îáãéíêó Takeshi OKUMURA, Kiminori ENOMOTO, Nobuaki TOGASHI and Katsuyoshi OH-ISHI Department of Applied Chemistry, Faculty of Science and Engineering,Chuo University, 1 13 27, Kasuga, Bunkyo-ku, Tokyo 112 8551 The CO 2 absorption property of Li 4 SiO 4 was investigated by thermogravimetry. Two kinds of sintered Li 4 SiO 4 samples were prepared at 700?C and 1000?C. The CO 2 absorption rate of the powdered Li 4 SiO 4 samples was measured in 100 vol CO 2 atmosphere at nine selected temperatures in the 620 700?C region, and the measured data were discussed by the rate theory. The CO 2 absorption reaction of the Li 4 SiO 4 would be a pseudo first order reaction. For these samples, apparent reaction rate constants k were measured at different measurement temperatures, and activation energies were estimated by the Arrhenius plot. For both the samples, the estimated activation energies were about 115 kjmol in the 620 660?C regionandabout56kjmol in the 680 700?C region. The large difference between these activation energies seems to depend on the surface state of the Li 4 SiO 4 particle reacting with CO 2. Received March 8, 2007; Accepted June 14, 2007 Key-words : CO 2 absorbent ceramics, Lithium silicate, Power plant, Rate theory, Rate constant,arrhenius plot Å Û Ÿ ý Ê Ú êñ CO 2 d Ú Å CO 2 d Ý Ò æÿ ì e Õæÿ ì h Á í æÿ ì øú Ú ýõ Ú ÝÊ CO 2 d Ù CO 2 Ú Õ CO 2 œ Ù CO 2 œï d Ý Ê r CO 2 ø ø 1 7 Ú ø Li 2 ZrO3 8 14 Õ LiFeO2 15,Li 4 SiO4 16,17 ù CO 2 Ý CO 2 ø CO 2 Ý ý Li 4 SiO 4 1g Û0.367 g CO 2 Ý h Li 4 SiO 4 400 CO 2 Ù 500 700?C CO 2 Ý Ú êñ d Õ Ê Ú Ú Li 4 SiO 4 700?C Þ CO 2 Ý v ÝÓ Ò Û CO 2 ~p Ê Ú Ù Å Ú Li 4 SiO 4 CO 2 ~p Û Li 4 SiO 4 ø 18 20 Ù 1 CO 2 Ý Ú Li 4 SiO 4 CO 2 Ý{ 2 Li 4 SiO 4 CO 2 1 ì òæÿ ì Ú 3 CO 2 Ý Li 4 SiO 4 CO 2 Ë uú Li 4 SiO 4 s CO 2 g Li 2 CO 3 s Li 2 SiO 3 s 1 r Li 4 SiO 4 Ý CO 2 ~p Ò Ù ù ÝÓ ø Ó ý Ê Ú Li 4 SiO 4 CO 2 êñý þ Ó ÛÝø Ú Ó n mg p Ý Ý 21 Ú kg Li 4 SiO 4 pý CO 2 d CO 2 Ý Ý Ð ñïó Ú p Õ CO 2 Ó ÚÓ ý Û ÊÚ n mg p Ý Li 4 SiO 4 CO 2 Ý ÙÛ 1 þen n n k ÙÊÐ Ý Ú ÝÓ Li 4 SiO 4 CO 2 Ž Ê Li 4 SiO 4 Ý CO 2 ~ z Ý Ú ñï Ý p Li 4 SiO 4 p p Li 2 CO 3 99.999 í SiO 2 99.99 í Ý ÙÛ Ù Li 2 CO 3 SiO 2 Ý Ú pýº 491
492 º Ý Li 4 SiO 4 CO 2 œ œõ œ { Ý Ð œ ÒÚ º ÅÝøÅ Li 2 CO 3 SiO 2 Ý Li 2 CO 3 SiO 2 2 1 š ÙÒ 1 ÙÛ ú Ú Ý œ œ 700?C 20 h ÙÊ œ 1000?C 20 h º Å ÙÛ 2 Li 4 SiO 4 pý Ú pý X XRD Å p Ž Ýø p Ý SEM JSM T20 t Ý Ú p Ž ÙÊ CO 2 pý Ð CO 2 CO 2 º TGD 9600 º ULVAC RIKO Ý ø º ð ð pö ø Ù Ò ÝÝø Ú400?Cmin u œ ² 100 vol CO 2 êñý 0.1 MPa 150 mlmin Ù CO 2 êñ Ý50 mlmin 300 mlmin Li 4 SiO 4 p20 mg Ù Ò pý 5.5 mm 4.5 mm 0.5 mm 5.0 mm ü ó Ò ó ú º Ž œ CO 2 êñ z ŸÒ p Li 4 SiO 4 üó r Ú r CO 2 Ý Ù 10 CO 2 êñý150 mlmin CO 2 20 mg Li 4 SiO 4 Ê Ú Ù CO 2 êñ Li 4 SiO 4 CO 2 Ý Ó Ù 2 1, 2 Ý 1 p Ý Ú1000?C 5?Cmin u u Ú p Á º DTA Ý 2 p Ý Ú 400?Cmin u u p Ú p Á Á Ý CO 2 Ý 620, 630, 640, 650, 660, 670, 680, 690, 700?C 9 øco 2 Ý Li 4 SiO 4 p ù Ý SEM Ý ÿ ÚÝ Ý Ù Û þe n k Ý Ž Ú 22 24 1 2 Ý Ý 2 3 Li 4 SiO 4 Li 4 SiO 4 ² Ý P CO2 CO 2 k þe nýù d Li 4SiO 4 k Li 4 SiO 4 t PCO2 dt d Li 4SiO 4 k Li 4 SiO 4 t 2 P CO2 dt 2 3 ² 100 vol CO 2 êñý0.1 MPa 1 2 Ú Ù 4 Ú Li 4 SiO 4 Ý a, CO 2 Ý x 4 5 Ù ù ln Li 4SiO 4 0 Li 4 SiO 4 t t k PCO2 ln a x a t k PCO2 4 5 Ž 2 3 Ú 6 Ú 7 1 1 k PCO2t Li 4 SiO 4 t Li 4 SiO 4 0 1 a x 1 a k PCO2 t 6 7 5 7Ó Ó Ó ú þen n ÙÊ Úþe n k Ý Ê p œ 700?C 20 h ÙÊ œ 1000?C 20 h º Å ÙÛ Ú Li 4 SiO 4 p Ž Ý Ò XRD Ýøp 700?C XRD Ý Ðí Li 4 SiO 4 uú Ûp Li 4 SiO 4 25 Ž 1000?C º Å Ú Li 4 SiO 4 p Ó Ž ÚÒÚ Ú Li 4 SiO 4 p q Ý SEM Ý ÿ ÿ Ý A, B 700?C Ù 10 20 mm ÝÓ p 1000?C Ù 60 80 mm ÝÓ p Ú CO 2 3.1 Ú Li 4 SiO 4 p CO 2 Ý Ð Ò pý p Û p Ù pý SEM ÿ Ý 2 a, b p Ó Ù 10 20 mm ÙÊ 60 80 mm Ù Ú Li 4 SiO 4 p CO 2 Ý Li 4 SiO 4 CO 2 Ð Ò 100 vol CO 2 œ700?c Ú pý Li 4 SiO 4 Ý Ú1000?C 5?Cmin u u Ú p Á CO 2 ÁÓ CO 2 Á º DTA Ý Ý p Á 3 u 550?C Ú u Ò Ú 680?C Ú ² u 710?C 36.7 mass z Ý 710?C 1000?C 0 massý s 17 Û Li 4 SiO 4 p Û Ê Ú Á
~ Journal of the Ceramic Society of Japan 115 [ 8 ] 2007 493 Fig. 1. in air. XRD pattern of the Li 4 SiO 4 sample sintered at 700?C for20h Fig. 3. Temperature dependences of weight change and DTA signal of the powdered sample sintered at 700?C in 100 vol CO 2 atmosphere. Fig. 4. Time dependence of weight change of the powdered sample sintered at 700?C at 660, 680 and 700?C in 100 vol CO 2 atmosphere. Fig. 2. SEM photographs of the sintered Li 4 SiO 4 samples and the powdered Li 4 SiO 4 samples for the CO 2 absorption measurement. A Sintered sample 700?C, B sintered sample 1000?C, a powdered sample 700?C, b powdered sample 1000?C. DTA Ð 3 700?C º í 712?C 759?C 2 º í þú Ú Li 4 SiO 4 CO 2 º 710?C º Li 2 CO 3 Ý ÊÚ Li 4 SiO 4 p 700?C p CO 2 Ý Ð Ò 3 e Ú 620, 630, 640, 650, 660, 670, 680, 690, 700?C 9 Ý Ê Ú Li 4 SiO 4 p ÁÝÚÁ CO 2 Á þú 660, 680, 700?CÝ660?C 2 Á Õ CO 2 Á 680, 700?C Á Û ² ÛÚ 5 Á 660?C ÙÛÓ 700?C 5 Á 36.7 mass Ú 1 700?C 5 Ó Ê Ú 700?C Li 4 SiO 4 Ý p CO 2 1Ý Ð Ò 1 ÙÊ 2 Ý 700?C, CO 2 150 mlmin p Á CO 2 Á Ý Û CO 2 ÁÝ 5 1 ÙÊ 7 2 ú Ý Ýþ 2
494 º Ý Li 4 SiO 4 CO 2 Fig. 5. Reaction rate analysis for CO 2 absorption at 700?C ofthe powdered sample sintered at 700?C. The symbols and correspond to the first-order reaction and second-order reaction, respectively. The apparent rate constant k is estimated by the slope in this figure. Fig. 7. Arrhenius plot for the apparent rate constant k and temperature T of the powdered samples sintered at 700?C and 1000?C. Table 1. Activation Energy E a Estimated in Two Kinds of Temperature Regions Fig. 6. Temperature dependence of the apparent reaction rate constant k of the powdered samples sintered at 700?C and 1000?C. ú y 1 ú Ú140 Û 140 ÙÛ ÝÓ Ú 140 Û þú Ó 1 ÝÓ 5 Ú140 Ú700?C, CO 2 150 mlmin p þe n k Ý r Ý 700?C p 1000?C p þe n k Ý 620, 630, 640, 650, 660, 670, 680, 690, 700?C 9 Ý Ýþ 700?C p 1000?C p Ó k Û 670?C u Ý k 700?C z Ó r 1000?C p k 700?C p k š k u 670?C Ù Li 4 SiO 4 þe n k p ÝÓ ý ñ Ý þe n k Ý8ý ñ Ý E a æÿ ì A R œ n T Ýù ln k ln A E a RT 8 6 þe n k Ö n ln k Ý n 1T ú Ý Ú 620 660?C Ú 660 680?C ln k 680 700?C Ê 8 7 E a R 620 660?C ÙÊ680 700?C þe æÿ ì E a Ý Ýù ù 1 Ýþ 700?C ÙÊ1000?C p Ó 680 700?C æÿ ì 620 660?C šð 670?C CO 2 Ž ÝÊ Ú 700?C ÙÊ1000?C p E a Þ Ž Ê 6 ÙÊ 7 þú 670?C þe n k ² u Ù Ê æÿ ì E a Ê s o 17 Li 4 SiO 4 CO 2
~ Journal of the Ceramic Society of Japan 115 [ 8 ] 2007 495 Fig. 8. SEM photographs and imaginary figures of Li 4 SiO 4 particles in CO 2 absorption reaction at those temperatures. A before the reaction, B after the reaction proceeded until 20 at 620?C, C after the reaction proceeded until 60 at 700?C, D after the reaction completed at 700?C. a the case that seems to correspond to A situation, b the case that seems to correspond to B situation, c the case that seems to correspond to C situation, d the case that seems to correspond to D situation. 1 Ù œ Û ø q Li 2 CO 3 Li 2 SiO 3 CO 2 Li 4 SiO 4 Ý SEM Ý ÿ Ý 8 A D Aº Å œ Ú Li 4 SiO 4 p q Ý CO 2 Ý Li 4 SiO 4 ù B 620?CÁ 20 C 700?C Á 60 D 700?CÁ 100 CO 2 Ýp SEM Ú CO 2 Li 4 SiO 4 Ý e Ý Ú Ý a d a Ý Li 4 SiO 4 Li 4 SiO 4 CO 2 Ý b Ù Li 4 SiO 4 ù Li 2 CO 3 Li 2 SiO 3 Ú BLi 4 SiO 4 ù þú ž Ù Li 4 SiO 4 Li 2 CO 3 Li 2 SiO 3 ý CO 2 q Ú e 5 1 ú Ú140 Û ø Ù Li 2 CO 3 Li 2 SiO 3 ÙÛ Li 4 SiO 4 CO 2 Ú ø Ò Ù ý Ê Ú 1 Li 4 SiO 4 ù Ú Li 2 CO 3 Li 2 SiO 3 Ý n CO 2 2 ÚÕ CO 2 Li 2 CO 3 Li 2 SiO 3 Ý n Li 4 SiO 4 Ú ý 1 Ê Li 4 SiO 4 Li n Li 2 CO 3 Li 2 SiO 3 Li n Ó Û Li ² Þ Ó Ê Ú Li n Õ èå ² Ò Li n Ù Å Ú ý 1 Û ý ý 2 ÊLi 2 CO 3 Li 2 SiO 3 ý Li 4 SiO 4 CO 2 Li 4 SiO 4 CO 2 Ò Li 4 SiO 4 CO 2 ² Ú Ï CO 2 n ÛÕ e éý CO 2 Ò CO 2 SiO 2 Ò Ý n Ù Ú 26 28 Ù CO 2 Ï n Ù CO 2 ø Ó Ê Ú e 5 þú Ù Li 4 SiO 4 CO 2 Ú140 Ó 0 Ú 0 Ú Ú Li 2 CO 3 Li 2 SiO 3 Å 680?C CO 2 ² uý 2 ý Ù Ó Ê Ú Ù Å Ú q ý 3 CO 2 Ï n Ê Ó Ó u ÙÛ Li 2 CO 3 Li 2 SiO 3 Li 2 CO 3 ò Ó 8 c Ù Li 2 CO 3 Li 2 SiO 3 Ê Ú C Ýþ 680?C CO 2 pù Li 2 CO 3 ò Ó ÙÛ Li 2 CO 3 e
496 º Ý Li 4 SiO 4 CO 2 Ê Ú CO 2 ² Li 4 SiO 4 CO 2 Ù Ž ø ÓÊ Ú Å ÊÚ œ CO 2 ² Ý Li 4 SiO 4 CO 2 Ýø œ CO 2 ² þe CO 2 Fig. 9. CO 2 flow rate dependence of the apparent reaction rate constant k at 680?C of the powdered sample sintered at 700?C. Ù œ CO 2 Ï Õ Û Li 4 SiO 4 CO 2 ÙÛ ÛÕ Li 4 SiO 4 CO 2 ø Li 2 CO 3 ò 714?C 700?C ò 9 Ù ù Ù CO 2 Ý Ê Ú Li 2 CO 3 l Li 2 O s CO 2 g 9 CO 2 Li 4 SiO 4 Li 2 O Ú CO 2 Ê Li 2 CO 3 Ê Ú í Û ÙÛ CO 2 Li 2 CO 3 Õ Li 2 O Ý Ï Li 4 SiO 4 CO 2 Li 2 CO 3 Li 2 SiO 3 Ú ø Ê Ú 8 d 8 Dp ù ÿ p ÝÊ Ú Ù Å Ú ý 3 Li 4 SiO 4 CO 2 ø ý ý Ù Li 4 SiO 4 Li 2 CO 3 Li 2 SiO 3 Ú ÙÛ Li 4 SiO 4 Li 4 SiO 4 CO 2 þe nõ æÿ ì Ê Ú Li 4 SiO 4 Ý CO 2 ~p Ý h ý 700?C Li 4 SiO 4 Ý p Ý680?C CO 2 Ý50, 100, 150, 200, 300 mlmin CO 2 Ýø Ý p 680?C þe n k CO 2 50 100 mlmin ² u 100 300 mlmin CO 2 50 mlmin 100 mlmin k u Å þú CO 2 Li 4 SiO 4 ÛÝ Ò CO 2 ²Ê 9 Li 4 SiO 4 CO 2 Ð Li 4 SiO 4 ù Ž CO 2 ² Ó Ý Ò Li 4 SiO 4 CO 2 º Ý 620 700?C Ú 9 Li 4 SiO 4 CO 2 ÁÝ 1 ÙÊ 2 Ù Ýø ÙÛ 1 1 ÙÊ 2 Ý Ýø Li 4 SiO 4 CO 2 1 Ê Ú 2 þe n k T ý ñ ú Ú 620 660?C Ž ø 670?C Ž ² Li 4 SiO 4 ù 3 Li 4 SiO 4 Ý CO 2 ~p ø Li 4 SiO 4 Li 2 CO 3 Li 2 SiO 3 Li 2 CO 3 ò Ó { Ýø Û { Ý ó ì Ý Û ƒ ì CO 2 SEM ÿ Ú Ó Ý References 1 T. Kawai, Tansangasukyushugijutsu, NTSInc. 1991 pp. 333. 2 K. Ogawa, J. Japan Powder Association, 241, 8 9 1997. 3 U. Desideri and A. Paolucci, Energy Conversion & Management, 40, 1899 1915 1993. 4 P. Riemer, Energy Conversion & Management, 37 6 8, 665 670 1996. 5 A. Demirbas, Energy Exploration & Exploitation, 22 6, 421 427 2004. 6 J. Wang and E. Anthony, Ind. Eng. Chem. Res., 44, 627 629 2005. 7 T. Filburn, J. J. Helble and R. A. Weiss, Ind. Eng. Chem. Res., 44, 1542 1546 2005. 8 K. Nakagawa and T. Ohashi, J. Electrochem. Soc., 145, 1344 1346 1998. 9 K. Nakagawa and T. Ohashi, J. Electrochemistry, 67, 618 621 1999. 10 K. Nakagawa, Fine Ceramics Report, 17, 256 259 1999. 11 J. Ida and Y. S. Lin, Environ. Sci. Technol., 37, 1999 2004 2003. 12 R. Xiong, J. Ida and Y. S. Lin, Chem. Eng. Sci., 58, 4377 4385 2003. 13 K. Essaki, K. Nakagawa and M. Kato, J. Ceram. Soc. Japan, 109, 829 833 2001. 14 K. Essaki, K. Nakagawa, M. Kato and H. Uemoto, J. Chem. Eng. Jpn, 37 6, 772 777 2004. 15 M. Kato, K. Essaki, K. Nakagawa, Y. Suyama and K. Terasaka, J. Ceram. Soc. Japan, 113, 684 686 2005. 16 K. Nakagawa and T. Ohashi, The Sixth Conference and Exhibition of the European Ceramic Society, Abstract Vol. 1,
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