Korean Chem Eng Res, Vol 44, No 5, October, 2006, pp 535-539 CO 2 o g zo qkç ÇoiÇl*Çmm**Çm **Ç } n, * 139-846 ne o o 447-1 ** lvlo lrl 305-343 re o q 71-2 (2005 9o 20p r, 2006 4o 19p }ˆ) Effects of Alkaline Additives on CO 2 Removal by Joo-Won Park, Dong-Hwan Kang, Young-Do Jo, Kyung-Seun Yoo*, Jae-Goo Lee**, Jae-Ho Kim** and Choon Han Department of Chemical Eng, *Department of Environmental Eng, Kwangwoon University, 447-1, Wolgae-dong, Nowon-gu, Seoul 139-846, Korea **Thermal Process Research Center, Korea Institute of Energy Research, 71-2, Jang-dong, Yuseong-gu, Daejeon 305-343, Korea (Received 20 September 2005, accepted 19 April 2006) k l d pp d rpl m k m ~rp l t pn l p l m ~ˆp ZrO 2 m l rs m, p p o l K 2, NaCl, LiCl p k mp ~ l} l n m ~ k ml p p K 2 >NaCl>LiCl>Na 2 p ˆ p p partial meltingl p p p ep SEM npˆp sq p pl, XRD ~ k mp r plv k p pl NaClp n n p l 60 rp oep mp ~ n 700~750 o Cl rpl p p ov k k p p ˆv kk h Abstract Effects of alkaline additives on the CO 2 removal reaction have been investigated by a thermogravimetric analyzer was synthesized by soild reaction of ZrO 2 with and then alkali chemicals were added to the synthesized and then heat treatment was carried out Addition of alkali chemicals enhanced the reactivity of with the following order; K 2 >NaCl>LiCl>Na 2, which were resulted from the formation of partially melted SEM photographs showed the presence of melted state and the XRD results showed that the chemical states of added salts were not changed Addition of NaCl caused the induction time of about 60 min at the initial reaction stage and the addition of Na 2 inhibited the decomposition of at about 700~750 o C Key words:, Alkali Salts, Partially Melting, CO 2 Removal, Diffusion 1 q p lrp p l nn p lv pm l p kp l np p mm rl v p t džp sp, qm p lvop n p l p }p rp mm rl p m p l p p l n l rl n ln pmem p n o mmvp To whom correspondence should be addressed E-mail: chan@kwackr p kv }p p pp p vp k m r p o rp }p p n pp l d rp pn d rsp n kp l mp pl p l v l[1-4] v, d rp pn o dp d rrm CO 2 p rp rl lk s rr t m, kl k r p n p pn l lp, d rp n m, kl nr l CO 2 p le m, k l lk rrp o mmll CO 2 535
536 toë ËsmËoËpqËq Ë p rrl t CaO, MgO p ˆmp np p γ-al 2 O 3 l v p pn p lm o p pn rl v l[5] Nakagawam Ohashi[6]p ll lithium zirconate( ) 450 o Cl 550 o Cp m ol CO 2 rpp vtp 20Í r r pr l p rp m, Xiong Ida [7, 8]p l K 2 ~r n l CO 2 p rp 234Í v m p pm o 400~700 o C vl m p m p p ~rl p r l l l r v l mp ~rp sl CO 2 r p l erp, ll ZrO 2 m n l lt pn CO 2 r e p m r p o k k ~r n p m, XRDm SEMp pn l CO 2 rp p m k mp ~ p m pp m 2 m ll ZrO 2 m v l n m ZrO 2 m p 1:1 l kšp lˆmp ~ l l 1,000 o C, 24e l rs m ~ r K 2, NaCl, LiClp n m r p rp rs m p n,zro 2 m ~r p kp 11:10:02 m p m p ~ r n n ~rp rp l p rs l p m (LiCl, NaCl)p ~ mp, LiClp n 600 o Cl NaClp n 800 o Cl rp e rs pure modified pq lt(tga51, TA Instrument) pn l pr 50 mgp ql } n 40 o Cj de pm o 400~800 o C l mˆ CO 2 d 24e k tpeˆ CO 2 r e p e m p r e XRDm SEMp pn l e p p m ~r e p K 2, NaCl, LiClp l ~ l modified op e p l r CO 2 p kp m 3 y n K 2 ~r n l r e p ee m Fig 1 do 150 ml/minl m K 2 ~r n K 2 / p pml p rp r pp el e p Fig 1l p p p n pm 400 Cl o CO 2 l pp n kp pm 500~600 Cl r p pp o p pm 700 Cl p pm p l o p p l CO 2 p rpp v v m l p m p l K 2 ~r o44 o5 2006 10k Fig 1 Conversion of absorbents for various reaction temperatures n CO 2 l pp v ˆ pp pp n v m s r pl CO 2 r p ˆ p K 2 ~r n n p pq l pm vl p l pp np l CO 2 p v p [7, 8] p sp l pq lp partial meltingp plp K 2 / p [8]l p v v K 2 ~ n ZrO 2 m Op nkp p pml kp r CO 2 e km p pp ppˆ[9] (s) + 01 (l)+02k 2 (l)+co 2 (g) 032 (l) + 078 (s) + 02 K 2 (l) + ZrO 2 (s) (1), K 2 ~ n pe (1) p kp sq l ko pp v K 2 ~v kp p n, pv e kp v k pp v l p l p p pe (2)l p m p s r pl pl p pv kkk l k pp n p s r pp ˆ p p kl CO 2 p rp l s r pp dp o p (s) + CO 2 (g) 032 (l) + 078 (s) + ZrO 2 (s) (2) pm 500 o Cl ~r s e p p ~r s rl m p e m Fig 2l e m m p ~r n n pp o ep sq p rn r~rp pp s r pl pl n ltl p o ep sq prp npl lrep nl p K 2 m Na 2 ~r n
CO 2 re k ~r 537 Fig 2 Conversion of absorbents as a function of reaction time at 500 o C Fig 3 CO 2 removal by alkaline additives for various reaction temperatures n p pp lp s r pl pl m ~r n n m sr pl p l p p po m ~p n ˆm q qk qp v CO 2 p p p p, m p ~r n n m q~p prp ˆm l m p n np p p r p ml p m p m p n vp np m 600 o Cm 800 o C k ml pp p ln p m ml n n ep r p m, ml ~r p Fig 3p pm ~rp sl pr r p e p lm p pm 400~600 o C ol NaClp rn ~rp n pm v l pr r v m p K 2 m LiClp ~ pr q rp mp 600 o Clp K 2 m LiClp rp 151 g CO 2/g sorbent, 149 g CO 2/g sorbent ˆ pm 600 o Clp NaClp n CO 2 p rp ˆ p p NaClp rp 804 o C p ml p p p p n pm 400~600 o Cl m p o CO 2 rp ˆ p Na 2 700 o C pp ml ~r p ˆ Na 2 p p pp o l m CO 2 r e p nl pl Na 2 pn pm p e Fig 4l e m l pp k e K 2 m p lt p K 2 ~ prp n pm 700 o Cl carbonatep l p pp ˆ CO 2 rpp p v v mp Na 2 ~ r n n CO 2 rpp pm 750 o Cv n v v kpp p m p ~ Fig 4 Conversion of absorbent(na 2 / ) for various reaction temperatures r s rl pf CO 2 p rm rp rl ppp lt k ~r ~ p s o l XRD nl Fig 5 pure modified p XRD e p l e m p p n 2theta value 20,26,43l t peak p sp p pp p pl ~r tp Na 2, K 2, LiCl, NaCl p peak ˆ p rsl pl p v kpp p pl p ˆ p r p kk o l SEM p ee m Fig 6p m k mp ~ p SEM vp r p p n rp ~ ˆ ~r tp n rp Korean Chem Eng Res, Vol 44, No 5, October, 2006
538 toë ËsmËoËpqËq Ë Fig 5 XRD patterns of and alkaline salts added ˆp agglomerate ˆ ov p ˆ ˆmp ~r n n pqp n qkv ˆp agglomerate m m p ~ n p qp rp v m pq p v ˆp p m ˆmp ~r n np r p v SEM vm p qp pqp agglomerationl p l p p r p kk o l ET p ee m, Table 1l ˆl Table 1l pm p ~r tp l rs p n r v p k p p ~r tpl p l rp pq p p ol p, p p opp p p p Fig 7p pm 500 o Cl m k mp ~ p p r, p SEM vp e p p p vl p n p rs l p p rsp p pl Fig 8p C, Dm p ~r n n p pr p e npl ppp Žk pp pq pl sp p k pl p k lm p ~r tpl p l npp p ml l p p p CO 2 rpp p olp p lt p Fig 6 Scanning electron micrographs of and alkaline salts added prior to reaction Fig 7 Scanning electron micrographs of fresh and reacted samples at 500 o C in 100 CO 2 Table 1 ET of fresh and reacted samples at 500 o C in 100 CO 2 (500 o C CO 2 ) (500 o C CO 2 ) Surface area (m 2 /g) 11973 21161 39844 16653 Pore volume (cm 3 /g) 0001159 0002310 0004275 0001739 o44 o5 2006 10k
4 ll p pn l d l d CO 2 r q mp e p l p p p m (1) k mp ~ rp v m, ~rl p pq lp partial meltingl p CO 2 p v p (2) k mp ~ p pp lp e l n 4sp k ~rp p K 2 >LiCl>Na 2 >NaClp p sl (3) prp SEM/XRD l kp sq p m ~r n k mp r p lpp p m (4) Na 2 ~r n n 700 o C pl p ov kkp NaClp n n p l oep m p p qoq nlp 21C Žll l m 2006 n l vo l lld y 1 Jing, T, Niu, Y and Zhong,, Synthesis of Higher Alcohols from Syngas over Zn Cr K Catalyst in Supercritical Fluids, Fuel Processing Technol, 73, 175-183(2001) 2 Rostrup-Nielsen, J R, Syngas in Perspective, Catal Today, 71, CO 2 re k ~r 539 243-247(2002) 3 Yan, Q G, Weng, W Z, Wan, H L, Toghiani, H, Toghiani, R K and Jr Pittman, C U, Activation of Methane to Syngas over a Ni/TiO 2 Catalyst, Appl Catal A: Gen, 239, 43-58(2003) 4 Kondo, M, Gasification of Waste Plastics and Fuel Cells Power Generation, Journal of the Japan Institute of Energy, 32(2), 76-78 (2003) 5 Effendi, A,GHellgardt, K, Zhang, Z-G and Yoshida, T, Characterisation of Carbon Deposits on Ni/SiO 2 in the Reforming of CH 4 CO 2 Using Fixed- and Fluidised-bed Reactors, Catalysis Communications, 4, 203-207(2003) 6 Nakagawa, K and Ohashi, T, High Temperature CO 2 Absorption Using Lithium Zirconate Powder, Proceedings-Electrochemical Society, 45, 370(1998) 7 Xiong, R, Ida, J and Lin, Y S, Kinetics of Carbon Dioxide Sorption on Potassium-doped Lithium Zirconate, Chemical Engineering Science, 58, 4377-4385(2003) 8 Ida, J, Xiong, R and Lin, Y S, Synthesis and CO 2 Sorption Properties of Pure and Modified Lithium Zirconate, Separation and Purification Technology, 36, 41-51(2004) 9 Ida, J and Lin, Y S, Mechanism of High-temperature CO 2 Sorption on Lithium Zirconate, Environ Sci Technol, 37(9), 1999-2004 (2003) 10 Pfeiffer, H and Knowles, K M, Reaction Mechanisms and Kinetics of the Synthesis and Decomposition of Lithium Metazirconate Through Solid-state Reaction, Journal of the European Ceramic Society, 24, 2433-2443(2004) 11 Pineda, M, Palacios, J M, Alonso, L, García, E and Moliner, R, Performance of Zinc Oxide ased Sorbents for Hot Coal Gas Desulfurization in Multicycle Tests in a Fixed-bed Reactor, Fuel, 79, 885(2001) 12 Tatsuro, H, Hiroaki, H, Takehisa, F, Yukio, K and Toshiaki, M, Effect of Added asic Metal Oxides on CO 2 Adsorption on Alumina at Elevated Temperatures, Appl Cata A: Gen, 167, 195(1998) Korean Chem Eng Res, Vol 44, No 5, October, 2006