습식탄산화 반응을 활용한 시멘트계 재료의 CO2 고정화에 관한 실험적 연구

Abstract

지구 온난화로 지난 100년 간 지구의 평균 온도가 0.74℃ 상승하였고 우리나라는 세계 평균의 2배에 이르는 1.5℃가 상승하였다. 특히 국내 이산화탄소 배출량은 2009년에 출간한 IEA(International Energy Agency) 보고서 'KEY WORLD ENERGY STATISTICS'에 의하면(2007년 이산화탄소 배출량 기준) 4억8,871만 톤으로 조사 대상국가 중 9위이며, 그 증가율은 1990년에서 2007년까지 113% 증가하여 OECD국가 중 2위이고, 1인당 이산화탄소 배출량 증가율은 88.6%로 OECD국가 중 1위로 이는 국내 이산화탄소 배출의 심각성을 잘 보여주는 지표이다.1) 기후변화를 방지하기 위하여 2005년 교토의정서가 공식 발표되어 범세계적으로 이산화탄소 규제가 강화되었고, 현재 미국, 일본, EU 등 38개국(Annex B)이 2008～2012년 사이 CO2 전체 배출량을 1990년 수준 대비 평균 5.2%로 하는 감축목표를 수립하고, 배출권 거래제(Emission Trading, ET), 공동 이행(Joint Implementation, JI), 청정개발체제(Clean Development Mechanism, CDM) 등 3가지의 국제협력수단을 허용하여, 전 산업단계에 있어 노력하고 있다.2) 우리나라도 2013년부터 의무감축대상국에 해당되어 2009년 정부 발표에 의하면 3,000만 톤(전체 배출량의 약 4%)의 이산화탄소를 저감할 계획이다. 이를 대비하기 위하여 현재 이산화탄소 포집 및 저장 연구(CCS, Carbon Capture & Storage)가 활발히 진행 중에 있으나 포집된 이산화탄소를 단기간에 저장 또는 처분하는 대안 마련이 시급하다. 오늘날 우리나라의 시멘트 산업은 연간 5,500여만 톤을 생산하는 세계 굴지의 시멘트 대국으로 성장하였고(통계청), 철강, 석유화학산업 등과 함께 경제 및 산업발전을 이룩하는 원동력이었으며, 국가의 중추 기간산업으로 건설 산업에서 비중이 매우 큰 사업이다. 그러나 시멘트 산업은 막대한 양의 석회석 채굴에 따른 산림자원의 파괴와 생산과정에서 1,450℃ 소성에 따른 에너지 고비용 문제, 시멘트 제조 공정에서 발생되는 다량의 CO2 등으로 인해 반환경산업으로 인식되고 있다.2) 본 연구는 시멘트계 재료의 Ca 성분을 이용하여 이산화탄소를 주입 및 반응시키는 화학 실험을 바탕으로 CO2 저감 대책과 반응생성물인 CaCO3의 생성으로 인한 고부가가치 창출에 대한 기초 자료를 제공하는 데에 그 목적이 있다. 이를 위하여 본 연구에서는 CO2를 안정적으로 고정화 할 수 있는 Ca(OH)2 성분을 이용한 이산화탄소 흡수 매커니즘을 검토하고 시멘트 수용액을 이용한 CO2고정화 실험 및 습식탄산화 반응을 통해 생성되는 CaCO3의 입도와 성분을 확인하여 고부가가치산업을 창출할 수 있도록 검토하였다.| The mean temperature of earth has rised to 0.74℃ because of global warming during a decade and that of Korea has rised to 1.5℃ which amount to twice more than the global average. Especially, domestic CO2 emission amount is 488.71 billion ton based on CO2 emission amount in 2007, ranked ninth in investigation-targeted countries according to 'KEY WORLD ENERGY STATISTICS' established by IEA(International Energy Agency) in 2009 and the increasing rate has rised up to 113% from 1990 to 2007, ranked second in OECD nations. Also, the increasing rate of CO2 emission amount per person is 88.6%, ranked first in OECD nations. This is the indicator that shows the seriousness of domestic CO2 emission. To prevent climate change, Kyoto Protocol was announced formally in 2005 and CO2 regulations have been toughened. Thus, currently, 38 nations(Annex B) such as America, Japan. EU and so on have established the reduction goal which makes total amount of emission become 5.2% on average compared to 1990. Also, they have tried hard among overall industry phases, accepting 3 international cooperation methods, Emission Trading(ET), Joint Implementation(JI), Clean Development Mechanism(CDM). Korea has been also included in reduce the nation’s greenhouse gas emissions since 2013, so according to the announcement of Korea government in 2009, they have the plan to decrease 30 billion tons of CO2(4% of total emission amount). To prepare for this, the study for Carbon Capture & Storage has been going on actively, but the alternative way of store and disposing of captured CO2 in short period of time is needed urgently. Nowadays, cement industry of Korea has grown one of the world's best-known cement nation which produces 55 billion tons a year. It is a driving force which accomplished economy and industry development with steel and petrochemistry industry. Also, it is the industry which has a great importance in construction industry as a pivotal basic industry of the nation. However, cement industry has been recognized as a anti-environment industry by destruction of forest resources caused by a large amount of limestone excavating, energy high expenditure problem occured by 1450℃ firing in production process and massive CO2 emission made by cement production process. This study has the purpose in providing not only CO2 reduction strategies based on the chemical experiment which inject and react to CO2 using Ca component of material affiliated with cement but also basic data about creating high value made by producing reaction product CaCO3. For these purposes, in this study, CO2 absorbtion mechanism using Ca(OH)2 which is able to make fixation stable was studied, grain-size and components of CaCO3 which is produced by CO2 fixation experiment using cement aqueous solution and the wet carbonation reaction was checked.; The mean temperature of earth has rised to 0.74℃ because of global warming during a decade and that of Korea has rised to 1.5℃ which amount to twice more than the global average. Especially, domestic CO2 emission amount is 488.71 billion ton based on CO2 emission amount in 2007, ranked ninth in investigation-targeted countries according to 'KEY WORLD ENERGY STATISTICS' established by IEA(International Energy Agency) in 2009 and the increasing rate has rised up to 113% from 1990 to 2007, ranked second in OECD nations. Also, the increasing rate of CO2 emission amount per person is 88.6%, ranked first in OECD nations. This is the indicator that shows the seriousness of domestic CO2 emission. To prevent climate change, Kyoto Protocol was announced formally in 2005 and CO2 regulations have been toughened. Thus, currently, 38 nations(Annex B) such as America, Japan. EU and so on have established the reduction goal which makes total amount of emission become 5.2% on average compared to 1990. Also, they have tried hard among overall industry phases, accepting 3 international cooperation methods, Emission Trading(ET), Joint Implementation(JI), Clean Development Mechanism(CDM). Korea has been also included in reduce the nation’s greenhouse gas emissions since 2013, so according to the announcement of Korea government in 2009, they have the plan to decrease 30 billion tons of CO2(4% of total emission amount). To prepare for this, the study for Carbon Capture & Storage has been going on actively, but the alternative way of store and disposing of captured CO2 in short period of time is needed urgently. Nowadays, cement industry of Korea has grown one of the world's best-known cement nation which produces 55 billion tons a year. It is a driving force which accomplished economy and industry development with steel and petrochemistry industry. Also, it is the industry which has a great importance in construction industry as a pivotal basic industry of the nation. However, cement industry has been recognized as a anti-environment industry by destruction of forest resources caused by a large amount of limestone excavating, energy high expenditure problem occured by 1450℃ firing in production process and massive CO2 emission made by cement production process. This study has the purpose in providing not only CO2 reduction strategies based on the chemical experiment which inject and react to CO2 using Ca component of material affiliated with cement but also basic data about creating high value made by producing reaction product CaCO3. For these purposes, in this study, CO2 absorbtion mechanism using Ca(OH)2 which is able to make fixation stable was studied, grain-size and components of CaCO3 which is produced by CO2 fixation experiment using cement aqueous solution and the wet carbonation reaction was checked.