零CAL:消除石灰岩分解的二氧化碳排放,以去碳化水泥生产
Adriano Leão1,2, Marie Collin1,2, Swarali Ghodkhande1,2
1Laboratory for the Chemistry of Construction Materials (LC2), Department of Civil and Environmental Engineering, University of California, Los Angeles, California 90095, United States.
概括
一个新的零碳石灰 (ZeroCAL) 工艺使用石灰石在环境条件下生产水合石灰,几乎消除了二氧化碳排放和共同生产气. 这通过使用无碳前体来推进零碳水泥生产.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 环境科学 环境科学
背景情况:
- 传统的从石灰岩 (酸盐,CaCO3) 制成石灰的生产涉及高温 (∼800°C),导致显著的二氧化碳排放 (∼1二氧化碳/CaO) 和能源消耗 (∼1.4MWh/CaO).
- 水泥行业是全球二氧化碳排放的主要贡献者,需要开发低碳或零碳生产途径.
- 化石灰 (波特兰,Ca(OH) 2) 是用于水泥和石灰生产的零碳前体.
研究的目的:
- 在环境条件下从石灰岩 (CaCO3) 制造水合石灰 (Ca(OH) 2 的新途径.
- 显著减少或几乎消除与石灰生产相关的工艺二氧化碳排放.
- 开发一种可持续的方法来生产用于水泥制造的零碳前体.
主要方法:
- 零碳石灰 (ZeroCAL) 工艺包括三个阶段:溶解,分离/回收和电解.
- 步骤1:在基本条件下 (pH > 9) 使用乙烯基二胺四酸 (EDTA) 促进化剂溶解CaCO3和Ca2+复合.
- 步骤2:纳米过 (NF) 来从二碳酸盐中分离Ca-EDTA,然后进行酸性促进解复合,以恢复Ca和化剂再生.
- 步骤3:使用电解生成的性,从加丰富的流中迅速沉Ca(OH) 2,并共同生产H2和O2.
主要成果:
- 在ZeroCAL过程中,几乎完全消除了工艺二氧化碳排放,其排放量仅为前体CaCO3的1.5mol.% (9公斤二氧化碳/Ca(OH) 2).
- 生产1Ca(OH) 2需要大约1.35CaCO3,1.09水,0.79NaCl,以及约2MWh的电能.
- 该过程可以适应海水,产生诸如盐酸 (HCl) 和碳酸 (NaHCO3) 等副产品.
- 对于过程强化存在显著的机会.
结论:
- 在生产零碳水泥前体的过程中,ZeroCAL工艺通过在环境条件下利用石灰岩和最小的二氧化碳足迹,在生产零碳水泥前体方面取得了重大进展.
- 这种方法与工业运营的电气化相一致,可以利用现有的水泥厂基础设施.
- 产生的度通过Ca (OH) 2碳化促进了成本效益高且可扩展的CO2矿化,进一步促进了脱碳的努力.
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