他旭鹏,张源,万志军,等. 超临界CO2发泡混凝土的制备及固碳性能研究[J]. 煤炭学报,2024,49(10):4222−4234. DOI: 10.13225/j.cnki.jccs.LC24.0320
引用本文: 他旭鹏,张源,万志军,等. 超临界CO2发泡混凝土的制备及固碳性能研究[J]. 煤炭学报,2024,49(10):4222−4234. DOI: 10.13225/j.cnki.jccs.LC24.0320
TA Xupeng,ZHANG Yuan,WAN Zhijun,et al. Preparation and carbon sequestration properties of supercritical CO2 foamed concrete[J]. Journal of China Coal Society,2024,49(10):4222−4234. DOI: 10.13225/j.cnki.jccs.LC24.0320
Citation: TA Xupeng,ZHANG Yuan,WAN Zhijun,et al. Preparation and carbon sequestration properties of supercritical CO2 foamed concrete[J]. Journal of China Coal Society,2024,49(10):4222−4234. DOI: 10.13225/j.cnki.jccs.LC24.0320

超临界CO2发泡混凝土的制备及固碳性能研究

Preparation and carbon sequestration properties of supercritical CO2 foamed concrete

  • 摘要: 实现绿色低碳是推动煤炭产业高质量发展的必然选择。为了实现这一目标,提出一种采用超临界CO2相变发泡技术制备泡沫混凝土的方法,制备了一种兼具高孔隙结构和固碳能力的硅酸盐水泥基超临界CO2发泡混凝土。研究了超临界CO2对材料干密度、孔隙结构和固碳能力的影响规律及作用机制。结果表明:超临界CO2相变发泡混凝土制备过程是考虑硅酸盐水泥特性及其与CO2矿化反应特性的温压动态协调过程。利用超临界CO2相变发泡技术制备硅酸盐水泥基泡沫混凝土机理可分为CO2−水泥浆液共存、CO2−水泥浆液共溶、超临界CO2−水泥浆液共溶、卸压发泡4个阶段。提高实验压力可以增大超临界CO2−混凝土体系中的CO2质量分数,降低超临界CO2发泡混凝土的干密度,超临界CO2发泡混凝土干密度为787.14~993.52 kg/m3,变化范围为8.28%~19.20%。超临界CO2发泡混凝土孔隙率的发展受CO2在超临界CO2−混凝土体系中的扩散—溶解—反应行为影响,其孔隙率为47.87%~89.79%,增大实验压力,优化保压时间是制备高孔隙率超临界CO2发泡混凝土的发展方向。超临界CO2发泡混凝土泡孔总体呈均匀、规则、独立的圆孔,其孔径大致相同,约为0.2 mm。增大实验压力可以促进CO2矿化反应程度,有效优化泡孔结构及分布密度。每吨超临界CO2发泡混凝土骨架固碳率为6.32%~10.36%,泡孔储碳量为0.98~2.27 kg,具有明显的固碳潜力,但其制备工艺及参数仍需进一步改善。超临界CO2发泡混凝土有望发展为一种近零碳矿用功能性材料,对实现煤电一体化基地源头减碳意义重大。

     

    Abstract: Realizing green and low-carbon development will be a new requirement facing the coal industry. In order to address this problem, this paper proposed a method of preparing foam concrete using a supercritical CO2 phase change foaming technology, and a Portland cement-based supercritical CO2 foamed concrete with both high pore structure and carbon sequestration capacity was prepared. The effects of supercritical CO2 on the dry density, pore structure and carbon sequestration capacity of the material and its mechanism were investigated. The experimental results revealed that the supercritical CO2 phase change foamed concrete preparation process is a temperature-pressure dynamic coordination process considering Portland cement properties and its reaction properties with CO2 mineralization. The mechanism of Portland cement-based foamed concrete prepared by the supercritical CO2 phase change foaming technology may be divided into four stages: CO2-cement slurry coexistence, CO2-cement slurry co-solution, supercritical CO2-cement slurry co-solution, and unpressurized foaming. Increasing the experimental pressure can increase the CO2 concentration in the supercritical CO2-concrete system and reduce the dry density of supercritical CO2-foamed concrete, which varies from 787.14 to 993.52 kg/m3 with a range of 8.28% to 19.20%. The development of porosity of supercritical CO2 foamed concrete was affected by the diffusion-dissolution behavior of CO2 in the supercritical CO2-concrete system, and its porosity was 47.87%−89.79%. Increasing the experimental pressure and optimizing the holding time are the development direction for preparing supercritical CO2 foamed concrete with high porosity. The supercritical CO2 foamed concrete has uniform, regular and independent circular pores with approximately the same pore diameter of 0.2 mm. Increasing the experimental pressure can promote the degree of CO2 mineralization reaction and effectively optimize the structure and distribution density of the pores. Each tonne of supercritical CO2 foamed concrete has a carbon sequestration capacity of 6.32%−10.36% in the skeleton and 0.98−2.27 kg in the pore, which has obvious carbon sequestration potential, but the preparation process and parameters still need to be further improved. The results show that the supercritical CO2 foamed concrete is expected to be developed into a functional material with near-zero-carbon for mining, which is of great significance for realizing the carbon reduction at the source of coal power integration base.

     

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