新型低碳排放脱硫剂纳米氢氧化钙的制备、评价及应用研究

Study on preparation,evaluation and application of new low⁃carbon emission nano calcium hydroxide desulfurizer

传统石灰石-石膏湿法烟气脱硫(FGD)过程中,石灰石和二氧化硫反应会生成大量的二氧化碳,不利于中国“碳达峰”与“碳中和”目标的实现。通过利用廉价的起始原料,在聚乙烯亚胺(PEI)存在的情况下,制备了一系列具有纳米尺度的氢氧化钙,并采用SEM、XRD、BET、FT-IR等方法对样品进行了表征,用以替代传统石灰石。在模拟FGD实验装置下,研究了不同比表面积氢氧化钙和电厂用石灰石对二氧化硫吸收速率以及脱硫效率的影响,结果显示:在入口二氧化硫质量浓度为3 500 mg/Nm^(3)时,脱硫效率由石灰石的93.05%提升到了氢氧化钙的99.31%。利用韶关电厂1号机组(600 MW)湿法脱硫装置,研究了制备的新型纳米氢氧化钙脱硫剂的实际脱硫效果。结果发现,传统石灰石在使用高硫煤时,无法达到超低排放的要求,而加入部分氢氧化钙(质量分数为18.0%~22.5%)后,均可实现超低排放(出口二氧化硫质量浓度<35 mg/Nm^(3)),脱硫效率均高于99%,从而提高了FGD系统的高硫煤适应性。

In the traditional limestone⁃gypsum wet flue gas desulfurization(FGD)process,the reaction of limestone and SO_(2) generate a large amount of CO_(2),which is not favorable to the realization of“carbon peaking”and“carbon neutralization”.By using cheap starting materials and in the presence of polyethyleneimine(PEI),a series of nanoscale Ca(OH)_(2) were pre⁃pared to replace traditional limestone for FGD process.The samples were characterized by SEM,XRD,BET,and FT-IR.The effects of Ca(OH)_(2) with different specific surface area and limestone on SO_(2) adsorption rate and desulfurization efficiency were studied in a simulated experimental device.The results showed that when the inlet SO_(2) concentration was 3500 mg/Nm^(3),the desulfurization efficiency was increased from 93.05%of limestone to 99.31%of Ca(OH)_(2).The actual de⁃sulfurization effect of the new nano Ca(OH)_(2) desulfurizer was studied by using the wet desulfurization device of Shaoguan Power Plant Unit 1(600 MW).The results showed that the limestone could not meet the requirements of ultra⁃low emission by using high sulfur coal,but after adding part of Ca(OH)_(2)(18.0%~22.5%),the ultra⁃low emission could be achieved(the outlet SO_(2) concentration was less than 35 mg/Nm^(3)),and the desulfurization efficiency was all higher than 99%,thus improv⁃ing the adaptability of FGD system to high sulfur coal.