【作者】 万军；

【导师】 刘猛； 王虎；

【作者基本信息】 东南大学 ， 能源动力（专业学位）， 2024， 硕士

【摘要】 硫化氢（H₂S）作为国内主要的大气污染物之一,对工业生产、人体和环境均存在严重危害。钢铁厂高炉煤气中存在的H₂S作为主要的人为排放源之一,已成为我国钢铁行业清洁生产的重点控制对象。H₂S不仅会导致管路腐蚀、环境污染和毒害人体,它也是SO₂的重要来源之一。如果直接燃烧高炉煤气,H₂S将成为严重的SO₂来源,对下游脱硫工作造成很大困难。近年来铜铈基金属材料以其优秀的低温催化脱除H₂S活性受到科研人员的关注。本文提出以多孔负载材料活性炭为载体,负载铜铈基活性组分以制备新型H₂S吸附剂,实现低温下对高炉煤气中H₂S的精脱除,从而为钢铁行业高炉煤气精脱硫及其他行业脱除H₂S提供借鉴。首先,以H₂S的穿透吸附量、饱和吸附量和比表面积为评价指标,考察了不同制备方法所得吸附剂活性组分的活性变化,明确了制备工艺流程和吸附剂评价方法。对比筛选了活性组分元素比、添加助剂种类、负载材料、活性组分负载量等因素对铜铈基吸附剂吸附性能的影响,使用BET、FTIR、SEM-EDX等方法协同筛选最佳吸附剂。结果表明:溶胶凝胶法制备出来的吸附剂具有更高的活性;铜铈基活性组分中铜铈的摩尔比为4:3时,活性组分对H₂S的穿透吸附量更高,达到15.385mg/g;添加助剂元素Mn、Fe、Cr、Al、Co无法提升H₂S吸附的效果。采用机械球磨法将活性组分负载在木质活性炭载体上,结果发现吸附剂对H₂S的吸附效果明显改善,在活性组分负载量为15%wt时饱和吸附量达到最大为103.58mg/g。其次,对优选吸附剂、原料活性炭及H₂S吸附反应后产物,进行包括SEM-EDX、FT-IR、CO₂-TPD、XRD、TG等表征,结合VASP平台的DFT模拟计算,共同阐述吸附剂中H₂S的吸附原理。SEM-EDX结果表明,优选吸附剂中活性组分Cu元素及Ce元素分布均匀,负载稳定,且材料中含丰富的O原子;FT-IR结果表明优选吸附剂中含有包括OH-和C-O-C在内的多种含氧官能团,有利于H₂S的化学吸附;CO₂-TPD结果显示,吸附剂中的强碱性位点在吸附中起主导地位,负载活性组分后的吸附剂碱性相较于活性炭有所下降;XRD结果说明了吸附剂反应产物中,单质S为主要反应产物。根据以上表征结果,基于VASP构建了优选吸附剂对H₂S的吸附模型,针对H₂S在C原子表面的解离和吸附过程进行了模拟计算,结果表明,活性氧原子在吸附反应中起重要作用,生成的S原子形成稳定的S₈团簇,能垒为1.069e V。最后,基于最优的负载型铜铈基吸附剂CAC-15,探究了H₂S浓度、温度、空速、循环次数等影响因素对CAC-15脱除H₂S活性的影响;分析了高炉煤气中气体组分,包括CO、CO₂、HCl、H₂、O₂和SO₂对吸附剂活性的影响。结果表明:在20-120℃的温度范围内,以60℃为转折点,CAC-15的吸附活性大体上呈先增后降的趋势,以化学吸附为主,穿透吸附量-时间曲线对Bangham模型拟合情况最好;CAC-15对H₂S的吸附效果与H₂S浓度、空速、循环次数呈负相关;O₂和SO₂存在的条件会增强CAC-15的吸附活性,而CO、HCl、H₂和CO₂存在下会降低CAC-15吸附剂活性。在150℃下使用空气吹扫吸附剂,可以使吸附剂实现再生,且再生后的吸附剂饱和硫容可达238.19mg/g。更多还原

【Abstract】 Hydrogen sulfide（H₂S）is one of the main air pollutants in China,which is harmful to industrial production,human body and environment.As one of the main man-made emission sources,H₂S in blast furnace gas（BFG）has become the key control object of clean production in China’s steel industry.H₂S not only causes pipeline corrosion,environmental pollution and poisoning,but also is one of the important sources of SO₂.If blast furnace gas is directly burned,H₂S will become a serious source of SO₂,which is difficult for the downstream desulphurization.In recent years,copper-cerium-based metal materials have attracted much attention for their excellent catalytic removal of H₂S at low temperature.In this paper,a new type of adsorbent for H₂S removal from blast furnace gas at low temperature is proposed,which is supported on porous activated carbon and Cu-Ce-based active components.It can be used for reference for blast furnace gas desulfurization and H₂S removal in other scenes.Firstly,the change of the activity of the active components obtained by different preparation methods is evaluated by the breakthrough adsorption capacity,saturated adsorption capacity and specific surface area.And the preparation process and the evaluation method of the adsorbent are defined.The effects of Cu/Ce ratio of active component,kinds of additives,loading materials and loading mass of active component on the adsorption properties of Cu-Ce-based adsorbents are compared and characterized.BET,FTIR and SEM-EDX are used to characterized the best adsorbent.The results show that the adsorbent prepared by sol-gel method has higher activity,and the breakthrough adsorption capacity for H₂S is higher when the molar ratio of Cu/Ce is 4:3,reaching15.385 mg/g.The addition of auxiliary elements Mn,Fe,Cr,Al,Co can not improve the adsorption of H₂S.The active components are loaded on the wooden activated carbon carrier by mechanical ball milling.The results show that the adsorbent has an excellent adsorption effect on H₂S,the maximum saturated adsorption capacity is 103.58 mg/g when the active component loading was 15wt%.Secondly,the optimized adsorbents,activated carbon and H₂S adsorbents are characterized by SEM-EDX,FT-IR,CO₂-TPD,XRD,TG and DFT simulation on VASP platform.The adsorption principle of H₂S in adsorbent is described.The results of SEM-EDX show that the active components Cu,Ce and O are well distributed and the loading is stable.The results of FT-IR results show that the optimum adsorbent contained various oxygen-containing functional groups including OH-and C-O-C et al,which are beneficial to the chemical adsorption of H₂S.The results of CO₂-TPD the strong alkalinity site in the adsorbent plays a dominant role in the adsorption,and the alkalinity of the adsorbent after loading the active component is lower than that of the activated carbon.XRD results show S is the main reaction product.Based on the above characterization results,the adsorption model of H₂S on the surface of adsorbent is established on VASP,and the adsorption and dissociation process of H₂S on the surface of adsorbent are simulated,the active oxygen atom plays an important role in the adsorption reaction.The S atom formed a stable S₈ cluster with an energy barrier of 1.069 e V.Finally,based on the CAC-15 adsorbent,the effects of H₂S concentration,temperature,space velocity and cycle times on the H₂S removal activity are investigated.The effects of gas components in blast furnace gas,including CO,CO₂,HCl,H₂,O₂ and SO₂ are analyzed.The results show that in the temperature range of 20-120℃,with 60℃as the turning point,the adsorption activity of CAC-15 increased first and then decreased,and the chemical adsorption is the main type.The adsorption capacity-time curve fitted the Bangham model best,and the adsorption effect of CAC-15 on H₂S is negatively correlated with H₂S concentration,space velocity and cycle times.The adsorption activity of CAC-15 is enhanced in the presence of O₂ and SO₂,but decreased in the presence of CO,HCl,H₂and CO₂.The adsorbent can be regenerated by air blowing at 150℃,and the saturated sulfur capacity of the regenerated adsorbent can reach 238.19 mg/g.更多还原