煤化工VOCs吸附处理技术研究进展及展望

煤化工产生的挥发性有机物VOCs气体成分复杂且有毒有害,为了避免煤化工VOCs及其光化学产物对环境和人体健康产生危害,通过分析VOCs气体的排放控制及处理技术,指出煤化工VOCs吸附技术是可以控制VOCs排放、回收吸附材料及回收有价值VOCs的经济、有效的VOCs去除技术。通过分析煤化工VOCs吸附的物理与化学过程及其影响因素、解吸附的过程与方法,对常用的吸附材料的改性研究及发展进行了综述,通过对比不同吸附装置的结构、吸附特点及优缺点,将煤化工VOCs吸附技术与其他技术的组合实际工程应用进行了比较分析,并展望了吸附技术的未来研究方向。影响吸附过程的因素有吸附材料的结构特性、表面化学性质及亲疏性热稳定性等物理化学特性,被吸附物质VOCs的分子特性、吸附剂与吸附质之间的相互作用、不同吸附质之间的相互竞争、吸附环境等;物理吸附过程包括外表面传值吸附阶段、内部表面扩散阶段、不同孔径孔隙之间的平衡阶段;吸附剂微孔提供了主要的吸附位点,而中孔及大孔则增强了VOCs的扩散通道。吸附材料经过适当改性具有优异的VOCs吸附能力;采用H2O2浸渍法改性可提高活性炭纤维表面含氧官能团含量,吸附能力增强;采用具有强氧化性的浓硫酸等改性使活性炭表面具有含氧基团,增强活性炭对氮的吸附能力;用碱性氢氧化物改性的活性炭增加了比表面积,用酸改性可增加表面官能团,用KOH活化可获得更好的孔隙率。需要针对VOCs种类、浓度、流量及排放量等特性选择适合的吸附装置。吸附技术是控制煤化工VOCs排放和回收有价值VOCs再利用的经济、有效且具有前景的技术,可与其他技术组合处理VOCs气体,进行有利用价值VOCs气体的回收利用,实现VOCs废气排放达标。吸附技术未来研究重点是吸附材料改性(或定向改性)、新型改性方法及新型吸附材料研究、高效低成本吸附装置研究、多组分吸附质同时脱除研究,并提出了多组分VOCs吸附及解吸附的复合吸附装置研究思路。

Research progress and prospect of coal chemical VOCs adsorption treatment technology

Volatile organic compounds(VOCs)produced in coal chemical processes are complex,toxic and harmful.In order to avoid the harm of VOCs and its photochemical in coal chemical industry to the environment and human health,and based on the analysis of VOCs emission control and treatment technology,it is pointed out that the adsorption technology of VOCs is an economic and effective removal technology that can control VOCs emission,recover adsorption materials and valuable VOCs.Based on the analysis of the physical and chemical process of VOCs adsorption and its influencing factors,as well as the process and method of desorption,the modification research and development of commonly used adsorption materials were summarized and analyzed.By comparing the structure,adsorption characteristics and advantages and disadvantages of different adsorption devices,the combination of VOCs adsorption technology and other technologies in practical engineering application were compared and analyzed.Finally,the future research direction of adsorption technology was prospected.The factors that affect the adsorption process include the physical and chemical properties of adsorption materials,such as structural properties,surface chemical properties and thermal stability,the molecular properties of VOCs,the interaction between adsorbents and adsorbents,the competition between different adsorbents,and the adsorption environment,etc.The physical adsorption process includes:external surface value transfer adsorption stage,internal surface diffusion stage,equilibrium stage between pores with different pore sizes;adsorbent micropores provide the main adsorption sites,while adsorbent mesopores and macropores enhance the diffusion channels of VOCs.The adsorption material has excellent VOCs adsorption capacity after proper modification;the content of oxygen-containing functional groups on the surface of activated carbon fiber can be increased and the adsorption capacity can be enhanced by H 2 O 2 impregnation and modification.The surface of the activated carbon is modified by concentrated sulfuric acid with strong oxidation to enhance the adsorption capacity of the activated carbon for nitrogen.The surface area of activated carbon modified by alkaline hydroxide is increased,the surface functional groups are increased by acid modification,and the porosity is improved by KOH activation.It is necessary to select suitable adsorption devices according to the characteristics of VOCs,such as types,concentrations,flow rates and emissions.Adsorption technology is an economic,effective and promising technology to control the emission of VOCs from coal chemical industry and recycle valuable VOCs.It can be combined with other technologies to treat VOCs and recycle valuable VOCs,so as to achieve VOCs emission standard.The future research of adsorption technology can focus on the modification of adsorption materials(or directional modification),new modification methods and new adsorption materials,high-efficiency and low-cost adsorption device,simultaneous removal of multi-component adsorbate,and put forward the research idea of composite adsorption device for multi-component VOCs adsorption and desorption.