高效铁基固-液复合脱硫浆液的设计制备及其脱硫作用机制研究

The efficient removal of hydrogen sulfide (H2S) is an important research topic for the clean utilization of resources and environmental protection. The key is to develop efficient desulfurizer and advanced desulphurization technology. The traditional iron-based solid desulfurizers generally suffer from the low gas-solid mass transfer efficiency and poor desulfurization accuracy. As for the iron complex solution, their sulfur capacity is still unsatisfactory. Moreover, their organic ligands are easily to be degraded. To solve these problems, the major objective of this work is to prepare high-performance solid-liquid composite desulphurization slurry by integration with iron oxide nanodesulfurizer and iron complex solution. By controlling the structure and composition of the iron oxide and iron complex solution, the surface interaction between the iron oxide and iron(III) would be enhanced, allowing the two component to work synergistically during the processes of desulfurization and regeneration, which may achieve the efficient removal of H2S and rapid regeneration of desulfurizer. In addition, through the detail characterizations, the synergistic effect of the iron oxide and iron complex solution will be investigated and clarified. Furthermore, the theory and method to design the iron-based solid-liquid composite desulphurization slurry will be also proposed and established. The achieved findings will provide a theoretical foundation and technical source for the development of high sulfur capacity, high accuracy and regenerative iron-based solid-liquid composite slurry and new advanced desulfurization technology.

高效脱除硫化氢（H2S）是资源清洁利用和环境保护的重要研究课题，其关键是开发高性能的脱硫剂及高效的脱硫技术。本项目针对传统固体铁基脱硫剂气-固传质效率低、脱硫精度差和络合铁溶液脱硫剂硫容低、有机配体易降解的难题，提出将高硫容纳米铁氧化合物和络合铁脱硫溶液有机结合，调制出高效的固-液复合脱硫浆液，通过调控纳米铁氧化合物及络合铁溶液的结构和组成，强化络合铁离子与纳米铁氧化合物颗粒表面的配位作用，使二者在脱硫和再生过程中协同耦合，实现H2S高效脱除和脱硫剂快速再生的双重目标。同时，结合相关表征，阐明复合浆液脱硫和再生过程中纳米铁氧化合物与络合铁溶液的协同耦合作用机制，建立铁基固-液复合脱硫浆液的设计原理和方法，为发展新型高硫容、高精度和易再生的铁基固-液复合脱硫浆液和新型高效脱硫技术奠定基础。

硫化氢广泛存在于各种化石燃料和产品加工过程，本身剧毒、腐蚀性强，如不将其脱除将会导致腐蚀设备、催化剂中毒失活，若直接排放，则会带来严重空气污染和酸雨等灾害，因此高效硫化氢脱除剂和工艺，一直都是研究的热点。铁基脱硫剂因其成本低、硫容高等优势被广泛使用和研究。但其不同形态的铁基脱硫剂都还存在各种不足，为更高效的利用铁基脱硫剂，必须对其进行深入研究，开发新的脱硫剂种和工艺。为此，本项目从四个方面进行了研究：首先，开展了羟基氧化铁的制备、脱硫活性位点和作用机制研究，确立了羟基氧化铁表面氧空位、表面羟基和比表面积三者对其脱硫性能的影响规律。成功开发了适用于高空速和高穿透硫容的羟基氧化铁固体铁基脱硫剂，空速2000h-1，硫化氢浓度40000ppm反应条件下，该脱硫剂硫容达到理论饱和硫容55%左右，远高于目前商业脱硫剂20~30%左右的穿透硫容。其次，开展了系列铁改性复合氧化物硫化氢选择氧化催化剂的研究，揭示了表面氧空位和变价金属系统参与硫化氢催化氧化的反应机制，成功开发了系列硫化氢转化率高和硫磺选择性好的催化剂；此外，成功的开发了系列固体羟基铁和络合铁溶液复配的脱硫浆液，该浆液具有单位体积硫容高、脱硫和再生速率快，大大降低了传统络合铁溶液的循环量，同时拓展了铁基脱硫剂的应用场景。最后，针对脱硫后产生的铁基脱硫废剂，我们创新性的将其应用为悬浮床渣油加氢催化剂，发现铁基脱硫废剂呈纳米片状，具有易硫化、易分散和活性位点丰富特点，使其具有较高的渣油催化加氢性能。总之，相关铁基脱硫剂的制备研究丰富了铁基脱硫剂的种类，拓展了铁基脱硫剂的使用场景；相关脱硫剂的活性位点和脱硫作用机制的研究成果，可以为铁基脱硫剂的开发和应用提供重要理论指导。