锌钴钼复合脱硫剂中温脱硫与加氢催化耦合

Coupling of medium temperature desulfurization and hydrogenation catalysis of Zinc-Cobalt-Molybdenum composite desulfurizer

  • 摘要: 在当前的工业脱硫领域,处理脱硫剂产生的固废正面临巨大的挑战。为了缓解这一压力,实现固废资源化再利用已成为一项亟待解决的研究课题。为了更好地应对这一挑战,研究者们正致力于改进和优化脱硫剂。其中,钼元素因其独特的理化性质受到了广泛关注。采用溶胶凝胶法制备了钼改性的锌钴复合脱硫剂,以期提高其脱硫性能以及硫化后对噻吩的加氢催化性能。通过XRD、XPS和氮气吸附/脱附等表征手段分析了新鲜脱硫剂和硫化样的物相组成和结构并与其脱硫和加氢性能相关联。结果表明:钼物种通过影响比表面积、物相组成以及形成特定活性相前驱体等方式,增强了锌钴脱硫剂的脱硫及后续加氢性能。钼物种的引入与钴相互作用形成了与H2S更具反应性的CoMoO4物种,同时该物种也是CoMoS活性相的前驱体,这将对脱硫及后续加氢性能产生积极影响。此外钼改性提高了脱硫剂的比表面积,有利于活性位点的暴露,从而提高脱硫性能。在350 ℃的条件下,钼物质的量分数为20%的锌钴钼复合脱硫剂穿透硫容为223.6 mg/g。钼改性后MoS2和CoMoS活性相的形成是加氢活性提高的关键。当温度为250 ℃、压力为0.1 MPa、C4H4S质量浓度为(150±10) mg/m3、H2的体积分数为10%和体积空速为7 800 h−1的条件下,钼物质的量分数为20%的加氢活性是未改性的2.46倍,这表明钼改性显著提高了加氢脱硫性能。通过钼改性使脱硫剂的脱硫能力提高,同时使其硫化产物可作为噻吩加氢的高效催化剂,实现脱硫和加氢过程耦合,为废脱硫剂的再利用提供了新的途径。

     

    Abstract: In the current field of industrial desulphurization, the treatment of solid waste generated by desulphurization agents is facing great challenges. In order to alleviate this pressure, the realization of solid waste resource reuse has become an urgent research topic. In order to better meet this challenge, researchers are working on improving and optimizing desulfurizers. Among them, molybdenum has been widely concerned because of its unique physical and chemical properties. Molybdenum modified Zinc-Cobalt compound desulfurizer was prepared by sol-gel method in order to improve its desulfurization performance and hydrogenation catalytic performance for thiophene after vulcanization. The phase composition and structure of the fresh desulfurizer and vulcanized sample were analyzed by XRD, XPS and nitrogen adsorption/desorption, and correlated with their desulfurization and hydrogenation properties. The results showed that molybdenum species enhanced the desulfurization and subsequent hydrogenation performance of Zinc-Cobalt desulfurizer by influencing the specific surface area, phase composition and forming specific active phase precursor. The introduction of molybdenum species interacts with cobalt to form CoMoO4 species, which is more reactive to H2S, and is also a precursor of CoMoS active phase, which will have a positive impact on desulfurization and subsequent hydrogenation performance. In addition, molybdenum modification improves the specific surface area of the desulfurizer, which is conducive to the exposure of the active site, thus improving the desulfurization performance. Under a condition of 350 ℃, the zinc-cobalt-molybdenum composite desulfurizer with a molybdenum molar fraction of 20% exhibits a breakthrough sulfur capacity of 223.6 mg/g. The formation of active phases of MoS2 and CoMoS after molybdenum modification is the key to the improvement of hydrogenation activity. Under the conditions of 250 ℃, 0.1 MPa pressure, C4H4S mass concentration of (150±10) mg/m3, H2 volume fraction of 10%, and a space velocity of 7800 h−1, the hydrogenation activity of the catalyst with a molybdenum molar fraction of 20% is 2.46 times that of the unmodified catalyst, indicating that molybdenum modification significantly enhances the hydrodesulfurization performance. In this study, the desulfurization ability of desulfurizer was improved by molybdenum modification, and the sulfurized products could be used as high efficient catalyst for thiophene hydrogenation. The coupling of desulfurization and hydrogenation process was realized, which provided a new way for the reuse of waste desulfurizer.

     

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