Ben Salah Haifa, Nancarrow Paul, Al Othman Amani
Department of Chemical & Biological Engineering, American University of Sharjah, Sharjah P.O. Box 26666, United Arab Emirates.
ACS Omega. 2023 Aug 8;8(33):30001-30023. doi: 10.1021/acsomega.3c01952. eCollection 2023 Aug 22.
Sulfur dioxide emissions from fossil fuel combustion have been known to cause detrimental health and environmental effects. The currently used hydrodesulfurization (HDS) method employed by refineries has several drawbacks, such as excessive hydrogen consumption, high energy demand, and inability to remove complex organosulfur compounds, which have limited its ability to produce ultralow sulfur diesel (ULSD) at reasonable operating and capital costs. Ionic liquids (ILs) have been widely studied for their potential to replace conventional HDS. However, while their success has been demonstrated at the laboratory level, studies on industrial-scale feasibility and their integration into process simulators such as Aspen Plus are limited. In this work, 26 commercially available ILs have been screened using COSMO-based models and Aspen Plus for the desulfurization of diesel fuel and several possible process configurations have been examined. In particular, the challenge of ionic liquid regeneration, which has largely been ignored in the literature, has also been addressed and several potential regeneration methods have been proposed including extractive regeneration (E-RE) and stripping regeneration using nitrogen and air as stripping media (S-RE). The results indicate that, among the 26 ILs studied, 1-butyl-3-methylimidazolium thiocyanate is the most promising as a solvent for extractive desulfurization (EDS), E-RE, and S-RE. E-RE was found to be more effective for the removal of dibenzothiophene (DBT), while S-RE is more suited to the removal of thiophene and benzothiophene (BT). As a result, an optimized diesel desulfurization process using 1-butyl-3-methylimidazolium thiocyanate has been proposed that achieves ULSD with <10 ppm total sulfur in simulation studies, with complete recycling of the IL and minimal loss of the model diesel.
化石燃料燃烧产生的二氧化硫排放已被证实会对健康和环境造成有害影响。炼油厂目前使用的加氢脱硫（HDS）方法存在若干缺点，例如氢气消耗过多、能源需求高以及无法去除复杂的有机硫化合物，这限制了其以合理的运营和资本成本生产超低硫柴油（ULSD）的能力。离子液体（ILs）因其替代传统加氢脱硫的潜力而受到广泛研究。然而，尽管它们在实验室层面已取得成功，但关于工业规模可行性及其集成到诸如Aspen Plus等过程模拟器中的研究却很有限。在这项工作中，使用基于COSMO的模型和Aspen Plus对26种市售离子液体进行了柴油脱硫筛选，并研究了几种可能的工艺配置。特别是，文献中基本被忽视的离子液体再生挑战也得到了解决，并提出了几种潜在的再生方法，包括萃取再生（E - RE）以及使用氮气和空气作为汽提介质的汽提再生（S - RE）。结果表明，在所研究的26种离子液体中，1 - 丁基 - 3 - 甲基咪唑硫氰酸盐作为萃取脱硫（EDS）、E - RE和S - RE的溶剂最具潜力。发现E - RE对去除二苯并噻吩（DBT）更有效，而S - RE更适合去除噻吩和苯并噻吩（BT）。因此，提出了一种使用1 - 丁基 - 3 - 甲基咪唑硫氰酸盐的优化柴油脱硫工艺，在模拟研究中可实现总硫含量<10 ppm的超低硫柴油，离子液体完全循环利用，且模型柴油损失最小。
