多相反应体系的微界面强化简述

加氢、氧化等气液慢反应过程广泛存在于现代过程工业之中,这些反应过程一般受传质速率控制。因此,对这类多相反应体系的传质强化一直是研究热点之一。但总体而言,除外场和微通道(微流控)强化等一类强化反应器外,以往的研究大多集中于界面尺度为毫-厘米级的传统反应器的搅拌与混合方式、气泡分布状态、流体流型、构效关系等方面,而鲜有将研究视角投放到传统以米为直径计量单位的反应器平台上如何构建尺度为微米级的界面体系及其特殊效应方面。探讨了多相反应体系的微界面反应强化理念,并简述了微界面的涵义、微界面反应强化与构效调控方法、微界面反应器的结构与形成原理、微界面体系的微颗粒测试与相界面表征技术、微界面反应强化面临的问题与挑战等,以与本领域同行共同研讨。

微界面强化柴油加氢脱硫过程的模拟计算研究

出于对环境污染问题的关注与提高国六柴油等产品质量的要求,降低油品中硫含量一直以来广受关注.目前应用广泛的柴油脱硫技术主要是固定床催化加氢技术,为达到深度脱硫要求,传统工艺常采用升温加压、增大氢油比或油品循环等操作方式,导致设备投资高昂、工艺要求严苛和运行费用偏高.为了探究微界面反应强化技术对柴油加氢脱硫过程的强化效果,以固定床鼓泡反应器为例,构建微界面体系的构效数学调控模型,模拟计算并分析气泡尺度对柴油加氢脱硫效率的影响.理论计算表明,在工况条件(温度为350℃,压力为3.6 MPa,液时空速为3.0 h^(-1),氢油比为260 Nm^(3)·m^(-3))下,当气泡Sauter平均直径由5.0 mm减小至0.50 mm时,气-液-固微界面体系的体积传质系数增加约29倍,产品硫浓度从17.57μg·g^(-1)降至2.18μg·g^(-1),脱硫效果大幅度提高.这样的微界面加氢技术更容易实现国六柴油对硫含量不大于10μg·g^(-1)的质量要求.

Tuning strategies and structure effects of electrocatalysts for carbon dioxide reduction reaction

Carbon dioxide emissions have increased due to the consumption of fossil fuels,making the neutralization and utilization of CO_(2) a pressing issue.As a clean and efficient energy conversion process,electrocatalytic reduction can reduce carbon dioxide into a series of alcohols and acidic organic molecules,which can effectively realize the utilization and transformation of carbon dioxide.This review focuses on the tuning strategies and structure effects of catalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR).The tuning strategies for the active sites of catalysts have been reviewed from intrinsic and external perspectives.The structure effects for the CO_(2)RR catalysts have also been discussed,such as tandem catalysis,synergistic effects and confinement catalysis.We expect that this review about tuning strategies and structure effects can provide guidance for designing highly efficient CO_(2)RR electrocatalysts.