气固两相流过孔相分离的机制与调控

Serious gas-solid back-mixing in fluidized bed reactors results in a wide residence time distribution, which weakens its ability to obtain reaction intermediates with high selectivity. In a fluidized bed with baffles or a multi-stage fluidized bed, an "gas cushion" can be formed under the plate, i.e. gas-solid phase separation. In order to obtain plug-flow fluidized beds, the mechanism of gas solids phase separation through a narrow throat is investigated, based on the similar chocking phenomenon between solids flow and compressible flow with high Mach number. The present project includes the following parts: (1) Based on the compressibility of gas solids multi-phase flow, which can be described by sound speed and Mach number quantitatively, a physical model of gas solids separation through a narrow throat is established; (2) Based on the special of Mach cone, a measurement to detect the compressibility of gas solids flow is provided; (3) A novel reactor model including geometrical parameter (Knudsen Number) and operational parameter (Mach number) is provided, to guide the control of residence time distribution in fluidized bed reactor.

气固流化床内剧烈的气固返混导致反应器停留时间分布变宽，难以高选择性获得反应中间产物。在流化床内添加多孔板构件或建立多段流化床，通过在多孔板下方形成“气垫”或稀相区(即气固相分离)可有效抑制气固返混。本项目针对具有近平推流性质的流化床这一需求瓶颈，围绕气固两相流过孔相分离的机制，抓住颗粒流与高马赫数流过孔噎塞的相似性，拟完成以下工作：(1) 基于气固两相流的可压缩性，引入气固两相平衡声速和马赫数的概念，构建气固两相流过孔相分离的物理模型；(2) 基于激波特征发展气固两相流可压缩性的实验测量方法；(3)基于构件努森数和两相马赫数，建立含多孔板流化床的两参数反应器模型，指导开发特殊结构的多孔板调控气固流化床内停留时间分布。

本项目针对抑制流化床反应器内气固返混这一需求瓶颈，围绕气固两相流过孔相分离机制；基于扎实的物理模型(气固可压缩流一维过孔相分离)，发展测量手段，构建反应器模型；实现通过对技术瓶颈背后的核心科学问题的深入理解指导生产实际。本项目工作形成专著《气固两相流的“超可压缩性”》，并在AIChE J (当期Letter, 2022)、ACS Catalysis (2022)、Ind. Eng. Chem. Res. (封面论文, 2020)、Powder Technology(2020)以及《储能科学与技术》（特邀综述, 2022）等刊物发表论文7篇。申请国家发明专利4项，技术作价转移450万元。项目负责人在本项目资助期间，担任中国颗粒学会青年理事(2020)；入选2021-2023年度北京市科协“青年人才托举工程”，入选首届Particuology青年编委(2022-2025)，获得2020年度“博士后优秀学术专著出版资助”，2020与2021年度Particuology优秀审稿人，首届“中国化工学会博士论文奖”(2019)，首届“中国颗粒学会优秀博士生论文奖”(2018)，北京市优秀毕业生(2018)；先后主持中国石油天然气集团有限公司科技创新基金(2021)，沙特阿美国际合作基金(2020)，内蒙古科技厅重大项目子课题(2020)。