新型烃类化学链制氢工艺的基础研究

Chemical looping reforming represents an intensified reforming scheme that can directly and efficiently convert hydrocarbon into high purity hydrogen with reduced carbon emission and cost. The chemical looping process uses bimetallic oxygen carrier to supply oxygen and catalyst for hydrocarbon reforming for ensuring full fuel conversion and in-situ carbon capture, and the reduced oxygen carrier can be used to produce high purity hydrogen. Such hybrid looping scheme not only improves the hydrogen yield and purity with autothermal operation, but also eliminates capital intensive unit operations for water gas shift and air separation over the conventional processes. Leading research groups from Tianjin University and SINOPEC have jointly conducted feasibility study of the CLR system, and identified multidisciplinary knowledge and technology gaps such as the reaction mechanisms of both reforming catalysts and the carrier particles, their reactivity and recyclability behaviors and synergistic effects in the CLR process, the gas-solid reaction flow dynamics and control strategies for reactor design and operation, and the combined looping process synthesis and performance evaluation. In order to close these key gaps, both teams are proposing an integrated four-year program on the scientific principles and engineering approaches from atomic level to reactor and process scales to verify the CLR material and process advantages. The objectives are: (1) to understand the reaction mechanism and develop reaction models for both surface catalytic reaction and bulk phase diffusion; (2) to design and synthesize high reactivity high recyclability looping particles; (3) to develop suitable reactor configuration and operation condition for the CLR process scale up; (4) to conduct techno-economic analysis and optimize the chemical looping hydrogen production process design for efficient hydrogen generation with reduced carbon emission. Such goals will be achieved through carefully coordinated collaborative efforts between both teams, where each team provides unique and complementary expertise and research capabilities including catalysis science, DFT simulation, multiphase reactor engineering, engineering thermalphysics, and process system engineering. With advanced characterization and computational techniques, the research is expected to be a collaborative effort with strong potential for discovering (1) reforming reaction mechanism, (2) bulk/surface.structure-reaction performance interaction (3) regenerable looping particles with high reactivity and high carrying capacity, (4) optimal reactor configurations with enhanced gas solid interactions, and (5) integrated process models for assessing the performance of high temperature solids looping process. With these mechanistic insights, the proposed program will significantly advance the fundamental research and applied development in petroleum industry.

三床化学链重整是一项高度集成的先进制氢技术，利用双金属氧载体供氧并催化烃类重整反应，确保原料的完全氧化并原位脱除CO2，被还原氧载体不仅可以在自热操作条件下提高氢气产量和纯度，还可以节省传统流程中所需的高耗资水汽变换和气体分离等装置。天津大学和中国石化石油化工科学研究院对该技术的可行性进行分析，明确了从原子、分子级别到反应器、流程级别的多尺度跨学科知识与技术空白，拟通过密切协作和共同努力，1）理解氧载体的氧化还原反应机理，建立表面反应和体相扩散的反应模型；2）研究双金属氧载体的协同作用，理性设计和制备高性能循环氧载体颗粒；3）研究多床反应系统内气固流动方式，并设计验证合适的多床循环系统；4）进行技术经济分析，优化流程设计。项目团队可以在催化科学，DFT计算，多相流反应工程，工程热物理和过程系统工程等多方面发挥各自特长并优势互补，有效推动石化领域的基础研究。

化学链过程可以在能量转化的同时实现气体分离，为低碳氢气的生产提供一条清洁高效的路线。本项目围绕化学链制氢的核心问题，开展氧载体设计合成，反应过程强化和系统集成优化等多尺度工作，实现了预期的研究目标。针对化学链过程时空收率低的问题，提出金属氧化物结构调控新思路，通过表面反应催化和体相离子掺杂，实现氧载体氧化还原反应性能大幅提升，形成氧载体理性设计和系统表征方法；提出化学链低碳烷烃转化新工艺，推动具有自主研发产权的金属氧化物催化剂和配套反应-再生工艺开发；拓展化学链在低碳能源化工领域的应用，建立反应系统和流程模型，实现反应与分离过程集成优化，为化学链制氢过程强化提供基础理论与工艺放大指导。针对氧载体动力学性能差和结构稳定性差等问题，开发钨基双金属氧载体和钙钛矿型氧载体，通过体相掺杂提高晶格氧迁移能力，降低还原温度，提高氧载体还原度，同时在表面构建活性位，起到催化活化烷烃的作用，获得优异的烷烃转化率和产品选择性，氧载体长周期循环测试过程中结构和性能保持稳定。拓展化学链技术的应用，用于吸收增强式重整制氢过程，并设计并合成多功能催化剂。提出基于太阳能-风电-生物质供能耦合化学链制氢技术的多联产分布式能源系统，并进行系统模拟与参数优化。创新性提出化学链氧化脱氢工艺，并探究氧载体在化学链烷烃转化过程中氧物种的分布及活化转化机理，为新型低碳烷烃转化过程的设计和开发指明了方向。在本项目资助下，在J. Am. Chem. Soc. 、AIChE Journal、ACS Catalysis、化工学报等国内外权威杂志发表高水平学术论文30篇，并应邀为Nature Reviews Chemistry撰写综述。申请中国发明专利13项，PCT申请2项。天津大学与中国石化石油化工科学研究院、东南大学、美国俄亥俄州立大学在化学链制氢方面开展了联合研究。