Investigation of Chemical Looping Combustion with a novel two stage fuel reactor for reduction of CO2 emissions

与传统的火电厂工艺相比，化学循环燃烧(CLC)实现了固有的二氧化碳捕获，而不需要昂贵的氮气和二氧化碳分离。在汉堡理工大学固体过程工程和粒子技术研究所，一个25kWth的中试规模的CLC反应堆正在运行，该反应堆有两个燃烧反应堆阶段。第二个反应堆阶段可以提高挥发性燃料气体的转化率。在甲烷和煤的燃烧方面已经取得了经验。最近进行的第一次以木材为燃料的实验表明，转化率非常高。在未来，实现世界1.5摄氏度气候目标不可避免的负二氧化碳排放，应该通过使用生物质作为燃料来实现。本项目的目的是在两级25kWth CLC系统中研究木屑、污水污泥、农业废弃物和精制生物质作为燃料。由于燃料的组成不同，将对不同的反应机理进行详细的调查，并对中试装置的操作条件进行优化。将对启动和关闭以及负荷变化等过程动态进行调查。此外，还将开发一种新的反应堆概念：燃料反应堆阶段将被具有环形气体入口的喷动床取代，以实现更低的压力损失，这对未来的扩大至关重要。实验研究还将用于在开源流程模拟环境DYSSOL(固体过程动态模拟)中验证和扩展模型，该模型可用于未来设计和优化新的工厂配置。DYSSOL是在DFG优先计划(SPP1697)中开发的，在德国各地总共有27个子项目，并于2020年发布。这项工作的重点是热平衡的公式，以及一个接口连接DYSSOL和一个软件的CFD多相粒子在单元中的模拟。最后，对一个设想的100MW工业规模生物CLC装置进行了流程图模拟。首次将生物质颗粒气化、脱挥等全过程的流体力学和化学反应纳入到一个模拟中。中试规模的生物质实验和工业规模的数值模拟对于未来更大规模的设施的开发和设计至关重要。这项工作将评估《中图法》是否是未来利用碳捕获和储存生物能源的潜在候选者。

Compared to conventional thermal power plant processes, Chemical Looping Combustion (CLC) enables an inherent CO2 capture without the need for costly separation of N2 and CO2. At the Institute of Solids Process Engineering and Particle Technology at Hamburg University of Technology, a 25 kWth pilot-scale CLC reactor with two combustion reactor stages is being operated. The second reactor stage enables higher conversion of volatile fuel gases. Experience has been gained with the combustion of methane and coal. Recently conducted first experiments with wood as fuel showed very high conversion rates. In the future, negative CO2 emissions, which are unavoidable for reaching the world’s 1.5 °C climate targets, should be achieved by using biomasses as a fuel. The aim of this project is to investigate wood particles, sewage sludge, agricultural waste and torrefied biomass as fuel in the two-stage 25 kWth CLC system. Due to the different compositions of the fuels, a detailed investigation of the different reaction mechanisms and optimization of the operating conditions of the pilot plant will be performed. Process dynamics such as start-up and shut-down as well as load changes will be investigated. Furthermore, a new reactor concept will be developed: The fuel reactor stages will be replaced by a spouted bed with an annular gas inlet to achieve lower pressure losses, which are essential for future scale ups. The experimental investigations will also be used to validate and extend a model in the open-source flowsheet simulation environment DYSSOL (Dynamic Simulation of SOLids Processes), which can then be used in the future to design and optimize new plant configurations. DYSSOL was developed in the DFG priority program (SPP1697) with a total of 27 subprojects across Germany and published in 2020. The focus of this work is on the formulation of enthalpy balances as well as an interface to connect DYSSOL and a software for CFD multiphase particle-in-cell method simulation. At last, a flowsheet simulation of an entire hypothetical 100 MWth industrial scale bio-CLC plant will be performed. Here for a first time, the whole process with the hydrodynamics and the chemical reactions including gasification and devolatilization of biomass particles will be included into one simulation. Pilot-scale biomass experiments and industrial-scale numerical simulations are essential for the development and design of future larger scale facilities. This work will evaluate if CLC is a potential candidate for future use for bioenergy with carbon capture and storage.