加压流化床煤催化加氢气化炉放大的数值模拟研究

The pressurized fluidized bed catalytic coal hydrogasification is a promising technology for the coal-to-SNG process, and its scale-up has attracted much attention. In this project, a Computational Fluid Dynamics method is used. The coarse-grid CFD model is established based on the sub-grid scale modifications and coupled with the catalytic coal hydrogasification kinetics. Aiming to find out the bubble dynamics and the optimal supply of reactant gases into the gasifier, the simulation starts with the lab-scale reactor and then extends to the pilot-scale and the industrial reactors. Results under different scales are compared to investigate the bubble behavior and its scale-up law. Effects of embedded jets on the gas-solid flow and catalytic coal hydrogasification are also studied. The optimal way of distributed oxygen and hydrogen supply is proposed to prevent the hot spot and increase the carbon conversion and methane yield. The purpose of this project is to provide a theoretical basis for the design and scale-up of the pressurized fluidized bed catalytic coal hydrogasification reactor, and guide for similar fluidized bed reactors.

加压流化床煤催化加氢气化作为一种极具潜力的煤制天然气技术，其工业放大备受关注。本研究以计算流体力学模拟为主要方法，使用亚网格修正模型，耦合煤催化加氢气化反应动力学，构建粗网格框架下的气固流动、传递与反应模型。围绕气泡运动规律和反应气体最佳送入形式这两个关键问题，以实验室规模的气化炉入手，逐步模拟计算百吨级中试、千吨级工业装置。比较不同规模的模型结果，探寻气泡的运动特性及其放大规律，探索内置射流对气固流动、煤催化加氢气化反应的相互作用关系。最终确定分散进氧、分散进氢的最佳送气形式，避免高温热点的产生，并提高碳转化率和甲烷产率。通过本研究，为加压流化床煤催化加氢气化炉的工业设计和放大提供合理的理论依据，也为类似流化床反应器提供借鉴。

本项目采用计算流体力学模拟方法，开展加压流化床煤催化加氢气化炉的放大研究。研究首先分析了加压下的气泡运动行为，完善了气泡合并分裂速率模型。其次，项目基于颗粒尺度预测了气固两相流动、传递与反应的过程及相互耦合过程，探索了颗粒粒径、压力差异的影响规律，总结了适宜的颗粒粒径范围、压力及流化数。然后，通过内置射流分散进氢，提出了双射流的布置形式，优化了反应器结构和反应气体的送入形式，有效控制了气泡尺寸和高温热点。最后，通过开展气化炉尺寸逐级放大的模拟，探索了反应器的放大规律。研究结果为流化床反应器的设计和放大提供了合理的理论依据。