Abstract:

Hydrate storage and transportation (NGH) is a natural gas storage and transportation technology developed in recent years and has the potential to realize industrialization. However, the growth of hydrate is a reaction controlled by mass and heat transfer, so there are many uncertain factors in the scale-up experiment. Based on the chemical reaction kinetic and the mass and heat transfer in porous materials, a mathematical model of methane hydrate formation and heat transfer is established in hydrate reactor for the formation and heat transfer process in porous materials, which can be used to predict the hydrate formation and heat distribution in the reactor and guide the design and optimization of hydration reactor. The reliability of the model was verified by comparing with experimental data, and the hydrate reaction process in porous materials with different thermal conductivity was numerically simulated. The results show that the AARD between the simulated value and the experimental value is less than 6%, and the heat transfer model is highly accurate. Heat transfer is one of the key factors affecting the hydrate formation rate during hydrate reaction. When the heat conduction is poor, it is easy to form local overheating in the hydrate formation center, resulting in thermal inhibition of hydrate formation. When performing scale-up experiments on hydrate formation, special attention should be paid to thermal control inside the reactor.

Key words: hydrate, numerical simulation, heat transfer, hydrate formation, porous materials

摘要：

水合物储运(NGH)是近几年发展起来的天然气储运技术，已具备实现工业化的潜力。但水合物的生长是传质传热控制的反应，因此在放大实验中存在诸多不确定因素。针对该问题，对水合物反应器中多孔材料内甲烷水合物生成传热过程建立了基于化学反应动力学和多孔材料内传质传热的甲烷水合物生成传热数学模型，可用于计算反应器内水合物生成分布和热量分布，指导水合反应器的设计和优化。通过模拟与实验数据对比验证了该模型的可靠性，并对使用了不同热导率填料的水合反应过程进行数值模拟。结果显示，模拟值与实验值的绝对平均相对误差小于6%，生成传热模型准确性高；在水合反应过程中，热量传递是影响水合物生成速率的关键因素之一。导热不良时，易在水合物生成中心部分形成局部过热，对水合物生长造成热抑制。在进行水合物生成放大实验时，应特别注意反应器内部的热量控制。

关键词: 水合物, 数值模拟, 传热, 水合物生成, 多孔材料