石英砂介质中甲烷水合物生成过程和相平衡的实验研究

Experimental study on the formation and phase equilibria of methane hydrate in quartz sand media

关键词:  甲烷水合物  石英砂  成核  反应速率  气体消耗量

Key words:  methane hydrate  quartz sand  nucleation  reaction rate  gas consumption

摘要:

为研究小梯度温度范围内甲烷水合物在石英砂介质中生成过程的热力学和动力学特性,开展了定容条件下273.75 K、273.85 K、273.95 K 3种恒温水浴体系的甲烷水合物生成实验。研究结果表明:①反应温度越低,釜内甲烷水合物生成过程中反应热释放越快,相比于273.95 K的反应体系,273.75 K体系的反应釜内首次温度上升值为0.9 K,约为273.95 K体系的6倍；②随反应温度的增加,水合物的生成量和转化率逐渐下降；③反应温度越低,甲烷水合过程的前期反应速率越大,气液界面和石英砂表面生成的水合物薄膜阻碍了甲烷气与水之间的进一步传递,使得甲烷的单位消耗速率随反应的进行呈阶梯型递减。通过石英砂介质内甲烷水合物的生成实验,以期为工业上气体水合物的合成、储存与运输提供借鉴。

Abstract:

In order to study the thermodynamic and kinetic characteristics of the formation of methane hydrate in quartz sand media at a small temperature range, the methane hydrate formation experiments were carried out at 273.75 K, 273.85 K and 273.95 K constant temperature water baths in a constant volume reactor. The results showed that:(1) the reaction temperature was lower, the reaction heat released faster during the formation of methane hydrate in the reactor. Compared with the 273.95 K, the first temperature rise was 0.9 K in the reactor of 273.75 K system, about 6 times that of the 273.95 K system; (2) with the increase of reaction temperature, the production and conversion rate of hydrate decreased gradually; (3) the reaction temperature was lower, the rate of formation was higher at the early stage. The hydrate film formed on the gas-liquid interface and the quartz sand surface hindered the further transfer between methane gas and water, so the consumption of methane gradually decreased as the reaction progressed. The production of methane hydrate in quartz sand media was expected to provide reference for the synthesis, storage and transportation of gas hydrates in industry.