甲烷水合物在天然砂中的分解动力学研究

Investigation on decomposition kinetics of methane hydrate in natural sand

研究了在常压、275.1 K条件下,甲烷水合物在天然砂中的分解动力学,考察了天然砂粒径、水合物饱和度(40%,30%,20%)、NaCl对甲烷水合物分解过程中产气量及温度的影响。实验结果表明,在水合物饱和度相同的条件下,甲烷水合物在中值粒径为55μm的天然砂中初期分解速率最快。在水合物饱合度为30%~40%的天然砂中,在中值粒径为87μm的天然砂中获得了最大产气量;在水合物饱合度为20%的天然砂中,在中值粒径为24μm的天然砂中产气量最大。天然砂中的无机盐可以极大地促进甲烷水合物的分解。在含3.5%(w)NaCl溶液的沉积物中,当水合物饱和度约为30%时,甲烷水合物在中值粒径为87μm天然砂中产气量较纯水体系降低了约69.89%。

The decomposition kinetics of methane hydrate in natural sand under normal pressure and 275.1 K was studied.The natural sand particle size,hydrate saturation(40%,30%,20%)and NaCl salt in the gas production and temperature during the decomposition of methane hydrate were investigated.It was found that methane hydrate decomposed the fastest in the natural sand with a median particle size of 55μm under the same conditions of hydrate saturation.In hydrate deposits with the hydrate saturation of 30%-40%,the natural sand with a median particle size of 87μm was found to have largest gas production;while in hydrate deposits with 20%saturation,the natural sand with a median particle size of 24μm had the largest gas production.Inorganic salt could strengthen methane hydrate decomposition greatly in the natural sands.In the natural sand with a median particle size of 87μm containing 3.5%(w)NaCl,the gas production was reduced by 69.89%in contrast to the gas production in pure water system.