In view of the problems of pipeline blockage and equipment wear caused by large sand production in shallow marine gas-hydrate mining under seabed, based on the solid fluidized mining method, the idea of in-situ separation of natural gas hydrate was proposed. The downhole in-situ spiral separator was designed based on the physical parameters of hydrate mixed slurry. The correctness of the model was verified by CFD-Fluent software. Then, the performance of the separation device was studied from three aspects: solid phase hydrate volume concentration, solid phase sand volume concentration and inlet velocity. The results showed that within the scope of the study, the removal rate of sand and the recovery rate of hydrate were both about 80%. As the volume fraction of hydrate increased, the sand removal rate and hydrate recovery rate changed very little, and the separator pressure drop changed little. As the sand volume fraction increased, the sand removal rate decreased sharply, while the hydrate recovery rate increased sharply and the pressure drop increased sharply. As the inlet velocity increased, both the sand removal rate and the hydrate recovery rate increased, and the separator pressure drop also increased. The spiral separator exhibited very good performance in hydrate in situ sand removal purification. The saturation of hydrate had little effect on the performance of the separator, but the influence of silt concentration on the performance of the separator was obvious, and it needed to be considered in engineering application. The inlet velocity played a key role in the separation performance of the separator, and also determined the processing capacity of the separator. Appropriately increasing the inlet velocity could improve the separation efficiency of the separator to a certain extent. The analysis results have certain guiding significance for the exploitation of shallow hydrate reservoirs on the seabed.
Xuefeng LI Xia HE Guorong WANG Shunzuo QIU Shouwei ZHOU Qingyou LIU
. Numerical simulation of performance of spiral separator for natural gas hydrate purification[J]. The Chinese Journal of Process Engineering, 2019
, 19(3)
: 510
-515
.
DOI: 10.12034/j.issn.1009-606X.218273
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