Rapid formation of dry natural gas hydrate with high capacity and low decomposition rate using a new effective promoter

In this research, the effects of sulfonated Lignin (SL) on formation rate, capacity and stability of natural gas hydrate have been investigated and the results compared with those of hydrate formation in pure water and Sodium dodecyl sulfate (SDS) aqueous solution. Experimental results verified that the reactor pressure is reduced by 63.8% after 15 h when hydrate is formed in 500 ppm SL aqueous solution, while when using the same amount of SDS it is reduced no more than 57.8% after the same duration of time. It was also noticed that the formed hydrate when using SL had a lower decomposition rate than that of SDS aqueous solution. The reactor pressure increased 0.66 MPa during dissociation of SL natural gas hydrate after 70 h while in the case of SDS solution, at similar conditions this amount was 0.94 MPa. On the other hand, SL solution does not spume and so the formed hydrate is quite dense, brittle and dry which can be easily converted to powder while the hydrate formed in the SDS solution is foamy.