Fig. 4-Flow Curve of Hydrate Slurry with and without Antipolymer in Pure Water
The experiments were carried out at the initial flow rate of 230 L / h under different moisture content. It can be seen from the curve that although the new Anti-agglomerants agent can effectively improve the fluidity of hydrate slurry under different moisture content and alleviate the trend of plugging, the flow change trend of the system with Anti-agglomerants agent is usually disordered. Under the conditions of 50 % and 70 % moisture content, many times of the flow rate of the system temporarily dropped to zero before the hydrate slurry completely stopped flowing. We suspect that when hydrate blockage occurs in the system with Anti-agglomerants agent. The anti-agglomeration agent can decompose the hydrates that have been generated, aggregated or deposited on the wall of the pipe to restore the flow of the system, and the change of the hydrate aggregation state will also make the flow of the system change irregularly. Therefore, the flow change trend shown in the following figure will appear.
Through previous studies, it can be known that the polymer inhibitor can change the dispersion state of water molecules in oil-water emulsion to make the emulsion more stable, resulting in water dispersed in the oil phase in the form of water droplets. Gas hydrates formed on the surface of water droplets will be solubilized in the microemulsion and thus difficult to aggregate. Therefore, the polymer inhibitor can play an anti-coagulation role of hydrate particles in oil-water emulsion system. In pure water system, the mechanism of anti-agglomeration effect of anti-agglomeration agent may be different from that of oil-water emulsion. We believe that the aggregation behavior of hydrate crystals is closely related to the cohesion between hydrate particles. Coconut amide has a long alkyl chain, which can provide a more dense barrier, thereby effectively reducing the cohesion between particles. These molecules can reduce the interfacial tension and increase the contact angle between natural gas hydrate and water, so as to minimize the interaction between natural gas hydrate particles. In addition, AA also affects the liquid bridge between gas hydrate particles by breaking water molecules, thereby destabilizing the cohesion between hydrate particles. Fig. 5 shows the mechanism of hydrate Anti-agglomerants caused by Anti-agglomerants in self-made pure water system.