## 4 Conclusions  
Experiments on the dissociation of natural gas hydrate slurry in a flowing system were conducted in a high-pressure hydrate experimental flow loop. Important information on the microscopic decomposition of hydrate in the flow system was analyzed. The influences of flow rate, AA dosage, and water-cut on the micro-particle distribution characteristics were explored. Meanwhile, some outstanding conclusions were obtained.  
Firstly, hydrate particles, dissociating particles, and water droplets co-existed in a system during the hydrate slurry decomposition. It brought about various forms of collision and agglomeration among particles and droplets and strengthened the particle/droplet agglomeration (decomposition would result in slurry instability).  
Secondly, hydrate micro particles' shape and size influenced its dissociating probability. Different particles did not dissociate at the same time during the hydrate slurry decomposition.  
Figure 12: Influence of AA on mean chord length during the hydrate dissociation (**a**,**b**). (**a**) Influence of AA on mean chord length (5 MPa, 1.0 m/s flow rate, 25%water-cut); (**b**) Influence of AA on square-weighted chord length (5 MPa, 1.0 m/s flow rate, 25%water-cut).  
Figure 13: Influence of AA on chord length distribution during hydrate dissociation (**a**,**b**). (**a**) Influence of 0%-AA on chord length distribution; (**b**) Influence of 1%-AA on chord length distribution.  
Moreover, a firstly-increased-then-decreased periodic oscillating trend of particle/droplet number and chord length was found during the hydrate slurry dissociation. On one hand, this trend showed the intense interactions among particles/droplets. On the other hand, it indicated that these micro hydrate particles/droplets were in a dynamic coupling process of breakage and agglomeration. Thereinto, the particle/droplet number peak value represented the breakdown of decomposing hydrate particles or coalescing particles/droplets under the action of flow shear, while the peak valley illustrated the reoccurrence of agglomeration of the broken hydrate micro particles under the action of flow (which is one of the main reason for the blockage of pipelines in the process of hydrate slurry decomposition). Meanwhile, the existence of chord length peak values was mainly caused by the agglomeration of decomposing hydrate particles or coalescing particles/droplets under the action of flow shear.  
Finally, the trends of mean chord length and square-weighted chord length parameters would change with quantitative macro factors. The higher flow rate could restrain the particle/droplet agglomeration during the dissociation, and vice versa. The hydrate particle agglomerating tendency and plug probability went up with the water-cut. Anti-agglomerates (AA) could greatly prohibit micro-particle/droplet agglomeration during decomposition, resulting in relatively stable mean and square weighting chord length curves.  
Conceptualization, S.Z. and S.W.; Data curation, B.S. and X.S.; Investigation & Writing, X.L. and W.H.  
This research was funded by [National Science Foundation of China], grant number [51804046]; [National Science Foundation of China], grant number [51574045]; [National Science Foundation of China], grant number [51574044]; [PetroChina Innovation Foundation], grant number [2018D-5007-0602]; [Natural Science Research Project of Jiangsu colleges and Universities], grant number [18 KJB440001]; [Key Project of Jiangsu Provincial Key Research and Development plan (Industry Foresight and Common Key Technology)], grant number [BE2018065]; and [Enterprise Fund], grant number [KYH17020180].  
The authors declare no conflict of interest.