## 3 Results and Discussion
### Study on the Micro-Particle Distribution Characteristics  
Based on the study of micro-particle morphology during hydrate slurry dissociation in a pipeline system, this paper researched the particles' number as well as chord-length distribution characteristics with the aid of an FBRM. It was expected to characterize the dissociation mechanism of hydrate slurry from a micro-perspective. Two micro-particle processing methods--the arithmetic mean and square weighting--were used to characterize the trends of the overall average particle size and the big-particle size, respectively. Figure 6 presents the variation trend of particle/droplet numbers for different chord-length ranges during the hydrate slurry dissociation (initial system pressure 5 MPa, 25% water-cut). It can be observed in Figure 6 that a first increasing, then decreasing periodic oscillating trend of particle/droplet numbers appear for different chord-length ranges in the system. On one hand, this trend shows strong interactions among particles/droplets. On the other hand, it indicates that hydrate micro-particles/droplets were in a dynamic coupling process of breakage and agglomeration. That is, the increased number of micro-particles/droplets illustrate that particles were broken under the shear effect, while the decreased number proved the agglomeration. In general, the number of micro-particles/droplets in the dissociation could characterize the phenomena of the breakage and agglomeration, which is also in addition to the morphology study from the particle/droplet quantity. Figure 5: Gas emission quantity, decomposition rate, and pressure drop curves during the hydrate decomposition. Figure 7 presents the trends of the arithmetic mean chord length and the square weighting chord length under same experimental conditions. It can be observed that both the two-chord length tendencies were similar with the trend of the particle numbers in Figure 6. This proves once again that intense interactions occurred among particles/droplets during hydrate slurry dissociation, indicating the dynamic coupling process of breakage and agglomeration of micro-particles/droplets under the shear effect. In order to provide the theoretical foundation for the hydrate slurry transportation, this paper investigated the influences of several macro factors (i.e., flow rate, water-cut, AA dosage, etc.) on the particle/droplet chord length and distribution. In detail:  
(1). Influence of Flow Rate  
A series of experiments was conducted to study the influence of flow rate on fixed 10% water-cut and 8.0 MPa initial system pressure. The specific experimental results are shown in Figures 8 and 9. It was demonstrated in Figure 8a that the particle/droplet mean chord length fluctuated with time during the dissociation, forming a general trend of the first decline then increase. That was consistent with  
Figure 6: Variation trends of particle/droplet numbers during hydrate slurry dissociation. Figure 7: Variation trends of chord length during the hydrate slurry dissociation (5 MPa, 25% water-cut). the co-existing process that particles/droplets broke down at first and then agglomerated. When the flow rate rose to 1.2 m/s, the mean chord length went down with time in the dissociation process. It meant that under this flow rate, particles/droplets broke more frequently than they agglomerated in the system. In other words, high flow rate could restrain the particle/droplet agglomeration during hydrate slurry dissociation. Similarly, it can be seen in Figure 8b that the particle/droplet square-weighted chord length fluctuated with time during the dissociation yet showing a general trend of first up then down. This was due to the big particles/droplets in the system agglomerating at first and then disintegrating under the shear effect. While at 1.2 m/s flow rate, Figure 8b presented an alike trend as in Figure 8a. It also certified that high flow rate could restrain the big particle/droplet agglomeration during hydrate slurry dissociation.