Hydrate formation in oil–water systems: Investigations of the influences of water cut and anti-agglomerant

To investigate the characteristics of hydrate formation in oil–water systems, a high-pressure cell equipped with visual windows was used where a series of hydrate formation experiments were performed from natural gas + diesel oil + water systems at different water cuts and anti-agglomerant concentrations. According to the temperature and pressure profiles in test experiments, the processes of hydrate formation under two kinds of experimental procedures were analyzed first. Then, based on the experimental phenomena observed through the visual windows, the influences of water cut and anti-agglomerant on the places of hydrate formation and distribution, hydrate morphologies and hydrate morphological evolvements were investigated. Hydrate agglomeration, hydrate deposition and hydrate film growth on the wall were observed in experiments. Furthermore, three different mechanisms for hydrate film growth on the wall were identified. In addition, the influences of water cut and anti-agglomerant on the induction time of hydrate formation were also studied.

Preparation of TiCl_4 with multistage series combined fluidized bed

In order to solve the agglomeration problem in TiCl4 preparation,a new test in a multistage series combined fluidized bed was studied on a pilot scale.The pilot plant can make full use of titanium slag with a high content of MgO and CaO as the feedstock.Several experimental parameters such as chlorine flow and reaction temperature were discussed and the morphology and components of reaction product were analyzed.According to the results,the conversion rate of TiO2 is up to 90%.It is found that the combined fluidized bed has good anti-agglomeration ability because the accumulation of MgCl2 and CaCl2 on the surface of unreacted slag was carried out of the reactor.

Comprehensive Utilization of Complex Titania Ore

To fully utilize Panzhihua titanium resources, a new process was proposed. In the process, Panzhihua ilmenite concentrate was first reduced in a rotary hearth furnace （RHF） to produce a titanium-rich material and iron. The titanium-rich material was then used in a new chlorination process to produce TiCl4. The comparison of different groups of experimental results or calculation results showed that the utilization ratio of material was improved by using the titanium-rich material after pretreatment other than low level titanic ilmenite directly and the combined fluidized beds （FTF） were more likely to reduce bed height and reaction time than the single fluidized beds （Single F or Single T） under the condition of the same chlorination conversion ratio. Finally, the influence of reduction temperature and the anti-agglomeration capacity of the combined fluidized bed was analyzed.

Research progress on hydrate plugging in multiphase mixed rich-liquid transportation pipelines

The plugging mechanism of multiphase mixed rich-liquid transportation in submarine pipeline is a prerequisite for maintaining the fluid flow in the pipeline and ensuring safe fluid flow.This paper introduced the common experimental devices used to study multiphase flow,and summarized the plugging progress and mechanism in the liquid-rich system.Besides,it divided the richliquid phase system into an oil-based system,a partially dispersed system,and a water-based system according to the different water cuts,and discussed the mechanism of hydrate plugging.Moreover,it summarized the mechanism and the use of anti-agglomerates in different systems.Furthermore,it proposed some suggestions for future research on hydrate plugging.First,in the oil-based system,the effect factors of hydrates are combined with the mechanical properties of hydrate deposit layer,and the hydrate plugging mechanism models at inclined and elbow pipes should be established.Second,the mechanism of oilwater emulsion breaking in partially dispersed system and the reason for the migration of the oil-water interface should be analyzed,and the property of the free water layer on the hydrate plugging process should be quantified.Third,a complete model of the effect of the synergy of liquid bridge force and van der Waals force in the waterbased system on the hydrate particle coalescence frequency model is needed,and the coalescence frequency model should be summarized.Next,the dynamic analysis of a multiphase mixed rich-liquid transportation pipeline should be coupled with the process of hydrate coalescence,deposition,and blockage decomposition.Finally,the effects of anti-agglomerates on the morphological evolution of hydrate under different systems and pipeline plugging conditions in different media should be further explored.