| Hydrate gas storage and transportation technology utilizes the characteristics of large gas storage capacity and mild storage conditions,and converts gas into solid hydrate at low temperature and high pressure,so as to achieve the purpose of gas storage and transportation.application prospects.However,due to the slow formation rate of hydrate and the low actual gas storage capacity,the hydrate method has not yet achieved industrial application.In order to improve the rate of hydrate formation and the actual gas storage capacity,the water-in-oil emulsion was selected as the hydrate generation medium based on the fact that the huge surface area of water droplets in the water-in-oil emulsion can provide a good gas-liquid contact area for the formation of hydrates,to study the rapid formation of flowable hydrate slurry and the separation of hydrate particles.The main research contents of this paper are as follows:(1)Using oil-water emulsion as hydrate generation medium,hydrate formation rate and slurry fluidity were studied under the single action and mixed action of emulsifier and hydrate anti-polymerization agent,respectively.The results show that Span 20 has the best effect on promoting hydrate formation among all the single additives.The water content is 20 vol%and the hydrate gas storage capacity in the emulsion containing Span 20 can reach 177.7 V/V_w(standard gas volume/V_w).volume of water).With the increase of water content,the gas storage capacity of hydrate gradually decreases,and the phenomenon of hydrate coalescence gradually becomes obvious.All of the single additives studied in this work are not very good at preventing hydrate coalescence,even the most effective Span 20 can only prevent hydrate coalescence at low moisture contents of 5 vol%and 10 vol%.When the emulsifier is compounded with a high-concentration hydrate anti-polymerization agent,it will inhibit the formation of hydrate,and reducing the amount of hydrate anti-polymerization agent used can reduce the inhibition of hydrate generation while maintaining the anti-polymerization effect.Low water content,high Span 20 concentration,especially compound additives are effective solutions to solve the problem of hydrate fluidization with high conversion rate.(2)Aiming at the separation of hydrate particles in hydrate slurry,a process for continuously producing gas hydrates was proposed based on water-in-oil emulsion,and the specific resistances of the hydrate cakes formed from different emulsions and under different pressure drops were measured.The results showed that the specific resistances of the hydrate cakes increased with the increase of the pressure drop in two stages.The increase process is divided into two steps,and the increase is faster in the second stage.Increasing the concentration of emulsifier Span 20,anti-aggregation agent TBAB and PE all increased the hydrate cake resistance.The resistance of the hydrate cake formed with Span 20+TBAB as additive is much higher than that of Span 20 or Span 20+PE.Based on the measured specific resistance of the hydrate filter cake,the filtration rate for the assumed production task was calculated.The results show that when the concentration of TBAB is≥0.25 wt%as an anti-agglomeration agent,the filtration rate cannot meet the production requirements.According to the experimental results,a method involving filter medium pore size,additives and operating pressure difference is proposed to complete the efficient filtration of hydrate slurry and realize continuous hydrate production. |
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