The equilibrium compositions and properties of CO2/CH4/1,4-dioxane/water hydrate were studied for the first time at temperatures ranging from 273.65 to 281.35K and pressures ranging from 0.5 to 1.1MPa. The gas mixture consist of about 45% CO2 was used to be an exemplary for biogas and landfill gas operations. Equilibrium hydrate formation conditions for above system were measured. 1,4-Dioxane lowered equilibrium pressure by 2MPa comparing with pure water at some temperatures. This is an indication that structural transition from SI to SII was occurred.
As much as Montreal and Kyoto protocols enforcements increase, clathrate hydrate of CO2 attracts more attention as a means of CO2 capture and sequestration. A novel method to separate CO2 from gas mixtures is hydrate formation . Effect of additives on pure CO2 and CH4 hydrates have been studied comprehensively . Few compositional data were published about CO2/CH4 mixture hydrates and fewer data about the effect of additives on their equilibrium. A binary CO2/CH4 mixture forms only structure-I hydrate . Most of the previous researches reported equilibrium temperature and pressure of a feed stream with a known composition without equilibrium vapor analysis . Ohgaki reported partitioning of CO2 from a CO2/CH4 mixture at 280K. Vapor phase composition of CO2/CH4 mixture hydrate also was measured. Servio studied the effect of neohexane and observed a reduction in equilibrium pressure about 1MPa and concluded that CO2/CH4 /neohexane forms structure H hydrate. Addition of the organic compounds such as 1,4-dioxane to the system in small concentrations of almost 6 mole % relative to water leads to reduction of gas hydrate formation pressure . 1,4-Dioxane can form structure-II of clathrate hydrates with or without presence of a gas, like methane . Structure-II consists of 16 small cages (512) and 8 large cages (51264). Jager reported that for the methane/water/1,4-dioxane system the equilibrium hydrate formation pressure at a specific temperature was decreased by addition of 1,4-dioxane up to a concentration of 6 mol%. In the present work we provide the equilibrium hydrate formation conditions, partition coefficients and storage capacity measurements for CO2/CH4/1,4-dioxane/water system.
Publisher : ۲nd National Iranian Conference on Gas Hydrate (NICGH)
By : Reza Dorosti , Mehrdad Manteghian
File Information: English Language/ 8 Page / size: 0.98 KB
سال : ۱۳۹۲
ناشر : دومین کنفرانس ملی هیدرات گاز (NICGH)
کاری از : رضا درستی، مهرداد منقتانیان
اطلاعات فایل : زبان انگلیسی / ۸ صفحه / حجم : KB 0.98