Kinetics Of Gas Hydration Separation Under The Influence Of Temperature Dynamic Regulation And Promoters

Coal mine gas is the main companion product in coal mining process.It is a kind of clean energy,chemical raw materials and a major greenhouse gas.At present,the total volume of gas drainage in China is high while the utilization rate is low.The coal mine gas hydration separation and storage and transportation technology proposed by professor Wu Qiang team is of strategic significance for protecting the ecological environment,improving gas utilization rate and achieving sustainable development of the national economy.The current studies of gas hydrates have the problems of long induction time,slow formation rate.Therefore,this paper studies the method of shortening the induction time,increasing the gas consumption and growth rate of coal mine gas hydrate.It provides a theoretical basis for the realization of high-efficiency,fast and low-energy hydrate method for capturing CH₄ in coal mine gas.Firstly,we carried out experimental research on gas hydrate formation?G1?70%CH₄/24%N₂/6%O₂?,G2?60%CH₄/32%N₂/8%O₂??under the influence of temperature dynamic regulation with different sub-coolings.It clarified the Raman quantification factors of gas mixture and the calculation method of real-time monitoring of the concentration of each component in the mixed gas during the hydration process using Raman quantification factors.Results showed that the gas uptake and growth rate of the low sub-cooling systems are higher than those of the high sub-cooling system.The Raman intensity of the CH₄ in the gas phase gradually decreased with the hydrate formation.The Raman intensity and cage occupancy of the CH₄ in large and small cage in the hydrate phase gradually increased with temperature regulation.The hydration number gradually decreases and the hydrate structure gradually stabilizes.Furthermore,we carried out experimental studies on gas hydrate formation?G3?80%CH₄/16%N₂/4%O₂?and G4?90%CH₄/8%N₂/2%O₂??under the influence of different promoters?1.1mol%Tetrabutylammonium bromide?TBAB?/Tetrahydrofuran?THF?/Cyclopentane?CP??.The results showd that the gas uptake and growth rate of the G4 system are higher than those of the G3 system,and the gas uptake and growth rate of the THF system are higher than those of the TBAB and CP systems.In addition,it was found that the stable sII hydrate was formed in the presence of THF,according to the CH₄ Raman peak area ratios A_L,CH4/A_S,CH4 in large and small cages of each system.The hydration number of G3 and G4 system are 9.393 and 5.889,respectively.Obviously the G4 system was lower than the G3 system and was closest to the ideal hydration number of 5.67,indicating that the system produced relatively stable hydrates and had better methane capture effect.Finally,we carried out gas hydration separation experiments in the presence of different concentrations of Tetrabutylammonium fluoride?TBAF??0.15,0.5,0.8,1.5 mol%?and CP?5,10,15,20 vol%?.According to compare the gas uptake,growth rate,CH₄ recovery and separation factors in the hydrate formation process of each system.0.5mol%TBAF and 20vol%CP systems have the best influence on promoting hydrate formation.Based on this,0.3wt%tryptophan was added for compounding.The result found that the addition of tryptophan effectively shortened the time to the end of hydrate formation,significantly increased gas uptake,CH₄ recovery and separation factor.It can achieve safe and efficient capture of methane from coal mine gas.