Experimental Study On Rapid Formation Of Carbon Dioxide Hydrate

Carbon dioxide hydrate has attracted much attention because of its high gas storage capacity and low-cost carbon capture,but its low formation rate limits its application.To improve the formation rate of carbon dioxide hydrate,accelerators are usually used,and different types of accelerators have different effects.In order to study the effects of promotion or restriction between different types of accelerators,four different types of accelerators were used in this paper: kinetic accelerator sodium dodecyl sulfate(SDS),thermodynamic accelerator Tetra-n-butylammonium bromide(TBAB),nanofluidic nanographite and ionic accelerator sodium chloride(Na Cl),were applied to the formation of carbon dioxide hydrate in the form of single or compound,and the effects of different types of single and compound accelerators and different concentrations of compound accelerators on the formation of carbon dioxide hydrate at 3.3 MPa and 272.65 K were studied.The specific conclusions are as follows:(1)Among the single systems of SDS,TBAB,nanographite and Na Cl accelerator: the induced nucleation time of the SDS system is the shortest and that of the Na Cl system is the longest;The total production and total conversion increased rapidly at first and then slowly until unchanged,and increased the most at 5～10 min;The formation rate increased first and then decreased,and reached the maximum at 5～10 min;The amount,rate and conversion of TBAB system are the largest and that of Na Cl system is the smallest.(2)In the binary complex system,the induced nucleation time of the Na Cl-nanographite system is the shortest and that of the SDS-TBAB system is the longest;The total production total conversion increased rapidly at first and then slowly until unchanged,and increased the most at 5～10 min;The formation rate increased first and then decreased,and reached the maximum at5～10 min;The amount,rate and conversion of SDS-nanographite system is the largest and SDS-Na Cl system is the smallest.(3)In the multi-component complex system,the induced nucleation time of the SDS-Na Cl-nanographite system is the shortest and that of TBAB-nanographite-Na Cl system is the longest;The total production and transformation increased rapidly at first,then slowly until unchanged,and increased the most at 5～10 min;The formation rate increased first and then decreased,and reached the maximum at 5～10 min;The amount,rate and conversion of SDS-TBAB-nanographite system is the largest,and the SDS-Na Cl-nanographite system is the smallest.(4)In the system of TBAB and SDS with different concentrations: with the increase of SDS concentration,the induced nucleation time first increases and then decreases,among which the induced nucleation time of TBAB-0.06 g/L SDS system is the shortest and TBAB-0.24 g/L SDS system is the longest;The total production and total conversion increased first increase rapidly,then increase slowly until unchanged,and increased the most at 5～10 min;The formation rate increased first and then decreased;The formation rate,amount and conversion of TBAB-0.06 g/L SDS system are the largest and TBAB-0.48 g/L SDS system is the smallest.(5)In the system of TBAB and nanographite with different concentrations:with the increase of nanographite concentration,the induced nucleation time first decreases,then increases and then decreases.Among them,the induced nucleation time of TBAB-2.5 g/L nanographite system is the shortest and that of TBAB-7.25 g/L nanographite system is the longest;The total production and total conversion increased first increase rapidly,then increase slowly until unchanged,and the increase was the largest at 5～10 min;The formation rate increased first and then decreased;The formation rate,amount and conversion of TBAB-10 g/L nanographite system are the largest,and TBAB-5 g/L nanographite system is the smallest.(6)In the system of TBAB mixed with different concentrations of Na Cl:with the increase of Na Cl concentration,the induced nucleation time first increases and then remains unchanged.Among them,the induced nucleation time of TBAB-0.825 g/L Na Cl system is the smallest,and the induced nucleation time of TBAB-0.33 g/L Na Cl system,TBAB-0.495 g/L Na Cl system and TBAB-0.66 g/L Na Cl system is the same and the largest;The total production and total conversion increased first increase rapidly,then increase slowly until unchanged,and the increase was the largest at 5～10 min;The formation rate increased first and then decreased,and reached the maximum at 5～10 min;The formation rate,amount and conversion of TBAB-0.66 g/L Na Cl system are the largest and TBAB-0.0825 g/L Na Cl system is the smallest.