Preliminary Study On The Driving Force Of Gas Hydrate In The Liquid-liquid System

The refrigerant gas hydrates as the new air-conditioned storage media, compared with water,ice and eutectic salt, the refrigerant hydrates has a desirable melting temperature between 5-12℃, a high cooling heat capacity, the latent heat is comparable to that of ice (about 330KJ/kg), and the heat transfer efficiency is high.In the cold process which the refrigerant hydrate applies in the air conditioning accumulation, the fast production of hydrate is the technical key. Because the hydrate production process is complex, the domestic and foreign gas hydrate production dynamics research still also occupied the initial stage. In order to study the hydrate fast production method, this article obtained from the gas hydrate production driving force, to infer the liquid-liquid system gas hydration response production driving force formula, under the experimental study different driving force condition in the gas hydrate production process. The following work has been carried out.(1) In this article, we make use of theoretics and first and second law of thermodynamics knowledge, we derivate the math formulation about the driving force of liquid-liquid system with the Gibbs free energy function, to HCFC-141b refrigeration hydrate as example, we make use of formulation calculate the driving force of HCFC-141b gas hydrate in press range. The formulation is below:△g=△gT＋△gP＝△ν141b(peq-pexp)-△ν(pexp-peq)-s(Texp-Teq)This formula is mainly used to process of hydration with liquid to participate, so we can calculate the driving force of gas hydrate in the press and temperature areas, which could form the hydrate, so that we can ascertain the most driving force in any conditions, and provide a theoretical basis for making hydrate fast.(2) HCFC-141b hydrate can be formed at the temperature below 8.4℃under the atmosphere pressure. In this article, we investigate the influence of different temperature and pressure on the formation process of HCFC-141b hydrate in a quiescent system. we found that the more pressure and the lower temperature, the more driving force for hydrate, but in the stimulate of pressure, can generate hydrate quickly, in the same temperature, the HCFC-141b refrigeration hydrate generate easily in the 0.2MPa. Analysed the experimental dates, we know:on the one hand, there is the most driving force, that in this condition of temperature and pressure, the water molecule can reset so that form the configuration of gas hydrate, consequently, shorten the induction time enormously, promote hydrate formation fast; in the other hand, in the pressure stimulation and bigger temperature gradient conditions, the mass transfer make the two-phase mixture easily, so that provide a material basis, the energy transfer make the formation heat is discharged timely to ensure that cold conditions, accordingly promote the hydrate formation.The originality innovation of this paper was listed as follow:(1) Derived from liquid-liquid system of gas hydrate formation driving force against the formulation;(2) In the press stimulation and temperature gradient's action together, found that can promote the hydrate formation, so provides a method for the new air conditioning accumulation of cold medium's preparation, simultaneously may promote the refrigerant hydrate to take the new accumulation of cold medium to apply in the air conditioning industry, impels the air conditioning industry the development;...