Studying On Hydrate-based Desalination Technology In Water-in-Oil Emulsion System

Recently,hydrate desalination technology as a new desalination technology is received much attention at home and abroad,because it has many advantages.This work aims atstudying this technology on desalination of sea water in water-in-oil?W/O?emulsion and laying the foundation for the industrialization of this desalination technology.The main contents are:1.Under the atmospheric pressure environment,when the initial watercut in the water in oil emulsion keeps constant,the induction time of hydrate formation increased with increase of salinity of salty water.The higher the salinity,the higher the efficiency of desalination and the lower the fresh water yield.When the initial watercut keeps 40%,the highest desalination efficiency of 65.53% is obtained at the salinity 5%,while the highest fresh water productivity of 71.25% at the salinity of 2%.2.The experimental study is carried out on the hydrate formation of CH₄ + cyclo-pentane?CP?+ salt waterwater in oil system for desalination.When the watercut in W/O emulsion is greater than 30%,with the increase of the salinity,the hydrate formation rate is not significantly reduced,and therefore the initial watercut should be selected greater than 30% for the desalination experiment.In the hydrate-based desalination experiment under a pressurized environment,when the initial salinity is 2% and the watercut is 30%,the highest salt removal rate is reached to 74.73%.When the initial salt content is 3.5% and watercut is 40%,the largest amount of fresh water is obtained to be 87.50 %.3.The experimental study is also carried out on the hydrate formation of CO₂ + cyclo-pentane?CP?+ salt waterwater in oil system for desalination.When the initial salinity is less than 4%,the highest efficiency of desalination is obtained to be 83.1%.But with the increase of the salinity,the free water conversion rate decrease.When the initial watercut and salinity are 50% and 4%,respectively,the water conversion rate reach to the highest value of 70%.Compared the free water conversion rate and desalination efficiency at the same salinity condition,it is found that when the initial watercut is 50%,the amount of fresh water obtained is the largest.At the initial watercut is of 40 %,the free water conversion rate is the lowest but the salinity in the fresh water also is the lowest.