Dehydration With Organic Liquid Desiccants.

The removal of water from natural gas with organic liquid desiccants has become one of the most widely accepted methods of dehydration. Technical Data used in the field explained in petroleum courses in Islamabad.   Though a large number of organic materials can be used as liquid desiccants, by far the most generally used are the ethylene glycols. Ethylene glycol (EG), ethylene glycol (DEG), triethylene glycol (TEG), and tetra ethylene glycol (TRG) all can be satisfactorily used for dehydration of natural gas. However, by far the most widely used and generally accepted is TEG. Figure 14.19 shows a schematic flow sheet for  absorption dehydration of natural gas using an ethylene glycol. The flow sheet will vary little from one glycol to the next. Wet gas enters the absorber and flows up through a series of plates coming into contact with the concentrated glycol solution. The glycol removes from 75 to 95 % of the incoming water vapor in the gas, depending on the efficiency of the overall system. This lowers the dew point of the gas and the dehydrated gas leaves the absorber top and flows to the sales gas line.

There are practical limitations to using TEG for dehydration from both a dehydration-efficiency and an operating-cost standpoint. The lower the temperature in the contactor, the greater the viscosity of the glycol solution. As the viscosity of the solution increases, the efficiency of the contactor decreases, which results in less water-vapor removal per stage or plate. At temperatures below 50”F, a pronounced reduction in efficiency has been observed. At temperatures approaching the freezing point of water, the TEG solution becomes so viscous that the liquid is all but impossible to move through the system. Some more details of petroleum courses in islamabad are as under.

As the contact temperature increases, the vapor pressure of the solution increases, which results in higher vaporization losses of glycol and higher outlet water content of the gas. If the contactor temperature is increased to 120°F the vapor pressure of a 99-wt% glycol TEG solution will be almost twice what it is at 100°F with consequently larger vapor losses of the circulating solution. There is no reasonable pressure limitation on the use of TEG for dehydration. However, the maximum dew point depression appears to increase with pressure up to about 500 psi and then remains essentially constant for higher pressures. Dehydration units have been designed and operated satisfactorily at pressures as high as 2,000 psi. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join oil field after petroleum courses in Rawalpindi.