Kap 5&6

It lowers the heating value, can freeze, and cause solid hydrates whichreduce the pressure drop or plug the line, causes corrosion.

By separation for example gravity settling separator

There are four major sections in a typical separator regardless of shape and size:

• Inlet devices: entering fluids can have a high velocity; 6-10 m/s. The kinetic energy is high and must be used up before the fluid enters the gravity separation section.

• Gravity settling section: in this section liquid droplet large enough to settle by gravity (typically 150-300 μm) will do so.

• Mist extractor section: Droplet smaller than about 150-300 μm will not normally settle in the gravity section. Mist extractor can collect droplets with size of about 20-30 μm

• Liquid coalesce (collection) section.

Causes corrosion, lower heating value

NGL and condensate are separated by lowering the dew point temperature tocondense them. It can be done using three different techniques. This can be done byusing J/T expansion valve, mechanical refrigeration, or turbine expansion

 The mainstream enters a free knockout drum to separate any water.

 Gas and condensate pass through a heat exchanger to lower the temperature.

 To prevent hydrate glycol is injected.

 After the exchanger the gas and condensate pass through a chock valve (joule Thomson effect) to reduce the pressure

 The stream enters the low temperature separator further expansion occurs the temperature drops, and the water and condensate will condense.

 The gas will leave from the top of the separator as a cold gas and will be used in the heat exchanger and then to the next process as a sale gas.

 The condensate will be taken to a stabilizer column to extract the light fractions.

 Notice: The liquids must be stabilized by flashing to lower pressure or using a stabilization column. • When the condensate is flashed to a lower pressure, light hydrocarbons are liberated which may be disposed of in a fuel gas system.

 The stream enters the low temperature separator further expansion occurs the temperature drops, and the water and condensate will condense.

 The gas will leave from the top of the separator as a cold gas and will be used in the heat exchanger and then to the next process as a sale gas.

 The condensate will be taken to a stabilizer column to extract the light fractions.

 Notice: The liquids must be stabilized by flashing to lower pressure or using a stabilization column. • When the condensate is flashed to a lower pressure, light hydrocarbons are liberated which may be disposed of in a fuel gas system

 Gas and condensate from the well enter a heater to increase its temperature.

 Enters the turbe of the LTX (low temperature extractor) seprator not to be split but to increase the bottom temperature when the hydrate occure they will be melted and s eparated.

 From ltx separator to a chock drum to remove any free water (HPOK high pressure knockout drum)

 The stream enters another heat exchanger to keep the gasand condensate tempature ab ove hydrate occurance temperature (hydrate causes slugging in the prosess)

 Then passes the cock valve in the separator to reduce its temperature and pressure.

 In the ltx separator the stream expands the temperature drops

 Water and condensate will be in liquid phase and removed.

 The gas will be taken from the top some of it will be used in the heat exhanger to cool the oppsit stream in the heat exhanger the rest is sale gas.

 The distilate will be passed into low pressure seprator to extract the light fraction.

after water separation always, there is a water vapour in the gas. NO separation process is 100% efficient.

 Direct cooling

 Compression followed by consecutive cooling (expansion)

 Absorption Glycol Dehydration

 Adsorption (molecular Sieve, Silica Gel, or activated Alumina)

The last two approaches are more commonly used, as the first two usually cannot sufficiently dehydrate the gas to pipeline requirements

Absorption the water vapour mixes completely with the absorption agent (Glycol)

Adsorption: sticks to the surface (molecular Sieve, Silica Gel, or activated Alumina

absorption dehydration is a process where water vapour is absorbed in a counter-current absorption tower by using a specific liquid solvent that has special attractionor affinities to water. The liquid solvent is called a dehydrating agent or liquiddesiccant