INTRODUCTION: NATURAL GAS DEHYDRATION

In August 2014, I got an opportunity to work an an intern in OGDCL Nandpur Gas Dehydration Field.  

Nandpur gas dehydration field located in Kabirwala, Punjab between the green fields of cotton and rice alongside the bank of sujjabad canal. This field was got operational in 2005, working with the capacity of 50 MMSCFD. Nandpur field is central gas facility where gas gathered and process. After processing gas goes to Fauji Kabirwala Power Company Limited (FKPCL)

Natural gas is a clean ignition source of fuel and heat for our homes and industries but in order per natural gas to be useful like this, it must undergo many changes on its trip from well to end uses. How natural gas is transformed from its raw stage to useful product.

The natural gas coming out from wells often has too many contaminates, to meet the quality specifications of natural gas buyers, also the gas stream may contain NGL (Natural Gas Liquids) but could have an increase values its separate from the gas stream. So the gas is process to make it more useful and in some cases to make it byproducts, both are marketable.

The natural gas coming out of well is not quality gas, for to meet its quality requirements. It is necessary to pass through several units, which are following

1. Gas Well
2. Water Separator
3. Metering Station
4. Central Gas Facility
5. Gas Processing

      1. Gas Well

Gas processing is start from the well. Gas is coming out of the ground normally contain fluids such as oil and water but OGDCL Nandpur field face only water. These liquids must remove because the producer concerns the gas.

    

      2. Water Separator

A device used to separate Water from Gas know as separator.

     3. Metering Station

After separation gas is pass through orifice meter station by pipeline to the central processing facility. Kneading is a vital link in the process chain because in-order to maximize profits it is critical to know how much gas leaving the well and how much is arriving at the central process facility. A significant difference in those two amounts could indicate a problem, such as leak in pipeline. 

   

     4. Central Gas Facility

Now in-order to gas process efficiently, reaches pipe from many producing location to the central gas facility. This is called gas gathering. This gas gathering station can be in where from mile to thousands of mile and link and meet-up pipelines and booster stations that increase the gas pressure as needed to meet the gas at its processing destination. At Nandpur gas field gas reaches from producing location to central gas facility by his own pressure, there is no use of booster. 

      
     5. Natural Gas Processing

Gas Processing categorize into two process

• Contaminant removal

• NGL    removal (NGL removal method are excluded)

We face contaminants only at Nandpur gas field. Contaminant must be removed in-order to meet pipeline quality specifications. The common natural gas contaminants are

• Water

• H2S

• Inert gases (CO2, N2)

Note: Nandpur gas contains water which should be removed, gas is free of H2S and CO2 is under normal conditions but N2 is about 60-70% average in gas, we ignore this. This has a technical reason.