OPERATION OF HEATER TREATER

OPERATION OF HEATER TREATER

1. It is a horizontal vessel employing a vertical flow pattern. Heater treater employs method of heating , chemical action , electrical coalescence , water washing of oil and settling for demulsification of oil .
2. Movement of fluid through heater treater is controlled by a system of differential pressure combined with static heat .
3. Heater treater vessel is divided into four parts .
   i  . Inlet degassing section
   ii . Heating section .
   iii. Differential oil control chamber .
   iv. Coalescing section

INLET DEGASSING SECTION

Oil mixed with demulsifying chemical enters the heater treater through degassing section , above the fire tubes . Free gas is liberated from the flow stream and is equalized across the entire degassing and heating areas of the treater . The  degassing section , is separated from the heating section by baffles .The fluid travels downward from the degassing area and enters the heating section under the fire tubes through multiple orifice distributors .

HEATING SECTION

Heating section consist of a fire tube bent at 180°.

In 6ft. × 15 ft . heater treater , there is one tube ; in 8ft. × 20 ft . heater treater , there are two tubes . The constant level in this section is maintained by weir height . Oil enters this section from bottom of degassing section and passes through  heater at bottom and washing action takes place and free water and solids fall out of the oil stream . The water level in this section is controlled by a weighted , displacement type interface float which operates a water discharge control valve by instrument air acting on diaphragm . The oil allows water flow upward from the distributors section, surrounding the fire tubes , where the adequate temperature is attained .The increase in temperature of the oil releases some additional gas . The heat released some additional gas . The heat released gas then joints the free gas from the inlet section and is discharged from the treater through a gas back pressure control valve .

DIFFERENTIAL OIL CONTROL CHAMBER

The fluid which is heated should be transferd from the heating section over the fixed weir into a differential chamber for oil control , which contains a liquid level control float . The fluid travels downwards to near the bottom of the differential oil control chamber where the opening to the coalescing section distributors are located .

COALESCING SECTION (ELECTRICAL CHAMBER )

Heater treater operates under a high voltage potential on the electrodes for merging of the water droplets in the final stage of processing . The electrodes are suspended on the insulated hanger from the upper portion of vessel . The ‘Ground’ electrode is made up of solid steel hangers to provide proper grounding with the steel of the treater .

An externally mounted , oil immersed high voltage transformer is designed such that to provide the proper power supply to the electrodes .The transformer uses 240 volts in primary and supplies 16500 volts in secondary .The secondary unit having a high voltage is connected to charged electrode through a high voltage entrance which is specially designed in the form of a bushing for insulation .Secondary is also connected to voltmeter and external pilot indicator light .The oil and entrained water enter the coalescing section from the differential oil control chamber through multiple ,full length , metered distributor .As the oil and transformed water come into contact with each other the electrical field produced in the grid area, final coalescing of the water take place .

The water supply which is falling back into the water area at the bottom and the clean oil starts continuously rises to the top portion, and finally it enters at the collector and is comes out through the clean oil outlet of the control valve .