View source for Dry Sweet Gas Scrubber(PV-1108)

The dehydrated gas from [[TEG contactor(PV-1106)]] flows through the dry sweet gas scrubber where any TEG entrained in the sales gas is captured. The liquids that are captured are delivered back to the TEG flash drum. The water content of the gas is analyzed upon exiting the dry sweet gas scrubber and is used to adjust the TEG circulation flow to maintain sales gas quality.

Gas exits the scrubber through a demister pad which removes any remaining liquid droplets. The gas from the dry sweet gas scrubber then flows through a back pressure control valve and ESD before entering the TCPL or to the [[Sales Gas Compressor(KT-1601)]] to elevate the gas pressure for TCPL delivery if required.

[[File:DrySweetGasScrubber.png|center|frame|Dry Sweet Gas Scrubber]]

==Process Controls and Instrumentation==

The Dry Sweet Gas Scrubber (PV-1108) has the following level controls and instrumentation:
*a level glass to locally indicate the liquid level (LG-1093)
*a level transmitter and level control valve (LCV). The level transmitter (LV-1206) reading is relayed to DCS for onscreen display and is used by the DCS-based level controller. The controller modulates the LCV to maintain setpoint level under 0-100% range level control: (LV-1206) has a manual stop travel stop at 54% valve opening
*A High setpoint (LCH-1093) and a low setpoint (LCL-1093) will be accessible from the operating station to allow the operator to make changes as necessary, manipulating the liquid level of the sweet gas scrubber. The level between these two setpoints is the operating level of the vessel.
*When LCH is reached (LV-1206) will move to the fully open position and will remain open until a low level (LCL-1206) is reached. (LV-1206) will move back to the fully closed position, until a high level is reached again.
*The Dry sweet Gas scrubber also has a local pressuer gauge (PI-1205) and a local temperature indication (TI-1205) for local viewing by the Area Operator

==Process Alarms and Shutdowns==

The Sweet Gas Scrubber is equipped with alarms that appear onscreen at DCS:
*A high and low level alarms triggered by (LIT-1207) reading (low level 20 %/high level 55%)
*A low level shutdown (LALL-1207) is triggered at 4%
*A High level shutdown (LAHH-1207) is triggered at 81%

==Specialty Lines and Valves==

The dry sweet gas scrubber (PV-1108) is equipped with the following:
*drain valves (on level column and gauge glass) flow to the TEG drain tank.
*65# steam purge line for purging the vessel for shutdowns and turnarounds.
*a pressure relief device (PRV-1201) set at 1300 psi that relieves to the HP flare system, in the event of an over pressure situation.
*a choke tube located downstream of the Level Control Valve to prevent gas blow by

==Area Operator Monitoring==

In conjunction with the CRO, the Area Operator investigates high-level alarms promptly to rectify the cause. During monitoring rounds at the Dry Sweet Gas Scrubber, the Area Operator:
*checks for leaks
*checks that the level is at setpoint
*checks the pressure
*blows down the level glass and float column (Ensure to always check with the CRO when blowing down columns and switches)