The Logic Behind The Magic."H2S Removal system 7"

Amine Drain System.

 The drain system of amine unit is a closed system, where each drain line is tied into an underground pipe header, which flows into the Amine Drain Vessel. The system, from the piping, equipments and instrumentations, is hard piped and freely drained into Amine Drain Vessel.

The Amine Drain Vessel is located in the sump pit as the TEG Drain Vessel. The Amine Drain vessel is designed to store the entire liquid inventory of amine system. The vessel is constructed from CS lined with 3 layers epoxy lining and equipped with fireproofing insulation to anticipate pool fire condition in emergency case.

To prevent degradation of the solvent by air ingress, fuel gas blanketing is provided to drain vessel controlled by PCV-A, set at 0.27 barg and PCB-B set at 1.75 barg to release gas in case of built-up pressure at the vessel is maintained at about 0.1-0.3 Barg.

As the pit is open, rainwater could accumulate in the pit. Sum drain pumps are provided to pump the rain water out from the pit.

The drained solution is collected in the sumps provided at the following points where potential leakage or spillage is considered.

When amine solution liquid level is too high, the amine solution can be pumped back to the Amine Surge Vessle with the Amine Drain Vessel Pump.

The Logic Behind The Magic."H2S Removal system 6"

Amine Circulation System Control Narrative

The Amine Regenerator Overhead Cooler outlet temperature is controlled by TC. When outlet temperature of Amine Regenerator Overhead Cooler is decreases, VFD Speed Control is controlled by TC for preventing from more decreasing and increasing temperature.

 

Other controllers
The controller will used simple loop type with direct -reverse acting list as follows:

The Logic Behind The Magic."H2S Removal system 5"

Amine Circulating System.

The hot lean amine existing the amine regenerator flows into the lean side of lean/rich amine exchangers by means of heat lean amine pumps where heat is exchange with the cold rich amine from the flash drum. The cooler lean amine is further cooled to 45 degC in the lean amine air cooler. This is an air cooler utilizing stadard finned tubes and electric motor driven fans. Air cooler is equipped with bug screens and eazh bank includes one variable frequency drive (VFD) fan motor to assist in achieving close temperature control of the lean amine.

The Logic Behind The Magic."H2S Removal system 4"

Amine Regenerator Overhead Cooler Control Narrative

The Amine Regenerator Overhead Cooler outlet temperature is controlled by TC. When outlet temperature of Amine Regenerator Overhead Cooler is decreases, VFD Speed Control is controlled by TC for preventing from more decreasing and increasing temperature.

 

Other controllers
The controller will used simple loop type with direct -reverse acting list as follows:

The Logic Behind The Magic."H2S Removal system 3"

Amine Regeneration System.

The rich amine solvent from the contactor bottom flows to the Amine Flash Drum through level control valve. This level will let the rich amine pressure down from 46.3 to 5.5 barg. This is where the first stage of degassing of the solvent takes place. The drum is designed to allow the break out of the H2S and CO2. The drum is designed for liquid removal efficiency of 99% or greater for liquid droplet size of less then 70 micron, limiting the liquid carryover in the gas to be less than 0.1 gal.MMSCF, maximum oil carryover in the outlet water is 1% weight and maximum water carryover in the outlet oil is 1% weight.

Rich amine solution from the flash drum, at 31 degC flows into the lean/ rich amine exchangers and  is heated to about 93.5 degC. Proir entering the exchanger; the rich amine is filtered at the rich filter to removed any contaminant particles.

The Logic Behind The Magic."H2S Removal system 2"

Amine contactor System Control Narrative

Amine Contactor Inlet KO Drum level controller

Gap Control is applied to the inlet KO Drum level control. On normal process valve, the control valve controlled normally by level control. If PV decrease untuil reach low level alarm the controller will send command for 0% close to control valve, and if PV increase until high level alarm. The controller will send command for 100% open.

The Logic Behind The Magic."H2S Removal system 1"

The H2S removal system is usually utilizes Methyl Diethanolamine (Ucarsol) solvent to absorb content in the gas stream and reduce H2S concentration to 10 ppmv to meet sales gas specification.

 Ucarsol solvent is formulated to operate at a 15 +/- 5 % wt. Operating above this concentration range can lead to viscosity related problems such as in efficient acid gas absorption, hydrocarbon entraintment, poor heat transfer efficiency and higher pumping requirement. Operating below this will result in increase circulation rate and higher reboiler duty requirement. The system also includes regeneration of Ucarsol solvent to strip H2S gas and H2S tail gas is further treated in the thermal oxidizer prior disposal.