Sinclair ARU 1 Gas Contacting System Module C PDF

## Overview: Environmental regulations limit hydrogen sulfide (H2S) in fuel gas burned at the Sinclair Refinery. The Amine Regeneration Unit (ARU) 1/2 located in the Reformer Complex, uses methyldiethanolamine (MDEA) to remove acid gases from fuel gas streams. The amine is regenerated and reused in...

## Overview: Environmental regulations limit hydrogen sulfide (H2S) in fuel gas burned at the Sinclair Refinery. The Amine Regeneration Unit (ARU) 1/2 located in the Reformer Complex, uses methyldiethanolamine (MDEA) to remove acid gases from fuel gas streams. The amine is regenerated and reused in the absorption process. ### The Gas Contacting System - The first step in the Amine Regeneration Unit. - Receives sour gas from the Sour Gas Header, the #2 HDS Separation and Stripping System, and the #3 HDS Stripping System. - Amine absorption technology removes toxic H2S impurities and carbon dioxide (CO2). - Three parallel contactors are used. - Dilute MDEA solution is used to absorb hydrogen sulfide, resulting in "rich amine". - Sweetened fuel gas, free of hydrogen sulfide, is provided to the Fuel Gas Header to be used throughout the refinery. - The rich amine is fed to the ARU 1/2 or 3/4 Amine Regeneration System to be regenerated. ### Sour Gas - Contains hydrogen sulfide (H2S) and carbon dioxide (CO2) - Enters the subsystem from the #2 HDS and #3 HDS Stripper Overhead Accumulators (5PV-2206 and 13PV-2319) in the #2 HDS Separation and Stripping System and the #3 HDS Stripping System, respectively. - Flows to and from the Amine Settler (5PV-1615 in the Amine Regeneration System, as needed. - The combined sour gas stream is fed to the bottom of the HDS Stripper Contactor (5PV-1605) and flows upward. - The #4 HDS Overhead Accumulator release can also be lined up to 5PV-1605. ### HDS Stripper Contactor - 20 tray absorption tower. - Uses amine absorption technology to remove acid gases from the sour gas stream. ### HDS Stripper Contactor Subsystem - Receives sour gas from the #2 HDS Separation and Stripping System and the #3 HDS Stripping System. - Amine absorption technology removes acid gases such as hydrogen sulfide and carbon dioxide from fuel gas in order to comply with environmental regulations. ### Amine Settler 1/2 (5PV-1615/2248) - Weir system skims off lighter hydrocarbon liquid from the rich amine. - A portion of the skimmed oil is pumped by the Skimmer Pump (5P-146) from the settler to the Rich Amine Settling Tank (5PV-2244), on level control. - Slop oil enters 5PV-2244. **Purpose:** - 5PV-2244 is a vertical separation vessel that allows rich amine to separate out of the entering slop oil. ### Rich Amine Settling Tank (5PV-2244) - Due to the difference in densities, any rich amine in the entering slop oil streams settles at the bottom of 5PV-2244. It can be returned to 5PV-1615 for recovery. - Slop oil sits on top of the rich amine. It is routed from the settling tank to the Tank Farm Slop Oil Header. - If a known hydrocarbon fills the weir side of the Amine Settler (5PV-1615/2248), slop oil can be pumped by the Skimmer Pump (5P-146) directly to the Tank Farm Slop Oil Header, bypassing the Rich Amine Settling Tank (5PV-2244). ### Nitrogen - Enters the subsystem on flow and pressure control. - Can be sent to the Rich Amine Settling Tank, or routed to the flare **Purpose**: - To pressure up 5PV-2244 to push amine or hydrocarbon to their respective locations. - Then switched to the flare to relieve an excess pressure. ### MDEA - A dilute solution of methyldiethanolamine (MDEA) is fed to the top of the absorber on flow control. - Known as "lean amine" because it is free of acid gas. - The absorber can receive lean amine from either the Amine Regeneration Unit (ARU) 1/2 or 3/4 depending on the lineup. **Purpose**: - Due to its higher affinity for H2S over CO2, MDEA is used as a solvent to absorb the majority of the toxic hydrogen sulfide from the sour gas, while allowing some CO2 to "slip," or pass through the column. - As the lean amine flows down through the trays in the absorber, it contacts the counter-flowing gas stream. - The H2S and some of the CO2 in the sour gas stream, known as the "solute," transfers from the gas phase to the aqueous phase, where it reacts with amine. - This results in amine that is rich in hydrogen sulfide, known as "rich amine." ### Lean Amine - A portion of the lean amine from the ARU 1/2 or 3/4 is routed to the HDS Stripper Contactor (5PV-1605) as the solvent for H2S removal. ### Fuel Gas Contactors Subsystem - Receives sour gas from the Sour Gas Header. - Amine absorption technology is used in two parallel contactors to remove toxic hydrogen sulfide from the sour gas in order to comply with environmental regulations. ### Lean Amine - A dilute solution of methyldiethanolamine (MDEA) is fed to the top of the Fuel Gas Contactors on flow control. - It's known as "lean amine" because it is free of acid gas. - The contactors can receive lean amine from either the Amine Regeneration Unit (ARU) 1/2 or 3/4 depending on the lineup. **Purpose**: - Due to its higher affinity for H2S over CO2, MDEA is used as a solvent to absorb the majority of the toxic hydrogen sulfide from the sour gas, while allowing some CO2 to "slip," or pass through the column. - As the lean amine flows down through the trays in the absorber, it contacts the counter-flowing gas stream. - The H2S and some of the CO2 in the sour gas stream, known as the "solute," transfers from the gas phase to the aqueous phase, where it reacts with amine. - This results in amine that is rich in hydrogen sulfide, known as "rich amine." ### Lean Amine - A portion of the lean amine from the ARU 1/2 or 3/4 is routed to the HDS Stripper Contactor (5PV-1605) as the solvent for H2S removal. ### Lean Amine - A portion of the lean amine sent to 5PV-1604 can be routed through the #1 ARU Amine Filter East/West (5PV-2291/2292). **Pulse**: - Filters 5PV-2291/2292 remove debris from the lean amine to protect downstream equipment. ### Lean Amine - Filtered lean amine is sent to the suction of the Rich Solvent Pump West/East (5P-145/150) in the Amine Regeneration System. ### Fuel Gas Contactors - Sour gas enters the subsystem from the Sour Gas Header, which includes feed streams from the following units: the Gas Recovery Unit (GRU), Fluid Catalytic Cracking Unit (FCCU), #1 - #3 HDS Units, and the Flare Gas Recovery Unit. - The sour gas is fed to the bottom of the Fuel Gas Contactor (5PV-1604) and flows upward through the column. **Purpose:** - Similar to 5PV-2243, the Fuel Gas Contactor is a 20 tray absorption tower that uses amine absorption technology to remove acid gases from the sour gas steam. ### Sour Release Gas - The sour release gas from LEF Overhead Accumulator (5PV-1679) can be combined with the sour gas feed to 5PV-1604. - However, it is normally lines up to the FCCU due to environmental limitations and the amount of hydrogen sulfide present in the stream. ### Fuel Gas Contactors - The sweetened fuel gas, free of hydrogen sulfide, exits through the top of the Medium Pressure Fuel Gas Contactor (5PV-2243) and the Fuel Gas Contactor (5PV-1604). - It is sent to the Fuel Gas Header, on pressure control, to be used throughout the refinery. - A portion of the fuel gas exiting 5PV-2243 is sent to the Hydrogen Header. ### Rich Amine - Rich amine, containing the hydrogen sulfide that was absorbed from the sour gas feed, exits the bottom of the Fuel Gas Contactors on level control. - It is combined with the rich amine bottoms stream from the HDS Stripper Contactor (5PV-1605), pumped by the Stripper Contactor Bottoms Pump East/West (5P-111/112). - After each rich amine level control valve, the contactor bottoms flow is split and can be sent to either the ARU 3/4 Rich Amine Header, or to the ARU 1 Rich Amine Settler (5PV-1615), depending on the lineup. ### Rich Amine - Rich amine from each of the three contactors can be routed the ARU 3/4 Rich Amine Header. - From the header, the rich amine is routed to the ARU 3/4 Amine Regeneration System to be separated, regenerated, and reused as a solvent for hydrogen sulfide removal. ### Rich Amine - Rich amine from each of the three contactors can be routed to the ARU 1 Rich Amine Settler in the ARU 1/2 Amine Regeneration System to be separated, regenerated, and reused. ### Rich Amine - Rich amine enters the subsystem from the DEA Contactor (8PV-1701) in the Cat Poly Feed Treatment System. It splits and is sent to the bottom of the Medium Pressure Fuel Gas Contactor and to the rich amine stream to 5PV-1615, in order to be recovered.