PSGAS Process Summary
Perta Samtan Gas is designed to extract the optimum amount of natural gas liquids from a combination of gas sources at 250 MMscfd capacity available at the existing SKG-10 Prabumulih Barat gas metering station. An NGL Extraction Plant, which is located adjacent to the SKG-10 metering station, provides the means for extracting the natural gas liquids from the pipeline gases. Following extraction, lean (residue) gas is returned to the metering station and extracted liquids is transferred to a Fractionation plant which is located in the Pertamina Plaju / Sungai Gerong refinery, designation RU III at Palembang. A buried pipeline approximately 89.6kms in length transports the liquids to the refinery. At the refinery the liquid is fractionated and stored with ship loading facilities installed at an existing Jetty and transfer by pipe line to Dom Gas which is located at Plaju.
Metering Station (SKG-10)
The feed gas supplied to the NGL Extraction Plant is taken from two existing pipelines located in the adjacent SKG-10 gas metering station which are (1) 28″ Feed Gas Pipeline from SKG PPGS Benuang terminating at its pig receiver and (2) 20″ Feed Gas from SKG Musi terminating at its pig receiver. The feed gas is transferred to vertical type Inlet Slug Catcher to separate free condensate and water from pipeline gases. The seperated feed gas as vapor is transfered to feed gas metering to measure actual feed gas volume and gas composition and the lean gas whcih comes from extraction plant is transferred to lean gas metering at SKG-10 to measure lean gas volume.
NGL Extraction Process
The NGL extraction plant provide the means to extract NGL from gas pipeline. Extraction lean (residue) Methane gas (C1) and Ethane (C2) with the De-Ethanizer returned to the metering gas station and NGL extraction (Propane/C3, Butane/C4, Condensate/C5+) are transferred to the Fractionation plant that located in Refinery Unit III Pertamina Plaju/ Sungai Gerong, Banyuasin. NGL Extraction Plant in Prabumulih is designed to be self-sufficient by necessity in the provision of all utility systems, one and only across the line system, being feed gas supplier, back to lean gas, NGL pipelines, and has gas power generator facilities with capacity of 3×725 kW and 1 unit emergency diesel generator with a capacity of 537 kW. NGL Extraction Plant in Prabumulih located next to PEP-SBS gas metering station SKG-10, provides facilities to extract NGL from gas pipeline from PEP gas field in South Sumatra. The exhaust Methane (C1) and Ethane (C2) gases from De-Ethanizer process returned as a gas to gas metering station, whereas Propane/C3, Butane/C4, Condensate/C5+ is transferred to the Fractionation Refinery located in Refinery Unit III Sungai Gerong in Palembang by NGL pipelines size 8 inches 90 km long.
* Main Equipment
| 1. COMPRESSION SYSTEM |
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The Compression System is to increase natural feed gas pressure
The Compression System is to increase feed gas pressure to get the pressure for DHU requirement and increase lean gas pressure to get the pressure for entering gas netwerk SBS area |
| 1.1 Feed Gas Compressor |
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– Compressing feed gas (400 psig to 750 psig) |
| 1.2 Lean Gas Compressor |
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– Compressing lean gas (250 psig to 550 psig) |
| 2. DEHYDRATION SYSTEM |
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De-Hydration system is located downstream feed gas compression system prior feed gas entering cold process system (NGL Recovery System). Molecular Sieve adsorbent bed is used to treates feed gas to remove hydrate in gas before entering NGL Recovery System. |
| 2.1 Dehydration Unit |
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The dehydration units is consisted of 3×100% molecular sieve Dehydration Vessels (Absorption Step & Regeneration Step) |
| 3. NGL RECOVERY STSTEM |
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The core of the extraction plant is the self-refrigerating cryogenic-like facilities. The feed gas after treatment to remove hydrate at Dehydration System passes through two parallel heat exchangers, the Gas-Liquid Exchanger and the Feed/Resuidue Gas Exchanger to cool and partially condenses the feed gas |
| 3.1 Exchanger |
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Heat exchanging between dry feed gas & extream low temp’ gas circulated with other recovery processes |
| 3.2 Expander & Compressor |
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Process to decrease extreamly feed gas temperature from -35F to -125F |
| 3.3 Deethanizer Column |
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Separating process Lean Gas and NGL connected with cryogenic unit(exchangers & expander) |
GAS ENGINE GENERATOR A/B/C (01-G-5401 A/B/C)
As a power plant equipment and electricity distribution at Extraction refineries/plant. Capacity 725 kwh/GEG
GAS TURBIN COMPRESSOR FEED, LEAN & COMMON A/B/C (01-K-2101/2301 A/B/C)
Increase feed/lean gas pressure. For Feed gas from 420 Psig to 795 Psig, Lean gas from 270 Psig to 521 Psig. Capacity Feed Gas Compressor 125 MMSCFD/Compressor, Lean Gas Compressor 117,5 MMSCFD/ Compressor.
DEHYDRATION VESSEL (DHU) (01-V-2201 A/B/C)
The separation of water from gas content and regeneration process. Capacity = 250 MMSCFD
REGENERATION GAS HEATER (01-H-2201)
To heating the regeneration gas (Lean Gas) before entering into dehydration vessel (DHU).
HOT OIL HEATER (01-H-5701)
To heating Hot Oil before being used as a heater in Reboiler De-Ethanizer.
TURBO EXPANDER (01-K-3301)
To decrease Feed Gas pressure before entering to De-Ethanizer Column from 720 Psig – 210 Psig
DE-ETHANIZER COLUMN (01-C-3401)
To seperate light fraction C1-C2 (Lean Gas) from weight fraction C3-C6+ (NGL) using the extraction principle.
NATURAL GAS LIQUID PUMP (01-P-3501 A/B)
To deliver Natural Gas Liquid as a bottom product De-Ethanizer Column to Fractionation Plant, Sungai Gerong over the underground pipeline. Capacity = 350 USGPM
DE-ETHANIZER REFLUXS PUMP (01-P-3401 A/B)
Transfer fluida from Top De-Ethanizer Column to be return into De-Ethanizer Column in order to increase recovery. Capacity = 335 USGPM
HP FLARE STACK (01-ST-6401)
To burn exhaust gas of the process so as not to be exposed directly to environment. Capacity = 250 MMSCFD
