Deep Panuke Project Description - Encana

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Although the M&NP Option is the only option producing sales gas, the same product specificationrequirements will be met for SOEP Subsea Option as the SOEP facilities require a sweet feedstock.The amine-sweetening unit is based on physical absorption using a solvent to absorb the impurities (H 2 Sand CO 2 ). The solvent is then regenerated via heating to release the absorbed impurities. The process iscyclic, in which the amine is continuously circulated through the absorber/contactor to pick up theimpurities, then routed to a regenerator to release the impurities.Remaining CO 2 and H 2 S amounts not removed during the amine sweetening process remain in the salesgas, which is sent to market. The amine-sweetening unit is a closed loop system.The amine solvent used in the sweetening unit will be methyldiethanolamine, which will improve theselectivity between H 2 S and CO 2 absorption. The cyclic process can result in a build up of impurities inthe amine solvent over time. If the amine solvent requires a change, whether complete or partial (diluteout the impurities), it is removed from the process and shipped to shore for reclaiming (manufacturer toclean and recycle). Production will be halted when a complete change-out of amine solvent is required.The change-out of the amine solvent will be subject to the EPP.2.4.1.4 Acid Gas HandlingAcid gas from the amine regenerator will be compressed to approximately 15,100 kPa (from a feed pressureof 150 kPa) using a multi-stage compressor. Water condensing between the compressor stages recycledback to the processing facilities. The compressed acid gas will be injected into a suitable, subsurfacereservoir. Table 2.5 describes the design flow and composition for the acid gas injection system.The Project does have the capability to flare acid gas. The capability to flare the acid gas stream isrequired to provide operational flexibility in times of maintenance and/or operational issues.Table 2.5 Acid Gas Injection System – Composition and FlowDescriptionDesign DataMass Flow (kg/h) 8100STD Gas Flow (m 3 /hr) 5325Molar Flow (kgmole/hr) 230Pressure (kPa) 150Temperature (C) 56Component Mole %CO 2 63.2H 2 S 18.5CH 4 17.0C2 + 1.1H 2 O 0.24Note: The flow represents the total feed to the acid gas management system including acid gas from the amine system andH 2 S removed from the condensate fuel for the Mean Production Profile (Mean denotes the statistical Mean value of aprobability distribution).Deep Panuke Volume 4 (Environmental Assessment Report)· November 2006 2-34
2.4.1.5 DehydrationSweet gas from the amine-sweetening unit contains water that must be removed prior to hydrocarbondewpoint adjustment (M&NP Option) or prior to export (both options). The gas dehydration unit is aliquid desiccant process utilizing a solvent to absorb the water. The solvent, triethylene glycol (TEG), isthen regenerated via heating to release the absorbed water. The process is cyclic in which the TEG iscontinuously circulated through the absorber/contactor to pick up the water then routed to a regeneratorto release the water. A brief description of the process follows.Treated gas from the amine unit is routed to the TEG system for dehydration. The gas first is routed tothe TEG contactor in which the incoming gas flows counter current to the lean TEG. The lean TEGabsorbs the entrained water in the gas stream and reduces the water content of the gas.The rich TEG leaving the contactor cools the regenerator overheads and is routed to the TEG flashdrum. The flashed gas from the flash drum is routed to the flare. The flash drum liquids then passthrough the TEG charcoal filter (to remove trace hydrocarbons) and the TEG filter (to remove charcoal)before being heated in the TEG regenerator feed/effluent heat exchanger before entering the regenerator.The bottoms of the regenerator are heated to remove the water from the rich TEG. A small amount ofstripping gas is used to enhance the water removal of the regenerator. The regenerator overheads arecooled for tower top temperature control, with the overhead gas stream being routed to the flare.The water removed from the sweet gas dehydration process is removed from the top of the TEGregenerator in the overhead gas stream and routed to the low-pressure (LP) flare header. A large portionof the water in the overhead gas stream will condense in the flare piping or drum. The flare drumliquids will be pumped into either the inlet or test separators and the water portion of the liquids in theseseparators is routed to the produced water treating facilities. Non-condensable hydrocarbons will beflared.The lean glycol leaves the regenerator column, enters the TEG surge drum, then is cooled in the TEGregenerator feed/effluent heat exchanger. The lean TEG is further cooled in the lean TEG cooler(cooling medium cooler) before entering the TEG contactor.The dry gas from the TEG contactor passes through a coalescer to reclaim any entrained TEG leavingthe contactor in the overhead gas stream. The TEG is returned to the flash drum. The dehydrationprocess is a closed loop system. The circulating TEG builds up contaminants, primarily salts. Once thelevels build to a point, the risk of corrosion and or deposits increase to the point where removal ofsome/all the TEG is required and new TEG added. Rate of build up varies with the feed quality so it isdifficult to predict how long before this happens.Deep Panuke Volume 4 (Environmental Assessment Report)• November 2006 2-35
Page 1 and 2: 2 PROJECT DESCRIPTIONThis section p
Page 3 and 4: Potential Radioactive Components: T
Page 5 and 6: 2.2.2 Subsea Wells and FlowlinesThe
Page 10 and 11: 2.2.3.1 M&NP OptionThe proposed pip
Page 12 and 13: The onshore portion of the pipeline
Page 14 and 15: 2.3 Construction and Installation2.
Page 16 and 17: 2.3.2 Export PipelineA proposed pip
Page 18 and 19: A dedicated subsea umbilical will b
Page 20 and 21: Table 2.2 Construction MethodsCateg
Page 22 and 23: These subsea structures may be fast
Page 24 and 25: For the new production and injectio
Page 26 and 27: Figure 2.8Typical Production Well S
Page 28 and 29: 2.3.8.1 Drilling Fluid ProgramWater
Page 30 and 31: Table 2.4 Hydrostatic Fluid Dischar
Page 32 and 33: Acid GasInjectionFeed GasCompressio
Page 36 and 37: Spent TEG has no measurable H 2 S a
Page 38 and 39: Table 2.7 Water CompositionComponen
Page 40 and 41: 2.4.2 Utilities2.4.2.1 Electrical P
Page 42 and 43: will be designed considering emerge
Page 44 and 45: zones over the pipeline although th
Page 46 and 47: 2.7 Emissions and DischargesEnCana
Page 48 and 49: Table 2.8 Routine Project Emissions
Page 50 and 51: 2.7.1.1 Air PollutantsThe following
Page 52 and 53: esult in eye irritation, respirator
Page 54 and 55: Typically, a re-entry and completio
Page 56 and 57: 2.7.5.3 Deck DrainageDuring constru
Page 58 and 59: 2.9.2 Pipeline Leak PreventionThe p
Page 60 and 61: 2.9.5 Subsea Protection StructuresT
Page 62 and 63: • consider concept alternatives f
Page 64 and 65: Table 2.10Centre Substructure Type
Page 66 and 67: is much more weather-dependent than
Page 68 and 69: Table 2.11 Processing Location Alte
Page 70 and 71: After carefully considering the con
Page 72 and 73: Flaring acid gas consists of direct
Page 74 and 75: Table 2.13Produced Water Disposal A
Page 76 and 77: Therefore, injection into an annula
Page 78 and 79: Use of a dedicated condensate pipel
Page 80 and 81: is taken offshore on a special lay
Page 82: Table 2.15Acid Gas Injection Locati

Deep Panuke Project Description - Encana

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