Natural Gas Processing I Chapter 2 In-feed System PTRT 1317 Natural Gas Processing I Chapter 2 In-feed System

Gas Processing Remove oil and condensates Remove water Recover Natural Gas Liquids Remove Sulfur and Carbon Dioxide Remove impurities Mercury Oxygen BTEX (Benzene, Toluene, Ethyl benzene, Xylene)

Gas Processing Plant

Feed Gas Receiving System Initial treating unit in the gas plant Feed gas receiving system Condensate stabilization Condensate Light hydrocarbon liquid obtained by condensation of hydrocarbon vapors Varying proportions of butanes, pentanes Little or no methane or ethane Retains light components that are DISSOLVED in the hydrocarbon liquids Methane Ethane Propane

Feed Gas Reception (In-feed) System Feed gas can contain Hydrocarbon liquids Aqueous liquids Hydrocarbon and acidic gases Entrained solids Chemicals Corrosion control Hydrate inhibitors Compressor lubrication Reception system Pig Receiver/Launcher Slug catchers Feed gas heaters Separators Filters

Typical In-feed System 1000 psi gas Typical In-feed System 100 psi gas 100 psi water 100 psi condensate Every couple weeks Pig receiver used

Slug Catcher Velocity reduction causes liquids and solids to drop out Separated gases are heated to prevent hydrate formation during pressure reduction Separated liquids are filtered, heated and undergo a pressure drop before entering three-phase separator

This PFD describes the “most critical and important” in an Amine Treating Plant. The Inlet Gas separation and filtration equipment. When this equipment is sized properly and maintained properly, an Amine Plant’s overall operation will be improved. Foaming in an Amine Plant is the most common problem. Proper Inlet Gas separation and filtration equipment can eliminate most of this problem.

Slug Catcher Free Liquid is captured in the Slug Catcher. It is also used to capture the high volumes of liquid that arrive when pigging the pipeline. Inlet Gas From Gathering System Inlet Gas Out of Slug Catcher going to the Amine Plant

Slug Catchers Separates liquid slugs formed in pipelines Liquid waves grow large enough to bridge pipe diameter Liquid accumulated in low spots in pipeline Increased feed flow results in excess liquids Pigging pushes out the entire accumulated inventory of liquids in the low spots of the pipeline Maximum size of the slugs must be considered in design Holds several weeks of accumulation Temperatures, topography, gas composition 100 vol% hydrocarbons to 80 vol% water

Horizontal Vertical Pipe-fitting-type

This PFD describes the “most critical and important” in an Amine Treating Plant. The Inlet Gas separation and filtration equipment. When this equipment is sized properly and maintained properly, an Amine Plant’s overall operation will be improved. Foaming in an Amine Plant is the most common problem. Proper Inlet Gas separation and filtration equipment can eliminate most of this problem.

Inlet Separator Inlet Gas from Inlet Separator to Inlet Gas Filter Inlet Gas from Slug Catcher Inlet Separator Remove additional free liquids from the gas entering the Plant from the Slug Catcher.

This PFD describes the “most critical and important” in an Amine Treating Plant. The Inlet Gas separation and filtration equipment. When this equipment is sized properly and maintained properly, an Amine Plant’s overall operation will be improved. Foaming in an Amine Plant is the most common problem. Proper Inlet Gas separation and filtration equipment can eliminate most of this problem.

Inlet Filter Purpose: To remove small particles, liquid, and aerosols from the Inlet Gas.

Inlet Filter Inlet Gas from Inlet Separator to Inlet Filter Purpose: To remove small particles and aerosols from the Inlet Gas. Uses filter elements that the Inlet Gas flow through and the particles are captured in the filter elements. The aerosols and small liquid particles will also coalesce on the filter elements and will drain into the bottom sump of the Inlet Filter. Inlet Gas Filtration is the most critical equipment in reducing amine foaming problems. Inlet Gas from Inlet Separator to Inlet Filter Inlet Gas out of Inlet Filter to Amine Contactor Feed Heater (exchanger)

Equipment Selection and Design Pressure capacity of pig receiver and slug catcher must be same pressure capacity as pipeline High Integrity Pressure Protection System (HIPPS) valves allow for lower downstream pressures to be used by difficult regulatory practice to follow API 521, ASME Code Case 2211 Section VIII Incoming slug size determined using GPSA Engineering Data Book – Section 17

Design Basis and Specifications Hydrocarbon content of feed gas varies Plant process depends on composition so engineer bounds the plant design by three cases Lean feed Average feed Rich feed Gas receiving system usually defined by the rich feed in winter conditions Lean feed defines the turndown ratio of the plant design Turndown ratio = maximum output/minimum controlled output Condensate Product Specification (see text)

Typical Gas Feeds

Pig Receiver Needed unless pipeline transfers only dry gas and hydrocarbon liquids Periodically removes accumulations of liquids at low spots in the pipeline Prevents corrosion Improves efficiency Reduces pressure losses Limits maximum slug size Slug size determined by temperature, topography, pipeline length, and feed gas composition

Gas and Liquid Heaters Feed gas reception use heaters to raise the temp of gas and liquid separated by slug catcher Prevent hydrate formation Prevent retrograde condensate formation Maintain temp above minimum for downstream equipment Raise temp to requirement of gas-treating unit (95 ⁰F) High CO2 concentrations cause a kinetic reaction and generate heat Design of the heater must generate the require temps at low CO2 concentrations

Typical In-feed System 1000 psi gas Typical In-feed System 100 psi gas 100 psi water 100 psi condensate Every couple weeks Pig receiver used