Gas Treatment Plant Chris, Stephanie, Kyle, Mariam.

transcript

Gas Treatment Plant

Chris, Stephanie, Kyle, Mariam

What is Shale gas?

Is natural gas trapped within shale formations.

And why is it important?• Energy dependence • Reduce greenhouse

gas emissions

Purpose

• Take raw shale gas and purify.

• Produce compressed natural gas/pipeline gas.

• Produce liquefied natural gas (LNG)

• Supply methane for Ammonia Plant, Air Separations and Syngas Plant, the Direct Iron Reduction Plant, and Combined Heat/Power plant.

• Supply Nitrogen (N2) to Ammonia Plant.

• Produce natural gas liquids (NGL) for sale.

Shale Gas Composition

Design Basis

First Step:Water Removal and Condensation

Gravity Separation

Example of Horizontal Separator

First Step:Water Removal and Condensation

• Purpose: To separate gas/liquid phases.• Additionally water and NGLs may be

separated within the same unit given proper settling time.

• Proper pressure and liquid-level controls required.

• A mist extractor at gas exit captures droplets too small to settle by gravity.

• The sudden change in momentum generates the separation of liquid from gas.

Second Step:Acid Gas Removal

Second Step: Acid Gas Removal

Amine Treating• Most commonly used process

for removing sour gas in natural gas purification plants

Most Common Amines Used

• Monoethanolamine• Diethanolamine• Methylethanolamine• Diisopropylamine

Pressure Swing Adsorption (PSA)

BenfieldProcess• Thermally regenerated

cyclical solvent process

• Uses an activated, inhibited hot potassium carbonate solution to remove CO2, H2S and other acid gas components

Sulfinol Process

• For selective absorption of H2S, COS and mercaptans, while co-absorbing only part of the CO2

• The solvent is composed of Sulfolane, DIPA or MDEA and water

• Great for treating large quantity of gas such as natural gas which are at elevated pressure

Second Step:Separation H2S and CO2

Room-Temperature Ionic Liquid (RTILs)

• An ionic liquid comprising an anion having a carboxylate function and an effective amount of water is used as an adsorbent to selectively complex the CO2 yielding a gaseous stream with a greatly reduced CO2 content.

Third Step:Separation of H2S and recycle

Claus Process

Scot process

Clauspol process

Fourth Step:Dehydration

Glycol Separation

• Commonly used

• Triethylene Glycol

• Glycol absorbs water

• Can potentially vaporize hydrocarbons

Fifth Step:Nitrogen Removal

Methods: Cryogenics, Pressure Swing Adsorption, Membrane separation and lean oil absorption.

Cryogenics: The only widely acceptable method on the industrial scale.• Costs $0.30-0.50/Mscf for plants handling 75 MMscfd• Costs $1.00+/Mscf for plants handling 2 MMscfd or less.• Methane and Nitrogen condense at different temperatures -

256F and -346F respectively.

Membrane Process: No membrane alone has the Nitrogen/Methane separation characteristics.

PSA and Lean Oil Absorption: Prohibitively high capital costs and require lower volume flows.

Sixth Step:Natural Gas Liquid Recovery

Turbo Expander and Demethanizer

• Turbine through which a high pressure gas is expanded to produce work that is often used to drive a compressor

• Low-temperature distillation column to separate CH4 and Natural Gas Liquids (NGLs)

Seventh Step:Fractionation

Eighth Step:Liquefaction and compression

Eighth Step:Liquefied Natural Gas (LNG) Production

Example of coil-wound LNG heat exchanger

Composition:• Methane 90-95%• Nitrogen 1-4%

• C2+ hydrocarbons 1-5%

• CO2 <1%

LNG Transportation

LNG occupies 1/600th the volume of natural gas in gaseous form.

• LNG is necessary when no pipeline exists.

• Efficient method for exporting natural gas.

Example of LNG tanker

Questions?

Gas Treatment Plant Chris, Stephanie, Kyle, Mariam.

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