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Novel Method for Gas Separation. By: Chris Wilson For: Senior Capstone 2008. Overview. Current process New process Economic comparison. Natural Gas Processing The Way it is Done. Current process Remove excess water Remove acid gas Dehydrate Remove mercury Remove nitrogen
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Novel Method for Gas Separation By: Chris Wilson For: Senior Capstone 2008
Overview • Current process • New process • Economic comparison
Natural Gas Processing The Way it is Done • Current process • Remove excess water • Remove acid gas • Dehydrate • Remove mercury • Remove nitrogen • Separate NGL (ethane, and heavier hydrocarbons)
Water removal • Removes free liquid water and condensate gas • Sends the gas to a refinery • The water goes to waste
Natural Gas Processing Acid Gas Removal • Hydrogen sulfide • Mercaptans • Carbon dioxide • Acid gas removal processes • Amine treating • Benfield process • Sulfinol process • others
Natural Gas Processing Amine Treatment • Most common used amines • Monoethanolamine • Diethanolamine • Diisopropylyamine • Methylethanolamine • Hydrogen sulfide goes through a Claus process
Natural Gas ProcessingSulfinol Process • Used to reduce H2S, CO2, and mercaptans from gases • Great for treating large quantities of gas • Solvent absorbs the sour gas • Sulfolane is used
Natural Gas Processing Glycol Dehydration • Method for removing the water vapor from the gas • Usable glycols • Triethylene glycol – most commonly used • Diethylene glycol • Ethylene glycol • Tetraethylene glycol • Works by having the glycol adsorb the water
Pressure Swing Adsorption • Adsorbent material is used • Gas and material go under high pressure • Material adsorbs the gas ( H2S, mercaptans, CO2) • Disadvantages • Requires high pressures • Slow cycle times
Mercury removal • Current Processes • Activated carbon – through chemisorption. Activated has extremely high surface area • Mercury can damages aluminum heat exchangers • Those used in cryogenic processing plants • Those use in liquefaction plants
Nitrogen Rejection • Processes that can reject nitrogen • Cryogenic process • Absorption process (using lean oil or solvent) • Membrane separation • Adsorption process (activated carbon)
Natural Gas Processing Cryogenic Process • Common refrigerants used • Most common method for removal of impurities such as nitrogen • Disadvantages • Must reach extremely low temperatures • Only useful for large scale production
Natural Gas Processing Lean Oil Removal • Lean oil is fed countercurrent with the wet gas • Temperature and pressure are set to allow for the greatest absorption of unwanted gases
Natural Gas Processing Membranes • Driving force • Partial pressure • Type of material determine permeability D = diffusion coefficient (cm2/s) k = Henry’s law sorption coefficient (cm3/cm3cmHg) P1 = Permeability of component 1 P2 = Permeability of component 2
Demethanizer • The next step is to recover the NGL’s • Process • Cryogenics using a turbo-expander can be used • This is the most common • Lean oil adsorption can be used here
NGL recovery • Now the rest of the liquid is fed to three units • Deethanizer • Debutanizer • Depropanizer • Process • Each sent to a distillation column
Merox Processes • Mercaptan oxidation • Removes mercaptans from • Propane • Butane • Larger hydrocarbons
Novel Method • Technical information momentarily not available due to IP issues • However economics will be compared
Novel Method • Advantage • More cost effective than any previous methods • Less environmental impacts than previous methods • Separates all contaminants • Separates each component • Everything is done using one process