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By: Chris Wilson For: Senior Capstone 2008 Slide 2 Overview Current process New process Economic comparison Slide 3 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) Slide 4 Natural Gas Processing Everything Together Slide 5 Water removal Removes free liquid water and condensate gas Sends the gas to a refinery The water goes to waste Slide 6 Natural Gas Processing Everything Together Slide 7 Natural Gas Processing Acid Gas Removal Hydrogen sulfide Mercaptans Carbon dioxide Acid gas removal processes Amine treating Benfield process Sulfinol process others Slide 8 Natural Gas Processing Amine Treatment Most common used amines Monoethanolamine Diethanolamine Diisopropylyamine Methylethanolamine Hydrogen sulfide goes through a Claus process Slide 9 Natural Gas Processing Amine Treating Slide 10 Natural Gas Processing Sulfinol 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 Slide 11 Natural Gas Processing Sulfinol Process Slide 12 Natural Gas Processing Everything Together Slide 13 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 Slide 14 Natural Gas Processing Glycol Dehydration Slide 15 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 Slide 16 Natural Gas Processing Slide 17 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 Slide 18 Natural Gas Processing Slide 19 Nitrogen Rejection Processes that can reject nitrogen Cryogenic process Absorption process (using lean oil or solvent) Membrane separation Adsorption process (activated carbon) Slide 20 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 Slide 21 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 Slide 22 Natural Gas Processing Membranes Driving force Partial pressure Type of material determine permeability D = diffusion coefficient (cm 2 /s) k = Henrys law sorption coefficient (cm 3 /cm 3 cmHg) P 1 = Permeability of component 1 P 2 = Permeability of component 2 Slide 23 Natural Gas Processing Economics Slide 24 Demethanizer Slide 25 The next step is to recover the NGLs Process Cryogenics using a turbo- expander can be used This is the most common Lean oil adsorption can be used here Slide 26 Natural Gas Processing Cryogenic Process Slide 27 NGL recovery Slide 28 Now the rest of the liquid is fed to three units Deethanizer Debutanizer Depropanizer Process Each sent to a distillation column Slide 29 Sweetening NGLs Slide 30 Merox Processes Mercaptan oxidation Removes mercaptans from Propane Butane Larger hydrocarbons Slide 31 Natural Gas Processing Another Process Slide 32 Novel Method Technical information momentarily not available due to IP issues However economics will be compared Slide 33 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 Slide 34 Novel Method Slide 35 Current Method Slide 36 Economics - Amine Treating Slide 37 Amine Treating - Simulation Slide 38 Economics - Demethanizer Slide 39 Demthanizer - Simulation Slide 40 Economics - Dethanizer Slide 41 Deethanizer - Simulation Slide 42 Economics Slide 43 Built in Error