Presentation on theme: "Natural Gas Reservoirs"— Presentation transcript:
1 Natural Gas Reservoirs Commercialization of Nitrogen-RichNatural Gas ReservoirsAlbert Curtis & Monique WessLow Quality Natural Gas StatisticsIntroductionEngelhard Corporation’s Molecular Gate PSAAbstractNatural gas is one of the most vital sources of energy in the United States. It supplies approximately one half of all energy used in residential areas, and is one of the most promising fuel sources for industrial and commercial applications making up 18% of U.S. electricity generation by fuel sources1. Natural gas is a fossil fuel made up of primarily methane along with traces of heavier hydrocarbons such as ethane, propane, and butane. The gas is colorless and odorless, but generates a great deal of energy when combusted. Natural gas is favored because unlike other energy sources, the combustion of natural gas is clean and does not emit harmful substances into the atmosphere. The table below displays general composition percentiles of natural gas.With the natural gas supply in the United States not being able to support the nations demand for natural gas, the US will either have to find more sources for natural gas or import more natural gas from foreign countries. One of the potential sources to increase natural gas supply is to use nitrogen rich natural gas. The objective of this study is to identify and analyze potential uses for nitrogen rich natural gas reserves. An economic analysis will be shown on the feasibility of production and commercialization of nitrogen rich natural gas. The separation options include the purification of natural gas by cryogenic distillation, pressure swing adsorption, membranes, and molecular gate technology. The commercialization options include conversion of methane to synthesis gas and its derivates and combustion of natural gas for power generation. A mathematical model was built to determine the best process combination based on maximizing net present worth.--A mathematical model was coded and run using the Generic Algebraic Modeling System (GAMS) as interface based on Mixed Integer Linear Programming (MILP) (Cplex is the solver used).ChemicalFormulaComposition PercentileMethaneCH470-90%EthaneC2H60-20%PropaneC3H8ButaneC4H10Carbon DioxideCO20-8%OxygenO20-0.2%NitrogenN20-5%Hydrogen sulfideH2SRare gasesA, He, Ne, XetraceThe molecular gate pressure swing adsorption process, originally developed by Engelhard Corporation, has proven to be more cost effective than the traditional process. This adsorption is unique from other adsorption processes, as the nitrogen is adsorbed instead of the methane. The simplicity and reliability of this new technology has made it a leading option for upgrading nitrogen contaminated steams since its commercialization in The molecular gate nitrogen system is capable of handling flow rates as low as 0.5 MMscfd with the economics of scale increasing with flow rate.The Molecular GateTM adsorbent is titanium silicate (CTS-1) designed with size selective pore openings to remove nitrogen from methane. The molecular sieve with a pore size of 3.7Å is custom designed to allow smaller nitrogen molecules (3.7 Å) to adsorb into the bed, penetrating the crystalline structure while larger methane molecules (3.8 Å) are excluded exiting the column at feed pressure6. Figure 6 illustrates separation by use of the Molecular Gate.ResultsLow Quality Natural Gas ReservoirMolecular Gate Pressure Swing AdsorptionLow Quality Natural GasPipeline Quality Natural GasN2 <4%Q > 5 MMscf/dLow Quality Natural Gas ReservoirMolecular Gate Pressure Swing AdsorptionSteam ReformingWater Gas ShiftHaber-BoschBosch-MeiserBoilerSteam TurbineCentral Utility Plant UsageLow QualityNatural GasSteamElectricityUreaMethane/Nitrogen Stream mixture-Pipeline Quality Natural GasSyn GasHydrogenAmmonia15%< N2 > 30%Q > 5 MMscf/dLow Quality Natural Gas DefinedLow Quality Natural Gas ReservoirBoilerSteam TurbineCentral Utility Plant UsageSteam ReformingWater Gas ShiftHaber-BoschBosch-Meiser4%< N2 > 15%Q > 5 MMscf/dLow QualityNatural GasSteamHydrogenElectricitySynthesis GasAmmoniaUreaApproximately 30% of all natural gas reserves in the United States contain low quality natural gas (LQNG). LQNG is gas from any reservoir containing excessive amounts of non-hydrocarbon components which place the gas outside of pipeline specifications. The most common contaminates of natural gas are carbon dioxide, nitrogen, and hydrogen sulfide. These non-combustible contaminates lower the heating value of natural gas and must be removed prior to use. Aside from lowering the heating value, the contaminants are toxic, corrode pipe lines, and harm the environment1. While there is no universal standard or government regulation for LQNG, the most commonly used specifications between gas purchasers and suppliers are as follows.Natural gas cannot contain2:greater than 2% carbon dioxidegreater than 4% nitrogengreater than a 4% combination of carbon dioxide and nitrogen.Minor contaminates of natural gas include helium, argon, hydrogen, and oxygen, however these typically act as inert gases and pose no major problems in processing LQNG.Methane/Nitrogen Stream mixtureConverted From Synthesis GasProductGeneralProductionFormulaUsesMethanolSimplest alcohol, light, volatilesteam-methane reforming2H2 +CO →CH3OHantifreeze, solvent, fuel, intermediate in the production of other productsAcetic Acidweak carboxylic acidmethanol carbonylationCO + CH3OH → CH3COOHvinyl acetate monomer and aceticanhydrideFormaldehydesimplest aldehydeoxidation and dehydrogenation ofmethanolCH3OH → H2CO + H2polymers and a widevariety of specialty chemicalsDimethly EtherGaseous ethermethanol dehydration2CH3OH → CH3OCH3 + H2Oaerosol spray propellant ora refrigerantThe mathematical model produced three results depending on the nitrogen concentration of the natural gas as well as the size of the reservoir. With small natural gas reservoirs it is not profitable for additional processing of the natural gas due to the high startup capital costs of the equipment. If the reservoir size is greater than 5 MMscf/day the most profitable product is urea, the difference in the second and third results is that one keeps the nitrogen in the natural gas stream, which reduces the feed cost, however it increases the reactor sizes and capital costs.Urea MarketMajor markets:≈90% of urea goes into fertilizers≈10% in other commodity markets such as cigarettes, toothpaste, pretzels ect…The twenty-three processes examined as monetization options for LQNG are shown above. These options include:The removal of nitrogen to obtain pipeline quality natural gas.The combustion of natural gas as a fuel source to generate and sell electricity.The conversion of natural gas to synthesis gas by methane steam reforming. Several chemicals and fuels can be developed from synthesis gases that have potentially promising markets.ProductGeneralProductionFormulaUsesAmmoniacolorless alkaline gas with penetrating odorHaber-Boschprocess3H2 + N2 → 2NH3nitrogen source in fertilizer and the manufacture of ureaUreasolid produced as prills or granulesBosch- Meiser2NH3 + CO2 → NH2CONH2 + H2Ofertilizers, plastics, and protein supplement in animal feedHydrogenColorless, odorless gasSteam reforming / Water gas shift reactionCH4 +H2O → 3H2 + COprocessing of fossil fuelsand to produce ammonia or methanolSynthetic Fuelliquid hydrocarbonsFischer-Tropsch process3H2 + CO → CH4 +H2Odiesel and napthaSummaryAcknowledgementsReferencesThe evaluation of nitrogen rich natural gas lead to two major conclusions. The first being that the most economical way of separating the nitrogen from natural gas is using pressure swing adsorption with molecular gate technology. The second is that the most economical product produced from nitrogen rich natural gas varies by reserve capacity and nitrogen content. If reserve capacity is low the natural gas is most profitable by removing the nitrogen using the PSA process and selling the natural gas via pipeline. If reserve capacity is high the most profitable product produced is urea and is most economically produced by separating the nitrogen out of the natural gas before processing at high nitrogen contents and keeping the nitrogen in when processing at low nitrogen contents.Quang NguyenShi LiuRoman VoronovDr. Miguel J. BagajewiczOAchenson W.P, Hackworth J.H, Kasper S., McIlvried H.R, “Utilization of Low-Quality Natural Gas – A Current Assessment,” K & M Engineering and Consulting Corporation. January 1993.Bailey K., Farberow C., “Green is Seen in Fertilizers - A New Approach to Municipal Solid Waste Management,” University of Oklahoma. 1 May 2007.Lavaja J., Lawson B., Lucas A., “Upgrading Low BTU Gas of High Nirtogen Content to Power of Pipeline,” University of Oklahoma.Kidnay A., Parrish W., “Fundamentals of Natural Gas Processing,” 21 June 2006.Molecular Gate® Adsorption Technology, Guild Associated Inc., Copyright 2007.Processing Natural Gas, NaturalGas.org, Copyright 2004.Electrical Generation using Natural Gas, NaturalGas.org, Copyright 2004.
2 Pipeline Quality Natural Gas Synthesis Gas Hydrogen Ammonia Low QualityNatural GasMethanolSteamPipeline Quality Natural GasSynthesis GasHydrogenAmmoniaElectricityUreaFormaldehydeAcetic AcidDimethly EtherDiesel and NaphthaMethane/Nitrogen Stream mixtureLow Quality Natural Gas ReservoirMolecular Gate Pressure Swing AdsorptionSteam ReformingWater Gas ShiftHaber-BoschBosch-MeiserMethanol SynthesisMethanol OxidationCarbonylationDehydrationFischer-TropschBoilerSteam TurbineCentral Utility Plant UsageSold in MarketDiesel and NaphthaTalk about selling intermediates
3 Low Quality Natural Gas Pipeline Quality Natural Gas Low Quality Natural Gas ReservoirMolecular Gate Pressure Swing AdsorptionLow Quality Natural GasPipeline Quality Natural GasTalk about selling intermediates