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Commercialization of Nitrogen-Rich Natural Reservoirs. Albert Bradley Curtis S. Monique Wess Miguel Bagajewicz. Overview. Background. Background. Natural gas is one of the most vital sources of energy in U.S.
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Commercialization of Nitrogen-Rich Natural Reservoirs Albert Bradley Curtis S. Monique Wess Miguel Bagajewicz
Background • Natural gas is one of the most vital sources of energy in U.S. • It is made up of primarily of methane and significant quantities of heavier hydrocarbons • Several contaminants are common (CO2, N2, H2S) • Advantages over other fuel types: Lower capital cost, higher efficiency, lower air pollutant emissions
Background • Low quality natural gas (LQNG) has one or more impurities that prevent it from being put into a pipeline without going through a pretreatment process • Approximately 30% of known reserves contain LQNG • Lower heating value • Corrodes pipe lines • Lower Wobbe index – interchangeability of fuel types
Background • Most popular contaminants • Carbon Dioxide > 2% • Nitrogen > 4% • Hydrogen Sulfide > 4ppm • Water • Minor contaminants include • Helium • Argon • Hydrogen • oxygen
This Work Objective Perform an economic analysis on the feasibility of production and commercialization of LQNG
Power Generation Process Flow ----- Steam ----- Electricity LQNG *All intermediates can be used in other processes or sold in market Low Quality Natural Gas Steam Electricity Electricity
Power Generation and Synthesis Gas Process Flow ----- Steam ----- Electricity ----- Hydrogen Ammonia Nitrogen Product Streams *All intermediates can be used in other processes or sold in market Electricity Steam Nitrogen Plant Oxygen Low Quality Natural Gas Electricity Hydrogen Ammonia Urea Synthesis Gas Formaldehyde Low Quality Natural Gas Synthesis Gas Methanol Acetic Acid Synthesis Gas Dimethly Ether Diesel and Naphtha
Ammonia Urea Hydrogen Methane/Nitrogen Stream mixture Ammonia Urea Synthesis Gas Pipeline Quality Natural Gas Formaldehyde Synthesis Gas Methanol Nitrogen Plant Oxygen Acetic Acid Synthesis Gas Low Quality Natural Gas Dimethly Ether Power Generation and Synthesis Gas Process Flow ----- Steam ----- Electricity ----- Hydrogen Ammonia Nitrogen ----- Nitrogen rich stream Product streams *All intermediates can be used in other processes or sold in market Diesel and Naphtha Low Quality Natural Gas Steam Electricity Electricity Ammonia Urea Low Quality Natural Gas Synthesis Gas Formaldehyde Methanol Synthesis Gas Acetic Acid Synthesis Gas Dimethly Ether Diesel and Naphtha
PSA • Engelhard Corporation’s Molecular Gate PSA • Traps nitrogen while letting methane flow through at high pressure • Capable of reducing nitrogen content from 30% to 4%. • Adsorbent material is titanium silicate (CTS-1) designed with a pore size of 3.7 Ao
Molecular Gate Adsorber • Operates at pressure levels between 100 – 800 psia • Uses a series of 3-9 fixed bed adsorber vessels • Methane rich steam that is recycled to increase the methane recovery • Spent vessel is depressurized to produce a nitrogen rich low pressure fuel stream.
Synthesis Gas Production • Syngas consists primarily of carbon monoxide, carbon dioxide, and hydrogen • Synthesis gas can be generated by steam reforming of methane. • We considered steam reforming with and without nitrogen removal to investigate the impact of additional processing and reactor size • Used as fuel source or intermediate for production of other chemicals
Ammonia Urea Hydrogen Methane/Nitrogen Stream mixture Ammonia Urea Synthesis Gas Pipeline Quality Natural Gas Formaldehyde Synthesis Gas Methanol Nitrogen Plant Oxygen Acetic Acid Synthesis Gas Low Quality Natural Gas Dimethly Ether Power Generation and Synthesis Gas Process Flow ----- Steam ----- Electricity ----- Hydrogen Ammonia Nitrogen ----- Nitrogen rich stream Product streams *All intermediates can be used in other processes or sold in market Diesel and Naphtha Low Quality Natural Gas Steam Electricity Electricity Ammonia Urea Low Quality Natural Gas Synthesis Gas Formaldehyde Methanol Synthesis Gas Acetic Acid Synthesis Gas Dimethly Ether Diesel and Naphtha
Utility Integration • Use a fire-tubed boiler to create steam, which is used in Steam Methane Reforming. • This produces NOx emissions, which are regulated from the EPA.
Utility Integration • Using a turbine to convert steam to electricity, which is used inside the plant to fuel other processes and can be sold to outside markets. • Combustion Turbine Operation • Ambient air is drawn in and compressed • Fuel is introduced, ignited, and burned • Hot exhaust gas is recovered in the form of shaft horsepower
Mathematical Model • 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) • The objective function maximized is the Net Present Value (NPV) of the project
Mathematical Model • Specifications • 23 processes were considered • 20 years of production was assumed • Reaction stoichometry, raw materials, demand, operating costs, and product flow were included in the model • Began with a total available investment of $100,000,000
Mathematical Model • Why use a mathematical model instead of using Microsoft Excel? • Combinations: • 176,640,000
Mathematical Model Bring in clear copy and highlight equation for explanation
Mathematical Model • An Example: FCI(i,t) .. FC(i,t) =e= (Y(i,t)*alpha(i) + beta(i)*initialcapacity(i,t)); • i = Process • t = year • Y = binary expansion variable • alpha = Additional capital cost per mole • beta = Initial capital cost per mole • initialcapacity = variable
Below 5 MMscf/day < 30% N2 Ammonia Urea Hydrogen Ammonia Methane/Nitrogen Stream mixture Urea Synthesis Gas Pipeline Quality Natural Gas Formaldehyde Synthesis Gas Methanol Acetic Acid Synthesis Gas Low Quality Natural Gas Dimethly Ether Sold as pipeline quality gas Nitrogen Plant Oxygen Diesel and Naphtha Low Quality Natural Gas Steam Electricity Electricity Ammonia Urea Low Quality Natural Gas Synthesis Gas Formaldehyde Methanol Synthesis Gas Acetic Acid At 3 MM SCF/D 15% N2 NPV = $20,425,000 Investment = $475,000 Synthesis Gas Dimethly Ether Diesel and Naphtha
Above 5 MMscf/day 15% - 30% Ammonia Urea Hydrogen Ammonia Methane/Nitrogen Stream mixture Urea Synthesis Gas Pipeline Quality Natural Gas Formaldehyde Synthesis Gas Methanol Acetic Acid Synthesis Gas Low Quality Natural Gas Synthesis Gas Dimethly Ether Hydrogen Ammonia Nitrogen Plant Oxygen Urea Diesel and Naphtha Low Quality Natural Gas Low Quality Natural Gas Steam Electricity Ammonia Steam Nitrogen Low Quality Natural Gas Electricity Electricity Ammonia Oxygen Urea Low Quality Natural Gas Synthesis Gas Formaldehyde Methanol Synthesis Gas Acetic Acid At 10 MM SCF/D 25% N2 NPV = $138,600,000 Investment = $9,250,000 Synthesis Gas Dimethly Ether Diesel and Naphtha
Above 5 MMscf/day 4% - 15% Ammonia Urea Hydrogen Ammonia Methane/Nitrogen Stream mixture Urea Synthesis Gas Pipeline Quality Natural Gas Formaldehyde Synthesis Gas Methanol Acetic Acid Steam Electricity Synthesis Gas Low Quality Natural Gas Dimethly Ether Oxygen Nitrogen Plant Oxygen Diesel and Naphtha Low Quality Natural Gas Steam Electricity Steam Ammonia Nitrogen Urea Electricity Ammonia Urea Low Quality Natural Gas Syn Gas Hydrogen Ammonia Synthesis Gas Formaldehyde Methanol Synthesis Gas Acetic Acid At 10 MM SCF/D 10% N2 NPV = $169,350,000 Investment = $6,200,000 Synthesis Gas Dimethly Ether Diesel and Naphtha
Urea • Major markets: • ≈90% of urea goes into fertilizers • ≈10% in other commodity markets such as cigarettes, toothpaste, pretzels ect… • Price is quite volatile and is largely dependent on the price of nitrogen and natural gas. • Since nitrogen is included in utility integration, nitrogen price is no longer a variable.
Urea • The demand, however, is fairly constant and seems like a good business decision:
Future Prices • The current Urea Price: $390/ton • If future prices decrease more than 20%, compared to other products, another option should be considered. • The next highest process rout was the combination of formaldehyde and acetic acid.
Conclusions • Molecular gate pressure swing adsorption is the most cost effective way of separating oxygen. • After compiling the superstructure of processes in the mathematical model, the model gave three separate results dependent on the reserve size and nitrogen concentration.
Acknowledgements • Dr. Miguel Bagajewicz • Quang Nguyen • Liu Shi • Roman Voronov
References • http://www.naturalgas.org/naturalgas/processing_ng.asp#water • http://www.lowimpactliving.com/pages/your-impacts/electricity1 • “Green is Seen in Fertilizers” - A New Approach to Municipal Solid Waste Management - Carrie Farberow and Kevin Bailey • Upgrading low BTU gas of high nitrogen content to power or pipeline - Javier Lavaja, Bryce Lawson, Andres J. Lucas • http://www.moleculargate.com/