Novel Natural Gas to Liquids Processes: Process Synthesis and Global Optimization Strategies

Abstract

An optimization‐based process synthesis framework is proposed for the conversion of natural gas to liquid transportation fuels. Natural gas conversion technologies including steam reforming, autothermal reforming, partial oxidation to methanol, and oxidative coupling to olefins are compared to determine the most economic processing pathway. Hydrocarbons are produced from Fischer–Tropsch (FT) conversion of syngas, ZSM‐5 catalytic conversion of methanol, or direct natural gas conversion. Multiple FT units with different temperatures, catalyst types, and hydrocarbon effluent compositions are investigated. Gasoline, diesel, and kerosene are generated through upgrading units involving carbon‐number fractionation or ZSM‐5 catalytic conversion. A powerful deterministic global optimization method is introduced to solve the mixed‐integer nonlinear optimization model that includes simultaneous heat, power, and water integration. Twenty‐four case studies are analyzed to determine the effect of refinery capacity, liquid fuel composition, and natural gas conversion technology on the overall system cost, the process material/energy balances, and the life cycle greenhouse gas emissions. © 2013 American Institute of Chemical Engineers AIChE J, 59: 505–531, 2013

Multi‐scale systems engineering for energy and the environment: Challenges and opportunities

“…116 Since efficient utilization of natural gas reserves depends on effective resource management and allocation, Elia et al investigated the nationwide, regional, and statewide supply chain networks for GTL refineries. 117 A key input in this study was the design of the candidate GTL refineries, which was determined using the process synthesis and global optimization methods proposed by Baliban et al 116 The supply chain investigation elucidated the most profitable locations to build these refineries. To determine the strategic and tactical decisions associated with a GTL supply chain, Elia et al also investigated the strategic planning of these refineries.…”

“…118 The operations over the network spanned a time horizon of 60 years and candidate GTL refinery locations were located at the center of each county in the state of Pennsylvania. The design of the candidate GTL refineries in the strategic planning investigation was also determined using the methods proposed by Baliban et al 116 The results determined at which stage to build what types of plants and where to place them. As renewable sources of power, such as wind or solar, become more widespread across industries, it will become increasingly more important to consider the variabilities in the supply and demand of electric power.…”

Natural Gas to Liquid Transportation Fuels and Olefins (GTL+C2_C4)

“…A process superstructure that converts natural gas to liquid transportation fuels was previously developed (Baliban et al, 2013). Additionally, process alternatives for the production of C 2 to C 4 olefins and liquid fuels were investigated for a refinery that uses biomass and natural gas as feedstocks (Onel et al, 2014).…”

“…Previous studies have shown the viability of liquid transportation fuels production from single and hybrid feedstock systems (Baliban et al, 2010(Baliban et al, , 2012b(Baliban et al, , 2013. The existing superstructure (Baliban et al, 2010(Baliban et al, , 2012b(Baliban et al, , 2013 is enhanced to allow for the production and purification of the olefins. Therefore, an alternative process towards the production of liquid fuels should also consider the production of these high value petrochemicals.…”

Reliability Integration to Process Synthesis applied to GTL Processes

“…Creating a process superstructure and applying optimization is one solution for such a problem. This has been successfully solved with Mixed Integer Non Linear Programming (MINLP) for new GTL processes (Baliban et al, 2013). A superstructure with process model for GTL process synthesis is available (Ellepola et al, 2012).…”