Iron-based Chemical Looping Gasification Technologies for Flexible Syngas Production from Fossil Fuels with Carbon-di-oxide Capture: Process Systems Simulations, Techno-economic Analysis

• Main Author: Kathe, Mandar V
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2016
• Subjects: Chemical engineering
• ISBN: 9781392176627; 139217662X

The following study entails process simulations and techno-economic analysis based investigations of novel chemical looping partial oxidation processes. The moving bed reactor system analyzed in this dissertation provides chemical looping technologies several intrinsic advantages over conventional energy processing schemes. Chapter 2 focusses on optimizing the counter-current moving bed chemical looping system for H2 production from natural gas. The chemical looping process for H2 production from natural gas is optimized based on isothermal thermodynamic limits of an iron-based counter-current moving bed reactor system. The iso-thermal analysis is followed by a parametric sensitivity for energy balance for satisfying the auto-thermal heat balance. This is completed by computing temperature swings based on a net heat duty calculation for individual chemical looping reactors. Overall the chemical looping process is shown to have a cold gas efficiency of 77.6% (HHV basis) and an effective thermal efficiency of 75.1% (HHV basis), both of which are significantly higher than the baseline case. Chapter 3 discusses the Shale gas to Syngas process for integration into a Gas to Liquid fuel (GTL) plant. Following the methodology for an isothermal and an adiabatic analysis from Chapter 2, Chapter 3 identifies a suitable auto-thermal operating condition for the chemical looping reactors. The process simulation model is used to derive cost estimates based on standard engineering assumptions and completes a sensitivity analysis for several important economic parameters. The STS process is shown to require significantly lower natural gas feedstock than the conventional process baseline for producing the same amount of liquid fuels. The STS process lowers the capital cost investment for the syngas production section of a GTL plant by over 50% and if commercialized can be disruptive to liquid fuel production markets. Chapter 4 discusses the Coal to syngas (CTS) process for its technical and economic performance when integrated into a 10,000 tpd methanol plant. This chapter details the equipment sizing philosophy and cost methodology used in this dissertation for calculating economic performance of the novel processes developed. Further, sensitivity studies which analyze effect of economic parameters like the capital charge factor, natural gas price are considered to identify the critical technology parameters necessary to be de-risked for pilot scale and commercial scale operation of the CTS technology. The CTS process reduced the coal consumption by 14% for the same amount of methanol production. The CTS process also reduced the methanol required selling price by 21% over the corresponding baseline case with greater than 90% carbon capture. Chapter 5 discusses the two reducer chemical looping configurations and the fixed bed chemical looping configurations. The two reducer chemical looping configurations provide the flexibility for designing two different reducer reactors, each optimized to a specific fuel feedstock. The two reducer chemical looping configurations can improve over thermodynamic performance of a single reducer chemical looping configuration by providing the flexibility to get high solids conversion with high fuel conversions. The fixed bed operating strategy opens up ways to operate iron-based chemical looping system without solids circulation for high-efficiency production of syngas.