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Investigating Microchannel Reactors for Fischer-Tropsch Synthesis

Arias Pinto, Fabiana (2016) Investigating Microchannel Reactors for Fischer-Tropsch Synthesis. Master's Thesis, University of Pittsburgh. (Unpublished)

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Abstract

Microchannel reactors (MCRs) exemplify significant miniaturization of the physical dimensions and process intensification when compared with conventional industrial reactors, allowing for linear scaleup, flexible manipulations, and substantial capital cost reductions. MCRs have promising applications in Gas-to-Liquid (GTL) technologies, such as the Fischer-Tropsch (F-T) synthesis, particularly for monetizing small onshore and offshore gas fields, which is economically unfeasible with other conventional industrial F-T technologies. Even though MCRs were proposed for commercial implementations and demonstration plans have already been built, adequate literature publications on the use of MCRs in F-T synthesis is scanty and to the best of our knowledge many details concerning the hydrodynamics, mass transfer, heat transfer, and reactor performance are not available.
The overall objective of this study is to investigate the performance and the flow distribution of a MCR, using one-dimensional (1-D) and Computational Fluid Dynamics (CFD) models. A MCR consisting of 50 channels, each packed with 100-micron cobalt catalyst, operating under the low temperature F-T synthesis (500 K and 25 bar) was used to study the reactor performance. The inlet flow distribution was investigated using another CFD model with air at 298 K and 1.01325 bar. A 50-channel MCR was used in this investigation. The modeling results led to the following conclusions:
1. The 1-D model systematically predicted steeper hydrocarbon flow rate profiles when compared with those of the CFD model, however, both models converge to the same values at the channel outlet.
2. For one channel of the MCR, both the 1-D and CFD models indicated that increasing the H2/CO ratio in the feed increased CO conversion, C5+ yield, pressure drop, F-T reaction rate, and the heat transfer requirements. Increasing the inlet syngas velocity decreased CO conversion and increased the pressure drop. Also, increasing temperature, increased the F-T reaction rate, CO conversion and the C5+ yield, and decreased the pressure drop. Furthermore, under the conditions investigated, the F-T process in the MCR used was kinetically-controlled.
3. The CFD model used to investigate the flow distribution in the MCR showed that using a flow distributor resulted in a homogenous flow distribution and eliminated the strong gas recirculation.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Arias Pinto, Fabianafva2@pitt.eduFVA2
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairMorsi, Badie I.morsi@pitt.eduMORSI
Committee MemberEnick, Robert M.rme@pitt.eduRME
Committee MemberKlinzing, George E.klinzing@pitt.eduKLINZING
Date: 15 September 2016
Date Type: Publication
Defense Date: 2 August 2016
Approval Date: 15 September 2016
Submission Date: 2 August 2016
Access Restriction: 3 year -- Restrict access to University of Pittsburgh for a period of 3 years.
Number of Pages: 91
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Chemical and Petroleum Engineering
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Microchannel Reactor, Fischer-Tropsch, CFD Simulation
Date Deposited: 15 Sep 2016 20:18
Last Modified: 15 Nov 2016 14:35
URI: http://d-scholarship.pitt.edu/id/eprint/29089

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