ABSTRACT
Catalyst/Wax Separation ......................................................................... 272 15.3 Experimental Details ............................................................................... 276
15.3.1 Materials ...................................................................................... 276 15.3.1.1 Reagents ........................................................................ 276 15.3.1.2 Prototype Cross-Flow Filtration Module ...................... 277
15.3.2 Method ......................................................................................... 277 15.3.2.1 Cross-Flow Filtration Test ............................................ 277 15.3.2.2 Laboratory Pilot-Scale SBCR Unit ............................... 278 15.3.2.3 Constant Filter Flux Maintenance Procedure ............... 280 15.3.2.4 Chemical Analysis ........................................................ 280
15.4 Results and Discussions ........................................................................... 281 15.4.1 Effect of Added 1-Dodecanol on the Performance of Cross-
Flow Filtration with Polywax 500/655-Activated Catalyst Slurry . 281 15.4.2 Effect of Added 1-Hexadecene on the Performance of Cross-
Flow Filtration with Polywax 500/655-Activated Catalyst Slurry ........................................................................................... 283
15.4.3 Development of Filter Flux Maintenance (Passive) Procedure ... 285 15.4.4 Laboratory Pilot-Scale Tests in SBCR with Cross-Flow
Filtration Module Using FT Catalyst/Wax Slurry ....................... 287 15.4.4.1 Technical Difficulties Encountered for FTS in Pilot-
Scale Tests ..................................................................... 287
A continuous cross-flow filtration process has been utilized to investigate the effectiveness in the separation of nano sized (3-5 nm) iron-based catalyst particles from simulated Fischer-Tropsch (FT) catalyst/wax slurry in a pilot-scale slurry bubble column reactor (SBCR). A prototype stainless steel cross-flow filtration module (nominal pore opening of 0.1 μm) was used. A series of crossflow filtration experiments were initiated to study the effect of mono-olefins and aliphatic alcohol on the filtration flux and membrane performance. 1-hexadecene and 1-dodecanol were doped into activated iron catalyst slurry (with Polywax 500 and 655 as simulated FT wax) to evaluate the effect of their presence on filtration performance. The 1-hexadecene concentrations were varied from 5 to 25 wt% and 1-dodecanol concentrations were varied from 6 to 17 wt% to simulate a range of FT reactor slurries reported in literature. The addition of 1-dodecanol was found to decrease the permeation rate, while the addition of 1-hexadecene was found to have an insignificant or no effect on the permeation rate.
