Magnetic‐field augmented sedimentation of micron‐sized iron particles in a hydrocarbon

Abstract

The production of liquid hydrocarbon from syngas by the Fischer-Tropsch synthesis is accelerated by iron or cobalt catalysts. When this process is performed in a slurry bubble column reactor, fine catalyst particles are distributed in the liquid phase and these must be separated from the product before it can be further refined. Sedimentation is the most common and simple chemical engineering unit operation for separating suspended solids from liquids. It can be easily accomplished by holding the suspension in a settling tank for a period of time without incurring additional processing costs. However, sedimentation velocities are inversely proportional to particle size; if the solid particles are very small, the sedimentation velocity may be so low that the processing time is unacceptably long. This article deals with the effect of exposure to a magnetic field on the settling velocities of suspensions of iron particles in a hydrocarbon liquid. The results reveal that magnetic flocculation can substantially increase the settling velocities for catalyst particles in hydrocarbon liquids produced in the Fischer-Tropsch process.