Background
Extrusion is the process by which material is forced through a die under immense pressure to create a continuous shape with consistent cross-section. This method is a proven scalable technique for manufacturing fixed bed catalysts and catalytic supports at industrial quantities.
Technology
Figure 1: Cross section of a screw extruder where raw material, known as extrusion dough, enters from the top and exits as a compacted continuous stream as it pressed through a metal die (top).1/4-inch and 1/8-inch round dies (bottom)
Experimental
Extrusion can be used to manufacture catalysts with compositions including but not limited to alumina, silica, titania, zirconia, zeolites, active metal precursors, carbon, and other mixed metal oxides. Determining the chemical composition and proper extrusion parameters for catalysts that can withstand years of continuous service can be challenging when constraints on physical properties, cost, and catalytic performance must be considered.
Results
A recent project explored methods of increasing crush strength without significant modifications to the catalyst recipe. In customer pilot testing using prototype material, catalytic activity and selectivity were measured above target specifications. However, material attrition rates were also high, creating a need to increase crush strength without decreasing performance. Several recipe modifications were explored, Figure 1, and a solution was ultimately identified that increased crush strength by 50% without changing chemical composition and subsequent catalytic performance.
Figure 1: A comparison of the different crush strengths achieved by modifying extrusion parameters.
Figure 2: Extruded catalytic material.
Conclusions & Commercial Impact
Applied Catalysts + Technologies (AC+T) were successful in increasing catalyst crush strength without a negative effect on catalysts activity or selectivity. Results were used to develop a scaled production method to manufacture industrial quantities of material. Contact Applied Catalysts for quotes and additional information on custom or contract catalyst manufacturing.
