Spherical Catalyst Carriers with Unprecedented Size Uniformity
March 16, 2018
An increased demand for small-diameter (less than 3mm) spherical catalyst carriers led to the development of Saint-Gobain NorPro’s Accu® spheres. They can be effectively used in slurry or moving-bed reactors, where coking and constant catalyst regeneration is required.
The size of the carrier is optimized to balance pressure drop and external geometric surface area, while the internal surface area and porosity is tailored to a specific catalyst and chemical reaction. They are available in multiple formulations, compositions and properties in a range of sizes from 0.3 to 3.5mm.
What sets Accu spheres apart from other catalyst carriers is that the micro-sized spheres are produced with a narrow size distribution. This allows for high-geometric surface area, uniform packing and even flow distribution, which has drawn wide appeal in numerous markets, including chemical, petrochemical and refinery applications.
Accu® Spheres catalyst carrier key attributes:Accu
- Narrow size distribution
- Excellent control to average particle size
- Control of porosity
- Alumina, silica, titania, zirconia and mixed oxides
Figure 1. An illustration of Accu spheres with a target median diameter of 0.45mm, 1.6mm and 3.2mm.
Saint-Gobain NorPro: Case Study
Saint-Gobain NorPro’s innovative manufacturing process allows for excellent control over average particle size. When compared to UniSpheres® carriers, which is Saint-Gobain NorPro’s traditional mono-sized spherical catalyst carrier, the increased homogeneity of Accu Spheres is clearly evident. The particle size distribution has an average absolute error of just 1.5% with a span of less than 15% between D10 and D90.
Accu® Spheres Meet Tight Average Particle Size & Narrow Size Distribution
Figure 2: Graphs depicting average absolute error and typical sie distribution.
Accu® Spheres vs. UniSpheres® Properties- Improved Size Uniformity
|Technology||UniSpheres®||UniSpheres®||Accu® Spheres||Accu® Spheres||Accu® Spheres|
|Target median diamter (mm)||1.6||1.6||1.6||2.2||2.1|
|N2 BET surface area (m2/g)||248||237||279||214||204|
|Hg intrusion volume (cm2/g)||0.89||0.79||0.82||0.95||0.79|
|Average pore diameter (å)||94||87||93||10||106|
|PSD CAMSizer, D10 (µm)||1152||1380||1479||2071||2007|
|PSD CAMSizer, D50 (µm)||1493||1631||1587||2208||2133|
|PSD CAMSizer, D90 (µm)||1700||1825||1705||2345||2265|
|Deviation from target D50 (%)||6.7||1.9||0.8||0.4||1.6|
|Span (D90 - D10)D50 (%)||36.7||27.3||14.2||12.4||12.1|
Accu spheres are better at hitting target diameter and narrower particle size distribution.
Figure 3. Table showcasing the improved size uniformity of Accu spheres in comparison to UniSpheres media.
UniSpheres catalyst carriers are available in a range of sizes from 1.6 to 8mm. A unique forming mechanism is used to produce highly mono-sized particles, but when size uniformity is paramount Accu Spheres deliver a size range that is unprecedented.
Accu spheres address the need for a tightly controlled target diameter. With a target median diameter of 1.6mm, the mean diameter is within 0.8%, versus up to 6.7% for UniSpheres media.
Catalyst Carrier Customization
Figure 4 (right). Accu spheres address the need for a tightly controlled target diameter. With a target median diameter of 1.6mm, the mean diameter is within 0.8%, versus up to 6.7% for UniSpheres media.
Few vendors make comparable-sized spheres in large quantities, and those that do are typically limited in size or by material composition. Saint-Gobain NorPro Accu spheres are developed and prototyped for the intended application.
Their unique customer-driven capability is supported by a 100-tons-per-year development plant. They can tailor porosity and produce a range of sphere sizes in large quantities, in multiple compositions and with varying properties.
Refractory metal oxides commonly used as catalyst carriers include alumina, rare-earth metal oxides, zirconia and titania. Saint-Gobain NorPro has extensive experience in material science and raw material characterization. They can work with customers to optimize the finished carrier chemistry and physical properties.
They tailor a solution from tightly controlled alumina catalyst carriers, most commonly used in refinery applications, to proprietary material compositions. They can even produce a gradient of chemistries within each particle.
Saint-Gobain NorPro is one of the largest suppliers of catalyst carriers in the world and co-development has been a key to success. In fact, over 90% of sales are related to custom proprietary catalyst carrier projects with custom samples available upon request.