Pumping technologies are fundamental to success in an array of market sectors, from municipal water supplies to proprietary ultra-high vacuum (UHV) processing. Poor performance or malfunction in such applications can be extremely costly. Water loss due to leaks in pipelines is estimated to cost billions in annual revenue while inefficient vacuum leak rates in UHV processing can render experiment/production parameters void. These concerns are further amplified when pumps are required to operate in extreme conditions, which can cause conventional pump materials to deteriorate and fail.
Silicon nitride (Si3N4) is often used to engineer high-performance pump components for the most demanding industrial sectors: chemical processing, hydrocarbon extraction, oil and gas transport and supply, etc. It is a technical ceramic with outstanding thermomechanical properties and superior anti-corrosive capabilities compared to most engineering alloys. This guarantees an extended service life at higher operating speeds, elevated temperatures, and for liquids and slurries with challenging compositions.
Chemicals Industry: A Case for Silicon Nitride Pumps
The most common pump designs used in the chemicals industry utilize a mechanism that makes direct contact with the process fluid and vapors in a pump headspace (diaphragm, impeller, turbine, etc.). These components are essential in ensuring reliable performance and continuous operation to meet a plant’s bottom line. Stainless steels with elevated chromium (Cr) contents are often used in rotating shafts and impellers for many positive displacement (PD) pumps, as they offer sufficient corrosion resistivity for the most common caustic and acidic chemicals.
However, heterogeneities in flows can abrade the thin anti-corrosive film of stainless steel causing significant wear and tear over time. High flow speeds and pressures are also typically associated with increased internal operating temperatures which can reduce the performance capabilities and cause costly inefficiencies. There are countless ways for a chemical pump to catastrophically fail. Many of these risks can be mitigated by specialist materials like silicon nitride.
Silicon Nitride Pump Components
Industrial pumps are comprised of numerous integrated components that perform in tandem to induce and control a flow of material. Silicon nitride has been successfully integrated into pumping systems in impellers, seals, shafts, spindles, and nozzles that offer superior performance over conventional materials for extended pumping performance.
The chief advantage of silicon nitride in high-throughput chemical pumping systems is the outstanding chemical integrity of the material in demanding conditions. Even when operating at high pressures, flow speeds, and temperatures, silicon nitride is inherently resistant to both acidic and alkaline chemicals. Unlike stainless steel, however, beta-silicon nitride boasts a high-strength microstructure of interlocking needle-like crystalline grains that resist intragranular wearing for long-standing mechanical stability. This combination of physicochemical properties ensures optimal performance for more aggressive chemistries and slurries.
Silicon nitride also vastly exceeds stainless steels when it comes to high-temperature performance. Syalon 101 is one of the most trusted technical ceramics when it comes to chemical processing systems. It vastly outperforms austenitic stainless steels in terms of their hot-strength characteristics, with a maximum use temperature of 1200°C (2192°F). Stainless steels typically offer a significantly reduced operating temperature, with some specialist grades suggesting a maximum peak temperature of 1100°C (2012°F).
These properties offer a raft of tangible benefits for high-throughput pumping systems in demanding areas of application, which extend far beyond the chemical processing industry.
Silicon Nitride from International Syalons
International Syalons is one of the UK’s leading suppliers of silicon nitride parts and components for challenging areas of application. If you need any more information about constructing pumping components from silicon nitride, simply contact a member of the International Syalons team today.
