Operation and maintenance teams of power plant denitrification systems frequently encounter recurring faults with ammonia water circulation pumps, including corrosion leakage, blockage caused by crystal deposition, and unstable startup & shutdown performance. These issues mostly stem from blind pump selection that fails to match the physical and chemical properties of ammonia water as well as actual denitrification circulation working conditions.
The ammonia water adopted in denitrification processes generally has a concentration ranging from 10% to 25%, featuring volatility and weak alkalinity. Ammonia gas is categorized as flammable and explosive medium. Ordinary cast iron centrifugal pumps are highly susceptible to rust and corrosion, which will trigger ammonia gas escape and violate safety specifications for ammonia storage areas. Based on long-term field operation and maintenance data from power plant denitrification projects, Zoomlian Pump Industry specially recommends three dedicated circulation pump models to meet the piping and unit demands of different scenarios.
For conventional circulation of ammonia water and tank liquid replenishment in small and medium-sized denitrification units, the IH Series Stainless Steel Chemical Centrifugal Pump (Representative Model: IH65-50-160) is the top priority. Its wetted parts are standardly made of 304 stainless steel, and 316L stainless steel is optional for high-concentration ammonia water working conditions. Equipped with FKM double mechanical seals, the pump can withstand medium temperatures up to 100℃. Under rated working conditions, it delivers a flow rate of 30m³/h and a head of 30m, paired with an Ex d IIB T4 flameproof motor. It fully satisfies the 24-hour continuous circulating transportation requirement of denitrification systems and has become the standard configuration for incineration and thermal power denitrification projects across multiple regions.
When long-distance pressurized ammonia water delivery and high pipeline head are required, the DFP Self-balancing Multistage Anti-corrosion Centrifugal Pump is recommended. Adopting a self-balancing axial force structure, this pump runs without axial shimmy and causes extremely low wear to mechanical seals. The entire pump body undergoes anti-corrosion treatment to realize stable high-head pressurized conveying. It is ideal for centralized ammonia supply and circulation via main pipelines in large-scale power plant denitrification systems, effectively eliminating common defects of conventional multistage pumps such as seal leakage and axial abrasion, and greatly extending the maintenance cycle.
For closed circulation in ammonia zones with strict environmental supervision and mandatory zero-leakage requirements, the ZMQ Magnetic Drive Ammonia Pump is the optimal choice. This pump abandons the traditional shaft seal structure and relies on magnetic coupling for power transmission, fundamentally eliminating ammonia volatilization and leakage from the structural design. Wetted components are lined with fluoroplastic or fabricated from 316L stainless steel to completely avoid medium overflow risks. It fits inner circulation of underground storage tanks and closed denitrification chemical dosing loops, requiring no extra seal flushing pipelines and boasting the lowest frequency of later maintenance.
Key reminders to avoid improper selection: Copper fittings are strictly forbidden on all denitrification ammonia pumps, as copper will be rapidly corroded by ammonia water. Seal assemblies must be upgraded if the medium temperature stays above 80℃ for a long time. Complete flameproof protection and electrostatic grounding shall be equipped for all pump sets to comply with safety production standards of power plant ammonia areas. Matching flow rate and head parameters as needed enables stable operation throughout the entire denitrification technological process.