Hamworthy Combustion SCR De-NOx Scrubbers are designed to effectively reduce NOx content in flue and exhaust gases from utility boiler and/or steam generators when other NOx prevention techniques (e.g. Low-NOx Burners, Air Staging, Over Fire Air, Flue Gas Recirculation) or Selective Non-Catalytic Reduction (SNCR) are not sufficient to meet the required NOx emission limits.
Through the selection of best-in-class high activity catalyst, the proper design of the SCR reactor casing and an accurate CFD modeling of the gas flow conditioning devices, Hamworthy Combustion SCR De-NOx Scrubbers ensure compliance with the most stringent Environmental Regulations (e.g. European Directive 2001/80/EC, US EPA Clean Air Act, Saudi Arabia RCER 2004, etc.).
The reducing agent - an ammonia source - is injected and intensely mixed with the flue gas. The mixture then passes through a series of catalyst layers where the nitrogen oxides are converted into nitrogen and water vapor through the following reactions:
4 NO + 4 NH3 + O2 - 4 N2 + 6 H2O
6 NO2 + 8 NH3 - 7 N2 + 12 H2O
The NOx reduction efficiency is typically 90%, but it can be designed to achieve 99%. The reducing agent is injected at a temperature of typically 320-420°C (610-790°F). The maximum allowable temperature of catalyst is typically 490°C (915°F). The ammonia slip is typically less than 5 ppm, but it can be less than 1 ppm. The SO2/SO3 conversion is typically less than 1%. Guaranteed catalyst life is typically 16,000 hours but SCR can be designed for 24,000 hours or more. Catalyst modules are designed for easy handling and quick installation. Catalyst with large pitch size and sootblowers are installed in high-dust applications and/or when superior resistance to plugging is required. The design of: AIG, SCR reactor, gas ducts and gas flow conditioning devices is verified by extensive application of CFD modeling. Ammonia vaporization skids, NOx/O2 analyzer and dosing panel are designed for high reliability and can be CE marked and/or ATEX compliant upon request. Truck unloading stations, pumping stations and ammonia storage tanks can also be supplied.