12 DeNOx System
12.0.1 DeNOx process shall be selected in accordance with the following requirements:
1 For the boilers of newly-built or extended generating units，space for the flue gas DeNOx system shall be reserved or the flue gas DeNOx system may be constructed synchronously with the units，depending upon the approval comments on the environmental impact assessment reports of the project.CFB boilers should not be equipped with flue gas DeNOx system.For pulverized coal boilers，measures should be incorporated to reduce emissions of NOx when determining the structures of the furnace and the type of the burner.
2 For pulverized coal boilers，the flue gas DeNOx process shall be determined through techno-economic comparison by comprehensively considering such factors as unit capacity，coal quality，concentration of NOx emitted from boilers，requirements of DeNOx efficiency，availability and transportation conditions of DeNOx agent，wastewater discharge conditions，recycling conditions of by-products as well as the maturity level of the DeNOx process.For modified units，the characteristics of the site layout shall also be considered.
3 If the condition permits，the integrated desulfurization and DeNOx process may be employed if justified reasonable through techno-economic comparison.
12.0.2 The DeNOx agent shall comply with the following requirements:
1 Reliable source shall be available.
2 The DeNOx agent storage volume in the power plant shall be determined according to supply continuity，distance of supply source from the power plant，and transportation conditions.
3 Measures against volatilization and leakage shall be taken for the DeNOx agent preparation，storage and handling systems.If prevention against fire，explosion and poisoning is required，measures shall be taken to ensure safety.
12.0.3 If the use of catalysts is required for the DeNOx process，measures shall be incorporated to properly treat the spent catalysts.In order to avoid secondary pollution the use of recyclable catalysts shall be given priority.
12.0.4 No bypass flue duct should be provided for the DeNOx system.
12.0.5 If the DeNOx system results in significant increase in air pressure of the ID fan，it shall be taken into account when determining the furnace transient explosion proof pressure.
12.0.6 If installation of the DeNOx system has a potential of producing products that may corrode and clog up the air preheater，then the design of the air preheater shall incorporate special measures to mitigate or eliminate such effects.
12.0.7 The capacity and quantity of DeNOx plants shall be determined according to the following requirements:
1 The rated capacity of the DeNOx plants should be designed based on the flue gas flow from the boiler，with no margin added.
2 The DeNOx plants shall be arranged in unit system，that is，one DeNOx plant serves one boiler.
3 The temperature of flue gas at the inlet of DeNOx plant shall be taken as the flue gas temperature under normal operating conditions.Proper measures shall be taken to prevent damages to equipment when the boiler operates under abnormal operating conditions.
12.0.8 The DeNOx reaction control system should be integrated into the distributed control system（DCS），and the DeNOx agent preparation，storage and handling control system should be controlled through the programmable logic controller（PLC）or be integrated into the DCS.
12.0.9 The DeNOx system shall be arranged in accordance with the following requirements:
1 The DeNOx system should be arranged either in the boiler proper or near the flue duct at rear of boiler or the chimney，depending upon the process flow.
2 The DeNOx agent preparation，storage and handling system shall be located appropriately at a proper distance from the surrounding buildings.The adverse wind direction shall be considered when necessary.There shall be unobstructed roads and passage of egress in the plant area.
3 The DeNOx plant should be arranged outdoors provided that necessary protective measures shall be in place.