Calculation of ammonia consumption for flue gas denitration SCR
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I would like to ask everyone: in the SCR process for flue gas denitration, where ammonia is used as a reducing agent, how do you calculate the amount of ammonia that needs to be used? Some people believe that NOx should be treated as NO and calculations should be carried out based on the molar ratio, while others think that NOx should be converted into NO and NO2 for calculation, following the guidelines for denitration technologies in thermal power plants. Which method should be used for the calculation?
Calculations can be carried out strictly in accordance with the \"Q/DG 1-J004-2010 Technical Guidelines for the Design of Denitration Systems in Thermal Power Plants\". Regardless of the calculation method used, the results should be consistent, based on the following points: 1. The actual oxygen content in the boiler exhaust gases must be adjusted using a standard oxygen level of 6% (for example, the standard oxygen level for coal-fired boilers is 6%) ； 2. The volume fraction of NO in the flue gas is 95%, and that of NO2 is 5% (as specified in the guidelines) ； 3. Calculate the ammonia consumption or urea consumption based on the specified denitration efficiency (or final emission concentration). What can be confusing is the concentration of NOx, as **the concentrations specified in industry standards are based on NO2; therefore, it is necessary to convert the values related to NO, which adds a bit of complexity.
Do you mean that the conversion of NOx refers to converting NOx into 95% NO and 5% NO2? For example, if the NOx concentration is 500 mg/Nm3 (under standard conditions, on a dry basis, with 6% O2), then the equivalent value for NO is calculated as (500/2.05*0.95)*1.34 = 310.49 mg/Nm3, and the equivalent value for NO2 is 500*0.05 = 25. Is this the correct way to make such conversions?
Do you mean that the conversion of NOx refers to converting NOx into 95% NO and 5% NO2? For example, if the NOx concentration is 500 mg/Nm3 (under standard conditions, on a dry basis, with 6% O2), then the equivalent value for NO is calculated as (500/2.05*0.95)*1.34 = 310.49 mg/Nm3, and the equivalent value for NO2 is 500*0.05 = 25. Is this the correct way to make such conversions?
In actual operation, we always set it to NO by default
DL/T5480-2013 specifies this
DL/T5480-2013 specifies this