Discussion of calculation of flue gas moles quantity and its effect for CFB boilers in ASME PTC4

摘要

Circulating Fluidized Bed boilers play an important role for the clean and efficient utilization of the low quality fossil fuels. Compared with the ASME PTC4-2008, the new revision of ASME PTC4-2013 has made certain adjustment on the calculation of the flue gas mass and mole quantity for the circulating fluidized bed boilers. Based on theoretical analysis of the calculation formulas for the flue gas mass and mole quantity, it's proven that the calculation of the mass quantity for the flue gas in ASME PTC4-2013 is correct and certain error exists in the calculation of the flue gas mole quantity. Some suggestions are given for the modification of the existing mole quantity formulas for the CFB boilers, and new model put forward for the flue gas mole calculation. An example is put forward for verification of the calculation models. It's is shown by the example that based on formula for the flue gas mass quantity in the revision of PTC4-2013 the mass balance of the boiler can be guaranteed while there are certain deviation between the mole quantity calculated and the correct value. The result from the new revised mole quantity calculation formula suggested in the article coincides with the correct value perfectly and can solve this deviation. The effect on the final boiler efficiency is also calculated and indicated for the flue gas mole quantity deviation.