Refineries adopt holistic approach of tracking, analyzing & reporting SOx, NOx & CO2 emissions through a Model Based Business Process leveraging first principal Simulation, Data Based Inferential, On-line Analyzers, 3rd party inspection data & US EPA norms!!!
With SOx, NOx & CO2 e missions norms from regulatory authorities getting stricter day-by-day, refiners are increasingly forced to think of ways & means to monitor & record their stack emissions, ideally in real time through on-line data/analysis to back up the claims of following the norms laid out by the regulators. The practical challenges to achieve this are numerous like :
Online analyzers often run into calibration issues resulting in measurement challenges & this increases vulnerability on the quality of the values of SOx, NOx & CO2 being reported
Third party measurement of SOx, NOx & CO 2 means, that often, this shall be done only at a scheduled frequency (say once in 3 months) & also possibly it may not cover all the furnaces in each such frequency
Many times, the in-house tools/methods used for calculation of SOx, NOx & CO2 are not accepted inherently by Regulatory authorities as reliable basis (e.g. CO2 calculations based on NAAQMS / EPA norms) & thus not a substitute for ?eld analyzers
It is possible that for some of the furnaces (e.g. NHT, HCU, CDU, VDU, etc.) the SOx, NOx & CO2 is measured for combined stacks , i.e. individual stack performance can not be known & hence apportioning of contribution of a particular furnace to overall emissions is extremely difficult
NOX in mg/Nm3- CDU/VDU