Evaluation of a New Approach for Estimating the Amount of Flared Gas and Emission Estimation of Particulate Matters from Flaring of a Gas Process Plant

Particulate matter such as black carbon and soot produced due to incomplete combustion of hydrocarbons is one of the most critical and hazardous sources of air pollution, which can cause fatal diseases. Pars Special Economic Energy Zone is located in southern Iran, close to Naiband National Marine Park in Bushehr Province. Twelve natural gas processing plants and 16 huge petrochemical complexes have been developed in this area. They produce more than 70% of Iranian domestic natural gas and 45% of the petrochemical products. Due to the complexity of the process and possibly the lack of access to the best available technologies, daily more than 11,100 tons of gas are combusted at 60 active flares, which could be one of the main reasons for the release of black carbon and soot.. Due to the importance of the flow and composition of flared gas in estimating particulate matter, in the present study, based on actual process data and field measurements, flow rate and composition were determined and verified. To achieve this purpose, first, all of the control valves on the flare network were recognized and then, the flow rate and composition of the flared gas was calculated based on the equations and correlations of the valves. Finally, the particulate matter emission from the flares was calculated based upon the flared gas flow, composition and existing emission factors. The accuracy of the predicted flow rate was validated using a flowmeter. The actual cumulative measured flaring rates were compared with cumulative model flaring rates. By comparing the calculated cumulative flaring rate against measured values as determined by flow meters, the square of the Pearson correlation coefficient (SPCC) was found to be 0.986, showing high correspondence between measured and predicted values. The accuracy of the predicted composition by the model using gas chromatography indicates a deviation of less than 13% between predicted values and actual values. This point shows the acceptable accuracy of the method on an industrial scale for estimating the total particulate matter emitted from flaring.