Emission Source Characterization for Proactive Flare Minimization during Ethylene Plant Start-ups

Abstract

Ethylene plant start-ups generate huge amounts of off-spec products for flaring, which cause negative environmental and societal impacts, as well as tremendous raw material and energy losses that could be unitized to generate much more needed products. Thus, cost-effective start-up flare minimization strategies through proactive process design and operation are becoming more important and attractive to the industry. However, fundamental and quantitative studies on start-up flaring emissions are still lacking, such as (i) what kinds of emission species are contained in the flaring sources; (ii) how much of each emission source will be generated during one start-up; and (iii) what is the dynamic emission profile of each emission source with respect to the start-up time? In this paper, rigorous plant-wide dynamic simulations are employed to characterize flaring emission sources under different flare minimization strategies for an ethylene plant start-up. Deep insights of the emission source distribution and simulated dynamic emission profiles are provided. The study enriches the emission inventory with details for industry point sources, which have never been compiled previously. It also provides detailed technical support for both the industry and environmental agencies on evaluating and developing cost-effective flare minimization strategies in the future.