Pragmatic Approach toward Catalytic CO Emission Mitigation in Fluid Catalytic Cracking (FCC) Units

Aleksei Vjunov,Amy Dundee,Vasileios Komvokis,Claire C Zhang,Karl C Kharas,Bilge Yilmaz

doi:10.3390/catal11060707

Abstract

The need to mitigate the environmental footprints of refineries in a sustainable and economical way is widely accepted, yet there appears to be a lack of a unilateral pragmatic approach towards CO oxidation to CO2 among the refining community. In this work we share CO promoter design strategies that can afford a tangible and immediate CO conversion efficiency increase without a need for additional precious metal loading. The key focus is on the support material architecture that is essential to boost the CO conversion and reduce the NOx generation in the FCC unit. It was demonstrated that the suppression of Pt sintering as well as the enhancement of the oxygen mobility on the catalyst surface can afford an ~40% lower cost of Pt and ~20% lower usage rate compared to current industry-standard designs.

Highlights

The ever-more stringent environmental regulations on air pollution, especially that caused by the oil refining industry, are drawing more efforts by refineries to combat these harmful emissions [1]
We focus on the CO and NOx emissions as these are common and critical concerns during fluid catalytic cracking (FCC) catalyst regeneration as part of oil cracking
There appears to be essentially no difference between the three chosen Pt-loadings when the overall catalyst design is identical. This result may be somewhat surprising as this observation would suggest that a large fraction of the precious metal is apparently not contributing to the catalytic activity

Summary

Introduction

The ever-more stringent environmental regulations on air pollution, especially that caused by the oil refining industry, are drawing more efforts by refineries to combat these harmful emissions [1]. The resulting combustion of CO in the dilute phase, referred to as afterburn, can produce high temperatures, which can damage regenerator internal hardware, and, cause an FCC unit outage [5]. While seemingly minor, such a sequence of events would cause a major disruption in a refinery operation and would lead to substantial financial loss. Over the past years there have been numerous contributions to the field of CO oxidation chemistry These include extensive and fundamental studies using advanced techniques, many summarized in recent review articles [7,8].

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Results

Conclusion