Title : Slopless and flareless FCC startup: A case study in operational excellence and sustainable refining
Abstract:
Startup of Fluidized Catalytic Cracking Units (FCCUs) following planned or unplanned shutdowns is conventionally associated with significant hydrocarbon flaring and generation of off-spec “slop” oil, resulting in environmental emissions, reprocessing costs, and margin loss. This paper presents a practical and repeatable methodology implemented at the FCCU of HPCL Mumbai Refinery that enabled multiple slopless and near-flareless startups, transforming a traditionally high-loss activity into a controlled and sustainable operation.
The strategy emphasized pre-emptive stabilization of downstream systems and disciplined control of Main Fractionator hydraulics prior to feed introduction. Key interventions included:
- Internal circulation and pressure stabilization of the Gas Concentration Unit using external naphtha to ensure readiness for immediate product routing
- Full utilization of overhead condensers to maximize vapor recovery and minimize flaring,
- Careful thermal management to prevent pump cavitations and ensure stable pump-arounds and reflux
- A phased feed ramp-up to progressively build tray liquid holdup and stabilize tower temperature profiles.
Strict monitoring and control of pump-around flows, draw-off temperatures, reflux control, and column levels enabled steady-state attainment at each stage before further feed increase. As a result, zero slop generation and near-zero flaring were achieved, with Light Cracked Naphtha (LCN) and Light Cycle Oil (LCO) routed directly to on-spec tanks immediately after feed cut-in. Product quality remained within specifications throughout the startup period.
The paper discusses the operating philosophy, implementation challenges, trend-based analysis, and key learnings, and proposes a replicable best-practice framework for sustainable FCCU startups. The approach demonstrates how structured operations and proactive process control during transient operations can significantly enhance refinery reliability, profitability, and environmental performance.
Keywords: Operational Excellence, Loss-Free Startup, Slop Reduction, Flare Minimization, Sustainable Refining, Fluid Catalytic Cracking (FCC)
