Executive Summary
When a major Gulf Coast refinery planned a multi-unit turnaround and to ensure vapor controls, emissions controls and degassing of all tanks, vessels and pipe were dont per regulations, they faced a critical bottleneck: the flare header would quickly reach capacity during depressuring and decontamination, risking violations under the EPA Refinery Sector Rule (RSR) – 40 CFR Part 63 Subpart UUU.
Relying solely on flare gas recovery would have extended the turnaround 7× longer and cost millions in lost production and potential fines.
Envent engineered a custom flareless vapour control system with specialty H₂S scrubbers and high-capacity thermal oxidizers. The result: >99.99% destruction efficiency, zero fines, zero incidents, and the turnaround finished ahead of schedule.
Project At A Glance:
- Location: Gulf Coast Refinery
- Challenge: Multi-Unit Flareless Turnaround (High H₂S & VOC and Benzene Vapor Control)
- Solution: Custom H₂S Scrubbers with vapor scrubbers + EMTOS/EMECS Thermal Oxidizers for vapor free vessel and tank degassing
- Outcome: Zero Flaring, Zero Fines, Turnaround Completed Early
The Challenge: Multi-Unit Turnaround with Strict Flare Minimization
A large Gulf Coast refinery planned a major turnaround on multiple process units. Early scoping revealed the flare header would quickly reach capacity during depressuring and decontamination — risking violations under the EPA Refinery Sector Rule (RSR) – 40 CFR §63.670(o) work-practice standards and TCEQ flare-minimization requirements.
Key Constraints Regulatory Compliance The EPA RSR prohibits routine flaring during maintenance, startup, and shutdown (MSS) activities and requires ≥98% destruction efficiency on all depressuring vents. Uncontrolled releases could trigger fines up to $100,000+/day and Title V deviations.
Operational Demands High-volume, variable-composition vapors (up to 100,000 ppm H₂S, steam, unique hydrocarbons) required phased control without delaying the critical-path schedule.
Emission & Safety Risks Relying solely on flare gas recovery (FGR) would extend decontamination 7× longer, costing millions in lost production while risking visible flaring and community complaints.
Official EPA Resources
- Refinery Sector Rule Overview – Flare minimization and work-practice standards.
- 40 CFR Part 63 Subpart UUU – Requirements for depressuring and MSS events.
Envent’s Custom Flareless Turnaround Solution
Envent engineered a phased, multi-train vapor control system tailored to each turnaround stage:
Treatment Process & Destruction Details High-H₂S Depressuring Specialty Liquid Scrubbers neutralized up to 100,000 ppm H₂S before routing to oxidizers.
Steam-Out & Condensing Knockout drums + condensers removed water and protected downstream units.
Hydrocarbon Destruction EMTOS & EMECS Thermal Oxidizers with upgraded detonation protection delivered >99.99% DRE across all compositions.
Full Integration Turnaround Safety Skid + real-time monitoring ensured seamless tie-ins and zero backflow risk.
The system operated 24/7 with Envent operators and full redundancy.
Proven Benefits: Zero Fines, Ahead of Schedule
| Benefit | Project Impact |
|---|---|
| Emissions Compliance | Zero fines (vs. hundreds of thousands expected) |
| Destruction Efficiency | >99.99% vs. flare’s typical 95% |
| Turnaround Schedule | Completed ahead of schedule – millions in extra profit |
| Safety & Reliability | Zero incidents across high-H₂S & steam operations |
| Environmental Impact | No visible flaring, full RSR/MACT 2 compliance |
The refinery praised Envent:
“An extraordinary job… exceeded our compliance initiatives and helped us finish ahead of schedule.”
This project remains the benchmark for flareless multi-unit turnarounds on the Gulf Coast.
Planning a flareless turnaround under RSR/MACT 2? Get your Free EPA Refinery Sector Rule Compliance Review & Quote today. Call Envent’s Turnaround Division at 888-997-9465 or email [email protected] — we turn 7× longer jobs into on-time wins.
