Featured Project: Zero-Odor Degassing of 1,500 ppm H₂S Light Crude Tank – Northeast Terminal (Community-Adjacent)
A major Northeast P66 Refinery needed to degas a large crude tank containing 1,500 ppm H₂S and light, high-RVP crude for scheduled maintenance.
The tank was surrounded on three sides by residential neighborhoods, a retirement community, and a large community center. The previous degassing event triggered public complaints and local TV news coverage.
The local air district only permitted carbon adsorption — a technology that routinely breaks through on sour mercaptan vapors. Envent engineers worked with the New Jersey DEP to secure the permits and then performed the work.
Envent delivered the only compliant, zero-odor solution — and finished in 26 hours instead of the expected 3+ days.
The Challenge
- 1,500 ppm H₂S + mercaptans = immediate odor detection
- Light crude = rapid, high-volume vapor liberation
- Zero odor tolerance from neighbors and regulators
- Restricted to carbon adsorption only (no thermal oxidizers allowed)
- Must achieve <10% LEL for safe entry per OSHA 1910.146 Confined Space
Envent’s Engineered Zero-Odor Solution
Envent designed a high-flow hybrid liquid/carbon system capable of 4,000 SCFM with full redundancy:
| Component | Role & Internal Link |
|---|---|
| Dual-Train Liquid Scrubber | Proprietary chemistry protected carbon from H₂S/mercaptans |
| Activated Carbon Vessels | Final polishing of VOCs & residual odors |
| Hybrid Liquid + Carbon Systems | Combined wet + dry trains for maximum efficiency & protection |
| Multi-Port Manifold + Flow Diversion | Zero downtime during media/chemical change-outs |
| Nitrogen Suppression System | Maintained <12% O₂ per API 2015/2016 Safe Entry |
| Perimeter H₂S + VOC Monitors | Real-time fence-line monitoring |
Performance
- Adsorbed >12,000 lbs of VOCs & sulfur compounds
- 100% Destruction/Removal Efficiency across all trains
- Zero detectable odor at fence line — confirmed by independent monitoring
- Degassing completed in 26 hours (vs. 72-hour estimate)
Proven Results – Zero Complaints, Record Speed
| Benefit | Delivered Outcome |
|---|---|
| Odor Control | Zero complaints, zero media attention |
| Speed | 26 hours vs. 3+ days — new site record |
| Safety | <12% O₂ inerting, zero incidents |
| Compliance | 100% within local carbon-only restriction & EPA Method 21 monitoring |
| Cost Savings | Early tank return = hundreds of thousands saved |
This project is why Northeast terminals now specify Envent’s Tank Degassing Services and Hybrid Vapor Control Systems when carbon-only is mandated and odor is non-negotiable.
Facing a sour crude tank surrounded by homes? Need zero-odor, regulator-approved degassing? Get your Free Community-Adjacent Degassing Plan & Quote today. Call Envent’s Northeast Team at 888-997-9465 or email [email protected] — we keep you invisible to the neighbors and the news.
