Storage & Vessel Tank Degassing Solutions
North America's Most Experienced Tank Degassing Contractor
Envent Corporation operates the continent’s largest fleet of mobile thermal oxidizers and emission control systems, providing industrial tank degassing services for refineries, chemical plants, terminals, and pipeline facilities across the United States and Canada. Since 1992, we have safely degassed thousands of storage tanks, pressure vessels, reactors, and marine vessels while maintaining zero-incident safety performance and complete regulatory compliance with EPA BACT, MACT, and state air quality standards.
Our proprietary EMTOS (Envent Mobile Thermal Oxidation System) and EMECS (Envent Mobile Emission Control System) technology delivers 99.9%+ destruction removal efficiency on volatile organic compounds (VOCs) and hazardous air pollutants (HAPs), satisfying the most stringent environmental regulations including California’s South Coast Air Quality Management District (SCAQMD) Rule 1149, Texas Commission on Environmental Quality (TCEQ) Chapter 115, and Louisiana Department of Environmental Quality (LDEQ) air permit requirements.
Tank & Vessel Degassing Capabilities
Atmospheric Storage Tanks
- Above-ground storage tanks (crude oil, gasoline, diesel, ethanol, naphtha)
- Fixed-roof cone tanks (10,000 to 2 million+ barrel capacity)
- External floating-roof tanks (EFRTs) and internal floating-roof tanks (IFRTs)
- Horizontal cylindrical tanks and low-profile tanks
Pressure Vessels & Spheres
- LPG storage spheres (propane, butane, mixed NGLs)
- Bullet tanks and horizontal pressure vessels
- Butadiene, propylene, and ethylene storage (high-reactivity compounds)
- Ammonia refrigeration vessels
Marine & Transportation
- Crude oil tankers and product barges
- Chemical parcel tankers
- Railcars and ISO containers
- Vacuum trucks and transport trailers
Specialized Vessels
- Chemical plant storage silos and day tanks
- Wastewater treatment aerators and clarifiers
- Underground storage tanks (UST) during decommissioning
- Landfill gas collection systems
Technical Capabilities: EMTOS & EMECS
EMTOS (Envent Mobile Thermal Oxidizer System)
TECHNICAL SPECIFICATIONS:
- Vapor Processing Capacity: 250-4,500+ SCFM per unit
- Primary Applications: VOC abatement, HAP destruction, standard tank degassing operations
- Burner Input: 30-15 MMBTU/hr depending on unit configuration
TYPICAL DEGASSING PERFORMANCE:
- 150-ft diameter storage tank: Cleared to <1% LEL (assuming 500,000 gallon capacity, gasoline product)
- 250-ft diameter storage tank: Cleared to <1% LEL (assuming 2 million barrel capacity, crude oil product)
- Performance varies based on product vapor pressure, ambient temperature, and residual heel volume
EMTOS (Envent Mobile Thermal Oxidizer System)
TECHNICAL SPECIFICATIONS:
- Vapor Processing Capacity: High-volume configuration supporting 0-4000 cfm+
- Burner Input: 20-77 MMBTU/hr
- Primary Applications: High-throughput refill operations, large-diameter tank degassing, refinery turnaround multi-vessel projects
SPECIALIZED CAPABILITY:
EMECS units handle vapor generation during rapid tank refilling operations up to 20,000 barrels per hour, maintaining continuous vapor destruction while product loading proceeds. This eliminates the traditional delay between degassing completion and refill initiation, reducing total turnaround duration.
Performance Monitoring & Documentation
REAL-TIME MONITORING:
- Continuous temperature recording (chart recorders + digital data logging)
- Flame ionization detector (FID) or photoionization detector (PID) for vapor concentration
- Vapor flow measurement and totalizing
- Lower explosive limit (LEL) monitoring at tank vapor space
- Chamber pressure and oxygen concentration
DOCUMENTATION DELIVERABLES:
- Complete emissions summary report with total VOC mass destroyed
- Temperature data logs proving 1,400°F+ operation throughout project
- Destruction efficiency calculations and verification
- Regulatory compliance certification
- Formatted submittal packages for EPA, state, and local agency requirements
Regulatory Compliance & Standards
Envent’s engineering team navigates federal, state, and local air quality regulations to develop site-specific degassing plans that satisfy permit requirements before equipment mobilization. Pre-project regulatory analysis prevents work stoppages, permit violations, and environmental enforcement actions.
We provide proven compliance for:
- Federal Standards
Benzene NESHAP / BWON, Refinery Sector Rule (RSR), Refinery MACT I & II, and Chemical Sector MACT. - H₂S Management
Approved under EPA Alternative Monitoring Plan (AMP) for H₂S. - Regional Air Districts
SCAQMD Rule 1149, TCEQ Chapter 115, CARB Vapor Recovery, BAAQMD Reg 8-40, LDEQ, NJDEP, and Washington DOE. - International
Canadian CEPA Registry and provincial air emissions standards.
Efficiency Through Engineering: EMTOS Process Optimization
EMTOS & EMECS Performance Snapshot
Industry-Leading Performance & Compliance
Advanced combustion engineering combined with continuous emissions monitoring provides verifiable proof that your tank degassing operations satisfy local and federal air quality requirements during both routine maintenance and emergency response scenarios.
- Verified Emission Destruction
99.9% minimum destruction removal efficiency at 1,400°F+ chamber temperature, verified through continuous temperature monitoring and periodic third-party stack testing. Performance certification documented through EPA Method 25A (total gaseous organics) and Method 18 (specific compound analysis) when required by air permits or client specifications. - Comprehensive Project Documentation
Complete emissions monitoring data, temperature logs, vapor flow totalization, and regulatory compliance certification provided. All documentation formatted for EPA, state agency, and Title V permit reporting requirements. - Zero-Incident Safety Performance
OQ-qualified technicians with refinery, chemical plant, and confined space entry certifications. All field personnel maintain 40-hour HAZWOPER certification, H₂S awareness training, and client-specific safety qualifications (ISNetworld, Avetta, PEC SafeLand).
Related Services:
What Our Clients Say
Featured Case Study
The Problem: A structural roof collapse on a gasoline storage tank released high levels of volatile organic compounds (VOCs). This created an immediate fire risk and potential community impact, requiring urgent stabilization to meet strict air quality rules.
What We Did: Envent deployed the EMTOS (Envent Mobile Thermal Oxidation System) within hours. We set up a custom vapor recovery line to pull hazardous gasses from the tank while maintaining safe internal pressure. Our crews provided 24/7 monitoring, achieving 99.99% destruction of all gasoline vapors.
The Result: The site was safely stabilized with zero safety incidents. Envent’s fast response guaranteed 100% compliance with environmental regulators and prevented hazardous odors from affecting the surrounding area.
Storage & Vessel Tank Degassing: Frequently Asked Questions
What is the difference between EMTOS and EMECS units?
EMTOS (Envent Mobile Thermal Oxidation System) units are high-efficiency thermal oxidizers designed for VOC abatement and HAPs control, typically ranging from 250 to 4,500 CFM. EMECS (Enclosed Mobile Emission Control System) units are high-capacity combustion systems built to handle much higher BTU capacities and pressures, supporting tank refilling at speeds up to 20,000 barrels per hour..
Can Envent provide emission control during high-speed tank refilling?
Yes. Our EMECS high-capacity units are engineered to manage the large vapor volumes generated during rapid tank refilling operations. These systems can support product loading rates up to 20,000 barrels per hour while maintaining continuous vapor destruction and compliance with applicable air permit requirements.
What is the destruction efficiency of Envent’s thermal oxidizers?
Can Envent handle high concentrations of H2S or sour gas?
How quickly can Envent mobilize for an emergency?
Does Envent provide documentation for regulatory agencies?
Are your technicians qualified for refinery and pipeline work?
Yes. Envent has OQ-trained personnel qualified to work in complex industrial environments such as refineries, chemical plants, pipeline facilities, and marine terminals.
Can you degas vessels other than storage tanks?
Why is thermal oxidation recommended over other degassing methods?
Do you support compliance for specific regional rules like SCAQMD 1149 or TCEQ Chapter 115?
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