Direct Fired Thermal Oxidizer for Oil & Gas Application with Variable Process Loads
Executive Summary
Epcon engineered and supplied a tailored direct-fired thermal oxidizer (DFTO) for an oil & gas facility facing variable process loads and intermittent vapor/exhaust streams. The system reliably destroys volatile organic compounds (VOCs), hydrocarbon vapors, and other hazardous emissions from tank vents, loading/unloading operations, and process upsets — achieving high VOC destruction rates even under fluctuating flow conditions. Designed for flexibility, rapid startup, and robust operation, the DFTO solution offers the client regulatory compliance, operational confidence, and cost-effective emissions control for complex oil & gas exhaust profiles.
Project Overview
An oil & gas facility required a robust emissions-control solution to manage a wide range of exhaust streams: venting, loading/unloading of storage tanks, intermittent process upsets, and variable hydrocarbon vapor loads. These streams included high-concentration VOC and hydrocarbon vapors, often with frequent fluctuations. Epcon was selected to design, build, and commission a skid-mounted DFTO system capable of handling variable loads, providing fast response, and delivering reliable VOC/HAP destruction across all operating conditions.
The Challenge
The project involved several demanding challenges:
- The exhaust streams were high in VOC and hydrocarbon content, often presenting high-concentration, solvent-rich vapors which require reliable destruction.
- The facility experienced variable and intermittent loads — from near-idle venting to heavy loading/unloading events — making it difficult for standard continuous-flow oxidizers to maintain stable combustion and destruction efficiency.
- The solution needed to handle sudden vapor spikes or flow changes, maintain safe operation under varying oxygen and VOC levels, and avoid flammable-gas hazards while ensuring complete oxidation.
- Facility constraints: limited available footprint and requirement for a compact, skid-mounted system that could integrate with existing infrastructure without major site modifications.
- Regulatory compliance: The oxidizer had to deliver high destruction removal efficiency (DRE) for VOCs and hazardous air pollutants (HAPs), under all expected operating conditions.
Engineering Requirements
To address the above, Epcon defined clear engineering requirements:
- Provide a direct-fired thermal oxidizer (DFTO) designed for high-VOC / high-BTU hydrocarbon streams, capable of rapid ignition and stable operation under variable and intermittent exhaust flows.
- Include a vapor-buffer / accumulator or equivalent inlet stabilization system, to smooth out peak vapor flows from loading, venting or process surges — protecting the oxidizer and maintaining consistent combustion.
- Use a skid-mounted, compact layout (e.g. L-shaped or modular) to fit within space-constrained terminal or plant layouts; enabling relatively easy installation, minimal civil work, and quick integration.
- Equip with independent process-air and combustion-air blowers, robust burner and control system, safety interlocks, flame arrestors / safeguards, to ensure safe, reliable operation even under fluctuating load and VOC concentration.
- Ensure VOC/HAP destruction efficiency (DRE) ≥ 99% (or per project spec) across expected operating ranges — including low-flow, high-flow, and surge conditions. DFTO technology is well suited for high-concentration streams and intermittent use.
- Provide factory testing (FAT), skid-mounting, pre-wired controls & instrumentation, and on-site commissioning support — facilitating fast deployment with minimal installation downtime.
The Solution
Epcon’s delivery for the oil & gas client comprised:
- A skid-mounted DFTO unit, custom-engineered for hydrocarbon vapor and VOC abatement from tank-venting and process exhaust streams. The design includes a high-temperature combustion chamber, refractory lining, safety instrumentation, and weatherproof enclosure suitable for industrial oil & gas environments.
- Vapor-buffering and inlet-stabilization system, to handle intermittent loading/venting events and mitigate vapor spikes before reaching the oxidizer — thereby preserving combustion stability and safety while preventing overloading.
- A dual-blower configuration (process-air + combustion-air), modulating burner, and automated control logic (PLC-based) to manage variable flows and maintain required temperature and residence time for complete VOC destruction.
- Safety features: flame arrestors, explosion prevention measures, interlocks, and full compliance with relevant industrial safety standards, enabling operation under variable gas composition and flow conditions.
- Comprehensive factory acceptance testing (FAT) before shipping, followed by on-site installation supervision and commissioning — delivering a complete, ready-to-run DFTO system with minimal disruption to facility operations.
Technical Specifications
System Type: Direct-Fired Thermal Oxidizer (DFTO) for Oil & Gas Vapor Exhaust
Configuration: Skid-mounted, modular DFTO with inlet buffer/accumulator
Pollutants Treated: Hydrocarbon vapors, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) from tank vents, loading/unloading, process upsets
Operation Mode: Variable flow and concentration (intermittent venting, batch loading, continuous tank breathing), suitable for fluctuating load conditions
Destruction Efficiency (DRE): ≥ 99% VOC/HAP destruction under design conditions
Combustion Temperature Range: Typically 1,400–1,800 °F (typical for DFTO to ensure complete oxidation)
Air / Flow Control: Independent combustion-air and process-air blowers, modulating burner, safety interlocks, flame-arrestor / inert gas safeguards for flammable streams
Footprint & Layout: Compact skid-mounted “packaged” unit, suitable for retrofit or constrained site conditions
The Results
Upon commissioning, the DFTO system delivered:
- Reliable VOC and hydrocarbon vapor destruction — all venting, loading/unloading, and variable exhaust streams are safely combusted, converting harmful vapors to CO₂ and H₂O and eliminating VOC emissions.
- Consistent compliance under variable process loads, even during surges or intermittent events, thanks to inlet buffering and robust combustion controls, ensuring DRE targets are met.
- Fast startup and operational flexibility, enabling the oxidizer to start with minimal delay for intermittent vent events — avoiding the need for oversized continuous systems.
- Compact installation — skid-mounted design allowed integration without major civil works or facility modifications, minimizing downtime and capital expenditure.
- Cost-effective operation, especially compared to larger or more complex oxidizer types (e.g. regenerative) in applications with variable or intermittent flows: DFTO offers low capital cost and simple operation with high destruction efficiency.
- Enhanced safety and operational control, with robust controls, redundant blowers, and safety interlocks for handling potentially flammable vapor streams typical in oil & gas operations.
This installation demonstrates Epcon’s ability to deliver robust, flexible, and reliable DFTO-based emission control systems — ideal for oil & gas clients dealing with variable loads, high-VOC vapors, and complex venting operations.
Contact Epcon
Epcon designs, fabricates, and delivers turnkey DFTO systems and full air-pollution control solutions tailored to oil & gas, chemical processing, and industrial venting applications.
Contact Epcon engineering team to discuss a customized vapor-vent control or DFTO package adapted to your tank-venting, loading/unloading, or process-exhaust needs.
