Thermal Oxidizer with Comprehensive Heat Recovery for Continuous Web Processing Application
Executive Summary
Epcon delivered a custom-engineered Regenerative Thermal Oxidizer (RTO) with full heat-recovery to a continuous-web processing facility — enabling efficient destruction of solvent-laden exhaust, maximized energy reuse, and improved production throughput. The system achieves 98–99.5% destruction (DRE) on a 2-can RTO, includes solvent-bypass for high-load events, and incorporates multiple heat-exchangers (plate & shell + air-to-liquid) to recycle heat back into the ovens. As a result, the customer increased production by ~15% while staying within stricter emissions limits.
Project Overview
The customer— a manufacturer operating a continuous-web line — was upgrading its production and air-pollution control systems. Their existing emission-control setup was outdated and not able to meet new regulatory requirements for solvent vapor emissions during web processing. The goal: supply a turnkey oxidizer + heat-recovery solution that handles variable solvent loads, minimizes fuel/energy consumption, supports continuous operation, and integrates seamlessly with their ovens and web-processing equipment.
Epcon was awarded the contract and engineered a customized package: a regenerative RTO equipped with multiple heat-recovery stages (plate & shell heat exchanger and air-to-liquid exchanger), with safety features such as a high-solvent bypass for overload protection — ensuring both environmental compliance and energy efficiency.
The Challenge
- Solvent-laden exhaust from continuous web process: The manufacturing process generated volatile organic compounds (VOCs) and solvent emissions that required reliable abatement to satisfy air-quality regulations.
- Variable and unpredictable solvent load: At times, solvent concentration and air flow rates fluctuated — requiring the abatement system to handle both low and high load conditions without compromising destruction efficiency or safety.
- High energy/fuel demand if using conventional oxidizer: Without heat recovery, combusting solvent vapors at high temperatures (as required for VOC destruction) would consume large amounts of fuel, driving up operating costs. Thermal oxidizers without recovery are often less efficient for moderate VOC concentrations.
- Need for integrated, continuous operation: Given the continuous nature of the web processing line, any emissions-control solution had to run reliably around the clock, with minimal downtime or maintenance, and integrate with existing ovens/heat systems.
The Solution
To meet these challenges, Epcon defined and engineered a solution with the following specifications:
- A regenerative RTO sized and configured to handle the facility’s solvent-laden exhaust, with sufficient residence time, temperature, and turbulence to reach 98–99.5% VOC destruction efficiency (DRE) under varying load conditions.
- A solvent-bypass safety feature to handle occasional high-solvent loads without overloading the oxidizer — ensuring safe operation even during spikes in emissions.
- A comprehensive heat-recovery system including:
- A plate & shell heat exchanger to capture heat from oxidizer exhaust and feed it back into oven inlet air, reducing need for auxiliary fuel.
- An air-to-liquid (or air-to-air/air-to-water) heat exchanger to further recover waste heat for secondary processes or preheating, maximizing thermal efficiency.
- Turnkey engineering, fabrication, installation, commissioning and integration with the existing web-processing ovens and ducting — to minimize downtime and ensure compliance from day one.
Technical Specifications
Oxidizer Type: Regenerative Thermal Oxidizer (RTO), 2-canister design with solvent flow bypass capability for overload protection.
Destruction Efficiency (DRE): 98–99.5% VOC/HAP destruction — high performance under varying load conditions.
Heat-Recovery Configuration: Dual-stage heat recovery: plate & shell heat exchanger for pre-heating inlet ovens air; air-to-liquid (or equivalent) exchanger for supplemental heat reuse / process heating.
Safety Feature: Solvent-bypass line / overload protection to handle high concentration vapor loads without compromising oxidizer operation.
Process Integration: Integrated with continuous-web ovens and ventilation/ducting network; custom engineered for existing production line layout.
Operational Impact: Allowed for increased throughput (~ 15% production boost) while meeting stricter emissions limits; optimized fuel/energy consumption thanks to heat recovery.
The Results
After commissioning, the system delivered:
- High-efficiency VOC abatement — 98–99.5% destruction efficiency ensured compliance with environmental regulations and eliminated solvent emissions from the Web-processing line.
- Significant energy & fuel savings — thanks to the dual-stage heat-recovery system, much of the waste heat is recycled back into the ovens or other processes, dramatically reducing auxiliary fuel consumption compared to a non-recovered oxidizer.
- Improved production throughput — customer reported a ~15% increase in production capacity after installation, while still staying within stricter emissions limits.
- Reliable continuous operation under variable load — the solvent-bypass and robust RTO design allow the system to handle load fluctuations (both low and high solvent vapour) without loss of performance or shutdown.
- Lower total cost of ownership & operational efficiency — integrated system reduces need for separate burners/heat sources, lowers fuel bills, reduces maintenance compared to traditional oxidizer + oven + heat-exchanger piecemeal setups.
