Full-Electric Flameless Regenerative Thermal Oxidizer
⚡ DEC.e-RTO™ ⚡

Electric RTO • VOC and HAP emission control • industrial decarbonization

DEC.e-RTO™ is DEC's full-electric, flameless configuration of a Regenerative Thermal Oxidizer (RTO™). Electric heating replaces the gas-fired burner as the auxiliary heat source, while the regenerative ceramic system recovers heat from the treated gas and transfers it to the incoming process air.

In other words, an electric RTO, eRTO, full-electric RTO or flameless RTO can retain the regenerative operating principle of an RTO while removing the combustion burner used to supply auxiliary heat. The result is a technology platform for VOC and HAP abatement where electrification, local emissions reduction, energy recovery and site utility strategy are considered together.

For the broader engineering principles, maintenance, safety, economics and emissions-compliance framework, see the DEC.XTO™ Thermal Oxidizer Engineering Guide.

Why Full-Electric Flameless RTO?

Electrification changes the heat source without changing the fundamental regenerative architecture. The process air is still preheated through ceramic media, oxidation still occurs at the required temperature and the outgoing hot gas still regenerates the ceramic beds. The principal change is that the auxiliary combustion burner is replaced by an electrically heated system.

Eliminating the combustion burner

• No gas-fired burner is required for normal electric heating operation.
• No burner combustion air or conventional fuel train is required for the electric heat source.
• Burner-related thermal NOx and burner-related CO formation are avoided. This does not mean that every treated stream is inherently NOx-free: nitrogen-containing compounds in the process gas can still contribute to NOx formation and must be evaluated.
• Electric heating can provide precise, distributed heat input and controllability across the heater bank.

Modular electric heating architecture

DEC.e-RTO™ can be engineered with a modular electric heater bank providing distributed and controllable thermal input. A modular arrangement can support staged electrical loading, thermal-duty matching and maintenance planning, subject to the selected heater technology, oxidation temperature and project-specific design.

Because the electric heating path does not require a fuel-fired burner, the corresponding gas train and burner combustion-air functions are not required for electric heating. Electrical protection, heater controls, process safety, LEL management and applicable site requirements remain integral to the complete system design.

Where electrification can create value

The business case is not simply “gas versus electricity”. It depends on the complete operating envelope: VOC loading, heat recovery, operating hours, electricity and gas tariffs, electrical demand charges, available grid capacity, carbon intensity of electricity, production profile and required redundancy. DEC therefore treats electrical feasibility and lifecycle economics as part of the process-engineering assessment.

How DEC.e-RTO™ Works

1. Inlet and preheating. Solvent-laden air enters through the selected inlet path and passes through a ceramic honeycomb bed containing stored thermal energy.

2. Electric heating and oxidation. The preheated stream enters the oxidation chamber. Electric heaters provide the additional thermal energy required to reach and maintain the design oxidation temperature. DEC's current reference range for the page is typically 815–980°C, subject to VOC chemistry and the required destruction conditions.

3. Oxidation. VOCs and other oxidizable pollutants react in the presence of oxygen, producing primarily CO₂, water vapour and heat for hydrocarbon compounds. Pollutant-specific by-products must be evaluated for the actual process chemistry.

4. Regenerative heat recovery. The hot treated gas passes through another ceramic bed and transfers heat to the media.

5. Flow reversal. Dampers or switching valves reverse the flow sequence so that stored heat is returned to the next incoming contaminated stream. Multiple towers provide continuous operation.

Regenerative Heat Recovery, Energy Saving and Autothermal Operation

The regenerative ceramic beds are central to the energy performance of the DEC.e-RTO™. Heat released during VOC oxidation is not simply discharged: it is stored in the ceramic media and subsequently returned to the incoming exhaust stream.

Thermal efficiency versus electrical consumption

High regenerative heat recovery reduces the external heat duty required by the heaters. Under suitable VOC loading and stable operating conditions, the heat released by oxidation can sustain the required temperature and the electric heater duty can fall substantially. Auxiliary electrical consumption from fans, dampers, controls and other equipment remains and must be included in the site energy balance.

Additional heat recovery

When the process produces recoverable excess heat, DEC.WHR™ can be considered for useful heat recovery such as process air, thermal oil, hot water or steam, subject to the actual temperature level and heat sink. The objective is to move beyond abatement-only operation toward integrated energy recovery.

Electrical Infrastructure and Project Feasibility

A full-electric RTO cannot be evaluated from airflow alone. Heater capacity, startup duty and steady-state duty must be reconciled with the site's electrical infrastructure and operating profile.

Electrical data to evaluate

• Available electrical voltage, frequency, transformer capacity and switchgear capacity.
• Available connected load and spare capacity for the proposed heater bank and auxiliaries.
• Maximum demand, electricity tariff structure and demand-charge exposure.
• Electrical reliability, planned outages, backup strategy and production continuity requirements.
• Power quality, control architecture and integration with the plant electrical distribution system.
• Future production expansion and whether the electrical infrastructure can accommodate additional process loads.

Pressure drop and fan power

Regenerative heat recovery should be evaluated together with system pressure drop. Ceramic media, switching valves, ducts and other process components contribute resistance that directly affects fan duty and auxiliary electrical consumption. The optimum e-RTO design therefore balances heat recovery, media geometry, airflow, pressure drop and total operating energy rather than optimizing thermal efficiency in isolation.

Thermal and process data

• Normal, minimum and maximum exhaust airflow and temperature.
• VOC/HAP composition, concentration range, variability and %LEL.
• Moisture, particulate loading and potentially corrosive or reactive constituents.
• Halogenated, sulfur-, nitrogen- or silicone-containing compounds requiring specific assessment.
• Required DRE, permit conditions, operating hours and production cycles.

Preliminary feasibility should therefore combine process engineering, electrical engineering, emissions compliance and lifecycle economics.

Energy, Scope 1, Scope 2 and Decarbonization

Full electrification can materially change the emissions profile of thermal oxidation. Removing the gas burner can eliminate the oxidizer's direct fossil-fuel combustion emissions associated with auxiliary heating. The electrical energy used by the e-RTO is instead accounted for through the site's electricity consumption and therefore its Scope 2 footprint under the applicable accounting methodology.

Why the electricity source matters

The decarbonization benefit depends on the carbon intensity of the electricity supplied to the site. Renewable or otherwise low-carbon electricity can substantially increase the Scope 1-to-Scope 2 decarbonization benefit of full-electric oxidation. Conversely, a carbon-intensive grid can reduce or, depending on the complete energy balance, potentially offset part of the expected GHG benefit.

Energy savings versus fuel substitution

Electrification should not be described automatically as lower total energy consumption. The correct engineering question is whether regenerative heat recovery, VOC oxidation heat, improved controls and additional heat recovery reduce the site's total energy demand and operating cost while meeting the same emission requirement. Utility prices, demand charges and carbon factors should be evaluated over the expected operating profile.

NOx, CO and Secondary Emissions

Because DEC.e-RTO™ has no gas-fired burner, it avoids burner-generated thermal NOx and the associated combustion-related CO from the heating source. However, the statement “zero NOx” should not be applied universally to the entire treated exhaust stream.

Process-dependent emissions

• Nitrogen-containing VOCs or other nitrogen-bearing compounds can form NOx during high-temperature oxidation.
• Halogenated compounds can generate acid gases and may require downstream treatment.
• Sulfur-containing compounds can produce sulfur oxides or other sulfur species.
• Incomplete oxidation can result in CO or residual VOCs if the required temperature, residence time, mixing or oxygen conditions are not maintained.
• CO₂ remains a product of VOC oxidation and must be considered in the overall carbon balance.
• N₂O and other secondary emissions should be evaluated where relevant to the process chemistry and permit requirements.

This is why DEC's e-RTO engineering approach remains chemistry- and permit-driven rather than treating electrification alone as a guarantee of zero secondary emissions.

Safety, Controls and Operating Envelope

Temperature and concentration protection

DEC.HGB™ Hot Gas Bypass

DEC.HGB™ Hot Gas Bypass is a controlled protection architecture used to divert a defined portion of hot gas around regenerative media when configured temperature or concentration conditions approach the engineered operating limits. It is designed to protect the ceramic heat-recovery system during abnormal peaks while maintaining controlled process operation.

High VOC concentration can generate substantial oxidation heat. The RTO therefore requires monitoring and control of temperature, flow, pressure and VOC loading. Where abnormal concentration peaks could overheat the ceramic media, DEC.HGB™ can provide a controlled hot-gas bypass strategy.

Electrical and process interlocks

• Heater-bank temperature and electrical protection.
• Airflow and pressure permissives.
• High-temperature protection and automatic response.
• VOC concentration and LEL monitoring where required by the application.
• Damper/valve sequencing and position confirmation.
• Emergency shutdown and restart logic.
• Integration with plant PLC/DCS, alarms, trends and operating records.

Flameless does not mean risk-free

Eliminating the burner removes combustion-system hazards associated with the fuel train and flame, but the process remains a high-temperature oxidation system handling potentially flammable VOCs. Collection, LEL control, ducting, electrical protection, hot surfaces, ceramic media, pressure and process-specific hazards remain part of the safety assessment.

Industrial Applications for DEC.e-RTO™

DEC.e-RTO™ can be considered for industrial exhaust streams where regenerative thermal oxidation is appropriate and site electrification is technically and economically feasible.

• chemical and pharmaceutical manufacturing;
• automotive, mobility and component coating;
• battery and energy-storage manufacturing;
• semiconductor, electronics and advanced materials production;
• printing, packaging and converting;
• paint, coating and surface-finishing operations;
• composites and resin processing;
• plastics and polymer processing;
• industrial drying and solvent-based manufacturing;
• odour and HAP control where thermal oxidation is appropriate;
• existing RTO installations targeted for electrification or modernization.

Application suitability depends on airflow, VOC/HAP chemistry, concentration, temperature, moisture, particulate loading, corrosivity, LEL, required DRE and available electrical infrastructure.

DEC.XTO™ Integration and Complementary Technologies

DEC.e-RTO™ is part of the broader DEC.XTO™ Thermal Oxidizer technology family. It can be engineered with the same process, controls, safety and energy-recovery philosophy used across DEC thermal oxidation systems.

RBC pre-concentration

For high-volume, low-concentration VOC streams, DEC.RBC™ VOC Rotor Concentrator technology can be considered upstream of an RTO to reduce the gas volume sent to the thermal oxidizer and increase VOC concentration. This can reduce downstream equipment duty and support energy optimization where the complete process balance justifies the configuration.

HSU hybrid sorption architecture

DEC.HSU™ combines sorption and oxidation or recovery technologies. Upstream RBC integration is applicable to XTO, mainly RTO, and SRU platforms; downstream RBC integration is applicable to SRU RSG, RSV and RSC configurations.

DEC.WTE™ Waste-to-Energy integration

DEC.WTE™ (Waste to Energy) provides a dedicated DEC architecture for the controlled utilization of high-caloric waste and process streams as an alternative energy resource. Depending on the stream characteristics and project objectives, DEC.WTE™ can incorporate direct injection, liquid handling and controlled high-caloric-stream management, with configurations designed for integration with RTO or boiler architectures.

Where high-caloric or concentrated streams are involved, the engineering scope can include LEL management, applicable ATEX requirements, dilution, injection control, safety interlocks and energy-recovery strategy. DEC.WTE™ is distinct from DEC.e-RTO™: e-RTO defines the electric regenerative oxidation architecture, while WTE addresses the controlled energy utilization and handling of suitable waste or process streams.

DEC.CCH™ regenerative media

DEC.CCH™ Ceramic Channeled Honeycomb media provides the regenerative heat-storage function central to RTO operation.

DEC.HBT™ Heating Burner Train — for hybrid configurations

The DEC.HBT™ Heating Burner Train is the gas-heating interface used where a DEC RTO configuration incorporates a modulating gas burner. It is not part of the full-electric DEC.e-RTO™ heating system itself; it becomes relevant when the e-RTO platform is considered together with the DEC.h-RTO™ hybrid dual-energy architecture.

The HBT™ package provides the engineered fuel-gas train, regulation and burner-side control functions required for safe and controlled gas-fired heat input. Its design is coordinated with combustion-chamber temperature, airflow, burner modulation, safety interlocks and the overall RTO control philosophy.

DEC.h-RTO™ Hybrid Dual-Energy Regenerative Thermal Oxidizer

DEC.h-RTO™ Hybrid Dual-Energy Regenerative Thermal Oxidizer (RTO) is a bespoke architecture developed for applications where operational flexibility, energy security, startup capability and decarbonization must be addressed together. It combines a conventional modulating gas burner and an advanced flameless electric heating bank within a common regenerative oxidation system and shared combustion chamber.

The result is a dual-energy RTO that can be engineered to operate with 100% gas heating, 100% electric heating or a controlled combination of both, depending on the process condition, utility availability and operating strategy. The objective is not simply to add two heaters: the architecture, controls and thermal balance are designed so that the available energy sources can be managed as an integrated system while maintaining the required VOC oxidation conditions.

One RTO, two independent energy sources

DEC.h-RTO™ retains the regenerative ceramic heat-recovery principle of the RTO while providing two alternative sources of auxiliary heat:

• Modulating gas burner: provides high thermal capacity and rapid heat input, particularly valuable during cold startup, demanding transient conditions or periods when electrical capacity is constrained.
• Flameless electric heater bank: provides distributed, precisely controllable heat without fuel combustion at the heating source, supporting continuous operation with reduced dependence on fossil fuel.
• Shared combustion/oxidation chamber: both heating systems serve the same regenerative oxidation process rather than requiring two separate abatement trains.
• Integrated control philosophy: the electrical and gas heating systems are coordinated with temperature, airflow, VOC loading, regenerative-cycle sequencing and safety interlocks.

100% gas, 100% electric or hybrid operation

Depending on the engineered configuration and operating envelope, DEC.h-RTO™ can provide a full gas mode, a full electric mode or an intermediate dual-energy mode. This gives the plant an additional degree of freedom that is not available from a single energy source.

Energy-source transfer can be managed by the control system so that the oxidation chamber remains within its defined operating window. Where the process and control philosophy permit, the system can be engineered to change the dominant heat source without interrupting VOC abatement. Actual transfer sequences, ramp rates, permissives and backup logic are established during detailed engineering and depend on the process and site requirements.

Energy arbitrage and operating-cost flexibility

Because electricity and natural-gas prices can vary by hour, season, tariff structure and site, DEC.h-RTO™ can support an energy-arbitrage operating strategy. The plant can select the available energy source according to the complete operating economics rather than being permanently committed to either gas or electricity.

• Use electric heating when electricity economics, renewable availability, carbon objectives or site energy strategy make electrification attractive.
• Use gas heating when electrical demand charges, grid constraints or other utility conditions make gas the more practical heat source.
• Use dual-energy operation when both sources can contribute to the thermal balance and the process benefits from controlled load sharing.
• Retain an alternative energy path to improve operational resilience during abnormal utility conditions or planned electrical/gas outages, subject to the site's safety and continuity philosophy.

The relevant economic comparison is therefore not simply the unit price of electricity versus gas. DEC evaluates heater duty, regenerative heat recovery, VOC oxidation heat, auxiliary loads, operating hours, demand charges, tariffs, carbon factors and the required level of utility redundancy as part of the overall energy balance.

Rapid cold startup and high thermal capacity

One of the principal advantages of the hybrid architecture is the ability to retain the high thermal capacity of a modulating gas burner for cold startup. A fully electric RTO may require substantial installed electrical capacity if it is expected to bring a cold system rapidly to operating temperature. DEC.h-RTO™ can instead use the gas burner to accelerate heat-up, while the electric system remains available for subsequent operation or controlled transition.

This approach can be particularly relevant where production schedules demand short startup times, where electrical infrastructure is sized primarily for steady-state operation, or where the site wants electrification without making the entire startup strategy dependent on the grid connection.

Decarbonization without abandoning energy security

DEC.h-RTO™ can also serve as a staged electrification platform. A facility does not necessarily need to move directly from a conventional gas-fired RTO to a permanently full-electric configuration. The hybrid architecture can allow electric heating to carry an increasing share of normal operation while retaining gas as a strategic backup or high-capacity startup source.

When operated on electricity, the electric heating path has no direct fossil-fuel combustion at the heater and therefore avoids burner-related combustion emissions. However, electricity consumption remains part of the site's Scope 2 footprint, while operation of the gas burner retains direct Scope 1 emissions. The actual decarbonization benefit therefore depends on the operating mode, electricity source, energy demand, regenerative efficiency and annual operating profile.

Operational resilience and future-proofing

The dual-energy concept can provide a practical bridge between present utility infrastructure and future plant energy strategy. If grid capacity increases, electricity becomes more competitive or lower-carbon power becomes available, the operating profile can move toward greater electric utilization. If electrical supply is constrained, the gas system can provide an alternative heat source within the engineered operating envelope.

DEC.h-RTO™ is therefore not simply a compromise between a conventional RTO and DEC.e-RTO™. It is a purpose-designed dual-energy architecture for facilities that place a high value on production continuity, utility flexibility, startup performance and the ability to adapt the energy mix over the service life of the RTO.

DEC.h-RTO™ versus DEC.e-RTO™

Important: DEC.h-RTO™ is not a full-electric RTO. The gas burner remains an intentional part of the architecture and can be used whenever the engineered operating strategy calls for gas heating. The hybrid design is selected where the value of energy-source flexibility, startup performance and resilience justifies retaining that capability.

DEC.HGB™ Hot Gas Bypass and DEC.WHR™ Waste Heat Recovery

DEC.HGB™ concentration-peak protection

DEC.HGB™ can divert a controlled portion of hot gas around the regenerative media when oxidation heat causes the combustion chamber to approach a defined temperature limit. This protects the ceramic media during abnormal concentration peaks and supports safe operation.

DEC.WHR™ beneficial heat recovery

DEC.WHR™ can recover suitable excess heat for useful plant services such as process air, thermal oil, hot water or steam. The recoverable quantity and temperature must be established from the actual operating envelope and heat sink.

RTO Modernization, Retrofit and Replacement

Full-electric conversion can form part of a broader RTO modernization strategy. Depending on the existing architecture, vessels, ceramic media, valves, controls, heater location and electrical infrastructure, DEC can evaluate refurbishment, retrofit, deeper rebuild or replacement.

• Refurbishment: restore usable equipment and replace worn components.
• Retrofit: retain suitable equipment while adding electric heating, improved controls, heat recovery or other modernization features.
• Rebuild: reconstruct major subsystems where the existing architecture remains reusable.
• Replace: install a new RTO/e-RTO when the existing architecture cannot support the future process, emissions, capacity or safety envelope.

For projects involving an existing third-party RTO, see the RTO Dismantling, Relocation & Disposal Engineering Guide and the applicable DEC modernization engineering services.

Preliminary Feasibility: Information Required from the Site

For a preliminary feasibility assessment of an existing or proposed e-RTO application, DEC should receive enough information to characterize the process, emissions, utilities and physical constraints before selecting an architecture.

• Equipment photographs, including general arrangement, access areas and existing RTO identification plate.
• Manufacturer, model, serial number, year of manufacture and rated airflow.
• Existing P&IDs, process-flow diagrams and general arrangement/layout drawings.
• Process exhaust airflow, pressure, temperature and operating range.
• VOC/HAP composition, concentration range, %LEL and peak conditions.
• Moisture, particulate, corrosive, halogenated, sulfur-, nitrogen- or silicone-containing compounds.
• Existing ceramic media type, condition and loading arrangement.
• Existing valves/dampers, heater or burner information and control architecture.
• Electrical single-line diagram, available voltage, transformer/switchgear capacity and spare electrical capacity.
• Utility tariffs, operating hours and demand-charge information where available.
• Current permits, emission limits, stack-test data and monitoring requirements.
• Site-specific rules, electrical policies, safety procedures, permit-to-work requirements and access restrictions.
• Planned production changes, capacity increases and decarbonization targets.

The objective of the preliminary review is to determine whether full electrification, hybrid electrification, retrofit or replacement is technically appropriate before detailed engineering begins.

DEC.e-RTO™ is a custom-engineered APC system. Final performance, electrical demand, heat recovery and emissions must be established from the actual process conditions, applicable regulations and detailed engineering.