Hybrid Dual-Energy Regenerative Thermal Oxidizer
⚡ DEC.h-RTO™ ⚡
Hybrid RTO • Gas + electric heating • energy arbitrage • utility resilience • industrial decarbonization
DEC.h-RTO™ is DEC’s bespoke Hybrid Dual-Energy Regenerative Thermal Oxidizer (RTO) architecture. It combines a conventional modulating gas burner and an advanced flameless electric heating bank within the same regenerative oxidation system and shared oxidation chamber.
The hybrid architecture is engineered so that the plant can use 100% gas heating, 100% electric heating or a controlled combination of both, according to the process condition, thermal duty, utility availability, operating economics and site energy strategy. The purpose is to combine the rapid high-capacity heat input and utility independence of gas with the combustion-free heating path and electrification potential of electric operation.
For the wider thermal oxidation framework, see the DEC.XTO™ Thermal Oxidizer Engineering Guide and the DEC.e-RTO™ Full-Electric Flameless RTO reference page.
DEC.h-RTO™ Hybrid Dual-Energy RTO
gas + flameless electric heating
100% gas • 100% electric • hybrid
one regenerative abatement system
startup, resilience, arbitrage and decarbonization
DEC.h-RTO™ is not simply an RTO with two heaters. It is a purpose-designed dual-energy architecture in which the gas and electric heating systems, regenerative heat recovery, process controls and safety functions are engineered as one operating system.
DEC.h-RTO™ Hybrid RTO Engineering Reference
1. DEC.h-RTO™ Hybrid Architecture
DEC.h-RTO™ retains the core regenerative operating principle of a modern DEC.XTO_RTO™: process exhaust passes through regenerative ceramic media, heat is stored and recovered cyclically, and VOCs are oxidized in the controlled high-temperature oxidation zone. Hybridization changes the way auxiliary heat is supplied to that common thermal system.
One regenerative system, two heat sources
The architecture combines two independent auxiliary heat sources around a common oxidation chamber:
Modulating gas burner
Provides high thermal input and rapid heat-up capability. It can support cold startup, high transient duty, electrical-capacity constraints and an alternative operating path when gas availability is part of the site's resilience strategy.
Flameless electric heating bank
Provides distributed, controllable heat without fuel combustion at the heating source. It supports normal electric operation, staged electrification and reduced dependence on fossil-fuel heating.
Shared oxidation chamber
The gas and electric systems do not represent two independent abatement trains. They serve the same regenerative oxidation process. The control architecture coordinates heat input, chamber temperature, airflow, VOC loading, regenerative-cycle sequencing and safety permissives.
Hybridization is an energy-system architecture, not merely a heater substitution. The value comes from managing two energy sources around one regenerative oxidation process.
2. Three Operating Modes: Gas, Electric and Hybrid
DEC.h-RTO™ can be engineered around three principal operating modes. The permitted modes, transition sequences and operating envelope are established during detailed engineering and depend on process conditions and site requirements.
100% Gas Mode
The modulating gas burner supplies the auxiliary heat duty. This mode is particularly useful for rapid startup, high thermal demand or periods when electrical capacity or electricity economics are unfavorable.
100% Electric Mode
The flameless electric heating bank supplies the auxiliary heat duty. The system operates without burner combustion at the heating source, supporting an electrification-focused operating strategy.
Dual-Energy Mode
Gas and electric heating contribute according to the engineered control strategy. Load sharing can be used when both utilities are available and the thermal balance benefits from coordinated operation.
Controlled transition between energy sources
Where the process and controls permit, the dominant heat source can be changed while maintaining the required oxidation conditions. Transition logic can include ramp limits, temperature permissives, heater staging, burner modulation, airflow constraints, purge requirements and fallback logic.
What is determined during detailed engineering?
- Minimum and maximum electric heater duty.
- Gas burner turndown and maximum thermal input.
- Permitted transition rates and temperature bands.
- Utility-loss detection and automatic fallback logic.
- Start-up, shutdown and restart sequences.
- Interlocks preventing incompatible gas/electric commands.
3. Thermal Balance and Regenerative Heat Recovery
The hybrid system must be evaluated as a complete thermal balance. Regenerative heat recovery reduces the auxiliary heat requirement by transferring heat from the treated exhaust back to the incoming process air. VOC oxidation can also contribute heat when the pollutant load is sufficiently high.
Regeneration remains central to both modes
Whether the auxiliary source is gas, electricity or both, the regenerative ceramic system continues to recover sensible heat. DEC.CCH™ Ceramic Channeled Honeycomb provides the thermal-storage function required for cyclic regenerative operation.
Pressure drop, fan duty and total energy
The regenerative media and switching system introduce pressure drop that affects fan power. Hybrid energy selection therefore cannot be optimized independently from airflow resistance: thermal recovery, pressure drop, fan duty and heater duty should be evaluated together as part of the complete plant energy balance.
Why hybridization does not eliminate the need for thermal optimization
Electric heating can remove burner combustion but does not remove the fundamental process heat duty. The required electrical load is influenced by airflow, inlet temperature, VOC concentration, moisture, heat recovery, oxidation temperature, heat losses and operating profile. Similarly, gas consumption is determined by the residual thermal duty after regenerative and process heat contributions.
Engineering principle
The correct comparison is therefore total site energy demand and operating profile, not simply the nominal efficiency of an individual heater.
Additional heat recovery
Where suitable heat sinks exist, excess thermal energy can be recovered through DEC.WHR™ or an application-specific heat-recovery arrangement for process air, thermal oil, hot water, steam or other useful services. Recoverability depends on temperature level, duty, operating hours and heat-sink availability.
4. Energy Arbitrage and Operating-Cost Strategy
A principal reason to hybridize an RTO is that the economic value of electricity and natural gas is not constant. Tariffs, demand charges, seasonal prices, renewable availability, grid constraints and carbon-related costs can change the preferred operating mode.
Energy arbitrage
Energy arbitrage means using the dual-energy architecture to select or combine the available heat sources according to the plant's operating economics and technical constraints. The decision should be based on the complete energy balance rather than commodity price alone.
Electricity can be prioritized when the site has favorable electrical economics or low-carbon power availability; gas can be prioritized when electrical demand charges, grid constraints or other conditions make gas more practical; hybrid operation can be used when both sources contribute to the required thermal balance.
What should be included in the economic model?
Utility economics
Electricity tariff, demand charges, gas tariff, seasonal variation, contracted capacity and expected operating hours.
Process energy
Airflow, VOC load, moisture, inlet temperature, oxidation temperature, regenerative effectiveness and auxiliary electrical loads.
Strategic factors
Carbon accounting, energy security, production continuity, maintenance strategy, future utility changes and decarbonization targets.
5. Cold Startup, Transients and High Thermal Capacity
Cold startup is one of the strongest technical arguments for a hybrid architecture. A full-electric RTO may require substantial installed electrical capacity if the site expects rapid heat-up from ambient conditions. DEC.h-RTO™ can retain the high thermal capacity of the gas burner for startup while preserving electric operation for the subsequent production period.
Rapid heat-up strategy
The gas burner can provide high-rate heat input during the initial thermalization of the system. As the regenerative media and oxidation chamber approach the required operating condition, the control strategy can reduce gas input and transfer duty to the electric heating bank where the operating envelope permits.
Transient process conditions
Hybridization can also provide additional flexibility when production changes rapidly, VOC loads vary, process airflow changes or the plant experiences a temporary utility constraint. The thermal-control strategy must remain subordinate to the required oxidation, safety and emissions conditions.
Cold-start feasibility questions
- Required time from ambient to permitted VOC-processing temperature.
- Available electrical capacity during startup.
- Gas availability and burner turndown.
- Required production restart time.
- Permitted startup and shutdown emissions conditions.
- Interaction with fans, valves, purge systems and regenerative-cycle sequencing.
6. Utility Resilience and Energy Security
DEC.h-RTO™ can provide an alternative thermal-energy path for sites where continuity of VOC abatement is important. The gas burner can remain available when electrical capacity is unavailable, while the electric heating bank can provide an alternative when gas supply is constrained, subject to the engineered operating envelope and site safety philosophy.
Grid disruption
If electrical supply is interrupted, the hybrid system can be engineered to use the gas path as an alternative heat source where the process, controls and utility systems permit.
Gas disruption
If gas supply is interrupted, the electric heating path can provide an alternative mode where sufficient electrical capacity exists and the electric heater system is designed for the required duty.
Resilience is not automatic
The presence of two energy sources does not by itself guarantee uninterrupted operation. Utility redundancy, switchgear, transformers, gas pressure, backup power, controls, purge systems, instrumentation and safe-state logic must all be evaluated.
7. Decarbonization: Scope 1, Scope 2 and Staged Electrification
DEC.h-RTO™ provides a pathway between conventional gas-fired operation and full electrification. It can allow electric heating to carry a larger share of normal operation while retaining gas capability for startup, contingency or selected operating conditions.
Scope 1 considerations
When the gas burner is operating, its fuel combustion contributes direct Scope 1 emissions. In electric operation, the heater itself does not combust natural gas or other fossil fuel at the heating source.
Scope 2 considerations
Electric operation shifts the energy requirement to electricity. The associated Scope 2 footprint depends on the electricity source, contractual arrangement and applicable accounting methodology.
Energy saving versus fuel substitution
Electrification should not be described as an energy saving by definition. The regenerative RTO architecture is already designed for high heat recovery. The decarbonization value of electric operation is primarily associated with changing the energy source and reducing direct combustion, while the overall energy demand still depends on process and thermal conditions.
DEC.h-RTO™ can allow a site to move progressively toward electric operation rather than making the entire plant energy strategy dependent on immediate full electrification.
- Retain gas capability for cold startup.
- Increase electric utilization as grid capacity improves.
- Prioritize electric operation when lower-carbon electricity is available.
- Retain gas as a strategic contingency where justified.
8. Controls, Sequencing and Safe Energy Transfer
Hybridization increases the control-system responsibility because two independent heat sources must be coordinated with one oxidation process. The control philosophy must prevent unstable or conflicting commands and maintain the defined operating envelope.
Core control variables
- Combustion/oxidation chamber temperature.
- Inlet and outlet temperatures.
- VOC concentration and process loading where instrumentation is available.
- Airflow and pressure.
- Electric heater duty and power quality.
- Gas burner firing rate and gas pressure.
- Regenerative valve sequencing and cycle timing.
- LEL/UEL-related process protection parameters.
Energy-source transfer logic
A typical strategy may use permissives to establish the receiving energy source before reducing the active source. The actual sequence is application-specific. Interlocks should prevent simultaneous operation outside the engineered thermal envelope and should place the system in a defined safe state if critical utility or instrumentation conditions are lost.
Controls should address at least
Normal operation
Load sharing, electric modulation, burner modulation, regenerative cycles and temperature control.
Abnormal operation
Utility loss, over-temperature, fan failure, valve fault, heater fault, burner fault, purge failure and instrumentation failure.
9. Safety, LEL and Process Protection
Where the process also contains high-caloric waste gases, concentrated VOC streams or suitable liquids, DEC.WTE™ provides the dedicated Waste-to-Energy architecture for controlled stream utilization. LEL conditions, applicable ATEX requirements, injection location, dilution, mixing, pressure, temperature and interlocks are established from the actual process envelope.
Removing or reducing burner operation does not eliminate the need for process safety. VOC-bearing exhaust can remain combustible depending on concentration, temperature, oxygen content and chemistry.
LEL and concentration management
The operating envelope must consider LEL/UEL, VOC chemistry, oxygen concentration, temperature, pressure, process variability and abnormal concentration peaks. Appropriate detection, dilution, purge and interlock strategies are established during engineering.
Temperature protection
DEC.HGB™ can be considered for concentration-peak protection where the oxidation chamber approaches configured thermal limits. The system can divert a controlled portion of hot gas around regenerative media according to the engineered protection philosophy.
Electrical safety
Electric heating introduces its own requirements for transformers, switchgear, protection, cabling, grounding, power quality, isolation and maintenance access. Electrical design must be integrated with the thermal and process-safety design.
Hybrid does not mean risk-free
The hybrid architecture changes the energy source; it does not remove the need for disciplined process safety, functional interlocks, safe shutdown, maintenance procedures and compliance with applicable electrical and environmental requirements.
10. Where DEC.h-RTO™ Can Create Value
Hybridization is particularly relevant where a site needs more than one of the following: rapid startup, high transient thermal duty, electrical-capacity optimization, gas/electric operating flexibility, utility resilience, staged electrification or decarbonization.
- chemical and pharmaceutical process ventilation;
- coating, printing, converting and surface-finishing operations;
- battery and advanced-material manufacturing where solvent-bearing exhaust requires thermal oxidation;
- automotive and industrial coating processes;
- composites, resins and polymer processing;
- industrial drying and solvent-based manufacturing;
- odour and HAP control where thermal oxidation is appropriate;
- existing RTO installations targeted for modernization and energy-source diversification.
Typical project drivers
Decarbonization
Reduce reliance on direct fossil-fuel combustion during selected or normal operating periods.
Energy flexibility
Respond to changing gas and electricity economics without redesigning the complete abatement system.
Continuity
Retain an alternative heat source for startup or selected utility-disruption scenarios.
11. DEC.XTO™ Integration and Complementary Technologies
DEC.XTO™ and RTO platform
DEC.h-RTO™ belongs to the broader DEC.XTO™ Thermal Oxidizer family and is primarily an RTO architecture. It can be engineered around the applicable regenerative tower arrangement, process airflow, VOC loading and emissions requirements.
DEC.e-RTO™ full-electric reference
DEC.e-RTO™ represents the full-electric end of the DEC RTO electrification pathway. DEC.h-RTO™ retains the gas burner intentionally where startup capability, energy security, utility flexibility or operating economics justify it.
DEC.RBC™ upstream pre-concentration
For high-volume, low-concentration VOC streams, DEC.RBC™ VOC Rotor Concentrator can be considered upstream of an RTO to reduce downstream gas volume and increase VOC concentration. This can materially change the thermal and electrical duty of the backend oxidation system when the complete process balance supports it.
DEC.HSU™ hybrid sorption architecture
DEC.HSU™ integrates sorption/concentration with thermal oxidation or solvent recovery. Upstream RBC integration is applicable to XTO, mainly RTO, and SRU platforms; downstream RBC integration applies to SRU RSG, RSV and RSC configurations.
DEC.WTE™ Waste-to-Energy integration
DEC.WTE™ (Waste to Energy) is DEC's dedicated architecture for controlled utilization of suitable high-caloric waste and process streams. It can incorporate direct injection, liquid handling and high-caloric-stream management, with configurations designed for integration with RTO or boiler architectures.
DEC.WTE™ addresses the stream-handling and energy-utilization function; DEC.h-RTO™ remains specifically the dual-energy RTO architecture combining electric heating and a modulating gas burner. Where both functions are relevant, their interfaces are defined by the process thermal balance, LEL/ATEX requirements, injection strategy and safety philosophy.
DEC.CCH™ regenerative media
DEC.CCH™ Ceramic Channeled Honeycomb media provides the regenerative heat-storage function central to the RTO.
DEC.HGB™ and DEC.WHR™
DEC.HGB™ can provide thermal protection during concentration peaks, while DEC.WHR™ can recover suitable excess heat for useful plant services.
12. Hybridization of Existing RTOs
Converting an existing gas-fired RTO to a hybrid gas/electric architecture is a feasibility and re-engineering project, not simply a burner replacement. The existing vessels, combustion chamber, ceramic media, valve arrangement, ductwork, fans, controls, gas train and electrical infrastructure must be evaluated together.
Refurbish
Restore existing equipment, including suitable media, seals, valves, instruments and controls.
Retrofit
Add electric heating and new control/energy features while retaining usable equipment.
Rebuild
Reconstruct major subsystems where the core architecture remains suitable.
Replace
Select a new hybrid RTO when the existing vessels, architecture, capacity or safety envelope cannot support the future requirements.
Existing-system compatibility assessment
- Existing combustion chamber dimensions and temperature distribution.
- Regenerative media condition, type and thermal capacity.
- Valve configuration, cycle timing and pressure drop.
- Fan capacity and electrical power.
- Gas train and burner turndown.
- Available electrical capacity, transformer and switchgear.
- Controls, PLC, instrumentation and safety systems.
- Existing permitting and emissions envelope.
For broader RTO modernization and dismantling considerations, see the RTO Dismantling, Relocation & Disposal Engineering Guide.
13. Preliminary Feasibility: Information Required from the Site
For a preliminary feasibility assessment of a hybrid conversion or a new DEC.h-RTO™ installation, DEC should receive sufficient process, equipment, utility and site information to establish the thermal balance and the feasible operating envelope.
For an existing RTO manufactured by another vendor, the site should disclose the following basic documentation where available.
- Clear photographs of the complete RTO, combustion chamber, burners, valves, fans, ductwork, electrical equipment and control panels.
- Equipment nameplate photographs showing manufacturer, model, serial number, design data and year of manufacture.
- General arrangement and layout drawings, including elevations and equipment clearances.
- Process and instrumentation diagrams (P&IDs) and airflow/process flow diagrams.
- Original technical data sheets, equipment specifications and operating manuals.
- Existing burner data, gas-train documentation and burner-control philosophy.
- Electrical single-line diagrams, transformer/switchgear information and available power capacity.
- PLC/HMI architecture, control narratives, I/O lists and relevant alarm/interlock documentation.
- Recent operating data, including airflow, inlet temperature, VOC concentration/loading, moisture and pressure.
- Emission-test results, permits and applicable site emission limits.
- Maintenance history, refractory/media replacement records and known equipment deficiencies.
- Site-specific safety rules, electrical rules, permit-to-work procedures, contractor induction requirements and other applicable site policies.
Utility data
Provide available electricity tariff information, contracted electrical capacity, gas pressure and availability, utility restrictions, backup-power philosophy and any planned infrastructure changes.
Site constraints
Available footprint, crane/access limitations, installation windows, shutdown duration, hazardous-area classification where applicable, noise restrictions and local construction requirements should also be identified early.
Preliminary output
DEC can then establish whether the project is more appropriately approached as refurbishment, retrofit, rebuild, replacement or a new hybrid RTO installation, and can identify the principal technical and utility constraints requiring detailed engineering.
DEC.h-RTO™ versus DEC.e-RTO™
| Characteristic | DEC.e-RTO™ | DEC.h-RTO™ |
|---|---|---|
| Auxiliary heat sources | Electric heating only | Electric heating + modulating gas burner |
| Full-electric operation | Yes | Yes, when selected by the engineered operating strategy |
| 100% gas operation | No | Yes, where engineered and permitted |
| Cold-start strategy | Electric heating supplies startup duty | Gas can provide high startup thermal capacity |
| Energy-source flexibility | Electricity-dependent | Two energy sources can be managed according to the operating strategy |
| Utility resilience | Dependent on electrical infrastructure and backup strategy | Alternative heat source can provide additional resilience |
| Decarbonization pathway | Full electrification | Staged or variable electrification with retained gas capability |
| Primary design objective | Full-electric operation | Energy flexibility, startup capability, resilience and staged electrification |
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.
DEC.h-RTO™ Frequently Asked Questions
Grouped questions covering hybrid architecture, energy strategy, startup, resilience, decarbonization, safety and project feasibility.
Hybrid RTO fundamentals
What is DEC.h-RTO™?
DEC.h-RTO™ is DEC’s Hybrid Dual-Energy Regenerative Thermal Oxidizer architecture, combining a modulating gas burner and a flameless electric heating bank around a shared regenerative oxidation chamber.
Is DEC.h-RTO™ a full-electric RTO?
No. DEC.h-RTO™ retains a gas burner as an intentional energy source. It can, where engineered, operate in 100% electric mode, 100% gas mode or a controlled dual-energy mode.
What is the difference between DEC.h-RTO™ and DEC.e-RTO™?
DEC.e-RTO™ is the full-electric configuration. DEC.h-RTO™ adds a modulating gas burner so the plant can retain a second heat source for startup, resilience, energy flexibility or staged electrification.
Does hybridization require two separate RTOs?
No. The architecture is based on one regenerative oxidation system and shared oxidation chamber with two auxiliary heat sources.
Energy, operating modes and economics
Can DEC.h-RTO™ operate on 100% gas?
Yes, where the engineered configuration and applicable operating requirements permit it.
Can DEC.h-RTO™ operate on 100% electricity?
Yes, where the electric heating system is sized for the applicable operating envelope and the site has sufficient electrical capacity.
Can gas and electricity operate together?
Yes. A controlled dual-energy mode can be engineered where both sources contribute to the thermal balance.
What is energy arbitrage in a hybrid RTO?
It is the ability to select or combine gas and electric heating according to utility economics, demand charges, carbon objectives, process conditions and site energy strategy.
Does hybridization automatically reduce energy consumption?
Not necessarily. The RTO still has a defined thermal duty. Hybridization primarily changes and diversifies the energy sources; total energy demand depends on regenerative recovery, VOC loading, airflow, temperature and process conditions.
Startup, resilience and decarbonization
Why retain a gas burner if the RTO can be electric?
The gas burner can provide high thermal capacity for rapid cold startup, demanding transient conditions or periods when electrical capacity is constrained.
Can DEC.h-RTO™ provide backup during a grid outage?
Potentially, if the gas system, controls and site utilities are designed to support the required fallback mode. Backup capability is project-specific and is not automatic.
Can the electric system provide backup if gas is unavailable?
Potentially, where sufficient electrical capacity exists and the electric system is engineered for the required duty.
Does electric operation eliminate Scope 1 emissions?
It can eliminate direct fuel combustion emissions associated with the gas heating source while operating electrically. The site’s Scope 2 footprint then depends on the electricity source and applicable accounting method.
Is DEC.h-RTO™ suitable for staged electrification?
Yes. It can allow electric heating to carry a larger share of normal operation while retaining gas capability for startup, contingency or selected operating conditions.
Controls, safety and project engineering
Can the energy source be changed without interrupting VOC abatement?
Where the process and controls permit, the system can be engineered for controlled energy-source transition while maintaining the required oxidation conditions. Transition sequences and permissives are established during detailed engineering.
Does an electric heater remove LEL requirements?
No. VOC-bearing process exhaust remains subject to combustible-mixture and process-safety considerations. LEL/UEL, oxygen, temperature, pressure and concentration variability must be assessed.
Can DEC.h-RTO™ be integrated with DEC.RBC™?
Yes. DEC.RBC™ can be considered upstream of an RTO for suitable high-volume, low-concentration VOC streams, reducing downstream gas volume and increasing VOC concentration.
Can DEC.h-RTO™ be integrated with DEC.HSU™?
Yes. DEC.HSU™ provides the broader hybrid sorption architecture combining RBC concentration with thermal oxidation or solvent recovery. Upstream RBC integration applies to XTO, mainly RTO, and SRU; downstream RBC integration applies to SRU RSG, RSV and RSC.
Can an existing third-party RTO be converted to DEC.h-RTO™?
Potentially. The project requires a technical feasibility assessment covering vessels, combustion chamber, regenerative media, valves, fans, burner, controls, electrical infrastructure, safety systems, permits and site constraints.
What information should the site provide for preliminary feasibility?
Photos, nameplate/model information, GA and layout drawings, P&IDs, technical data, burner and gas-train data, electrical single-lines, controls documentation, operating data, emissions information, maintenance history and site rules/policies are among the key inputs.
Assess Your Hybrid RTO Strategy
DEC can evaluate a new or existing RTO against the DEC.h-RTO™ dual-energy architecture, including thermal balance, electrical feasibility, gas capability, controls, startup strategy, energy economics, decarbonization and utility resilience.
