Heating Burner Train for Thermal Oxidizers
🔥 DEC.HBT™ 🔥
High-velocity combustion • wide turndown • flame stabilization • RTO thermal support
DEC.HBT™ is DEC's Heating Burner Train architecture for industrial thermal oxidizers and combustion chambers. It combines a suitably engineered burner with the fuel, combustion-air or oxygen supply, ignition, flame supervision, control and safety functions required to deliver stable and controllable heat input.
The burner is not simply a heat source. In a thermal oxidizer, it is an engineered combustion device that must work with the chamber geometry, process airflow, VOC mass loading, oxygen availability, operating temperature, residence time and regenerative heat-recovery system. DEC.HBT™ is therefore designed around the complete thermal and combustion duty rather than burner nameplate capacity alone.
For the wider thermal-oxidation framework, see the DEC.XTO™ Thermal Oxidizer Engineering Guide.
DEC.HBT™ Heating Burner Train
DEC.HBT™ is engineered as a complete heating and combustion package. Burner capacity, fuel train, combustion air, ignition, flame supervision, control valves, permissives and shutdown logic are selected from the actual thermal duty and process-safety requirements.
DEC.HBT™ Engineering Reference
Why the Burner Matters in Thermal Oxidation
A thermal oxidizer must maintain the conditions required to oxidize VOCs, HAPs and other combustible pollutants. The burner supplies or supplements the thermal energy needed to establish and maintain those conditions, but its performance is inseparable from airflow, chamber geometry, residence time, oxygen availability and heat recovery.
In an RTO, the burner is often most heavily loaded during cold startup, when the ceramic beds have not yet accumulated sufficient stored heat. As the system warms up and the process contributes more heat, burner demand can decrease. Under suitable process conditions the RTO may become autothermal, meaning pollutant oxidation plus regenerative heat recovery provide enough thermal energy to maintain the required operating temperature without continuous main-burner firing.
The burner is part of the thermal balance
DEC.HBT™ is sized from startup duty, minimum process load, maximum process load, operating temperature, heat recovery, fuel properties, airflow and the required turndown range—not from airflow alone.
Temperature, Time and Turbulence — the Three Ts
Thermal oxidation depends on three interrelated conditions: Temperature, Time and Turbulence. The burner directly influences the thermal and mixing environment, while the combustion chamber and RTO architecture provide the required residence time and overall flow pattern.
Temperature
The burner must provide enough controllable heat to reach and maintain the specified oxidation temperature under the applicable process conditions. The required temperature depends on pollutant chemistry, concentration, oxygen availability, residence time and the performance target.
Time
The burner does not create residence time by itself. Chamber volume, flow rate and temperature establish the conditions under which pollutants remain in the oxidation zone. Burner flame length and heat-release distribution must therefore be compatible with the chamber geometry.
Turbulence
High-velocity burner designs can generate strong turbulent mixing between combustion products, combustion air and the surrounding process exhaust. This promotes rapid mixing and helps reduce localized fuel-rich or oxygen-deficient zones. The objective is controlled, repeatable mixing—not uncontrolled flame impingement, pulsation or instability.
How DEC.HBT™ Works
1. Controlled fuel and oxidant supply
The HBT supplies the selected fuel and combustion air or, where specifically engineered, oxygen-enriched oxidant to the burner. Typical fuels include natural gas, propane, LPG and hydrogen, as well as other suitable combustible gases subject to the fuel properties, pressure, materials and safety design.
2. Ignition and flame establishment
The burner starts under defined permissive conditions. The ignition system establishes the pilot or ignition flame, flame supervision confirms combustion, and the main fuel path is enabled according to the approved burner-management sequence.
3. High-velocity combustion and mixing
The burner introduces fuel and oxidant at engineered velocities and flow ratios. The resulting flame and hot-gas envelope interact with the process exhaust inside the combustion chamber, creating the mixing environment required for stable thermal oxidation.
4. Modulation and thermal control
Fuel input is modulated to match the instantaneous thermal requirement. Depending on the burner and control architecture, operation can range from maximum heat input during startup to low-fire or pilot operation at low process load, and potentially to complete main-burner shutdown when the RTO is demonstrably autothermal.
5. Continuous supervision
Fuel pressure, combustion air, flame status, temperature, valve positions and other required permissives are monitored. If a required condition is lost, the burner-management system places the fuel system in the defined safe state.
Stable combustion across the complete operating envelope
A burner that performs well only at design load is not sufficient. DEC.HBT™ is engineered for startup, normal production, minimum-load, fluctuating-load and defined upset conditions within the approved operating envelope.
Startup, Warm-Up and Supplemental Heat
For an RTO, the burner is typically the primary thermal input during startup. The objective is to raise the ceramic regenerative beds and combustion chamber to the required operating conditions before process exhaust is introduced according to the approved startup sequence.
- Cold startup: maximum or high-fire operation may be required to overcome the thermal mass of the chamber, ceramic media and associated equipment.
- Warm-up: burner input is progressively reduced as the system approaches the operating temperature.
- Production: the burner supplies only the supplemental heat required after regenerative recovery and process heat release are accounted for.
- Low-VOC operation: burner modulation bridges the gap between process heat and the required oxidation temperature.
- Shutdown/restart: the fuel system follows the defined purge, isolation, ignition and restart logic.
Autothermal Transition and Burner Turndown
An RTO approaches autothermal operation when heat released by VOC oxidation, together with recovered heat from the regenerative media, is sufficient to offset heat losses and maintain the required operating temperature. This is an energy-balance condition rather than a fixed burner setting.
As the process heat contribution increases, the burner can modulate downward. Depending on the approved operating philosophy, it may reach low-fire/pilot operation or the main burner may shut off completely while the RTO remains within its required thermal and emissions envelope. If VOC loading falls, inlet conditions change or losses increase, burner heat must be restored.
Key variables include VOC mass loading and LHV, airflow, inlet temperature, moisture, heat-recovery efficiency, oxidation setpoint, ambient conditions, purge and leakage losses, and the actual burner turndown capability.
Fuel, Combustion Air and Oxygen Flexibility
DEC.HBT™ can be engineered around different combustible gases and oxidant arrangements. The fuel selection affects burner design, fuel-train components, pressure regulation, flame speed, materials, controls and safety requirements.
| Fuel / oxidant | Engineering considerations |
|---|---|
| Natural gas | Industrial fuel option; burner capacity, supply pressure, gas-train components and control range are matched to the thermal duty. |
| Propane / LPG | Requires fuel-specific pressure regulation, vaporization or supply conditions, fuel-train sizing and combustion design. |
| Hydrogen | Requires dedicated assessment of flame speed, flashback, leakage, detection, materials, burner geometry, fuel-train components and safety logic. |
| Other combustible gases | Applicability depends on composition, heating value, contaminants, pressure, flame characteristics and the approved process-safety basis. |
| Combustion air | Flow, pressure, temperature and oxygen concentration influence flame stability, heat release, mixing and the available turndown range. |
| Oxygen-enriched service | Project-specific engineering is required because combustion intensity, flame temperature, materials, controls and fire-safety conditions change substantially. |
Flame Stabilization, High Velocity and Combustion Quality
The burner nozzle, quarl, mixing geometry and surrounding chamber are selected to establish a stable flame across the required operating range. The design must avoid flashback, flame detachment, excessive pulsation, unstable ignition and unwanted flame impingement.
High velocity is useful because it can enhance turbulent mixing and distribute combustion energy into the surrounding process gas. However, velocity is not an objective in isolation: excessive velocity, inappropriate momentum ratios or poor chamber integration can create pressure fluctuations, flame instability or unacceptable heat-release patterns. Burner performance is therefore evaluated together with the chamber geometry and process flow field.
Burner Management, Ignition and Safety Interlocks
DEC.HBT™ incorporates the burner-management functions required by the project safety design. The burner management system is distinct from the overall RTO control sequence, although both must be coordinated.
- fuel isolation and controlled fuel admission;
- combustion-air permissives and airflow proof;
- pre-ignition and post-trip purge requirements;
- pilot or ignition sequence and flame proving;
- fuel-pressure and valve-position supervision;
- low-fire / high-fire or modulating control;
- high-temperature and process interlocks;
- flame-failure response and automatic fuel shutoff;
- emergency-stop and defined safe-state logic;
- alarm, trip and restart management.
Safety functions are not bypassed to maintain burner operation. The exact permissives, trip logic, purge times and restart sequence are established from the approved control narrative, applicable codes, fuel characteristics and site requirements.
Integration with DEC.XTO™, DEC.e-RTO™ and DEC.h-RTO™
DEC.XTO™ and regenerative thermal oxidation
DEC.HBT™ is applicable as the heating and combustion package for suitable fuel-fired DEC.XTO™ configurations, including regenerative thermal oxidizers. Burner duty is coordinated with regenerative heat recovery and the process thermal load.
DEC.e-RTO™ • full-electric flameless RTO
A full-electric DEC.e-RTO™ replaces the conventional fuel-fired heating source with electric heating. DEC.HBT™ therefore applies where a combustion burner is part of the selected architecture; it is not required for normal electric heating operation. The distinction allows DEC systems to use the appropriate heat-source architecture for the project.
DEC.h-RTO™ • hybrid dual-energy RTO
DEC.h-RTO™ combines electric heating with a modulating gas burner. In this architecture, the DEC.HBT™ burner train can provide the combustion-based component of the dual-energy thermal system, with control logic coordinating electric and fuel-fired heat input.
DEC.RBC™ and DEC.HSU™ • upstream emission management
Where VOC concentration management is required upstream of the thermal oxidizer, DEC.RBC™ or DEC.HSU™ can alter the thermal load presented to the RTO. Burner capacity and turndown should therefore be assessed against the complete upstream/downstream process envelope.
DEC.HBT™ and DEC.HGB™ Thermal Protection
DEC.HBT™ and DEC.HGB™ address different functions. HBT supplies controlled combustion heat; HGB is a thermal-protection layer that can divert a controlled portion of hot gas around regenerative media when defined thermal limits are approached.
The two functions can therefore be part of the same RTO safety and thermal-management architecture: HBT manages required heat input, while HGB can address defined excess thermal loading. Neither replaces upstream concentration management, LEL/ATEX assessment or the complete process-safety system.
Burner Replacement, Retrofit and RTO Modernization
DEC.HBT™ can be considered for new systems and for modernization of existing thermal oxidizers where the burner, fuel train, combustion air system or controls have reached the end of their useful service life or no longer match the process duty.
- existing burner capacity and turndown;
- fuel type, pressure and available utility capacity;
- combustion-air fan and ducting;
- chamber dimensions and burner mounting arrangement;
- flame scanner and ignition hardware;
- fuel-train valves, regulators and pressure instrumentation;
- PLC/BMS architecture and available I/O;
- temperature and airflow instrumentation;
- current operating profile, nuisance trips and maintenance history;
- process changes affecting VOC loading, LHV or airflow.
Upgrade the burner as part of the complete RTO
Replacing a burner without reviewing fuel train, combustion air, controls, chamber conditions and process heat balance can simply transfer the original limitation to a new component. DEC approaches burner retrofit as a system-engineering task.
Preliminary Engineering Information
A preliminary DEC.HBT™ assessment typically requires:
- RTO / thermal oxidizer type and manufacturer;
- normal, minimum and maximum airflow;
- inlet temperature and moisture;
- VOC/HAP composition, concentration and mass loading;
- available LHV or estimated process heat release;
- required oxidation temperature and residence-time basis;
- fuel type, pressure, composition and availability;
- combustion-air pressure, temperature and fan data;
- oxygen availability if oxygen-enriched combustion is considered;
- burner capacity, turndown and existing flame-safeguard information;
- P&IDs, burner/fuel-train drawings, electrical single-lines and control narrative;
- operating history, alarm/trip history and maintenance records.
Need to assess a burner or RTO?
DEC can evaluate burner duty, fuel train, combustion air, controls and thermal balance as part of a new RTO, burner replacement, retrofit, revamping or modernization project.
FAQs • Frequently Asked Questions
HBT fundamentals
What is DEC.HBT™?
DEC.HBT™ is DEC's Heating Burner Train architecture for thermal oxidizers. It combines the burner with fuel, combustion-air or oxygen supply, ignition, flame supervision, control and safety functions needed to provide controlled thermal input.
What is the primary function of an RTO burner?
The primary function is to provide supplemental thermal energy, especially during startup and low-VOC operation, and to bridge the gap between recovered/process heat and the required oxidation temperature.
Does an RTO burner always run continuously?
No. Depending on the process heat load and regenerative heat recovery, burner demand can reduce after startup and an RTO may operate with low burner input or become autothermal. The actual operating envelope is process- and design-specific.
Operation and thermal control
What are the Three Ts of thermal oxidation?
Temperature, Time and Turbulence. Temperature provides the thermal condition for oxidation, Time relates to residence in the oxidation zone, and Turbulence promotes mixing between the process exhaust and combustion environment. Burner and chamber design must work together to provide the required conditions.
Why are high-velocity burners used in thermal oxidizers?
High-velocity burner designs can promote turbulent mixing and distribute combustion heat into the surrounding process exhaust. The required velocity and momentum are project-specific because excessive or poorly directed velocity can create instability, pulsation or unwanted flame impingement.
What does burner turndown mean?
Turndown is the ratio between the maximum stable burner heat input and the minimum stable heat input under the specified operating conditions. Wide turndown helps an RTO follow changing process heat loads from startup through low-VOC and autothermal operation.
What is the autothermal point?
It is the process condition where VOC oxidation heat plus regenerative heat recovery are sufficient to maintain the required operating temperature without continuous main-burner firing. Changes in airflow, VOC loading, inlet temperature, moisture and heat losses can move the system above or below this condition.
Fuel and burner configuration
What fuels can DEC.HBT™ use?
Depending on the project, DEC.HBT™ can be engineered for natural gas, propane, LPG, hydrogen or other suitable combustible gases. Fuel properties, pressure, composition, flame characteristics, materials and safety requirements determine the applicable burner and fuel-train design.
Can DEC.HBT™ use oxygen instead of combustion air?
Oxygen-enriched or oxygen-based combustion can be considered for specific applications, but it requires dedicated engineering because combustion intensity, flame temperature, materials, controls and fire-safety conditions change substantially.
Can DEC.HBT™ burn hydrogen?
Yes, where the project is specifically engineered for hydrogen. Hydrogen service requires appropriate burner geometry, flashback protection, leakage control, detection, materials, fuel-train components and safety logic.
What is included in a burner train?
The exact package is project-specific, but a burner train can include fuel isolation and control valves, regulators or conditioning components, pressure instrumentation, combustion-air equipment, ignition and flame supervision, and the associated permissives and safety interlocks.
Safety, controls and retrofit
What happens if the flame is lost?
The burner-management system detects loss of proven flame and places the fuel system into the defined safe state, normally by isolating fuel according to the approved safety sequence. The exact logic depends on the burner, fuel, applicable requirements and site control philosophy.
Why is purge required before ignition or restart?
Purge requirements are used to clear potentially combustible mixtures from the relevant combustion spaces before ignition or restart. Purge timing and airflow proof are established by the approved burner-management and process-safety design.
Can DEC.HBT™ replace an existing RTO burner?
Potentially. A retrofit assessment should cover the burner mounting, chamber geometry, fuel pressure and composition, combustion-air system, fuel train, controls, flame safeguard, electrical interfaces, operating temperature, process heat load and applicable safety requirements.
How does DEC.HBT™ relate to DEC.HGB™?
HBT provides controlled combustion heat. DEC.HGB™ provides a separate thermal-protection function that can divert a controlled portion of hot gas around regenerative media when defined thermal limits are approached. The two functions can be coordinated within an RTO thermal-management and safety architecture.
