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Closed-Loop Thermal Oil · Oil / Gas Fired

Oil/Gas Fired Thermal Oil Boiler for High-Temperature, Low-Pressure Process Heat

EPCB oil/gas fired thermal oil boilers deliver 1,200–9,400 kW (100–800 ×10⁴ kcal/h) of high-temperature process heat at up to 320°C, with 92–93% rated thermal efficiency. They heat thermal oil in a closed loop rather than generating steam — reaching 320°C at a design pressure of only 1.1 MPa, because the operating pressure is driven by circulation, not temperature. They fire diesel, heavy oil, natural gas, LPG, or coke oven gas. This is an indirect high-temperature heating system, not a steam source.

Request a Custom Quote Thermal Oil vs Steam
1,200–9,400
Rated Power
kW (100–800 ×10⁴ kcal/h)
320°C
Max Working Temp
High-temperature process heat
1.1 MPa
Design Pressure
Low pressure at high temp
92–93%
Thermal Efficiency
At rated conditions
The Core Decision

Thermal Oil vs Steam — When Each Is the Right Choice

The defining advantage of thermal oil is reaching high temperature at low pressure. Because thermal oil transfers heat through a pumped closed loop rather than by pressure-temperature equilibrium, this series reaches 320°C at just 1.1 MPa. Delivering heat from condensing saturated steam at the same 320°C would require pressure in the roughly 11 MPa class — the contrast that drives the choice between the two systems.

Choose Thermal Oil When

  • The process needs high, precisely controlled temperature — typically 180–320°C — without the high pressure a saturated steam system requires at those temperatures
  • You want to avoid high-pressure vessel risk, water treatment, blowdown losses, and steam-trap maintenance
  • The process is indirect heating — chemical reactor jackets, asphalt, textile stenters, wood-panel hot pressing, edible oil, plastics, printing
  • Heat duty falls within 1,200–9,400 kW and maximum temperature stays within the 320°C rating and the selected oil's limits

Choose Steam Instead When

  • The process needs steam directly — sterilization, humidification, direct steam injection, and direct-contact heating all require a steam boiler
  • The required temperature exceeds this series' 320°C rating — higher-temperature processes need a different medium such as molten salt
  • The process runs below about 150°C and you already have steam infrastructure in place — steam may remain more practical
  • Your existing plant utilities are steam-based and the process does not benefit from the low-pressure, high-temperature advantage

The decision rests on three things: your process temperature, whether you need steam directly, and your existing plant utilities. Describe your process and we will confirm which path fits — there is no advantage to thermal oil if your process actually needs steam, and no advantage to steam if you need precise high temperature at low pressure.

Industry Fit

Applications for High-Temperature Indirect Heating

Thermal oil heating suits processes that need stable, precisely controlled temperature in the 180–320°C range delivered indirectly through a heat exchanger, jacket, or platen — without the pressure a steam system would require at the same temperature.

Chemical Processing

Reactor jacket heating and process loops needing precise, stable temperature control without high-pressure steam infrastructure.

Asphalt & Bitumen

Storage tank and process heating where consistent high temperature keeps material workable without localised overheating.

Textile Finishing

Stenter, calender, and dyeing-range heating where uniform platen and roller temperature determines product quality.

Wood-Panel Pressing

Hot pressing and lamination of plywood, MDF, and particleboard, where platen temperature uniformity drives bond quality.

Edible Oil Processing

Refining and deodorising stages requiring controlled high temperature delivered indirectly to product-contact surfaces.

Plastics & Printing

Extrusion, calendering, and drying processes where fast, accurate temperature response is essential to throughput and quality.

Not sure thermal oil is right for your process? If your process needs steam directly, runs below ~150°C with existing steam infrastructure, or exceeds 320°C, a steam boiler or alternative medium may fit better. Describe your process and required temperature and we will confirm the right path before you commit to a system.

Technical Data

Rated Parameters and Output Range

Full output range for this series. All models share a design pressure of 1.1 MPa and a rated maximum working temperature of 320°C. Fuel consumption and circulation flow are design reference values confirmed against your fuel and operating point at the engineering stage.

EPCB thermal oil boiler closed-loop system layout with circulation pump and expansion tank

A Closed-Loop System, Not a Single Unit

An EPCB thermal oil boiler is more than a heater — it is a complete high-temperature heat-transfer solution. Around the heater, the loop relies on a circulation pump to drive oil through your process, an expansion tank to take up the oil's expansion as it heats, the thermal oil charge itself, and an intelligent control system that holds temperature and guards against over-temperature and low flow.

We engineer and supply the whole package as one matched unit. Working from your heat load, required process temperature, and plant layout, EPCB sizes heater capacity, pump head and flow, expansion tank volume, and controls to your loop. By tuning heat output, circulation flow, and the system temperature difference (ΔT) across the heater, the unit is built to deliver stable, efficient, and safe heat for processes in chemicals, textiles, food, and similar industries.

Rated Power (kW) Heat Output (10⁴ kcal/h) Thermal Efficiency Circulation Flow Thermal Oil Charge Electrical Load
1,20010092%100 m³/h0.8 m³37.5 kW
1,40012092%100 m³/h1.2 m³49.5 kW
1,80015093%160 m³/h2.1 m³57.5 kW
2,40020093%160 m³/h2.6 m³61.5 kW
2,90025093%200 m³/h3.5 m³75 kW
3,50030093%200 m³/h7.8 m³75 kW
4,70040093%260 m³/h8.4 m³98.5 kW
5,90050093%300 m³/h8.8 m³121.5 kW
7,00060093%340 m³/h10.5 m³148.5 kW
8,20070093%400 m³/h11.2 m³155 kW
9,40080093%520 m³/h11.5 m³195 kW

The thermal oil charge (0.8–11.5 m³) is a significant upfront cost budgeted separately from the heater, and a recurring cost as the oil is replaced over the system life. Note the sharp step between the 2,900 kW (3.5 m³) and 3,500 kW (7.8 m³) models — confirm the oil charge and its cost implication with engineering if selecting near this boundary. Electrical load shown is for the circulation pump, burner, and controls — not the heat output.

Rated Power (kW) Diesel (kg/h) Natural Gas (Nm³/h) Main Pipe DN Vertical Ø × H (m) Horizontal Ø × L (m)
1,20099.0121.01252.2 × 3.51.92 × 4
1,400118.8145.31252.2 × 41.95 × 4.3
1,800146.9179.61502.4 × 4.42.4 × 4.3
2,400195.8239.51502.7 × 5.12.52 × 5.3
2,900200.0239.22002.8 × 6.52.8 × 6.3
3,500293.7359.22003.2 × 6.72.92 × 6
4,700391.6479.02003.2 × 73.23 × 6.7
5,900406.9486.72503.3 × 7.53.26 × 7.45
7,000587.5598.72503.5 × 8.23.26 × 7.9
8,200565.5718.42503.62 × 9.23.62 × 9
9,400685.4838.23003.7 × 9.63.6 × 9.48

Fuel consumption figures are design reference values at rated load. Actual consumption depends on fuel calorific value (natural gas figures are referenced to a standard heating value matched to your local gas), system operating temperature, and load profile — for heavy oil, LPG, and coke oven gas, consumption is recalculated against the specific fuel's energy content. Vertical units use less floor area but need greater ceiling height; horizontal units spread the footprint but lower the height requirement. For output above 9,400 kW or temperatures beyond 320°C, a separate engineering review applies.

System & Fuel

Components, Thermal Oil Selection, and Fuel Options

Two selection variables sit outside the heater rating itself and materially affect performance and cost: the thermal oil you choose, and the fuel the burner is configured for. Both are confirmed during engineering, before manufacturing.

Thermal Oil — A Selection Variable in Its Own Right

This series is rated for 320°C maximum working temperature, but the selected oil must also be checked against its own maximum bulk temperature and maximum film temperature. Film temperature at the coil wall runs higher than the bulk outlet temperature, and exceeding the oil's film limit causes cracking, carbon deposits, and degradation. Mineral oils are economical up to their rated limits; synthetic oils tolerate higher temperatures and last longer at higher cost. The right oil depends on how close your operating temperature runs to these limits.

Fuel Options — Configured Before Manufacturing

This series fires diesel, heavy oil, natural gas, LPG, or coke oven gas, with the burner configured to your fuel. Heavy oil requires preheating; natural gas and LPG require confirmation of inlet pressure and calorific value. Coke oven gas requires confirmation of gas composition (H₂, CO, CH₄, H₂S, moisture, tar) — and because it contains toxic CO and wide-flammability-range H₂, it requires a burner safety design suited to that gas. Confirm fuel type at inquiry so the combustion system is configured correctly.

The most common oversight we see is treating the boiler as a standalone purchase without budgeting the full system — circulation pump, expansion tank, the oil charge, and the oil's ongoing monitoring and replacement. Working through the complete system and its operating costs at the engineering stage gives a realistic comparison against alternatives and avoids surprises after commissioning.

Safety & Maintenance

Fire Protection, Oil Maintenance, and Standards

Thermal oil is a combustible medium, which makes fire and over-temperature protection a defining design consideration for this product class — one that does not apply to water-based steam systems in the same way. Keeping the system within its rated temperature and maintaining adequate flow is essential to safe operation.

Over-Temperature & Low-Flow Protection

The system includes over-temperature protection, flow and level monitoring, and a low-flow interlock — because low circulation flow lets film temperature climb and can start a cracking-and-fouling cycle in the coil. Maintaining adequate flow is a safety function, not just an efficiency one.

Thermal Oil Degrades — Plan for It

Thermal oil degrades over time through thermal stress and oxidation; it is not a one-time charge. Periodic sampling for viscosity, acidity, and carbon residue is part of normal operation, and the oil is replaced when it degrades beyond acceptable limits. This ongoing cost belongs in a realistic total cost of ownership.

One Matched System, One Supplier

The heater, circulation pump, expansion tank, controls, and safety devices are engineered and supplied by EPCB as a single matched package — not parts sourced from separate vendors and hoped to work together. Because the protection logic, flow monitoring, and over-temperature interlocks are sized to the same heater and loop, the safety chain behaves as one system, with one team accountable from design through commissioning.

ISO 9001 indicates the manufacturer's quality system and is not a substitute for product-level pressure or fire-safety compliance — request the certificate referencing your specific model rather than a general image. Because there is combustion, local air emission permits may also apply. Confirm all applicable requirements for your destination market before order.

Why EPCB

Engineering & Operating Advantages

For high-temperature indirect heating, four characteristics determine whether a thermal oil system delivers reliably over its life — temperature reach at low pressure, integrated system supply, coil-protective control, and multi-fuel flexibility.

Thermal oil boiler coil delivering 320 degrees C at low 1.1 MPa pressure
01

320°C at Just 1.1 MPa Design Pressure

Because the loop pressure is set by circulation rather than temperature, the system reaches 320°C at 1.1 MPa — avoiding the high-pressure vessel risk a steam system faces at the same temperature, and the dedicated operator and inspection regime that high-pressure steam often requires.

Integrated thermal oil heating system with pump expansion tank and controls
02

Integrated System, Sized to Your Loop

We supply the heater, circulation pump, expansion tank, controls, and the thermal oil charge as one engineered package — pump head, expansion volume, and controls sized to the heater output and your process loop, so the system fits your ΔT rather than being assembled from mismatched parts on site.

Thermal oil boiler control system with over-temperature and low-flow protection
03

Coil-Protective Control

Over-temperature protection, flow and level monitoring, and a low-flow interlock guard against the film-temperature rise that drives coil cracking and fouling. The control system protects the asset that is most expensive to replace — the heating coil — not just the process setpoint.

Multi-fuel burner for thermal oil boiler firing diesel gas LPG or coke oven gas
04

Multi-Fuel Burner Configuration

Diesel, heavy oil, natural gas, LPG, or coke oven gas — the burner is configured to your fuel before manufacturing, including the specific safety design coke oven gas requires. This lets the system match the lowest-cost fuel available at your site rather than a single default.

Compliance

Certifications: Coverage Scope & How to Verify

Certification depends on the destination market, design pressure, and applicable pressure-equipment and fire-safety rules. ISO 9001 indicates the manufacturer's quality system — it is not a substitute for product-level pressure or fire-safety compliance. Request the certificate referencing your specific model and design pressure.

ISO 9001 quality management certificate for EPCB boiler manufacturing
ISO 9001 — Quality Management System
CE PED declaration document for eligible thermal oil boiler configuration
CE / PED — Eligible EEA Configurations
EAC conformity certificate for thermal oil boiler export to Eurasian Economic Union markets
EAC — Applicable EAEU Markets
SGS boiler supplier assessment certificate for EPCB industrial boiler
SGS Boiler Supplier Certificate

What to confirm for your market. For EU-bound projects, confirm whether PED 2014/68/EU applies to the heater body, expansion tank, piping, and safety devices, and request the model-specific CE Declaration of Conformity. For the US and other markets, confirm whether the applicable ASME section (for example Section VIII for the relevant pressure components) and local pressure-equipment registration apply. For fire and combustion safety, review NFPA 87 (Standard for Fluid Heaters) or the destination market's equivalent fluid-heater standard during engineering.

Because there is combustion, local air emission permits may also apply. For Southeast Asian, South Asian, Middle Eastern, and African markets, import registration requirements vary by country — confirm before issuing the purchase order. Third-party inspection by Bureau Veritas, SGS, or TÜV can be arranged before dispatch on request.

Procurement Workflow

Delivery Process & What Affects Lead Time

Every custom thermal oil boiler system from EPCB moves through defined engineering stages, with client sign-off on drawings before manufacturing begins. Because this is a system rather than a single unit, the engineering stage establishes the full package — heater, pump, expansion tank, oil, and controls.

1
Process & Heating-Type Assessment Critical Gate

Confirm process heat duty, maximum temperature, required outlet/return oil temperatures, and — first — whether the process needs thermal oil or steam. This gate confirms the product fits the process before anything else proceeds.

2
System Sizing & Fuel Configuration

Match heater output, circulation flow, and ΔT to your loop; size pump head and expansion tank; select thermal oil against your operating temperature; configure the burner to your fuel.

3
Engineering Drawing Approval

System drawings issued for client review and written approval before manufacturing begins. Changes after sign-off affect lead time and cost.

4
Manufacturing & Factory Testing

Heater and system components manufactured and tested; pressure and safety-device checks performed. Test records issued in the documentation package.

5
Third-Party Inspection Where Required

Bureau Veritas, SGS, or TÜV inspection before dispatch where the market or project requires it. Include in your initial inquiry so it is scheduled before the shipment date.

6
Delivery & Commissioning Guidance

Technical support for system installation, oil charging, and commissioning, including first heat-up and oil dehydration guidance — a step specific to thermal oil systems that protects the oil and coil from the start.

The cost surprise to avoid is budgeting only the heater. The thermal oil charge, circulation pump, expansion tank, and the oil's ongoing replacement are real line items — working them through at the engineering stage gives a realistic total cost of ownership and a fair comparison against alternative heating methods.

Inquiry Inputs

What to Confirm Before Requesting a Quote

An accurate quotation is possible once the following are confirmed. Without them, any price or lead-time figure remains conditional.

01
Process Heat Duty (kW or kcal/h)

Based on peak process heat demand — the basis for model selection within the 1,200–9,400 kW range.

02
Maximum Process Temperature (°C)

The defining parameter, with margin below the 320°C rating and within the selected oil's bulk and film temperature limits.

03
Outlet & Return Oil Temperature

So the system ΔT matches the circulation flow and your process loop — the basis for matching the heater to your process.

04
Thermal Oil or Steam?

Confirm the process needs indirect high-temperature heating, not direct steam — the single most important fit question for this product.

05
Fuel Type

Diesel, heavy oil, natural gas, LPG, or coke oven gas — with inlet pressure and calorific value for gas, viscosity for heavy oil, or full composition for coke oven gas.

06
Configuration & Thermal Oil

Vertical or horizontal based on floor area, ceiling height, and maintenance access; mineral or synthetic oil preference, with budget for the oil charge (0.8–11.5 m³, sharp step at 3,500 kW).

07
Electrical Supply

Capacity for the circulation pump, burner, and controls — 37.5–195 kW by model, separate from the heat output rating.

08
Destination Market & Standards

Applicable PED/CE, ASME, NFPA 87, air emission permit, and registration requirements for your destination — confirm before issuing the purchase order.

FAQ

Frequently Asked Questions

What is the difference between a thermal oil boiler and a steam boiler?

A thermal oil boiler heats thermal oil in a closed loop and circulates it to your process; a steam boiler generates steam from water. The advantage of thermal oil is reaching high temperatures — up to 320°C on this series — at a low 1.1 MPa design pressure, because the loop pressure is set by circulation rather than by temperature. Delivering heat from condensing saturated steam at a similar 320°C would require pressure in the roughly 11 MPa class. Thermal oil suits indirect high-temperature heating; steam is required where the process needs steam directly.

What is the maximum temperature, and what if my process needs more?

This series is rated for a maximum working temperature of 320°C. The thermal oil you select must also stay within its own bulk and film temperature limits, since film temperature at the coil wall exceeds the bulk oil temperature. Processes needing higher temperatures require a different medium such as molten salt — share your process temperature so we can confirm suitability or recommend an alternative.

How much thermal oil does the system need, and is it a recurring cost?

The oil charge ranges from 0.8 m³ (1,200 kW) to 11.5 m³ (9,400 kW), with a notable step up at the 3,500 kW model. Thermal oil is a significant upfront purchase and a recurring cost, since it degrades over time and is replaced when sampling shows it past acceptable limits. Budget both the initial charge and periodic replacement into the total cost of ownership.

Can it run on coke oven gas or LPG?

Yes — this series fires diesel, heavy oil, natural gas, LPG, and coke oven gas, with the burner configured to your fuel before manufacturing. For coke oven gas, confirm the gas composition during engineering; because it contains toxic CO and high-hydrogen content with a wide flammability range, the burner and safety system are designed specifically for that gas. For natural gas and LPG, confirm inlet pressure and calorific value.

Which standards apply to a thermal oil boiler?

It depends on your market. For the EU, confirm whether PED 2014/68/EU applies and request the CE Declaration of Conformity; for the US and other markets, confirm the applicable ASME section and pressure-equipment registration. For fire and combustion safety specific to fluid heaters, NFPA 87 or the local equivalent should be reviewed. Confirm the certification referencing your specific model and design pressure before order.

Before Selecting

Confirm Process Temperature and Heating Type First

Whether an oil/gas fired thermal oil boiler is the right fit depends on three conditions: a process needing high-temperature indirect heating (typically 180–320°C) rather than direct steam, a maximum temperature within this series' 320°C rating and the selected oil's limits, and a heat duty within the 1,200–9,400 kW range.

The most common oversight we see is treating the boiler as a standalone purchase without budgeting the full system — circulation pump, expansion tank, the oil charge, and the oil's ongoing monitoring and replacement. Working through the complete system and its operating costs at the engineering stage gives a realistic comparison against alternatives and avoids surprises after commissioning.

To begin, share your process heat duty, maximum process temperature, required outlet/return oil temperatures, fuel type, and preferred configuration with our engineering team. If you are weighing thermal oil against steam, describe your process so we can confirm the better fit; if a specific certification, standard, or fuel such as coke oven gas is involved, include that in your first message.

Talk to an Engineer
  • Process heat duty — kW or kcal/h, based on peak demand
  • Maximum process temperature — with margin below 320°C
  • Outlet / return oil temperature — to match system ΔT and flow
  • Thermal oil or steam? — confirm indirect heating, not direct steam
  • Fuel type — diesel, heavy oil, gas, LPG, or coke oven gas
  • Configuration & oil — vertical/horizontal, mineral/synthetic, oil charge budget

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