Waste heat recovery from
Thermal Oil Heaters

Cold spot corrosion problems limit heat recovery. The polymer air preheater is corrosion resistant and can boost your Thermal Oil Heater efficiency.

Improve Thermal Oil Heater efficiency >95%

Prevent corrosion & fouling

Reduce CO₂ emissions

Your Thermal Oil Heater has additional heat recovery potential

Improve thermal oil heater efficiency

The Thermal Oil Heater efficiency can be improved to > 95%, by using a polymer air preheater or economiser.

Lower CO₂ emissions

Every 1% efficiency increase of your Thermal Oil Heater results in 1% CO₂ emission reduction.

Decrease fuel costs

By recovering additional heat, less fuel is needed to achieve the required duty of your Thermal Oil Heater.

Waste heat recovery on Thermal Oil Heaters is limited by corrosion problems

10-15% of the energy is lost via the stack

Thermal Oil Heaters are applied in the industry where such high temperatures are required that can not be generated with steam. They are reliable systems because you do not have to deal with high pressures, water treatment and condensate losses that typically exist when you operate a steam boiler. However most installed Thermal Oil Heaters tend to have a low thermal performance, in the range of 85 to 90%.

Cold Spot corrosion problems

All fuels contain acidic elements. When you burn the fuel and cool flue gas too deep, then – depending on the fuel type – the acidic elements will become corrosive and the installed heat exchangers will suffer from cold spot corrosion due to the relatively cold metal surface temperatures. This limits heat recovery. If you can prevent this problem, enhancing further thermal efficiency is possible. This results in extra energy savings.

How to recover more waste heat from your Thermal Oil Heater

Use flue gas heat to warm up combustion air

The simplest and most economical way to improve the efficiency of your Thermal Oil Heater is by applying combustion air preheating. The heat from the flue gases is recovered and used to preheat the cold combustion air entering the burner. Hot air is burned which means that you need less fuel to achieve a certain duty. A polymer air preheater of HeatMatrix enables heat recovery to a flue gas temperature of less than 100 ºC and can boost heater efficiencies to 95% and higher.

Corrosion free heat recovery

The polymer air preheater can be installed in series with a metal air preheater to recover heat over a very broad temperature range and ensures a reliable operation. If you already have a metal air preheater on your Thermal Oil Heater, the addition of a polymer air preheater will further boost efficiency.

The polymer air preheater protects the metal air preheater for local corrosion and the metal air preheater protects the polymer air preheater for high temperatures. The polymer air preheaters of HeatMatrix are suitable for flue gas coming from burning any kind of fuel ranging from natural gas to fuel oil.

Waste heat recovery systems for Thermal Oil Heaters

Polymer Air PreHeater

Heat up combustion air by extracting heat from flue gas. The air preheater is corrosion resistant & anti-fouling and is easy to maintain and clean.

Industries with Thermal Oil Heaters

Industries

Case study: Industrial Cookie Bakery

20% gas reduction

The industrial bakery has the ambition to reduce energy consumption of the manufacturing process. In the production process of cookies many fatty ingredients are used like butter and chocolate. In the oven fouling baking vapours are extracted and currently released to the atmosphere at high temperature. The bakery would like to recover heat from these vapours to reduce overall energy consumption.

Because of the smooth surface of the polymer tubes the HeatMatrix polymer APH has a low tendency of fouling. This aspect in combination with an in-situ cleaning system made it the perfect combination for heat recovery at this bakery. One heat exchanger was installed which cooled down all the baking vapours from the oven.

Circulation air send to the oven is preheated from 15 to 103°C, which resulted in a heat recovery of 143 kW and a reduction of the oven gas consumption of 20%.

Technical Assessment of heat recovery on your Thermal Oil Heater

Our process engineers assess the technical feasibility of additional heat recovery on your thermal oil heater. The potential reduction in CO₂ emissions, energy consumption and costs is determined.

FAQ's

How does a Thermal Oil Heater work?

Fuels like natural gas are combusted in a thermal oil heater. The heat from the flue gases is transferred to the thermal oil in a radiant and convective heat exchange section inside the thermal oil heater. The thermal oil is circulated through the different sections and absorbs the heat from the flue gas and gets heated-up.

What are Thermal Oil Heaters used for?

Thermal oil is the energy carrier for processes that require high temperatures that typically can’t be served with steam. Typical temperature range for the thermal oil is 250-350ºC. A thermal oil heater heats the thermal fluid to the required conditions.

How does waste heat recovery on a Thermal Oil Heater work?

Waste heat recovery on a thermal oil heater is typically done using an air preheater. Downstream of the convection section the flue gases are guided through an air preheater. In the air preheater the flue gas heat is transferred to the combustion air. The preheated combustion air is fed to the burners. The elevated combustion air temperature lowers the required fuel input to the thermal oil heater.

Benefits of waste heat recovery on a Thermal Oil Heater?

An air preheater on a thermal oil heater can reduce the fuel consumption up to 20%. The lower the stack temperature, the higher the achieved fuel efficiency. Using a polymer air preheater in combination with a metal air preheater can result in a fuel efficiency of >95%.