design thermal oil heater

12 Apr 2019

Design Thermal Oil Heater

Design Thermal Oil Heater



1. Thermal Oil Heater is a type of heating transfer machine using Thermal Oil Fluid as a heat transfer medium and can work to temperatures of 320 ° C or more, according to the specifications of the Oil. In contrast to steam which reaches a pressure of 70 bar for the use of temperatures of 285 ° C, Thermal Oil Heater works only at the pressure of the circulating pump so that it is safer and devices that need heating do not need to be designed with special construction.
2. The working life of Thermal Oil Fluid (in a good TOH system) is generally more than 5 years and no additions are needed as long as there are no leaks in pipes or heating equipment, and does not require cleaning because the inside of the heating coil is not crusty like in Steam Boilers .


3. Some things that can be taken into consideration are why you should choose thermal oil heater.

a. Works at high temperatures with low pressure

b. Precise temperature control

c. No need for oil treatment

d. There are no heat losses from condensate and blowdown as in the steam boiler

e. There is no corrosion on the inside of the TOH pipe

f. Low maintenance costs

g. Full Automatic and easy operation that does not require special operators


4. Thermal Oil can be supplied in Vertical construction to save space and be efficient because it uses the Integrated burner. Some types of burners are designed to be able to use hot air by using “Air Pre Heater”, that is by utilizing the exhaust gas remaining combustion so that the combustion of fuel (liquid) is more perfect. Or Thermal Oil in Horizontal design, depending on user needs.
“Heating Coil” is made of Seamless Boiler Tube which is continuously continuous. Each welded joint is carefully worked out, and a “Pressure Test” with gas media is up to 1.5 times the operating pressure. Oil flows in the coil at a certain speed to avoid overheating, which can cause oil damage due to the formation of charcoal.
5. The hot gas from combustion heats the flow of thermal oil in the combustion chamber as radiant heat and then heats the oil in the convection coil through between the coil at a certain speed in 3 pass in the opposite direction to the flow direction of thermal oil. The turbulence produced by the gas as it passes through the coil results in an increase in Heater efficiency and the effect of cleaning the coil of soot that may stick to the outside of the coil.


6. Each unit is equipped with accessories, including:

a. Heating Coil / TOH unit complete with cover

b. Circulation Pump

c. Tank Expansion

d. Collecting Tank

e. Valves

f. Strainer

g. Differential Pressure Switch or Pressure Gauge with Switch

h. Control Panel


7. Thermal oil heater can be the cause of a serious accident and it has happened. So the user of this machine must run it according to the procedure. Operators who have run must have taken TOH operator training and followed operating instructions according to the user manual provided by the machine maker.

8. Thermal oil heater is a heat generating machine with media oil heated in a coil pipe. Generally thermal oil has an instrument consisting of a fuel burner / engine, circulation pump, expansion tank, oil storage tank, pipes and control panel.
9. Coil TOH is designed in a spiral shape, heated by a gas-fueled burner, solar / light oil, heavy oil / residue or other fuels that aim to increase the temperature of the oil itself.
10. Circulated oil is heated to temperatures of 300 0C or as needed. Oil is heated in a coil pipe, then transferred to other equipment that requires the heat. After heat is absorbed, the oil is returned to the heater by pushing the circulation pump.
11. Tank expansion is needed in the system to anticipate discharge when oil is heated. Oil storage tanks (collecting tanks) are also assembled in systems for oil storage, during emergencies or during maintenance.


12. Main requirements Ideal oil for heat transfer is:

a. High boiling point
b. Good heat stability
c. Low freezing point
d. Good heat transfer properties
e. Not easily oxidized
f. Non-toxic and odorless

13. Examples of the properties of TOH oil are:

a. Density / density at 2000C 760 Kg / m³
b. Specific Heat 2.4 kJ / kgK
c. Flash Point 1800C
d. 3700C Ignition Points
e. Boiling point / boiling point 3300C
f. Pour point / pour point -180C
g. Thermal expansion coefficient 0.00076 / 0C


14. Temperature limiter is installed to avoid excessive heat in the exhaust gas that uses liquid or gas fuel as fuel. This instrument also functions as an oil leak detector in the combustion chamber. If that happens, the liquid will burn and leave the soot that continues to stick and accumulate, eventually causing excessive heat to the exhaust gas.


15. When there is a failed fire on the burner with liquid or gas fuel, the flame detector will catch a signal that there is no combustion in the combustion chamber. Then the flame detector will order the burner to disconnect the fuel supply, so there is no buildup of fuel in the combustion chamber.
16. The function of the flame detector must be checked every day and recorded. Pull the flame sensor from the socket and then test it by covering the glass flame detector, only to see the function of the system that the fuel should not be supplied and stop immediately automatically.


17. Flow limiter is a safety equipment to read the flow in the coil. In general, it uses a “differential pressure switch” that is installed on a thermal oil heater outlet. Some manufacturers install a “pressure gauge with switch” to read the oil oil pressure on the coil. If the pressure is less than recommended or exceeds normal operating pressure, the burner will be turned off automatically. This happens if a blockage in the oil pipe is found or the circulation pump does not work properly.


18. In the expansion tank it is recommended to be equipped with an Oil level buoy. Every hot oil lost due to leakage is indicated by the burner’s death. These leaks are usually found in boiler pipes, circulating pump seals, flanges and pipes in the line system. If this leak occurs inside the heating furnace, it will cause an explosion.


19. The main parameter of thermal oil heater is from operating temperature. The pressure is not very influential because the pressure difference will not affect the temperature of the operation. Pressure in a thermal oil system is basically just a circulation pump pressure.
20. When the temperature of the oil in the unit has reached the upper temperature limit setting, the heat input from the combustion burner (or furnace) will be stopped, but the circulation continues to run. When the temperature drops again, the burner will turn on again after being ordered by the temperature controller.