1、 Characteristics of synthetic thermal oil

Based on years of experience and lessons learned from using synthetic thermal oil, the following characteristics of synthetic thermal oil are summarized:

1. High temperature resistance: Synthetic heat transfer oils have the characteristic of high temperature resistance, and if used properly, they can run for a long time.

2. High density: above 1.0g/cm3, relatively speaking, it has a higher specific heat than other ordinary synthetic oils and mineral based heat transfer oils, with a volumetric transport capacity and more heat carried.

3. Low freezing point: Most synthetic heat transfer oils have a relatively low freezing point (<-30 ℃), making them very suitable for cold regions. There is no need to worry about pipeline blockage when used in winter.

4. Not easy to burn, low toxicity, non corrosive equipment, odorless, safe and reliable

5. The structure is basically aromatic, and the composition is relatively simple, consisting of one or two or three types, with narrow fractions and low vapor pressure.

6. Moderate viscosity: low viscosity, easy to transport.

The above characteristics are important for the rational use of thermal oil. In practical production, it is necessary to highlight its advantages and avoid its shortcomings in order to leverage the advantages of synthetic heat transfer oil and optimize heating in production.

2、 Principles for the use of synthetic thermal oil

By adopting different usage strategies based on the characteristics of different thermal oils, the service life of thermal oils can be extended. However, several commonalities of synthetic thermal oils are effective for their rational use in practical production.

The use of synthetic thermal oil follows four principles:

1. Isolate the air

Due to the aromatic structure of synthetic heat transfer oil, it is easily oxidized upon contact with air, resulting in a deterioration of the quality of the heat transfer oil. Its oxidation rate is much higher than that of alkane structure heat transfer oil. Therefore, when using synthetic heat transfer oils such as hydrogenated triphenylene, the first important thing is to seal the heat transfer oil and not let it come into contact with air.

There are two methods to isolate the air:

Nitrogen sealing: Seal the high-level heat transfer oil tank with nitrogen gas.

Liquid seal: Seal the high-level tank with the same type of heat transfer oil, which is very suitable for both large and small enterprises.

2. Prevent excessive temperature in the high-level expansion tank

Research has shown that the temperature of the heat transfer oil in the high-level tank should not exceed 60 ℃. Once it exceeds 60 ℃, the thermal oxidation degradation reaction of the heat transfer oil begins to accelerate.

There are two methods to prevent excessive temperature in high-level tanks:

The diameter of the expansion pipeline under the high-level tank should match the capacity of the thermal oil furnace and should not be too thick. If it is too coarse, the temperature of the high-level tank will increase, and if it is too fine, it cannot meet the process requirements. Therefore, choosing the appropriate expansion tank diameter is crucial.

The position of the oil and gas separator is also crucial, and it should be kept as far away as possible.

3. Prevent ultra-high temperature degradation of heat transfer oil in the heat medium furnace

This is a principle that everyone is familiar with and very important. How to implement it?

(1) It is necessary to ensure that the linear flow velocity of the heat medium in the furnace tube is ≥ 2.5 m/s. Therefore:

Choosing a heat medium pump correctly requires that its flow rate and inlet/outlet pipe diameter meet the requirements, which is very important.

A bypass pipeline with a pressure control valve needs to be added to the heat transfer oil heating circuit pipeline

Reasonable design of thermal oil furnace: The flow rate of thermal oil in each furnace tube must be balanced

(2) The heat inside the combustion furnace needs to be balanced to avoid overheating.

(3) Minimize the set temperature at the outlet of the thermal oil furnace while meeting the process (temperature) requirements.

4. Keep the thermal oil clean

Generally, the filters brought with the equipment by thermal oil furnace manufacturers are Y-shaped filters, which have insufficient area and need to be modified to filter out impurities, coke, etc. in the thermal oil circuit.

If the above four points are achieved, the synthetic heat transfer oil will be used well and the service life will be extended.