Solution

Temperature sensor for naphtha cracking furnace

Thermocouple
Petrochemical
Furnace

Naphtha, also known as crude gasoline, is a petroleum product obtained by distillation and separation at different temperatures and pressures in an oil refinery. Through thermal cracking, naphtha becomes the basic raw material for petrochemical products such as ethylene and propylene.

The naphtha cracking furnace consists of three sections: the convection section, the crossover section, and the radiant section.
The raw naphtha is thermally cracked as follows:
– Preheated in the convection section and mixed with dilution steam
– Heated to a temperature just before the reaction starts in the crossover section
– Sent into the reaction tubes (cracking tubes) in the radiant section, where it is thermally cracked by radiant heating from radiant burners arranged on the side walls of the furnace.

Features

As the pyrolysis reaction progresses, the by-product coke forms a layer on the inner wall of the reaction tube (coking), which increases the pressure loss inside the reaction tube and at the same time reduces the thermal conductivity, lowering the operating rate of the pyrolysis furnace.
As the coke layer grows, i.e., the thermal conductivity of the reaction tube decreases, the temperature of the outer wall of the reaction tube rises, so temperature control is required to ensure that the outer wall temperature (skin temperature) of the reaction tube does not exceed the upper limit of the allowable temperature of the tube material. In addition, a phenomenon called carburization occurs in which carbon dissolves inside the reaction tube base material due to coking, which shortens the life of the reaction tube. Since the timing of decoking of the cracking furnace has a significant impact on the operating efficiency of the plant, hundreds of COT skin thermocouples are installed per cracking furnace to control the reaction tube outlet temperature (COT), and our thermocouples are used in this field.

Contact for temperature sensor for naphtha cracking furnace