A research team led by Sin Jung Sok, a researcher at the Faculty of Earth Science and Technology, has developed an ultrasonic mixer to improve the combustibility of heavy oil burners by ultrasonic waves generated by the steam in a tubular furnace.
This technology can help to make ultrasonic waves by high pressure steam to change the carbon chain structure of heavy oil whose relative viscosity is over 200 and to decrease the viscosity. It leads to the improvement of spraying characteristics of burners and to the sharp reduction of consumption of heavy oil necessary for oil processing.
The ultrasonic mixer has 1st ultrasonic wave generator, mixing unit of heavy oil ― steam, 2nd ultrasonic wave generator, spraying unit, etc.
In the 1st ultrasonic wave generator, high pressure steam that passes through the jet orifice, resonator and reflector can make ultrasonic waves of 14~17kHz, which enter the heavy oil ― steam distributor.
In the heavy oil ― steam mixing unit, the heavy oil coming in four tangential directions through the heavy oil ― steam distributor is mixed with steam. Then, the mixed liquid is sprayed. At this time, the chain structure of the heavy oil is destroyed primarily by the ultrasonic waves.
When the sprayed liquid causes the 2nd resonance while passing the resonator of the 2nd ultrasonic wave generator, most of the heavy oil particles are pulverized to be smaller than 20㎛. The purpose of the 2nd ultrasonic wave generation is to break up the liquid particles mixed through the heavy oil ― steam distributor into smaller ones.
In the spraying unit, heavy oil and steam are mixed evenly and sprayed through 8 holes. The size of about 90% of heavy oil particles is within the range of 10~20㎛.
The intensity of ultrasonic wave is 200dB at the 1st ultrasonic wave generator and 220dB at the 2nd one.
If the size of heavy oil particles is below 30㎛, the combustion efficiency of heavy oil in tubular furnaces reaches higher than 95%, which equals the case of combustion of heavy oil whose relative viscosity is 100.
The introduction of this device to tubular furnaces for oil processing can lower the flue temperature by 15~20℃ and reduce the consumption rate of oil. It can also improve the spraying quality of liquid and raise the combustion efficiency in the burners of tubular furnaces.
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