victorpbr
Mechanical
- Oct 13, 2014
- 74
Hello,
I visited a sugar plant last week and found myself intrigued with an ozone injector there present and did not fully understand the physics behind it. I made an sketch and attached it. They use it to kill bacteria on the sugar cane juice without using chemicals.
So basically it works like a venturi, where there is an area reduction of about 25, after the reduction of area there is a pressure reduction that creates negative gage pressure which then causes a gas (Mixture of Ozone and Oxygen) that comes from a pipe at ambient pressure to be injected.
So far so good, the thing that really intrigued me is that this piece of equipment is situated at 15 meters above the line of water at the tank, and the people there said that this was the only way to get a propper vaccum and that if the height was lower it would not work (they said they tested it), another interest fact is that the fluid inside the is kept risen 4-6 meters above the water line at the tank I also do not quite understand that, initially I thought that this was because of the negative pressure generated at the injector, but this low pressure is very localized, and the pressure a few centimeters after the area growth should already be equal to ambient pressure, what causes this?
Clearly I'm missing something, could anyone help me firgure this?
Just to provide more data, here are some parameters I could measure there
The pressure and the head of the injector is of 3,5 kgf/cm2
The sugar cane juice flow is of 100 m3/h
The gage pressure measured at the gas inlet at the injector is 8" mmHg (-0,26 bar)
The gas production is 3Nm3/min
I visited a sugar plant last week and found myself intrigued with an ozone injector there present and did not fully understand the physics behind it. I made an sketch and attached it. They use it to kill bacteria on the sugar cane juice without using chemicals.
So basically it works like a venturi, where there is an area reduction of about 25, after the reduction of area there is a pressure reduction that creates negative gage pressure which then causes a gas (Mixture of Ozone and Oxygen) that comes from a pipe at ambient pressure to be injected.
So far so good, the thing that really intrigued me is that this piece of equipment is situated at 15 meters above the line of water at the tank, and the people there said that this was the only way to get a propper vaccum and that if the height was lower it would not work (they said they tested it), another interest fact is that the fluid inside the is kept risen 4-6 meters above the water line at the tank I also do not quite understand that, initially I thought that this was because of the negative pressure generated at the injector, but this low pressure is very localized, and the pressure a few centimeters after the area growth should already be equal to ambient pressure, what causes this?
Clearly I'm missing something, could anyone help me firgure this?
Just to provide more data, here are some parameters I could measure there
The pressure and the head of the injector is of 3,5 kgf/cm2
The sugar cane juice flow is of 100 m3/h
The gage pressure measured at the gas inlet at the injector is 8" mmHg (-0,26 bar)
The gas production is 3Nm3/min