Original situation
The Yankee dryer ran on steam straight from the boiler: 6,000 kg/h, raised by burning 660 litres of B-C (bunker) oil an hour, at a machine speed of 1,100. Its blow-through steam went to the condensate system.
Technical enhancement
- A Jetomat® (Baelz 590) went in on the Yankee dryer’s steam supply.
- Boiler steam now enters as the Jetomat’s motive steam, and the Jetomat returns the Yankee’s blow-through steam to the dryer with it.
The result
| Before | After | |
|---|---|---|
| Boiler steam | 6,000 kg/h | 4,100 kg/h (−31.7%) |
| B-C oil | 660 L/h | 440 L/h (−33.3%) |
| Machine speed | 1,100 | 1,240 (+12.7%) |
- About Rs 1.1 crore of fuel a month, on the plant’s own basis: 220 L/h less oil, 720 hours a month
- Faster machine on less steam, read from the boiler-house trend records (2008)
Why it works
A Yankee needs a steady flow of steam through it to clear its condensate, so part of the steam always leaves as blow-through steam. Without recovery, that steam has to be made good with fresh boiler steam. The Jetomat uses the pressure of the boiler steam to draw the blow-through steam back and return the mix to the Yankee, so the boiler supplies only the steam that condenses on the shell.
Takeaway
A Yankee always passes some steam straight through. Recirculate it with a Jetomat and the same boiler runs a faster machine on less fuel.
