dmar054
Industrial
- May 25, 2012
- 2
We've reinstalled several jacketed kettles after about a year of storage. Prior to storage and in the same application, they'd worked well. Now, heating is barely adequate
during our first batch and marginal to inadequate thereafter.
Here is what I know, and BTW my discipline is instrumentation, electrical and control so please be gentle. The kettles are uninsulated stainless steel, about 300 gallon capacity,
half cylinder shape with a dimpled jacket around the bottom third. Steam piping is a 4" header pressurized to 90 psi with about 15' of 3/4" vertical piping to the kettles, all
as yet uninsulated. Steam admission is controlled by hand operated valves at the kettles and there is a safety relief valve at each kettle set at 100 psi. Condensate discharge
is via a short 3/4" pipe through a condensate trap to atmosphere. There are no pressure gauges at the kettles themselves.
The heated fluid is a food slurry the consistency of thick soup. Initial temp is about 140 to 150, and the goal is to elevate the temperature to 180 degf or higher, but no
more than 200 degf, in fifteen to twenty minutes.
After several days of testing, our first batch in each kettle heats to 180 degf in twenty to thirty minutes. Subsequent batches stall at 165 to 170 and we have no idea why. Steam
header pressure is constant so steam supply doesn't seem to be an issue. I've tried continuous condensate removal and see essentially little or no condensate which I suppose
confirms little if any heat transfer, but I frankly don't know how much condensate to expect. So what's going on here? And why is there a marked difference in behavior between batches?
Is it because the kettles are preheated?
Any advice or observations will be appreciated.
during our first batch and marginal to inadequate thereafter.
Here is what I know, and BTW my discipline is instrumentation, electrical and control so please be gentle. The kettles are uninsulated stainless steel, about 300 gallon capacity,
half cylinder shape with a dimpled jacket around the bottom third. Steam piping is a 4" header pressurized to 90 psi with about 15' of 3/4" vertical piping to the kettles, all
as yet uninsulated. Steam admission is controlled by hand operated valves at the kettles and there is a safety relief valve at each kettle set at 100 psi. Condensate discharge
is via a short 3/4" pipe through a condensate trap to atmosphere. There are no pressure gauges at the kettles themselves.
The heated fluid is a food slurry the consistency of thick soup. Initial temp is about 140 to 150, and the goal is to elevate the temperature to 180 degf or higher, but no
more than 200 degf, in fifteen to twenty minutes.
After several days of testing, our first batch in each kettle heats to 180 degf in twenty to thirty minutes. Subsequent batches stall at 165 to 170 and we have no idea why. Steam
header pressure is constant so steam supply doesn't seem to be an issue. I've tried continuous condensate removal and see essentially little or no condensate which I suppose
confirms little if any heat transfer, but I frankly don't know how much condensate to expect. So what's going on here? And why is there a marked difference in behavior between batches?
Is it because the kettles are preheated?
Any advice or observations will be appreciated.
