cooling steam to water

[mustangs]

Hi all,

I have a machine that is generating steam at atmospheric pressure. The steam passes along about 10 feet of piping and then through a series of condensers.

After leaving the condensers, the steam continues to flow out of the system and eventually into the atmosphere. The steam at this point is around 1-5 psig and can range anywhere from 80-140 deg F and the physical properties are the same as clean water.

I need to know how to adjust my calcs so that I can lengthen the pipe coming out of the system and have no steam coming out. This will likely produce a lot of water that will simply be fed into an adjacent tank.

Any ideas on how to accurately deal with the change of state and figure out how much piping needs to be put in would be a huge help.

thanks

Mustangs

 

[TD2K]

You need to increase the duty in your condensers, not add piping if this really is a problem (why is it a problem?)

If the water is coming out at 80F to 140F, then the 'steam' you are seeing is due to the water's vapor pressure versus the air's relative humidity. A quick look at the steam tables will show that you don't have steam at 1 to 5 psig and 80F to 140F but rather subcooled water.

 

[sailoday28]

I have a machine that is generating steam at atmospheric pressure. The steam passes along about 10 feet of piping and then through a series of condensers.

I ASSUME SOME OF THE STEAM HAS CONDENSED AT A PRESSURE LESS THAN ATMOSPHERIC.

After leaving the condensers, the steam continues to flow out of the system and eventually into the atmosphere.
HOW DOES THE NON CONDENSED PORTION FLOW TO THE ATMOSPHPERE?


The steam at this point is around 1-5 psig.
FROM ORIGINAL CONDITION OF ATMOSPHERIC PRESSURE??

AT 80-140 deg F and the physical properties are the same as clean water.

Please clarify the flow problem.

 

[EdStainless]

How about adding a water spray in the duct, or maybe you need some mist elimination pads for the condensate to collect on.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[mustangs]

Alright, I got some answers to the questions that were asked and soome more particulars about the problem.

First, I can't have any steam coming out of the system because it has been installed close to an airport and there are really strict regulations about the times when steam is coming out of the neighboring facilities. Apparently pilots don't like it.

Second, I think I need to clarify how the steam is being produced. There is propane that is being sprayed and ignited in the form of a mist. The burning of the propane heats up my water solution that is also sprayed in the form of a mist but is just beside the burning propane. This all gets moved by a blower which is driven by a 40 hp motor. The blower moves the low pressure steam at a rate of 2300 ACFM. The steam temperature is controlled by a gas valve which regulates the amount of propane entering the system. The steam temperature is generally in the neighbourhood of 195F when it leaves this section of the machine.

The steam gets moved along the 10 feet of pipe and through a water jacket and a series of condensers. It then leaves the system at around 80-140F and 985-1500 CFM depending on several factors that all have to do with the cooling fluid and the weather conditions on a given day.

I haven't investigated using a water spray or mist elimination pads yet. I will do that later on today.

My real problem right now is figuring out when my steam (or subcooled water) will condensate back into water with an outside temperature of around 80F.

I can do the heat loss calculation in terms of W/m but I don't how much heat or what temperature the steam would have to get to in order for it to condense. Also because of my limited heat transfer knowledge, I only would be able to approximate this value based on a number of conditions (like steady state, which I know don't apply)