We have a gas at 280F. This gas is sent to Amine unit for further polishing.If the amine unit is approx 2 miles downstream would there be any temperature drop
There will certainly be a temperature drop, especially if the pipe is not insulated. If you need to maintain the 280F, you will have to insulate and add heat tracing. Of course I don't know the system and the chemistry may not allow this, but you could calculate the temperature drop and increase the 280F to whatever you need to have the right temp at the amine unit.
By the way, older homes are built with copper water piping, which is a pretty good conductor, so don't expect as dramatic a drop as from your hot water tank to your shower.
The basic convective heat transfer equation of Q=h*A*delta_T, where:
>> h heat transfer coefficient
>> A area
That said, your piping insulation, fluid flow rate, solar load and ambient air also need to be factored in. Overall, there's no simple closed-form solution, but there are thermal analysis programs that could probably do the numerical analysis.
You can potentially set up a lumped parameter model of the pipe and at least get a reasonable swag.
We have a gas at 280F. This gas is sent to Amine unit for further polishing.If the amine unit is approx 2 miles downstream would there be any temperature drop
If the pipe is relatively well insulated, then the process follows that of a Fanno line.
It should be a fairly straight-forward heat-transfer problem. You'll need to figure out what your average or minimum ambient temperatures are- perhaps ASHRAE handbooks would have that info.
If this has any influence on the design (pressure and temperature changes) then i would recommend that you get a qualified person to look at it. Use an in-house expert or hire a consultant.
Your questions are very "basic". How will you document and QA any calculation based on what you can read here?