Pump Start-up and steady state heat transfer model 1

[19omalley90]

Hi everyone,

I am trying to model the start-up and steady state heat transfer for a steam jacketed pump which is used to pump bitumen.

The bitumen is solid in the pump and the steam enters the jackets and heats up the bitumen via conduction. This makes it more complicated because the temperature difference changes as the bitumen heats up.

What needs to be considered is the heat transfer into the bitumen from the steam jackets, the heat loss from the bitumen to the atmosphere and the composite heat transfer coefficients for the system including steam side, potential steam side fouling and the shell.

I'm not really sure where to start and was looking for some help.

If anyone is able to help I would really appreciate it, I can provide any information should it be required.

Thanks!

 

[racookpe1978]

"If anyone is able to help I would really appreciate it, I can provide any information should it be required."

Many people "can" help.
No one "can help" (nor will help!) if YOU do not provide any information.

And "you" have provided none. No masses (pump, pipe, weight of bitumen). Nothing.
No initial temps. No final temps.
Pump insulation values or thicknesses?
Temperature of steam? State of steam at inlet and exhaust?
Size of pump? Length of adjacent pipes (also filled with solid bitumen?)

Tell you what. Why don't "you" look up all of the variables and equations and parameters are relevant to "your" problem and then let us know what parts you don't understand. The process of looking up things (like the thermal mass of your pump and the specific heat of bitumen (solid and molten) and the heat of melting of your particular "flavor" of bitumen and the mass of your bitumen inside your pump and your pipes will start you on your process of education.

Then, when "you" have shown us what part of your problem you don't understand and cannot get from your boss and your company's knowledge, we can work on the remainder ... with, no doubt, much more civility that this rather curt response.

 

[MortenA]

just one question from me: How will you solvw a start-up case (a trancient situation) as a steady state problem? IMO thats a contraindication.

Best regards

Morten

 

[19omalley90]

I get the feeling that I may have offended Mr. Racookpe1978, I apologise for being vague.

I don't want YOU to do it for me, I want to do it myself and all I am asking for is some help as to where to begin and what I need to consider (apart from what I mentioned).

I haven't really dealt with heat transfer models before so this is new to me and I would really appreciate some pointers and tips to get me started.

I think that somewhere in the torrent of abuse that came from racookpe1978 I have some info to find which is helpful.

Thank you very much for your prompt response!

 

[racookpe1978]

OK. But I hope you will learn "what to ask" under such circumstances. 8<)

See, what I asked for is what YOU need to know to begin. And we, unfortunately, cannot help until we know those same things.

Your problem breaks down into a heatup (transient) and a steady state problem. Solve them separately.

You have to heat up a large mass of steel (the pump) and steel (inlet pipe) and steel (outlet pipe) each of a different weight and a different shape. Each will contain a large masses of solid bitumen, which has to heat up from ambient to the melting temperature, through the melting phase change, into a liquid state. (Once liquid, the steady state problem begins. )

To heat up these six different masses with three different heat jackets, each with steam from a common (?) steam line of unknown temperature and pressure - thus an unknown (to us!) amount of available heat energy and differential temperature between inlet steam and outlet steam, inlet steam temperature and beginning bitumen + steel temperature.

Start with the two pipes: Area? Mass of steel, mass of bitumen, temperature of inlet steam, outlet steam/condensate, etc. BEGIN your problem by solving the pipe problem. Use those equations and those assumptions to start your pump problem.

Start with the basics: write your equation for heating the steel pipe (mass, temp at start, temp at final, heat capacity of steel, area exposed, heat available fro the steam enthalpy1 - enthalpy 2), etc) heatup with the steam. Make some assumptions YOU can change in your spreadsheet as data becomes available: (talk to your boss!!!) about what steam flow is available/should be assumed/can be bought/what minimum time is required to be used for heatup/etc.

 

[willard3]

I'm with Mr Cook here.

You pose a question with no data and expect, miraculously, that some answer to a complicated heat transfer problem will spring fully-formed from the head of Zeus. Engineering doesn't work like that......you are going to have to put in the effort to at least frame the problem so it can be understood by Engineers.

If you don't know any heat transfer, I suggest you take a course or hire somebody who does. Thermodynamics and heat transfer are not simple.

 

[MortenA]

@19omalley90, going back to you original post - as others also stated: What you have is not a SS problem but a tracient one. This can be solved in different ways. In some cases you may be able to solve it analytically (you will venture into the dark realm of differentioal equations) perhaps by nomogarms (som old dues solved the equations and put them into nomograms) - if you are lucky and you system looks like the original. It may also be solved using e.g. excel and consideing the system as discreete timesteps, solve the heat transfer problems as SS for each timestep, update system parameter (temperatures) and then progress to next timestep etc. In all cases you need to establish your system model. Maybe you case is too much for this type of forum? Try to see if there are people in your organisation that could help you or geta consultant?

Best regards

Morten