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Hi all, I'm afraid this question is more of a question about what questions to ask as we have an issue on site which I am not really involved with, yet I feel we maybe missing something. My understanding of the system is that we have a process stream of steam fed from a crystaliser and topped...

Thanks for the info, very usefull. I really should have paid more attention in fluid mechanics!

I'm sure this has been covered in a million other threads but I'm looking for some typical values for the heat tranfer co-efficient for air. 1) In the case of indoor air at ambient temp with little circulation. 2) Outdoor process unit exposed to wind and so on. Thanks, James

The shell temp is higher than predicted from commisioning. We are trying a different liner than we usually use with a higher thermal conductivity. The observed temperature is 320°C for the new liner whereas the supplier predicts 250 and my calcualtions predict 260 - 276°C depending on...

The supplier has assumed a figure of 1300°C as a worst case scenario. The temperature at which we tap our metal is 1050 - 1150°C (measured by dip thermocouple). I assume that this is the interior wall temperature in my calculations.

I have now calculated a figure for the temperature of the shell following the procedures described above. For an emmisivity of 0.94 and a h value of 2.5, I come to a shell temp of 260°C if the inside temperature is 1300 as in the suppliers assumption, the supplier calcualted 250. Our...

Ione, no offence taken, I am always just wary that I am wasting people's time by asking for solutions to problems that are simple. I thing I understand the iterative approach now. Thank you all for your contributions.

Please forgive me if I'm not understanding something simple here? I have had a good look at the attached paper, thanks for that, but does it not require an outside wall temperature for the equation for the heat dissipated from the outside surface?

They have stated in their emails that the calculation is based on steady state, but they have not provided details of the calcuation. The temperature we are observing is higher than they predict. I expected this as the new liner has a higher conductivity (lower resistance) than the previous...

I have a rotary furnace with a new lining (270mm brick, 70 mm brick, 10mm insulation board and 15mm steel liner. The supplier has given us some figures on what the shell temp should be at our tapping temp, 1300°C. I am trying to work out how they have calcualted the shell temp as our...

thank you that has cleared my blank mind which was clearly the problem.

I think I am just having a mind blank here so apologies if this is simple! I have two gas streams mixing (flue gas and air). I know the flow rate of the combined stream, I also know the temperature of all three streams and can calculate the combined Cp. I need to know the flow rates of the...

The burner runs on pure O2, we have no reason to suspect that the control system for the burner ratio is not controlling properly. The furnace is used for reduction of metal oxides which is where a significant proportion of the CO is coming from. It is possible to control the CO level by...

Thanks for that, hadn't considered NOx. Not sure that NOx would be a problem in this case as we are way off our limits for NOx at the moment and the burner runs pure O2 so not much present immediately downstream of furnace. The only air ingress happens on charging furnace when the door is...

I have been asked to investigate meands of reducing the CO level in flue gas from our rotary furnace. The options we are looking into are: Provision of a controlled excess of O2 to the burner nozzle (Simplest option but concerns over product quality) Installation of afterburner in exhaust...