1.The heat used to fire the kettle reboiler at the bottom of the distillation column comes from a furnace. The walls of the furnace are built of a 150 mm of refractory of thermal conductivity of. The surface temperatures of the inner and outer faces of the refractory are 1400 K and 540 K respectively. An engineer on your team reckons that installing a layer of insulation could bring about a 50% reduction in heat loss. The engineering manager is excited at this prospect, as this could result in a significant reduction in operational costs. She has asked you to do the relevant calculations (and show all workings clearly) to verify or otherwise this claim, before taking any decisions.
If a 25 mm thick layer of the insulation material being proposed has a thermal conductivity of, what temperatures will its surfaces attain if the inner surface of the furnace is to remain at 1400 K? What will be the percentage reduction in heat loss with the installation of the insulation? Write a report to the engineering manager, making your recommendations. The manufacturer manual for the insulation has the following coefficients of heat transfer from the outer surface of the insulation to the surroundings (at 290 K) at different temperatures in Table Q
A linear stretch of a piping system forming a by-pass of the main line is now under your responsibility. Consider the following fluids and recommended speeds (Table 1). Using acommercially available pipe diameter,determine the maximum flow the by-pass line is capable of withstanding, in m3/s. Consider the cases where water and chlorine flow through the commercially available pipe. Also, determine what type of flow is exhibited in both cases. What significance does this determination have on the system?
An important accessory of a pipeline, especially in the case of a main line served with a by-pass, is the safety valve / relief valve. With the discharge (water) from the last stage (Project Task 4) , you are now capable of dimensioning a relief valve.
In the above equation,
Avalveis the required orifice area [in2]
Qis the discharge [gallons per minute] – OBS: U.S. gallons
Padjis the adjustment pressure [psig] – pressure at which the valve starts to open
Pcountis the counter pressure [psig] – pressure at the discharge of the valve
SGis the specific gravity of the fluid
Dimensionthe valve for the by-pass line andchoosebetween a safety valve and relief valve, explaining the differences between both. The by-pass line follows the same pressure specification of the main line, represented by the 2D flowchart (Figure 4) of the pressure reduction station on the back. Replicate this flowchart in an A3 drawing (use a CAD software), representing the installation of the selected valve for the by-pass line.
Dimensioning a valve means to calculate, via equation 1, an orifice corresponding to an admission diameter and an output diameter, according to the API-RP 526 Standard, as indicated in Table 2:
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