Question 64

The Correct Answer is D **Explanation for Option D (637.42°F):** The superheater outlet temperature is calculated by adding the given temperature elevation (the degree of superheat) to the saturation temperature of the steam at the given pressure. 1. **Find the Saturation Temperature ($T_{sat}$):** According to the steam tables (specifically Illustration SG-0004) for steam at 400 psia (absolute pressure), the saturation temperature is $444.59^\circ\text{F}$. 2. **Determine the Temperature Elevation ($\Delta T$):** The steam is elevated by $192.83^\circ\text{F}$. 3. **Calculate the Superheater Outlet Temperature ($T_{out}$):** $$T_{out} = T_{sat} + \Delta T$$ $$T_{out} = 444.59^\circ\text{F} + 192.83^\circ\text{F}$$ $$T_{out} = 637.42^\circ\text{F}$$ Therefore, the superheater outlet temperature is $637.42^\circ\text{F}$. **Explanation of Incorrect Options:** * **A) 192.83°F:** This is the temperature *elevation* (degree of superheat) only. It does not account for the initial saturation temperature of the steam. * **B) 247.31°F:** This value is likely the result of an incorrect calculation, possibly subtracting the temperature elevation from the saturation temperature ($444.59^\circ\text{F} - 192.83^\circ\text{F}$), or using an incorrect saturation temperature (such as 212°F used for standard atmospheric pressure). * **C) 444.59°F:** This is the saturation temperature of the steam at 400 psia. This would be the temperature of the steam *before* it enters the superheater, or if it were still saturated, not the final superheated outlet temperature.