$1700$ barrels per hour of $30\frac{A}{P}$I crude oil is cooled from $180F$ to $140F$ in a counterflow shell and tube heat exchanger with $550,000l\frac{b}{h}r$ of $60\%$MEG$-40\%H_{2}O$ cooling medium. The cooling medium enters the exchanger at $100F.$ The heat capacity of the oil is $0\mathrm{.}505\frac{\text{B}\text{t}\text{u}}{lbmF}$ and the heat capacity of the cooling medium is $0\mathrm{.}762\frac{\text{B}\text{t}\text{u}}{lbmF}.$ The overall heat transfer coefficient is $58\mathrm{.}2\frac{\text{B}\text{t}\text{u}}{hf{t}^{2}F}.$ Crude oil is in the tube side of the heat exchanger.

a$)$ Calculate the exchanger heat transfer rate, the temperature of the cooling medium leaving the exchanger, and the exchanger surface area.

b$)$ Select a suitable shell and tube configuration for this service and calculate the mean temperature difference in the exchanger.

The mixing ratio of water and antifreeze should lie between $60$:$40$ and $50$:$50.$ This usually corresponds to antifreeze protection from $-25C$ to $-40C.$ The minimal mixing ratio should be $70$:$30$ and the maximal $40$:$60.$ Further increasing the proportion of antifreeze $($e$.$g$.30$:$70)$ does not lower the freezing point any further.