Overall heat transfer co-efficient for cooling of hydrocarbons by water is about

ANS:C - 50 -100 BTU/hr. ft.²°F

The overall heat transfer coefficient for cooling hydrocarbons by water typically ranges from 50 - 100 BTU/hr. ft^2°F. Explanation:

• The overall heat transfer coefficient (U) represents the combined resistance to heat transfer across all interfaces involved in the process, including conduction within materials, convection at fluid-solid interfaces, and radiation if applicable.
• When cooling hydrocarbons (such as oil or petroleum products) with water, heat transfer occurs primarily through convection between the hydrocarbon and the cooling water.
• The units commonly used for the overall heat transfer coefficient include BTU/hr. ft^2°F, W/m^2°C, and Kcal/hr.m^2.°C. These units represent the rate of heat transfer per unit area per unit temperature difference between the two fluids.
• In the given options, the range of 50 - 100 BTU/hr. ft^2°F is consistent with typical values for overall heat transfer coefficients in such applications.