Question

A feed of 4535 kg/h of a 2.0 wt % salt solution at 311 k enters continuously a single-effect evaporator and is being concentrateq to 3.0%. the evaporation is at atmospheric pressure and the area of the evaporator is 69.7 m 2. sattirated steam at 383.2 k is supplied for heating. since the solution is dilute, it can be assumed to have the same boiling point as water. the heat capacity of the feed can be taken ascp = kjjkg' k. calculate the amounts of vapor and liquid product and the overall heat-transfer coefficient u.

Answer 1

The student is tasked with calculating the vapor and liquid product amounts and the overall heat-transfer coefficient for an evaporator process, but vital data for this are missing. An in-depth understanding of mass and energy balance principles is needed to perform these calculations in engineering.

Step-by-step explanation:

The student's question relates to the calculation of quantities and an overall heat-transfer coefficient for a single-effect evaporator used in concentrating a salt solution. To find the amounts of vapor and liquid product, we need to use mass balance and energy balance equations. However, the necessary specific data such as latent heat of vaporization, specific heat capacity, and the initial and final temperatures are not provided. These values are essential for calculating the overall heat transfer from the steam to the solution and for determining the heat-transfer coefficient (U).

Additionally, one might utilize the data provided in example calculations involving latent heat of vaporization of water and specific heat capacities in different contexts to solve similar problems. An understanding of these concepts is crucial for engineering students dealing with unit operations like evaporation.