1. The document describes a single effect evaporator used to concentrate a sodium chloride solution. It discusses the components, heat and mass balances, and factors that affect evaporation rates. 2. An example problem is presented to calculate the steam consumption, economy, and heating surface area required for a specific evaporator concentrating a sodium chloride solution from 5% to 20% solids. 3. The calculations involve setting up heat and mass balances to determine stream flow rates and energies, then using the known heat transfer rate and temperature differences to calculate the required heating surface area.