What is boiling point elevation and why is it important in evaporator design?

Boiling point elevation (BPE) is the increase in boiling point of a solution compared to pure solvent at the same pressure, caused by dissolved solutes lowering the solvent's vapor pressure. BPE increases with concentration and varies with solute type. It is critical in evaporator design because it reduces the effective temperature driving force (reduces dT available), requires higher steam temperatures or more evaporator effects, and must be accounted for in energy and area calculations.