University:
University of Cambridge
Course:
Chemical Engineering
Academic year:

2019
Views:

475

Pages:

17
Author:

Mikki L

INCLUDE THIS QUESTIONNAIRE TOGETHER WITH THE ANSWER SHEETS UPON UPLOADING IN THE PROVIDED SUBMISSION LINK, otherwise your papers will not be checked. Deadline for Submission is not later than Nov. 6, 2021 Sat. at 10:00PM. 1. It is desired to concentrate a sugar solution from 10% to 50% solids in a triple effect evaporator connected for Mixed Feeding (II-I-III). A vacuum of 660 mm Hg (vs a 762 mm barometer) is maintained in the third effect. Steam is available at 205 kPa. The evaporator area is 50 m². The feed enters at 21°C. Cp of the solution vary with concentration according to the following equation: Cp = 4.18-3.5x+2.17x2 (kJ/kgK), x is wt. fraction of the solution; BPR's are negligible. Heat transfer coefficients are 2840, 1990 and 1420 W/m²K for the first, second and third effects. Calculate the evaporator Evaporation rate. 2. A double effect evaporator system connected for backward feeding is used to concentrate a KOH solution from 20% to 40% solids. The feed enters at 25°C and steam at 180°C. The last effect is maintained at 54°C. Overall heat transfer coefficient is 3000 in the first effect and 1500 W/m²K in the second effect. The feed rate is 1500 kg/hr. Find the evaporator area. Assume Cp constant at 4.187 KJ/kgK for all solutions HONOR PLEDGE:

Design Probe (Hematra)

of 17

Description

Free up your schedule!

Take 5 seconds to unlock