Project ForgeProcess Calculations
Material Balance
GATE 2017
Hard
A salt solution (40wt%, 90°C) enters a crystallizer at 25°C, forming a pentahydrate crystal (anhydrous MW=135). Solubility at 25°C is 20wt%. The feed flowrate (kg/s) for a production rate of 100 kg/s of hydrated salt, rounded to nearest integer, is
200 kg/s(± 3 accepted)
Explanation
Pentahydrate MW=135+5×18=225. Anhydrous salt fraction in crystal=135/225=0.6, so crystal carries 100×0.6=60 kg/s salt. Overall salt balance: 0.4F=60+0.2(F−100) ⟹ 0.2F=40 ⟹ F=200 kg/s.
Source: GATE CH 2017 (2017)
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