Question

Dry salt is to be produced at a rate of 20000 kg/h by evaporating water from a feed containing 20% nacl. the brine (27% nacl) leaving the evaporator may either be recycled to the evaporator or may be discarded. if the brine produced is 25% of the weight of dry salt, calculate:

the feed rate if the brine is recycled

Answer 1

To calculate the feed rate when the brine is recycled, we need to determine the amount of salt in the brine leaving the evaporator.

Step-by-step explanation:

The weight of the brine can be calculated by multiplying the dry salt rate by the brine's weight percentage. The amount of salt in the brine can then be calculated by multiplying the weight of the brine by the salt's weight percentage. The feed rate when the brine is recycled is the sum of the dry salt rate and the salt in brine rate.

To calculate the feed rate when the brine is recycled, we need to determine the amount of salt in the brine leaving the evaporator. Given that the brine is 25% of the weight of dry salt, and the dry salt is produced at a rate of 20,000 kg/h, we can calculate the weight of the brine as follows:

Weight of brine = 25% * 20,000 kg/h = 5,000 kg/h

Next, we need to determine the amount of salt in the brine leaving the evaporator. The brine is 27% NaCl, so the weight of salt in the brine is:

Weight of salt in brine = 27% * 5,000 kg/h = 1,350 kg/h

Finally, we can calculate the feed rate when the brine is recycled:

Feed rate = Dry salt rate + Salt in brine rate = 20,000 kg/h + 1,350 kg/h = 21,350 kg/h