Question

in general when would one purify a material prior to feeding it to a process unit? give at least one example for each case you state

Answer 1

Generally we purify the material prior to feeding it to process unit . There are many cases in which we cannot utilize materials without purification whether these are obtained from nature (for example, crude oil, Ore,) or prepared in the laboratory. Either Separation or purification by some method is necessary.

there are many examples

1. crude oil - the raw crude oil extracted from the oil wells can not be used directly because it contains many impurities such as high carbon chains compound and some elemental impurities that can harm our process operations. As a consequnce to prevent our process units from some undesirable hazards we first purify crude oils in different fracions.

example- Distillation of crude oil

2. Evaporation - In evaporation we can purify drinking water because we know that if we drink impure water that can cause many desease in human body.

example - Nacl formation from sea water

3. Screening- i will take one familiar example of wheat floor.

when wheat comes from grounds contains sand particles and some other materials. if we will not screen these materials then we will not get the desired quality of wheat floor. so we can understand that if we want to maintain quality, uniformity, similarity of product then we need to give feed also in pure form.