Question

What are the two major reasons for difference in material in and out flow values in the crude (petroleum) distillation unit? Please computer writing, a clear answer to the exact requirement.

We have this example, and the question below is required to solve it according to the results of the example. I have attached the reason but I want exactly the two main reasons.
Example

Question

The answer but I want 2 main reasons

Answer 1

1. using mass balance :If we see products from off gas (SG 0.635) to heavy diesel (SG 0.854) in the table we find (50.03/101.3=.4937) roughly 49.33 % volume contribution of these products involved in total volume.If we multiply volume of these products to their respective specific gravity (1.33*.635+7.27*.680+.........+6.99*.854 = 40) then we find mass contribution is only 40% of total amount. due to this specific gravity of lighter products we get more volume of refinery products.

2.The total volume of products refineries produce(output) is greater than volume of crude oil (input) because most of the products we make have lesser density than crude we processes on average US refineries produces 44.69 US gallon of refinery products after processing 42 US gallon of Crude.We can also say that number of refinery off gas (LNG, methane, etc) or straight run naphtha have very low specific gravity (SG 0.635 and SG 0.685respectively) also contribute in volume of refinery products which lower than crude SG 0.8685