What will be the cost of bio gas contained in 40 cubic meter plant to change into LP gas ?

Question

We are planning to build a plant which can covert bio-gas into LP gas that has the capacity of 140 Kg of LP gas per day.

Answer 1

You cannot convert bio gas to LP.  Bio gas is methane CH4.  LP is Liquefied Petroleum Gas and is either Propane or a Propane Butane Mixture  C3H8 or C4H10.

If you wanted to liquefy the Methane, that would be called LNG, liquefied Natural Gas.  The cost would be in the millions of dollars and you would consume 20% of the bio gas in energy to liquefy it.