## Compressibility Factor / Z Factor

Compressibility factor of gases is a thermodynamic property which is used to modify the ideal gas equation for real gases.

Ideal gas equation states,

PV = nRT

This ideal gas equation is modified for real gases as,

PV = ZnRT, here Z is the compressibility factor for the given gas.

The compressibility of a gas depends on the particular gas as well as temperature and pressure conditions.

## Calculating compressibility factor for natural gas

Compressibility charts available in literature are commonly used for calculation of compressibility factor / Z factor. These charts express compressibility values as a function of reduced temperature and reduced pressure. For example, this compressibility factor table for air.

Reduced temperature, T_{r} = T / T_{c}

Reduced pressure, P_{r} = P / P_{c}

where T_{c} and P_{c} are critical temperature and pressure values respectively.

Compressibility charts are based on empirical findings. For natural gas, compressibility factor depends on - temperature & pressure conditions, composition of the gas in terms of N_{2}, CO_{2} and H_{2}S content.

This calculator helps in calculation of the compressibility factor for a natural gas based on Brill and Beggs Z factor correlation.