Which pump is commonly used to transport flammable gases in liquid form such as LPG and LNG?

The appropriate choice for transporting flammable gases in liquid form, such as Liquefied Petroleum Gas (LPG) and Liquefied Natural Gas (LNG), is a positive displacement pump. This type of pump works by trapping a fixed amount of liquid and then forcing it into the discharge pipeline.

Positive displacement pumps are particularly suited for handling liquids with varying viscosities and are capable of moving liquids at a consistent and predictable flow rate under pressure. This characteristic makes them effective for transporting LPG and LNG, which can be flammable and require careful handling to ensure safety and efficiency in systems.

In contrast, diaphragm pumps, peripheral pumps, and centrifugal pumps have limitations regarding the type of liquids they can effectively move, especially concerning the specific characteristics of flammable gases in liquid form. Centrifugal pumps, for example, are typically more efficient for moving less viscous fluids but can experience issues with cavitation when handling certain liquids under varying pressure conditions. Thus, while these other options may have their own applications, positive displacement pumps are specifically designed to manage the safe transportation of flammable liquids like LPG and LNG.