Petroleum gas

Petroleum gas is an in-game fluid used in refining and chemical processes. Like other fluids, Petroleum gas can be moved by pipes and pumps, but it can also be packaged into Barrels for long-distance transport or for places where laying Pipe is impractical. Barrels containing Petroleum gas behave as items that hold a fixed quantity of the fluid and can be carried, stored, loaded into trains, or put into chests and inventories.

Barrel handling is two-part: filling an Empty crude oil barrel with Petroleum gas produces a Petroleum gas-filled Barrel item, and emptying a Petroleum gas-filled Barrel returns the fluid Petroleum gas and an Empty crude oil barrel item. Filling and emptying barrels are handled by production buildings that process fluids into and out of barrel items; these operations consume the usual machine crafting time and energy. The Empty crude oil barrel itself is a craftable item and its availability depends on unlocking Fluid handling technology.

• Barrels allow transport of Petroleum gas where Pipe networks are inconvenient or impossible, for example when resource fields are distant from the main factory.
• Petroleum gas-filled Barrels can be moved by logistic means, loaded into trains, stacked in chests, and carried in a player’s inventory.
• Emptying a Petroleum gas-filled Barrel restores the fluid Petroleum gas back to the processing network and returns an Empty crude oil barrel item for reuse.
• The Empty crude oil barrel is obtained through crafting and is required to fill another Barrel; access to Fluid handling technology is required to produce or process barrels.

Practical use cases include collecting Petroleum gas at remote refining sites, shipping it to a central chemical plant, or temporarily storing surplus fluid as items when piping capacity is limited. Barrels are a flexible but lower-throughput alternative to continuous Pipe networks; use them for intermittent transfers, emergency supply runs, or when building Pipe infrastructure is not yet desirable.