A raw gas collection system for collecting raw gas from a plurality of aluminum smelting pots is equipped with a plurality of branch ducts (28d), each of which is arranged to channel a respective branch flow (38d) of raw gas from an aluminum smelting pot to a collection duct (26A), which is common to and shared by the branch ducts (28d). Each of said branch ducts (28d) is, near an outlet (52d) thereof, equipped with a curved section (50d) for aligning the branch flow (38d) with a flow direction of raw gas (27A) already present in the common collection duct (26A), and a constriction (54d) for accelerating the branch flow (38d) through the branch duct outlet (52d) into the common collection duct (26A). Furthermore, each of said branch ducts (28d) is equipped with a heat exchanger (40d) for removing heat from the respective branch flow (38d) of raw gas. The combined flow resistance of the constriction (54d) and the heat exchanger (40d) reduces the need for adjusting the respective branch flows (28d) using dampers, thereby reducing the power required to transport the raw gas.