2500 Fuel Capacity
The item id for Frost Gas Large in unturned is 36078. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Useable: Fuel
Size_X: 2
Size_Y: 2
Size_Z: 0.595
Fuel: 2500
Blueprints: 1
Blueprint_0_Type: Tool
Blueprint_0_Supplies: 1
Blueprint_0_Supply_0_ID: 36077
Blueprint_0_Supply_0_Amount: 5
Blueprint_0_Level: 1
Blueprint_0_Skill: Craft
Blueprint_0_Build: 27
Use_Auto_Icon_Measurements: False