Product pipelines transport refined mineral oils such as gasoline, diesel fuel, and heating oil but also secondary products such as vaseline, paraffin, bitumen, petroleum coke, lamp oils, and lubricants from refineries to storage and distribution centers. Additionally, gases filtered out in the oil and natural gas production process (butane, ethane, propane) are transported in liquid aggregate state to refineries where they are separated again. As opposed to oil and gas pipelines, product pipelines do not solely transport one specific type of goods. Moreover, they serve to carry several different products consecutively or even simultaneously.