问答题 翻译：As more and more ethane and propane are extracted form natural gas, the control of the But or heating content of gas becomes mere important.

问答题 翻译：In other countries products pipelines may move refined products from coustal refinery or tanker unloading terminals to the interior of the country to supply populated areas.

问答题 翻译：Products pipeline can often carry serveral different products in the same pipeline.