Natural gas purification plants must remove co2 because the methane is heading for a liquefied natural gas tanker and must be kept free of cold , solid carbon dioxide ( dry ice ) that could clog the system or because the co2 concentration is too high ( above 3 percent ) to be allowed on the natural gas distribution grid 天然氣純化廠中,由于甲烷要導(dǎo)入液化天然氣槽,必須嚴防冰冷堅硬的二氧化碳(乾冰)可能堵塞系統(tǒng),或二氧化碳濃度過高(超過3 % )導(dǎo)致無法用于天然氣供配網(wǎng),因此必須脫去二氧化碳。