The ConocoPhillips Optimized Cascade® Process is designed around a "two-train-in-one" reliability concept that has been successfully proven in more than four decades of plant operation. This schematic illustrates the basic features of the process.
Hovering over the different refrigerant systems provides a visualization of the operation of the system. Even when a compressor is off line, (clicking on the red button) the plant continues operating at a reduced rate. This feature results in high plant availability to maximize LNG production.
Natural gas is first treated to remove contaminants including CO2, water and mercury before entering the liquefaction section of the plant. The treated gas is then chilled to approximately –260 degrees Fahrenheit in successively colder heat exchangers that use propane, ethylene and methane as refrigerants. Product leaving the methane exchangers is LNG ready for storage.
The LNG product is then pumped into insulated storage tanks before being loaded on special ships to be transported to LNG import terminals around the world. Gases which continually boil out of the LNG as it warms slightly in the storage tank are captured and returned to the process to be re-liquefied. At the receiving terminals the LNG is transferred to storage tanks, re-gasified and shipped via pipeline to domestic users.