Author: bomuo

Cryogenic processes capitalize on the fact that methane and nitrogen change phase (from gas to liquid) at different temperatures. By manipulating and controlling the pressures and temperatures in the system, the methane is liquefied and collected as it drops out of the gas. The gas is then re-vaporized, yielding a sales stream with nitrogen levels that conform to pipeline quality standards. The excess nitrogen is either flared or vented to the atmosphere. Because of the temperatures involved (-240 to -250 degrees), the long cool down time and extensive equipment required, cryogenic systems are most often used for large projects where processing volumes exceed five million cubic feet per day and in those instances where nitrogen levels range from 30% to 40% or higher. The low temperatures allow the plant to recover over 90% of the ethane in the natural gas. Most new gas processing plants use cryogenic recovery technology.

An LNG plant is highly energy-intensive and refrigeration section is the main consumer of energy. The operational flexibility and efficiency of the refrigeration section are critical to the overall efficiency of the LNG plant. Main cryogenic heat exchanger or MCHE is the heart of the refrigeration section and is the most important heat-transfer equipment in a base-load LNG plant. It cools and liquefies natural gas to –162 C. For process optimization, we need to look from an integrated point of view and MCHE is one of the most critical equipment in LNG process.

Refers to low temperature and low temperature technology. There is no precise temperature for an upper boundary but -100 degrees C is often used