Liquid Nitrogen Wash

High-purity syngas preparation

For the production of low-carbon ammonia, preparing an inert-free syngas is a critical step. Raw hydrogen (typically sourced from an Amine Wash or Rectisol™ unit) and high-pressure nitrogen from an Air Separation Unit are fed into the Liquid Nitrogen Wash unit. Both of these streams are first cooled down against the outgoing product gas.

The raw hydrogen is fed to the bottom of the nitrogen wash column, while the condensed nitrogen liquid is introduced at the top. This cryogenic washing process safely and effectively removes trace impurities such as methane, argon, and carbon monoxide, which are then recycled as fuel gas. Finally, high-pressure nitrogen is added to the process stream to establish the exact stoichiometric N₂/H₂ ratio of 1:3 required for ammonia synthesis.

Unmatched scale and flexibility 

Designed to meet the demands of massive industrial applications, a single Liquid Nitrogen Wash unit can achieve a production capacity of up to 450,000 Nm³/h (4,000  tonnes per day) of pure ammonia synthesis gas.

Beyond syngas preparation, the technology offers excellent flexibility for generating valuable co-products. Depending on specific project requirements, the system can co-produce methane and LNG. This process is highly optimized, offering low specific energy consumption for methane and LNG co-production (requiring only 0 to 900 kWh/tonne of LNG). Furthermore, all our Cold Boxes are engineered to meet the highest safety standards in the industry.