Technological Secrets: How a Modern CO2​ Plant Ensures 99.9% Purity

Achieving high-purity carbon dioxide (99.9% and above) requires a complex multi-stage process that forms the core of any modern ${\text{CO}}_2$ plant. This recovery process transforms raw ${\text{CO}}_2$, obtained as a byproduct of fermentation, combustion, or chemical processes, into a final product suitable for even the most demanding industries, such as food manufacturing.

Step-by-Step Engineering Flow

The recovery process at a ${\text{CO}}_2$ plant is divided into several key stages:

1. Pre-Purification (Defoamer and Scrubber): The inlet gas first enters a defoamer, where liquid inclusions are removed. Following this, the scrubber (washing column) uses water and specialized nozzles to remove most soluble organic impurities and odors.

2. Compression and Cooling (Compressor): The purified gas is fed into a specialized oil-free piston compressor. This is critically important to prevent contamination of the ${\text{CO}}_2$ with lubricants. The gas is compressed to a pressure of 1.6-1.9 MPa, necessary for subsequent liquefaction.

3. Drying: To prevent the formation of ${\text{CO}}_2$ hydrates and equipment corrosion, the gas must be maximally dried. This starts with cold drying (reducing the temperature to 0-6 °C), after which the gas enters a deep dryer (adsorber) where the dew point is brought down to below $-60{}^{\circ }\text{C}$.

4. Deep Purification and Liquefaction: Final purification is key to achieving the 99.9% standard. The gas is liquefied in an evaporative ${\text{CO}}_2$ condenser. During liquefaction, non-condensable gases (such as ${\text{N}}_2$ and ${\text{O}}_2$) are vented, significantly boosting purity.

5. Distillation: The liquefied ${\text{CO}}_2$ is directed to a purification tower (distillation column) where mass exchange occurs. This stage eliminates the final volatile impurities, ensuring maximum product purity.

Every element in this chain (from the oil-free compressor to the cryogenic storage tank) is crucial, confirming that a modern ${\text{CO}}_2$ plant is a high-precision engineering complex.