For industrial applications, Carbon Dioxide (CO2) is primarily produced through a sophisticated process often involving the capture and purification of CO2 from flue gases, a common byproduct of combustion processes. This method ensures a consistent supply of high-purity CO2 essential for various industrial needs.
The process of obtaining industrial-grade CO2 from flue gas involves several key stages, focusing on absorption, release, compression, and purification.
The CO2 Production Process from Flue Gas
The production of CO2 for industrial use, particularly from combustion flue gases, is a multi-step process designed to isolate and purify the gas.
1. Flue Gas Pre-treatment and Scrubbing
Before CO2 can be effectively captured, the raw flue gas, which contains various impurities from combustion, must be cleaned. This initial stage removes particulates and other contaminants that could interfere with subsequent processes.
- Method: The flue gas first undergoes scrubbing using agents like water or soda ash. This step is crucial for removing undesirable components, preparing the gas for CO2 absorption.
2. CO2 Absorption
After initial scrubbing, the cleaned flue gas is directed to an absorption unit where the CO2 is selectively captured.
- Process: The CO2 from the flue gas is absorbed into a specialized solution. This solution is designed to have a high affinity for CO2, allowing it to "soak up" the carbon dioxide while other gases pass through.
3. CO2 Release (Desorption)
Once the absorption solution is saturated with CO2, the gas needs to be released from the solution for collection.
- Mechanism: The solution containing the absorbed CO2 is heated. This heating, often powered by the very combustion process that generated the flue gas, causes the CO2 to be released as a raw gas. This step regenerates the absorption solution for reuse, making the process efficient.
4. Compression
The raw CO2 gas, now separated from the absorption solution, is still at a relatively low pressure and needs to be compressed to prepare it for further purification and industrial application.
- Equipment: The CO2 obtained is led to a vertical, two-stage, dry-running (Oil-Free) compressor. The "dry-running" and "oil-free" nature of the compressor is critical to prevent contamination of the CO2 with lubricants, ensuring high purity. This compression increases the gas's density and pressure, making it suitable for storage and transport.
5. Purification
Even after compression, the raw CO2 may contain trace impurities that need to be removed to meet stringent industrial purity standards.
- Method: The compressed CO2 is then directed to a high-pressure potassium permanganate purifier. Potassium permanganate is a strong oxidizing agent used to remove specific undesirable compounds, ensuring the final CO2 product is of the required purity for applications in various industries, from food and beverage to chemical manufacturing and medical uses.
The following table summarizes the key stages in industrial CO2 production from flue gas:
| Stage | Description | Key Process/Equipment |
|---|---|---|
| 1. Flue Gas Scrubbing | Removal of impurities (particulates, other gases) from raw combustion flue gas. | Water/soda ash scrubbing |
| 2. CO2 Absorption | Selective capture of CO2 from the pre-treated flue gas into a chemical solution. | Specialized absorption solution |
| 3. CO2 Release | Heating the CO2-rich solution to release the raw CO2 gas, regenerating the absorption solution. | Heating by the combustion process |
| 4. Compression | Increasing the pressure and density of the raw CO2 gas for easier handling and further processing. | Vertical, two-stage, dry-running (Oil-Free) compressor |
| 5. Purification | Final removal of trace impurities to achieve industrial-grade purity standards. | High-pressure potassium permanganate purifier |
This structured approach ensures that the CO2 produced is highly pure and suitable for a wide range of industrial applications, contributing to various manufacturing processes, carbonation of beverages, and even medical uses.
