Carbon dioxide (CO2) has a bad reputation – especially in the natural gas business. Although this gas molecule generally occurs in low concentrations in gas reserves, developers need to remove it as quickly as possible. The reason is that a temperature drop below -57 degrees Celsius is all that is needed to convert pure CO₂ to solid dry ice, which settles in the processing plant and causes blockages. Operators usually avoid this problem with an upstream amine scrubbing step. At several million euros per plant, this chemical solution is extremely expensive, however. Now, Linde has developed and qualified an alternative solution to this problem –at no extra cost. Skipping the amine scrubbing step completely, Linde’s approach is based on a CO₂-tolerant gas processing flow.
In other words, concentrations of up to 0.5 percent of this otherwise problematic gas can now be tolerated in the natural gas stream without any risk of harmful solid deposits. The concept behind this new solution is ingeniously simple. The diluted CO₂ is maintained in a temperature range that is warm enough to prevent it from freezing. It may then remain within the final natural gas stream, where it is of no consequence in low concentrations. A Russian operator recently selected this innovative process technology for a plant currently under construction. Given the right configuration, Linde’s solution has the potential to benefit many other natural gas processing customers by eliminating the need for an entire process step.