Amine regeneration towers are crucial in industries like natural gas processing and oil refining. They remove acidic gases, mainly carbon dioxide (CO2) and hydrogen sulfide (H2S), from gas streams using amine solvents. This article explains how these towers work, why they're essential, and what goes into their design.

1. What is Amine Gas Treatment?

Amine gas treatment uses amine solvents to absorb acidic gases. The sour gas, containing CO2 and H2S, is brought into contact with an amine solution. The amine reacts with the gases, forming water-soluble salts. Common amines include MEA, DEA, MDEA, and DIPA, and the choice depends on the specific gas mixture and desired removal level. The process has two main steps: Absorption, where the sour gas is processed in an absorber tower and the amine solution absorbs the acidic gases, resulting in a "sweet" gas, and the amine solution becomes "rich" in these gases; and Regeneration, where the rich amine solution is sent to the regenerator tower, and the absorbed gases are stripped out by heating the solution, and the amine solution is then cooled and reused.

2. How Does an Amine Regeneration Tower Work?

The amine regeneration tower removes absorbed acid gases from the rich amine solution to produce a reusable lean amine solution. A typical tower includes a vessel, internal components (packing or trays) to improve contact between liquid and vapor, a reboiler for heating, a condenser to cool overhead vapors, a reflux system to return condensed liquid, and piping for input and output. The regeneration process involves several steps: Rich amine enters the tower, and as it flows down, it contacts rising vapors from the reboiler. This heat releases the CO2 and H2S. The released gases and water vapor rise, while the amine solution flows down, now mostly stripped of the acid gases (lean amine). Overhead vapors go to a condenser, which cools them, and some of the condensed liquid is returned to the tower as reflux to improve separation. The remaining vapors, now rich in acid gases, are sent for further processing.

3. Designing an Amine Regeneration Tower

Careful design is essential for an efficient tower. Key factors include: The type and concentration of amine used affect regeneration temperature and energy use; operating pressure influences the boiling point of the amine solution and how easily gases are stripped; The temperature profile within the tower must be controlled for efficient regeneration; The internal design affects mass transfer, pressure drop, and tower capacity; Energy usage in the reboiler and the amount of reflux affect operating costs and separation efficiency; Materials must resist corrosion.

4. Introducing Phoenix Equipment Stock # 22177

We are offering an unused carbon steel amine regeneration tower, built by Chemetics. Approximately 91’ Tall x 13’ diameter lower section, 7’ diameter upper section. Rated 50 psig @650F. ASME coded. Estimated weight 93000 lbs. Never installed due to project cancellation and built 2013. Modifications may be necessary for your needs. Repurposing such a tower can be cost-effective, faster than buying new, and more sustainable.

Conclusion

Amine regeneration towers are crucial for removing acid gases in various industries. Their design and operation require careful consideration. Repurposing existing towers can be a valuable option.