High-Gravity Rotating Bed Technology: The Amine-Loop CCUS Process Advancing Toward a New Generation of High Efficiency

To achieve the net zero emissions by 2050 target, Carbon Capture, Utilization and Storage (CCUS) technology has become a global key to carbon reduction. To address the shortcomings of the traditional amine chemical absorption method, notably the large size of absorption towers and their tendency to clog, ECOVE has innovatively introduced the High-Gravity Rotating Bed (HiGee) technology. By deploying innovative equipment and establishing a pilot plant, ECOVE seeks to develop carbon-reduction solutions that are more flexible, efficient, and space-saving.

Implementation of High-Gravity Rotating Beds for Efficient and Flexible Carbon Reduction

Among CCUS technologies, Amine Chemical Absorption is the most mature post-combustion capture CCUS technology due to its rapid reaction rate and high selectivity. It has been successfully deployed at numerous large power plants and industrial facilities worldwide—for example, Boundary Dam coal-fired power plant in Canada and Petra Nova coal-fired power plant in the United States—demonstrating its reliability in capturing carbon dioxide (CO₂) from flue gas. However, conventional amine technologies typically employed an absorption tower configuration, which was bulky and generally very tall. For existing plants with limited space, integrating such large structures poses significant challenges.

To overcome this bottleneck, ECOVE proactively implemented a compact technology centered on the High-Gravity Rotating Bed (HiGee). We have completed a pilot plant within the facility's existing space and begun validating the process operating boundaries, including the operating windows for  absorption and regeneration, amine circulation stability, and the effects of rotational speed and liquid-gas (L/G) ratio. These tests will help confirm key engineering design parameters—such as the equipment’s operable range during long-term operation, its response to flue gas fluctuations, and its behavior under field conditions—in order to develop models that will serve as important foundation engineering data for future deployment at Energy from Waste plants and various industrial emissions sources.

Traditional Tall Tower vs. High-Gravity Rotating Bed

Traditional amine absorption towers rely on gravity to maintain gas-liquid contact efficiency through tower height, packing, and liquid membrane distribution. Such configurations commonly faced large equipment footprints and high spatial requirements, and were susceptible to clogging and increased pressure drop caused by flue gas particulates or viscous amine solutions, which increased maintenance difficulty.

In contrast, the high-gravity rotating bed used centrifugal force generated by high-speed rotation to intensify gas-liquid contact, thereby increasing mass transfer rates; as a result, it could complete the same capture tasks within a much smaller footprint and became a more field-deployable alternative to conventional absorption towers. The primary differences between the two are shown in the table below.

Comparison of Traditional Amine Absorption Towers and High-Gravity Rotating Bed

Why ECOVE Adopted the RZB (Rotating Zigzag Bed)?

High-gravity rotating beds were commonly available in two forms: The Rotating Packed Bed (RPB) and the Rotating Zigzag Bed (RZB). Although the RPB had high theoretical efficiency, it often clogs under actual flue-gas conditions, caused by dust or high liquid viscosity.

ECOVE adopted RZB in consideration of maintenance requirements for long-term operational stability. Advantages include:

1. Anti-clogging capability: The zigzag channels have no fine pores and is not affected by dust or high-viscosity liquids.
2. Stable mass transfer: The flow-directing effect of the zigzag produces a uniform distribution of the liquid membrane.
3. Suitable for continuous operation: Low pressure drop and smooth performance.
4. Ease of maintenance: Simple to clean and maintain, leading to higher user acceptance.

Operational Mechanism of Modularized Carbon Capture

The high-gravity amine carbon capture system is primarily composed of an absorption section, a regeneration section, and a condensation section, forming a single closed loop to maintain stable operation:

1. Absorption section: After cooling and dust removal, the flue gas enters the high-gravity absorption unit and contacts the lean amine, forming rich amine solution.
2. Regeneration section: The rich amine is heated to release CO₂ and converted back to lean amine suitable for reuse.
3. Condensation section: Moisture and amine mist are removed from the regenerated gas to obtain high-purity CO₂.

High-Gravity Amine-Loop Carbon Capture System

To maximize performance of the high-gravity rotating bed, a balance must be achieved among several parameters:

1. Amine selection: Monoethanolamine (MEA) has the advantages of a fast absorption rate and predictable reaction, but it is prone to oxidative degradation and requires relatively high regeneration energy consumption. Commercial-scale applications typically employ blended amines (such as MDEA and PZ+MEA) to enhance the stability of amine and reduce the energy required for solvent regeneration.
2. Adjustment of the liquid-gas ratio (L/G): An L/G that is too low caused absorption efficiency to decline, whereas an L/G that is too high increased pump load. It was necessary to strike a balance between reaction efficiency and equipment load to form a stable membrane or droplets, thereby ensuring thorough reaction.
3. Rotational speed adjustment: When the rotational speed is too low, an adequate membrane could not be formed. It is necessary to adjust the rotational speed in coordination with the liquid-gas ratio so that the flow regime reaches optimal high-gravity conditions.
4. Absorption temperature control: The operating temperature was maintained at approximately 40°C. Excessively high temperature led to reduced absorption efficiency.
5. Regeneration temperature setting: The regeneration temperature was directly proportional to CO₂ desorption effectiveness and to energy consumption; excessively high temperatures accelerated amine degradation, so an optimal balance had to be achieved.

Develop an Integrated Low-Carbon Solution

High-gravity rotating-bed technology not only improves mass transfer efficiency and reduces equipment footprint, but also helps advance carbon management technologies into a new stage. Through a modular, highly stable, and easily integrable design, the technology is more readily introduced into Energy from Waste plants, boilers, and other existing industrial facilities, becoming a practically applicable carbon-reduction tool.
	
At present, ECOVE's pilot plant is actively collecting long-term operational data; these experiences will help establish more precise process models. In the future, by linking carbon capture, management, and reclamation, ECOVE aims to provide an integrated low-carbon solution spanning from the emissions end to the reuse end. It will assist industries in reducing carbon emissions while converting captured CO₂ into valuable resources, achieving a win-win for the environment and the economy, and continue to deliver more resilient, sustainable carbon-reduction technologies in operational plants.