Frequently Asked Questions

Can a co-flow absorber achieve 90%+ CO2 capture?

It is often thought that very high capture rates cannot be achieved using a co-flow design. There are three contributing factors to this misconception.

  1. As the gas flows down the column the concentration of the target component (i.e. CO2) reduces.
  2. As the solvent flows down the column it becomes more saturated. In combination with the first point, this reduces the driving force behind the absorption process.
  3. Because the absorption process releases energy, the solvent and gas temperatures increase progressively toward the bottom of the column. Because the solvent capacity is temperature dependent, this further contributes to a performance 'pinch' .
While all of these principles are true, they are offset by the extremely high performance of the system. For example the mixing of the gas and liquid phases allows for near perfect heat transfer between gas and liquid, reducing the impact of the third component. There are at least three system enhancements under consideration for development to further extend the upper capture limit if needed. If you would like to discuss a specific application, please contact us.

What Liquid/Gas ratios would the RFC typically support?

Unlike structured- or random-packing systems, the RFC is much less prone to flooding. The L/G ratio by mass, while dependent on fluid properties (density, surface tension and viscosity), a typical range would be from 3 to more than 7 (monoethanolamine data). However, for specific applications ICSI recommends you contact us directly.

What are the materials of construction?

The 'packing' is currently manufactured from woven 304 stainless steel mesh. This is independent of the materials or linings used in the absorber column shell. ICSI is discussing alternate materials for specific applications

What about sub-micron particle scrubbing?

The original Aqueous-Froth-Air (AFA) filter from which the RFC technology was developed was targeted at 99.999% capture of viruses, with particle sizes below 1 micron. Efficacy at sub-micron particle sizes will be determined by the RFC in combination with solvent characteristics and temperature control within the contactor column. Interested in sub-micron particle solutions? Contact us to discuss your specific requirements.

What about back-pressure?

Research into pulse-mode operation of reactors in the 1970's and 1980's indicated very high back pressures. This is one of the key innovations of the RFC work. The current version of the RFC packing is thirty to fifty times lower than described in the literature. Within the past year back-pressure has been further reduced to aproximately double that of a conventional counter-flow absorber per meter of contactor bed. However, requiring less than half the bed height results in equivalent system pressure drop in the RFC as for structured packing systems. Want to discuss a specific application? Reach out to our applications team.

What about Natural Gas sweetening (H2S or CO2 removal)?

While this is an interesting application for the RFC technology, an integrated system has not been developed to date. Conditions that would make this application worth exploring further include: - a compelling reason to reduce the size of the absorber (mobile applications?) - a compelling reason to reduce the column height (marine applications?) - a need for a simple 'roughing' stage that would remove bulk quantities of contaminant (but may not drive down to pipeline spec residual levels in a single stage) - a persistent fouling issue In most cases, the size of the absorption column and cost savings associated with size reduction or reduction of packing material are small with respect to the overall equipment cost, and with respect to the incremental engineering cost associated with a substantial redesign. This would make application of the RFC technology in these areas unattractive for one-of cases. If you are a systems integrator seeking to develop a series of standardized skids for this application, please contact us to explore further.

Can the RFC be used for odor control?

While this application has not been developed, this may be an excellent application for the the Regenerative Froth Technology. Our earlier AFA technology developed for the Office of Navy Research for extreme hazardous gases and sub-micron particles demonstrated excellent performance. Extraordinary levels of contact surface between gas and liquid in a very small space may lead to compelling performance. We would welcome an opportunity to work with a strategic partner with deep application insight. If you would like to discuss development of this application, please contact us.