Direct Air Capture (DAC) research demands precise and flexible temperature control to accurately assess adsorbent performance. Avantium R&D Solutions supports these needs by delivering custom-made solutions integrated into its Direct Air Capture Breakthrough Analyzers. These configurations enable researchers to optimize cycle times, improve data quality, and maximize effective equipment usage.

Below, we outline three temperature control approaches and demonstrate how rapid temperature cycling can substantially improve experimental efficiency.

Option A – Temperature-controlled oven

Four analyzer columns are housed inside a precision temperature-controlled oven.

Best for: experiments requiring excellent temperature accuracy and long-term stability.

• Adsorption temperatures as low as –10 °C (±0 .1 °C)
• Desorption temperatures up to 110 °C (±0.1 °C)
• Controlled ramp rates of 1 °C/min

Option B – Oven with additional internal heaters

This configuration builds on Option A by adding internal heaters for increased heating capacity.

Best for: higher desorption temperatures while maintaining good temperature control.

• Desorption temperatures up to 200 °C
• Faster heating rates up to 5 °C/min
• Slightly reduced accuracy above 110 °C

Option C – Proprietary rapid-cycling heating block

A dedicated heating block designed specifically for fast adsorption–desorption cycling in DAC applications.

Best for: maximizing throughput and minimizing non-productive time.

• Heating rates up to 30 °C/min
• Cooling rates up to 25 °C/min
• Rapid and repeatable thermal cycling between process steps

The selection of the most appropriate heating solution is highly dependent on the needs of the customer. When the main interest is long term stability, a run typically consists consecutively measuring a large numbers of cycles. Minimizing the time lost during temperature ramping can have a significant impact on the effective use of the equipment.

Desorption methods

An alternative reasoning to consider can be an interest in the modes and methods of desorption.

In the figure below a desorption curve of two typical amine-functionalized resins are shown. For both materials more than 98% of the desorbed CO₂ is removed before the dwell temperature is reached. If one is interested in desorption though for example displacement with steam, faster heating rates are preferred in order to achieve the desorption temperature before full desorption has been achieved. Conversely, at higher ramp rates the difference in onset temperature of the desorption curves of these materials cannot be determined. Also note the shoulder at low temperatures for adsorbent A, already showing significant desorption at room temperature, while the main peak of the same material exhibits an onset temperature of about 32 °C, indicating the presence of at least two distinct adsorption sites.

Note the difference in data resolution between the data sets in the figures above. This is due to a customization of the analytics. Adsorbent A is measured on an 8-channel system with dedicated sensor array per channel, while the Lewatit VP OC 1065 is measured on a 4-channel system with a single sensor array for all four channels. In the latter case the channels are measured sequentially, with the automated flush of the effluent volume and time matching handled by Avantium’s FlowPro® control software.

Practical Example: Adsorbent Comparison

In a typical experiment 200 mg of Lewatit VP OC 1065 with circa 1.5 mmol/g CO₂ capacity at 25°C and 50%RH is exposed to 100 mL/min 420 ppm of CO₂ in N₂ or synthetic air. The expected time-to-breakthrough is then within circa 5 h accounting for adsorption kinetics. For the same amount of 13X in dry, but otherwise the same conditions, a CO₂ capacity of circa 0.5 mmol/g is found. For the 13X the adsorption step can therefore be shortened to 1.5 hours. For the zeolitic material a higher desorption temperature can be considered to maximize the capacity, without risking damaging the adsorbent material, where Lewatit and other amine-functionalized resins cannot be exposed to >100°C without risking irreversibly damaging the material.

Effective use

In the table below the effective time spent on temperature ramp for both cases described above are calculated using the ramp rates for each option. This shows that the rapid temperature cycling of option C ensures a negligible amount of time lost between adsorption and desorption for both material types. For the Lewatit option B might already be a feasible alternative due to the higher CO₂ capacity (and thus longer adsorption duration) and the lower desorption temperature. In some cases, option A may be considered to be the best option given other requirements, such as temperature accuracy, unit footprint, available facilities, budget etc.

Choosing the Right Solution

There is no one-size-fits-all approach. The optimal heating solution depends on:

• Required temperature accuracy
• Target ramp rates
• Adsorbent stability limits
• Experimental throughput
• Laboratory space and budget constraints

All three options are available in four-column configurations, offering significantly higher efficiency than single-column systems or faster heating rates.

Supporting Your DAC Research

Whether your focus is high-precision thermodynamics, rapid material screening, or long-term adsorption stability, Avantium R&D Solutions provides configurable temperature control solutions tailored to your research goals.

Interested in optimizing your DAC experiments? Contact us to discuss the best strategy for your application.