CO₂ absorption equipment system installation.

CO₂ absorption equipment

Carbon dioxide is absorbed by granular amine compound bonded to a porous resin structure. The chemical reactions are as follows:

Absorption (filtration)

Amine+H₂O -> (Amine-H₂O) and ahead (Amine-H₂O) + CO₂ (Amine-H2CO3)

Desorption (regeneration)

(Amine-H2CO3) + heat Amine+H₂O + CO₂

As the absorbent becomes exhausted, the weakly bonded carbon dioxide can be desorbed by reversing the process equilibrium, or by heating the absorbent with warm air.

The filter consists of two identical filter units. As one unit is filtering, the other is regenerating and vice versa. Each filtering/ CO₂ absorption cycle takes 8 hours (can be modified according to customers’ requisites). CO₂ probe and control units monitor the CO₂ content downstream of the filter. When the CO₂ absorbent becomes exhausted, filtrating unit is changed to the other unit and the first unit starts regenerating. The process control unit controls the absorption and regenerating cycles automatically, so no user actions are required.

During filtration, the butterfly (wafer) valves of the filtering unit are open, and the shelter indoor air flows through the filter unit and is then circulated back to the shelter interiors.

Principle of operation:

Regeneration is an automatic process controlled by the process control unit. During regeneration, the butterfly valve to shelter interiors is closed. The air heating unit vacuums and heats indoor air, which then heats up the CO₂ absorbent. The heated air containing high levels of CO₂ is released outdoors or to CO₂ storages (see Figure on next page).

Overheat protection is done with two temperature-controlled switches, which open at < 200 °C.

Control unit

Carbon Capture - Heated air with high levels of CO₂ is released to CO2 storages

The process control unit is Siemens 12/24RC 6ED1 052-1MD00-0BA6.

The unit works with24 VDC and is powered by 6EP1332-1SH42.

Additional relay unit DM8 12/24R 6ED1 055-1MB00-0BA1 is also used.

Valve operation is controlled by outputs Q1 and Q2. The valves operate in 2 groups, valves1, 5, 3 and 8 are the first group connected to the output Q1. The second group, valves 2, 6, 4 and 7 are connected to the output Q2. Valves are of pneumatic type and spring return ones. Valve control schematics is illustrated in the figure 2. The compressor produces pressurized air for valves. Pressure is fed through magnetic valves to the filter valve groups

Pressure relief valve

Pressure relief valve is a pneumatic valve with spring return. It is constantly connected to the electrical inlet of the filtration unit. When electricity and therefore pressurized air is available, the safety relief valve is closed. In case of power failure or lack of pressurized air the safety valve opens and allows bypass through the filtration unit.

• Dimensions – see drawings in ENCLOSURES.
• Total operating weight of the filter with absorbent cells installed: Approx. 800 kg.
• Absorber Casing fabricated from AISI 304 Stainless Steel (Option 316L SS).
• Design Pressure: Atmospheric.
• Absorbent: An amine compound in Ø 1 mm polystyrene granules, 245 litres / eachCO₂ unit
• Weight of absorbent in one filtering unit: 150 kg; 300 kg total per the two filtering units of the filter.
• Residence Time during CO₂ absorption: 1.5 sec.
• CO₂ Absorbent Design Temperature during CO₂ absorption: 0° - 50°C.
• Magnehelic zero-centre pressure gauge to indicate pressure drop.
• Connections / Flanges: According to customer’s specifications.
• OPTION: Surface treatment of casing: Pickling.

• Filtration Efficiency: Up to 100% at 25°C, 608 Nm³/h absorption rate *
• Residence Time: Approx. 1.45 sec at 608 m³/h CO₂ absorption rate.
• Pressure Drop at 608 m³/h absorption rate:
  • Pre-Filters Clean: approx. 90 Pa
  • Pre-Filters Dirty: approx. 200 Pa **)

Pre filter replacement

The pre filters are located inside the breather unit. The service life of pre filters depends on the amount of dust particles in the indoor air. Normally the filters are replaced once or twice per year. Regeneration inlet pre filter is located upstream of the regeneration fan, near the floor of the filtration unit. Filtration inlet filters are located before filtration inlet valves.

CO₂ Absorbent replacement

The absorbent cells have to be stored in their vacuum packings. Depending on the frequency and duration of the operation, the absorbent cells must be replaced after approx. 180 days’ use.

The CO₂ breather filter itself is maintenance free, the CO₂ filter material has a long time depending on several conditions. The user needs only take care of the exchange of pre filters in the regeneration inlet and filtration inlets. The excess water must also be removed from the compressor unit.

Regeneration air inlet pre filter.

Left and right air inlet pre filters.

At the maximum 608 Nm³/h filtration air flow, the residence time is ideal 1.5 seconds. Depending on the monthly filtration rate, we estimate that the consumption of absorbent cells is roughly approx. one set for six months of operation. Since the initial set of absorbent cells is included in the equipment price and delivery, we estimate that you will not need any additional sets of absorbent cells unless the cells have been removed from their vacuum packings and been installed in the equipment, and further the absorber has been operating for at least six (6) months.

The pre-filters can be cleaned with a vacuum cleaner or by beating gently, but they cannot be washed. The cleaning should be done after the pressure drop indicated by the differential pressure gage has increased by 100-120 Pa. Pre and post filters should be replaced after the filter media has started to deteriorate.

• A)Manufacturer’s ISO 9001 Certificate.
• B) Certificates of Conformity.
• C) As-Built Drawings.
• D) Absorber Data Sheets.
• E) Material Certificates (EN 10204/3.1).
• F) Dimensional Control Reports.
• G) Leak Test Reports.
• H) Factory Acceptance Reports.
• I) IO&M Instructions.

Additional documentation is issued according to separate agreement.