Flue gas pressurization

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Category: Flue gas pretreatment

DESCRIPTION

Flue gas pressurization involves increasing the pressure of flue gases using blowers or compressors to facilitate efficient carbon capture. This process is essential for enhancing the performance of various carbon capture technologies by ensuring optimal gas flow and pressure conditions. The schematic shows increasing the pressure of the flue gas, which is at atmospheric pressure, to 1.2 bar using a blower. This is done to overcome the pressure drop in the downstream equipment. The schematic also shows a two-stage compression system where the flue gas is pressurized to a final pressure of 10 bars. In this case, the flue gas undergoes a series of compression, cooling, and separation stages.

Flue Gas Pressurization

REMOVED COMPONENTS

  • Water is removed as condensate after every compression and subsequent cooling stage.

FUNCTION IN CCU VALUE CHAIN

Flue gas pressurization ensures that the gas stream is at the required pressure for effective CO2 capture. Without proper pressurization, the efficiency of capture technologies such as absorption (hot potassium carbonate), adsorption (pressure swing adsorption), and membrane separation would be significantly reduced, leading to lower CO2 capture rates and higher operational costs.

LIMITATIONS

  • High energy consumption for compression to high pressures.
  • Potential for increased wear and maintenance of equipment.
  • Efficiency is dependent on gas composition and temperature.

ENERGY

Electricity is primarily used to power the blowers or compressors. The energy requirement varies based on the volume and pressure of the flue gas.

CONSUMABLES

  • Cooling water is used to cool the flue gas after each compression stage. It is generally recycled and not consumed.
  • No significant consumables are required for the pressurization process itself, apart from regular maintenance materials for the equipment.
Energy and Consumables
Parameter Value
Electricity (kWh/m3 flue gas) Equation1
Cooling water (t/t flue gas) -NA-

PB – brake power, Q1 – volumetric flowrate, P1 – inlet pressure, P2 – outlet pressure, ηB – isentropic efficiency, γ – specific heat ratio, ideal gas assumption, PC – consumed power, ηM – motor efficiency.

COSTS

The cost of flue gas pressurization varies based on the type of equipment (blower or compressor), the required pressure, and the volume of gas. Typical CAPEX calculation for blower and compressor can be calculated using the equations below.1 The OPEX is estimated by calculating the electricity requirement.

Equipment purchase cost (EPC) of blower:

FM is the factor for materials, considered 1 for carbon steel.

  • for centrifugal (turbo) blower (valid from PC 5 to 1000 HP): a=6.8929, b=0.79, c=0
  • for rotary straight-lobe blower (valid from PC 1 to 1000 HP): a=7.59176, b=0.79320, and c=-0.012900

Equipment purchase cost (EPC) compressor:

FD is the factor for drives, considered 1 for electric drives. FM and CB are the factors for materials and the expression of the base cost, the same as for blowers.

  • for centrifugal compressors (valid from PC 200 to 30000 Hp): a=7.5800, b=0.8, c=0
  • for reciprocating compressors (valid from PC 100 to 20000 Hp): a=7.9661, b=0.8, c=0
  • for screw compressors (valid from PC 10 to 750 Hp): a=8.1238, b=0.7243, c=0

TECHNOLOGY PROVIDERS

CONTACT INFO

Mohammed Khan (mohammednazeer.khan@vito.be)

Miet Van Dael (miet.vandael@vito.be)

ACKNOWLEDGEMENT

This infosheet was prepared as part of the MAP-IT CCU project funded by VLAIO (grant no. HBC.2023.0544).

REFERENCES

1.    Bilsbak V. Conditioning of CO2 Coming from a CO2 Capture Process for Transport and Storage Purposes. Norwegian University of Science and Technology; 2009. http://www.diva-portal.org/smash/get/diva2:348870/FULLTEXT01.pdf

2.    Anantharaman R, Bolland O, Booth N, et al. DECARBit: European Best Practice Guidelines for Assessment of CO2 Capture Technologies. Norwegian University of Science and Technology; 2011. Accessed November 3, 2018. https://www.sintef.no/globalassets/project/decarbit/d-1-4-3_euro_bp_guid_for_ass_co2_cap_tech_280211.pdf

3.    Adhikari B, Orme CJ, Stetson C, Klaehn JR. Techno-economic analysis of carbon dioxide capture from low concentration sources using membranes. Chem Eng J. 2023;474:145876.

4.    Zanco SE, Pérez-Calvo JF, Gasós A, Cordiano B, Becattini V, Mazzotti M. Postcombustion CO2 Capture: A Comparative Techno-Economic Assessment of Three Technologies Using a Solvent, an Adsorbent, and a Membrane. ACS Eng Au. 2021;1(1):50-72.

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