Feasibility of CO₂ capture in forest industries
Mero, Mario (2023)
Diplomityö
2023
School of Engineering Science, Kemiantekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2023061555514
https://urn.fi/URN:NBN:fi-fe2023061555514
Tiivistelmä
The high CO₂ emissions release in the forest industry is a problem of major concern. The emissions comes either from biogenic or fossil fuels sourced during the plant the operation. Thus, several CO₂ capture technologies has been proposed during the post combustion, precombustion, or the use of non-fossil fuels to meet the environmental requirement emissions.
For the present thesis work, the feasibility of the green liquor as a medium to absorb CO₂ from the flue gases in the forest industries due to his high Na₂CO₃ concentration is studied from a simulation and economic point of view. The software HSC chemistry is used to find the kinetics reactions of green liquor compounds, along with the equilibrium reaction of the green liquor species during the carbonation process. Meanwhile, the design process is performed by software Aspen Plus. First, the green liquor is sent to a reactor with O₂ at high pressure and temperatures to oxidise all the sulfur compounds into a stable Na₂SO₄ to avoid any H₂S gas production. Next, the flue gas containing CO₂, N₂ and O₂ and oxidate green liquor are put into contact inside an absorption tower, where chemical absorption reaction occurs, where 70.41% of the CO₂ in the flue gas is captured to react with the Na₂CO₃, to obtain NaHCO3 at a 35°C and 1 bar. Similarly, 98.54% of gaseous CO₂ is recovered from the decomposition of NaHCO3 to its initial s Na₂CO₃ and CO₂ species in the stripped tower operated at 75°C bar and 0.8bar, regenerating the composition of green liquor. Finally, the techno economic analysis revealed that for a project plan life of 20 years, and a CO₂ sale price of 50 €/ton, a NPV of 66.5 €MM, together with an IRR of 30.4% was achieved.
For the present thesis work, the feasibility of the green liquor as a medium to absorb CO₂ from the flue gases in the forest industries due to his high Na₂CO₃ concentration is studied from a simulation and economic point of view. The software HSC chemistry is used to find the kinetics reactions of green liquor compounds, along with the equilibrium reaction of the green liquor species during the carbonation process. Meanwhile, the design process is performed by software Aspen Plus. First, the green liquor is sent to a reactor with O₂ at high pressure and temperatures to oxidise all the sulfur compounds into a stable Na₂SO₄ to avoid any H₂S gas production. Next, the flue gas containing CO₂, N₂ and O₂ and oxidate green liquor are put into contact inside an absorption tower, where chemical absorption reaction occurs, where 70.41% of the CO₂ in the flue gas is captured to react with the Na₂CO₃, to obtain NaHCO3 at a 35°C and 1 bar. Similarly, 98.54% of gaseous CO₂ is recovered from the decomposition of NaHCO3 to its initial s Na₂CO₃ and CO₂ species in the stripped tower operated at 75°C bar and 0.8bar, regenerating the composition of green liquor. Finally, the techno economic analysis revealed that for a project plan life of 20 years, and a CO₂ sale price of 50 €/ton, a NPV of 66.5 €MM, together with an IRR of 30.4% was achieved.