CO_(2)capture costs of chemical looping combustion of biomass:A comparison of natural and synthetic oxygen carrier

Chemical looping combustion has the potential to be an efficient and low-cost technology capable of contributing to the reduction of the atmospheric concentration of CO_(2) in order to reach the 1.5/2°C goal and mitigate climate change.In this process,a metal oxide is used as oxygen carrier in a dual fluidized bed to generate clean CO_(2) via combustion of biomass.Most commonly,natural ores or synthetic materials are used as oxygen carrier whereas both must meet special requirements for the conversion of solid fuels.Synthetic oxygen carriers are characterized by higher reactivity at the expense of higher costs versus the lower-cost natural ores.To determine the viability of both possibilities,a techno-economic comparison of a synthetic material based on manganese,iron,and copper to the natural ore ilmenite was conducted.The synthetic oxygen carrier was characterized and tested in a pilot plant,where high combustion efficiencies up to 98.4%and carbon capture rates up to 98.5%were reached.The techno-economic assessment resulted in CO_(2) capture costs of 75 and 40€/tCO_(2) for the synthetic and natural ore route respectively,whereas a sensitivity analysis showed the high impact of production costs and attrition rates of the synthetic material.The synthetic oxygen carrier could break even with the natural ore in case of lower production costs and attrition rates,which could be reached by adapting the production process and recycling material.By comparison to state-of-the-art technologies,it is demonstrated that both routes are viable and the capture cost of CO_(2) could be reduced by implementing the chemical looping combustion technology.

Economic Comparison of Three Gas Separation Technologies for CO2 Capture from Power Plant Flue Gas

Three gas separation technologies,chemical absorption,membrane separation and pressure swing adsorption,are usually applied for CO2 capture from flue gas in coal-fired power plants.In this work,the costs of the three technologies are analyzed and compared.The cost for chemical absorption is mainly from $30 to $60 per ton(based on CO2 avoided),while the minimum value is $10 per ton(based on CO2 avoided).As for membrane separation and pressure swing adsorption,the costs are $50 to $78 and $40 to $63 per ton(based on CO2 avoided),respectively.Measures are proposed to reduce the cost of the three technologies.For CO2 capture and storage process,the CO2 recovery and purity should be greater than 90%.Based on the cost,recovery,and purity,it seems that chemical absorption is currently the most cost-effective technology for CO2 capture from flue gas from power plants.However,membrane gas separation is the most promising alternative approach in the future,provided that membrane performance is further improved.

Carbon capture and sequestration:The roles of agriculture and soils

Renewable energy as a replacement for fossil fuels is highly desirable,but the reality is that fossil fuels(especially coal and petroleum)will be major sources of global energy for many decades to come.Therefore,carbon capture is vital to reduce release of carbon emissions and other GHG’s to the atmosphere thereby mitigating global warming.This presentation is a review of the role of agriculture and soils in carbon capture.Carbon sequestration in soils is the process of transferring CO2 from the atmosphere into soils through crop residues.Soil carbon sequestration increases with practices long recommended to increase yields,such as no-till,manure application,agroforestry and cover cropping.It is a Win-Win-Win strategy―advancing food security,improving the environment,and mitigating global warming.Carbon enrichment in greenhouse culture is in widespread use and has been adopted by many commercial producers.It results in remarkable increases in yields of flowers and vegetables.Research has shown the same increase in yields of trees and field crops with higher CO2 concentrations.The question is,how can CO2 be applied to field crops to increase yields?Restoration of desertified lands would improve soil quality,increase the pool of C in soils and forests,reduce CO2 emission to the atmosphere,and improve soil quality.Sequestration of additional carbon in soils would reduce CO2 emissions to the atmosphere thus mitigating global warming.Reforestation of forests is important,but real trees have ecological limits.Artificial trees could be used to absorb CO2 from the air any place on the planet,from any source―power plants,vehicles,and all industrial applications.Addition of CO2 in irrigation water could reduce the pH and help restore alkaline soils.Research is needed to further clarify the cost and benefit of many agriculture technologies for capturing and storing carbon.