Chemical-Looping Combustion of Solid Fuels Using Manganese Ores as Oxygen Carriers

Schmitz, Matthias; Linderholm, Carl Johan; Hallberg, Peter; Sundqvist, Sebastian E.; Lyngfelt, Anders

doi:10.1021/acs.energyfuels.5b02440

Cited by 30 publications

(35 citation statements)

References 29 publications

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“…The high attrition rate of this Brazilian ore forced to add new material continuously, thus incorporating fresh alkali elements, which are present in the Mnore, to the CLC unit. Similar conclusions were extracted from 18 h of combustion with ilmenite/Mn-ore mixtures and other Mn-ores in the 10 kW th CLC unit [22,23], as well as with an Australian Mn-ore in a 100 kW th CLC unit [24]. But the contrary was found during the combustion of biomass at the scale of 10 kW th with braunite [25] and in a 2-4 MW th unit with the Brazilian Mn-ore [26].…”

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confidence: 73%

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Assessment of the improvement of chemical looping combustion of coal by using a manganese ore as oxygen carrier

Abad

Gayán

Mendiara

et al. 2018

Fuel Processing Technology

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Finding suitable low-cost materials to be used as oxygen carrier in Chemical Looping Combustion (CLC) of coal is a key issue to achieve the CO 2 capture at low economic cost. Recently, a Mn-ore from Gabon has been identified as an alternative to the state of the art of oxygen carriers based on minerals or wastes with high iron content. This Mn-ore showed a high reactivity and a long particle lifetime during batch characterization to be considered as a suitable oxygen carrier. To evaluate the potential of this material in CLC, this work analyses the behaviour of the Mn-ore during continuous combustion of a bituminous coal in a 0.5 kW th CLC unit. The CLC process was evaluated and the effect of the main operating variablessuch as fluidizing medium, oxygen carrier circulation rate, temperature, and solids inventory in the fuel reactor-on the combustion efficiency and CO 2 capture was investigated. A direct relation between the char conversion rate and the CO 2 capture is given, being mainly affected by the mean residence time of solids and temperature in the fuel reactor. The use of a carbon separation system with separation efficiency above 90 % would be required to achieve CO 2 capture rates higher than 95 %. Total oxygen demand values as low as 4.5 % were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than  > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-based low-cost materials previously tested, but with higher CO 2 capture rates.

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confidence: 73%

“…Tested Mn-ores from Brazil and Australia showed high attrition rates, with estimated lifetime in the 100-400 h interval [11,23,24] which is much lower than those estimated for an iron ore [27]. Recently, a Mn-ore from Gabon has been investigated in TGA and small fluidized bed reactor [11,18].…”

mentioning

confidence: 99%

Assessment of the improvement of chemical looping combustion of coal by using a manganese ore as oxygen carrier

Abad

Gayán

Mendiara

et al. 2018

Fuel Processing Technology

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“…The bed materials used in the experiments included two manganese ores, Sinaus and Mangagran, previously used in CLC experiments using continuous units, (Linderholm et al 2017;Schmitz et al 2016) and in batch fluidized beds (Sundqvist et al 2017). Further, LD slag, a by-product from the steel production process, and delivered by SSAB Merox, was investigated in this study.…”

Section: Methodsmentioning

confidence: 99%

Negative emissions of carbon dioxide through chemical-looping combustion (CLC) and gasification (CLG) using oxygen carriers based on manganese and iron

Mattison

Hildor

et al. 2019

Mitig Adapt Strateg Glob Change

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Carbon capture and storage (CCS) is an economically attractive strategy for avoiding carbon dioxide (CO 2) emissions from, e.g., power plants to the atmosphere. The combination of CCS and biomass combustion would result in a reduction of atmospheric CO 2 , or net negative emissions, as plant growth is a form of sequestration of atmospheric carbon. Carbon capture can be achieved in a variety of ways, one of which is chemical looping. Chemical-looping combustion (CLC) and chemical looping gasification (CLG) are two promising technologies for conversion of biomass to heat and power or syngas/methane with carbon capture. There have been significant advances made with respect to CLC in the last two decades for all types of fuel, with much less research on the gasification technology. CLG offers some interesting opportunities for production of biofuels together with carbon capture and may have several advantages with respect to the bench mark indirect gasification process or dual-bed fluidized bed (DFBG) in this respect. In CLG, an oxygen carrier is used as a bed material instead of sand, which is common in indirect gasification, and this could have several advantages: (i) all generated CO 2 is present together with the syngas or methane in the fuel reactor outlet stream, thus in a concentrated stream, viable for separation and capture; (ii) the air reactor (or combustion chamber) should largely be free from trace impurities, thus preventing corrosion and fouling in this reactor; and (iii) the highly oxidizing conditions in the fuel reactor together with solid oxide surfaces should be advantageous with respect to limiting formation of tar species. In this study, two manganese ores and an iron-based waste material, LD slag, were investigated with respect to performance in these chemical-looping technologies. The materials were also impregnated with alkali (K) in order to gauge possible catalytic effects and also to establish a better understanding of the general behavior of oxygen carriers with alkali, an important component in biomass and biomass waste streams and often a precursor for high-temperature corrosion. The viability of the oxygen carriers was investigated using a synthetic biogas in a batch fluidized bed reactor. The conversion of CO, H 2 , CH 4 , and C 2 H 4 was investigated in the temperature interval 800-950°C. The reactivity, or oxygen transfer rate, was highest for the manganese ores, followed by the LD slag. The conversion of C 2 H 4 was generally high but could largely be attributed to thermal decomposition. The K-impregnated samples showed enhanced reactivity during combustion conditions, and the Mangagran-K sample was able to achieve full conversion of benzene. The interaction of the solid material with alkali showed widely different behavior. The two manganese ores retained almost all alkali after redox testing, albeit exhibiting different

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“…Natural minerals are such a low-cost option for oxygen carriers, industrial by-products like slag the from Linz-Donawitz (LD) process are another option. The feasibility of using minerals as oxygen carriers in chemical-looping combustion has previously been investigated and demonstrated (Linderholm et al 2012;Moldenhauer et al 2018a;Schmitz et al 2016;Linderholm et al 2017).…”

Section: Potential Technology Impactmentioning

confidence: 99%

Avoiding CO2 capture effort and cost for negative CO2 emissions using industrial waste in chemical-looping combustion/gasification of biomass

Moldenhauer

Linderholm

Rydén

et al. 2019

Mitig Adapt Strateg Glob Change

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Chemical-looping combustion (CLC) is a combustion process with inherent separation of carbon dioxide (CO 2), which is achieved by oxidizing the fuel with a solid oxygen carrier rather than with air. As fuel and combustion air are never mixed, no gas separation is necessary and, consequently, there is no direct cost or energy penalty for the separation of gases. The most common form of design of chemical-looping combustion systems uses circulating fluidized beds, which is an established and widely spread technology. Experiments were conducted in two different laboratory-scale CLC reactors with continuous fuel feeding and nominal fuel inputs of 300 W th and 10 kW th , respectively. As an oxygen carrier material, ground steel converter slag from the Linz-Donawitz process was used. This material is the second largest flow in an integrated steel mill and it is available in huge quantities, for which there is currently limited demand. Steel converter slag consists mainly of oxides of calcium (Ca), magnesium (Mg), iron (Fe), silicon (Si), and manganese (Mn). In the 300 W unit, chemical-looping combustion experiments were conducted with model fuels syngas (50 vol% hydrogen (H 2) in carbon monoxide (CO)) and methane (CH 4) at varied reactor temperature, fuel input, and oxygen-carrier circulation. Further, the ability of the oxygen-carrier material to release oxygen to the gas phase was investigated. In the 10 kW unit, the fuels used for combustion tests were steam-exploded pellets and wood char. The purpose of these experiments was to study more realistic biomass fuels and to assess the lifetime of the slag when employed as oxygen carrier. In addition, chemical-looping gasification was investigated in the 10 kW unit using both steam-exploded pellets and regular wood pellets as fuels. In the 300 W unit, up to 99.9% of syngas conversion was achieved at 280 kg/MW th and 900°C, while the highest conversion achieved with methane was 60% at 280 kg/MW th and 950°C. The material's ability to release oxygen to the gas phase, i.e., CLOU property, was developed during the initial hours with fuel operation and the activated material released 1-2 vol% of O 2

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Chemical-Looping Combustion of Solid Fuels Using Manganese Ores as Oxygen Carriers

Cited by 30 publications

References 29 publications

Assessment of the improvement of chemical looping combustion of coal by using a manganese ore as oxygen carrier

Assessment of the improvement of chemical looping combustion of coal by using a manganese ore as oxygen carrier

Negative emissions of carbon dioxide through chemical-looping combustion (CLC) and gasification (CLG) using oxygen carriers based on manganese and iron

Avoiding CO2 capture effort and cost for negative CO2 emissions using industrial waste in chemical-looping combustion/gasification of biomass

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