The interplay between ternary molten carbonate and biomaterials during pressurized slow pyrolysis

The utilization of biomass for heat and power generation has aroused the interest of most researchers especially those of energy .In converting solid fuel to a usable form of energy,pyrolysis plays an integral role. Understanding this very important phenomenon in the thermochemical conversion processes and representing it with appropriate mathematical models is vital in the design of pyrolysis reactors and biomass gasifiers. Therefore, this study presents analytical solutions to the kinetic and the heat transfer equations that describe the slow pyrolysis of a biomass particle. The effects of Biot number, temperature and residence time on biomass particle decomposition were studied. The results from the proposed analytical models are in good agreement with the reported experimental results. The developed analytical solutions to the heat transfer equations which have been stated to be “analytically involved” showed average percentageerror and standard deviations 0.439 and 0.103 from the experimental results respectively as compared with previous model in literature which gives average percentage error and standard deviations 0.75 and 0.106 from the experimental results respectively. This work is of great importance in the design of some pyrolysis reactors/units and in the optimal design of the biomass gasifiers.

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The Characteristics of Products from Pyrolysis of Seaweed in Molten Carbonates

Transactions of the ASABE ◽

10.13031/trans.13303 ◽

2019 ◽

Vol 62 (3) ◽

pp. 787-794

Author(s):

Yi Wei ◽

Jitong Tang ◽

Jianbing Ji

Keyword(s):

Heat Transfer ◽

Thermogravimetric Analysis ◽

Molten Salts ◽

Molten Carbonate ◽

Gas Generation ◽

Slow Pyrolysis ◽

Gaseous Products ◽

Molten Carbonates ◽

Bio Oil ◽

Terrestrial Biomass

Abstract. The characteristics of the seaweed (SH) were investigated as a feedstock for slow pyrolysis and molten carbonate (MC) pyrolysis within the temperature range of 400°C to 600°C. SH differs from terrestrial biomass in its constitutional compounds and high N content. According to thermogravimetric analysis, decomposition of proteins and cellulose played the most important role in thermal degradation of SH. The yields and distributions of syngas and bio-oil from MC pyrolysis varied with temperature and were greatly different from those of slow pyrolysis. MC pyrolysis increased gas generation by 10.46 wt% while reducing solids yield from 38.10 wt% to 31.99 wt% at 600°C. Of the gaseous products, H2 was dominant, and CO2 was also prominent. Conversion of tar and acid in the bio-oil was significantly improved in the molten salts medium, while nitrogen content was significantly reduced in the bio-oil. MC pyrolysis minimized the obstacles to heat transfer during pyrolysis by heating the feedstock from both inside and outside. Keywords: Intensification, Molten carbonates, Pyrolysis, Sargassum horneri.

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Miscanthus to Biocarbon for Canadian Iron and Steel Industries: An Innovative Approach

Energies ◽

10.3390/en14154493 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4493

Author(s):

Trishan Deb Abhi ◽

Omid Norouzi ◽

Kevin Macdermid-Watts ◽

Mohammad Heidari ◽

Syeda Tasnim ◽

...

Keyword(s):

Carbon Content ◽

Ghg Emissions ◽

Hydrothermal Carbonization ◽

Ash Content ◽

Innovative Approach ◽

Thermochemical Conversion ◽

Partial Substitution ◽

Iron And Steel ◽

Slow Pyrolysis ◽

Ironmaking Process

Iron-based industries are one of the main contributors to greenhouse gas (GHG) emissions. Partial substitution of fossil carbon with renewable biocarbon (biomass) into the blast furnace (BF) process can be a sustainable approach to mitigating GHG emissions from the ironmaking process. However, the main barriers of using biomass for this purpose are the inherent high alkaline and phosphorous contents in ash, resulting in fouling, slagging, and scaling on the BF surface. Furthermore, the carbon content of the biomass is considerably lower than coal. To address these barriers, this research proposed an innovative approach of combining two thermochemical conversion methods, namely hydrothermal carbonization (HTC) and slow pyrolysis, for converting biomass into suitable biocarbon for the ironmaking process. Miscanthus, which is one of the most abundant herbaceous biomass sources, was first treated by HTC to obtain the lowest possible ash content mainly due to reduction in alkali matter and phosphorous contents, and then subjected to slow pyrolysis to increase the carbon content. Design expert 11 was used to plan the number of the required experiments and to find the optimal condition for HTC and pyrolysis steps. It was found that the biocarbon obtained from HTC at 199 °C for 28 min and consecutively pyrolyzed at 400 °C for 30 min showed similar properties to pulverized coal injection (PCI) which is currently used in BFs due to its low ash content (0.19%) and high carbon content (79.67%).

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Thermochemical Conversion of Biomass in the Presence of Molten Alkali-Metal Carbonates under Reducing Environments of N2 and CO2

Energies ◽

10.3390/en13205395 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5395

Author(s):

Tahereh Jalalabadi ◽

Behdad Moghtaderi ◽

Jessica Allen

Keyword(s):

Elevated Temperatures ◽

Eutectic Mixture ◽

Thermochemical Conversion ◽

Boudouard Reaction ◽

Molten Carbonate ◽

Carbon Particles ◽

Carbonate Decomposition ◽

Carrier Gases ◽

Lower Temperature ◽

The Impact

The impact of N2 and CO2 atmospheres on the interaction between Eucalyptus pilularis biomass and a ternary molten carbonate eutectic (Li2CO3: Na2CO3: K2CO3) has been investigated at 600 °C and 900 °C. For lower temperature conversion under CO2, prevention of volatile release in the eutectic treated biomass is slightly higher than under N2 injection; however, similar bubble-shaped morphology of the remnant char is observed under both carrier gases. By increasing the temperature to 900 °C under CO2, the reverse Boudouard reaction begins to consume carbon fuel, while molten carbonate gasification also accelerates the reaction to a lower temperature set point (shifted from ~735 °C to ~640 °C). The mass loss of carbonate under CO2 and N2 at 900 °C is 0 (negligible) and 18 wt.%, respectively. In the absence of carbon particles, the decomposition of carbonate to M2O (l) and CO2 (g), as well as molten salt vaporization, are the sole potential routes of weight loss in an inert gas. Previous observations of biomass and eutectic mixture thermochemical conversion under N2 have suggested carbon/carbonate gasification is dominant at elevated temperatures, with production of CO expected. However, analysis of gas chromatography (GC) suggests that carbon/carbonate gasification is the weaker pathway by producing only 7 vol.% of CO, compared with molten carbonate decomposition with 27 vol.% CO2 emission for this system.

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