Effect of Mg and K inorganic species on the chars properties derived - - PowerPoint PPT Presentation

Effect of Mg and K inorganic species on the chars’ properties derived from grape marc pyrolysis

• M. Jeguirim, L. Limousy, K. Thabet, L. Josien, L. Michelin, C. Vaulot
• S. Bennici

Université de Haute‐alsace, CNRS, IS2M UMR7361, F‐68100 Mulhouse, France e‐mail : simona.bennici@uha.fr

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BACKGROUND

Renewable: biomass energy is a renewable resource. Dependency on fossil Fuels is reduced. Carbon Neutral. Widely Available. Helps Reduce Waste. Can be used in various forms. It can be used to produce methane gas, biodiesel and other biofuels. It can also be used to directly generate heat or to generate electricity using a steam turbine. It can produce chars, with a wide panel of applications.

To diminish greenhouse gas emission (CO2)

Various sources

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WINERY WASTE VALORISATION PROCESSES

Grape marc residues as renewable resource

Grape marc residue has a high lignin and ash contents ensuring good potential for biochar production. Grape marc is worldwide available since 70 million tons of wine grape are annually produced. Up to 20% of the harvested wine becomes waste during wine production (stalks and seeds grape, skins). Biomass wastes can be transformed into clean energy and/or fuels by a variety of technologies.

Thermochemical conversion Combustion Pyrolysis Gasification

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Annual cash flow for investment in combustion and pyrolysis at different winery scales

From Zhang et al. Waste Management, 60, 2017, 173‐183

GRAPE MARC VALORISATION PROCESSES: ECONOMIC VIABILITY

Small wineries with a grape crush under 50 tons show the insignificance of the potential revenue and savings in comparison to the cost of the capital investment. For bigger size wineries, the potential revenue and savings increase when compared to the investment costs. Pyrolysis is seen to result in a net positive cash flow for wineries with a grape crush over 1000 tons. As comparison, combustion approaches, but never reaches, the break‐even point in wineries with an annual grape crush over 10000 tons.

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GRAPE MARC COMPOSITION

Cellulose Hemicellulose Lignine Mg, K, Ca, Na… Their presence modifies the thermal behaviour of biomass Contradictions on their catalytic or inhibitor behaviour Inorganics

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CHARS’ PREPARATION

Effect of inorganics on the chars’ morphological and structural properties Impact of inorganics on the pyrolysis kinetics Physico‐chemical characterization Pyrolysis at 300‐500 °C under N2 flow

Char

Gas Oil Impregnation Mg and K salt

Grape marc Granulometry: 0.25‐0.40 mm Washing

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PYROLYSIS: BIOMASS FRACTION DEGRADATION

5 °C/min, 100 mL/min N2

0,005 0,01 0,015 0,02 0,025 0,03 0,035 10 20 30 40 50 60 70 80 90 100 100 200 300 400 500 600

• DTG(%/s)

Masse(%) Temperature(°C) ATG-MR-B-500(5) DTG-MR-B-500(5)

• 0,05

0,05 0,1 0,15 0,2 0,25 0,3 20 40 60 80 100 120 100 200 300 400 500 600

• DTG(%/s)

Masse (%) Température (°C) ATG-Cell-com-B-500(5) DTG-Cell-com-B-500(5)

Cellulose Pure cellulose

Mass (%) Mass (%)

0,005 0,01 0,015 0,02 0,025 0,03 0,035 10 20 30 40 50 60 70 80 90 100 100 200 300 400 500 600

• DTG(%/s)

Masse(%) Temperature(°C) ATG-MR-B-500(5) DTG-MR-B-500(5)

Hemicellulose (not pure) Pure hemicellulose

Mass (%) Mass (%)

‐0,002 0,002 0,004 0,006 0,008 0,01 20 40 60 80 100 120 100 200 300 400 500 600 ‐DTG (%/s)

Mass (%)

Temperature (°C) ATG‐Hem‐mais(500)‐5 DTG‐Hem‐mais(500)‐5

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CHARS’ CHARACTERIZATION: XRF AND TG

Inorganics addition

KCl addition: Higher cellulose degradation rate (0.032 %s‐1) Lower hemicellulose degradation T Lower cellulose degradation T MgCl2 addition: Lower hemicellulose degradation T Much lower cellulose degradation rate (0.024 %s‐1)

A different effect of the various salts is observed in relation with the biomass fraction

‐0,005 0,005 0,01 0,015 0,02 0,025 0,03 0,035 0,04 0,045 100 150 200 250 300 350 400 450 500

DTG (%/S) Temperature (°C)

MR‐L‐500(5) MR‐K‐500(5) MR‐Mg‐500(5)" MR‐B‐500(5)

The char obtained by the original grape marc presents a high content

• f inorganics

Addition of KCl and MgCl2 was done

• n the washed biomass

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XRF

MR‐L‐500(5) MR‐K‐500(5) MR‐Mg‐500(5) MR‐B‐500(5)

MR‐B MR‐L MR‐K MR‐Mg Ea(kJ/mol‐1) 190 181 188 273 Ea (kJ/mol‐1) 198 160 141 123

Cellulose Hémicellulose KCl addition ‐ Lower activation energy for hemicellulose degradation  Catalytic effect ‐ No impact on the cellulose degradation MgCl₂ addition ‐ Higher activation energy for cellulose degradation  Inhibitor effect ‐ Lower activation energy for hemicellulose degradation  Catalytic effect

PYROLYSIS: ACTIVATION ENERGIES

0,01 0,02 0,03 0,04 0,05 0,06 0,07 0,08 0,09 0,1 2000 4000 6000 8000 10000 12000 DTG(%/s) Temps (s) MR-B-500(3) MR-B-500(5) MR-B-500(10) MR-B-500(15)

Time (s)

Different effect in relation to the different biomass fractions Impact of the biomass washing on the hemicellulose transformation Kissinger equation:

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K/min

CHARS’ CHARACTERIZATION: CO2‐ADS ISOTHERMS and SEM

Sample SCO2 (m2/g) VP,CO2 (<1nm) (cm3/g) MR‐B‐500 MR‐L‐500 MR‐K‐500 MR‐Mg‐500 189 213 225 220 0.054 0.059 0.065 0.061

MR-B- 500

Char morphology after washing and salts addition of the parent biomass

MR-L-500 MR-L-500 MR-K-500 MR-K-500 MR-Mg-500 MR-Mg-500

CO2 adsorption isotherms: surface area and pores volume Surface area and porosity increase by washing Cohesion loss of the carbon matrix KCl is visible as well defined crystals Good dispersion of MgCl2

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Char derived from grape marc

CHARS’ CHARACTERIZATION: INFRARED ANALYSIS

Wavelength (cm‐1)

Char functionalities at increasing pyrolysis T Char functionalities: salts addition (Tpy=300°C)

Intensity (A.U) Wavelength (cm‐1) Intensity (A.U) C‐H aliphatic C=0 aliphatic O‐H

T Loss of aliphatic groups at high pyrolysis T Decreasing of the aliphatic C=O band, degradation of volatiles New C=C groups detected at higher T, formation of aromatic compounds Decomposition of aliphatic esters Decreasing of the 1747 cm‐1 bands at 300 °C in presence of salts

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300°C 400°C 500°C

The char yield decreases with the T Volatiles production at high temperature Salts addition bring to the slight increasing

• f the char yield

Formation of more extended aromatic systems (graphitization)

CHARS’ CHARACTERIZATION: CHARS YIELD (BY TG) AND RAMAN

Echantillon D G ID/IG MR‐B‐400 1341 1575 0,97 MR‐B‐500 1341 1581 0,95 MR‐L‐500 1354 1579 0,97 MR‐K‐500 1345 1579 0,94 MR‐Mg‐500 1345 1585 0,93

ID/IG slightly decreases by increasing the pyrolysis T ID/IG slightly decreases with the addition of inorganics

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5000 10000 15000 20000 25000 30000 500 1000 1500 2000 2500 3000 3500 ( )

MR-B-500 MR-L-500 MR-K-500 MR-Mg-500

D G

Intensity (A.U) Wavelength (cm‐1)

MR-B-500 MR-L-500 MR-K-500 MR-Mg-500

↑ T ↑ [salt]

Yield (%)

CONCLUSIONS

KCl and MgCl2 salts display catalytic or inhibitor behaviors in dependence of the biomass fraction. MgCl2 decreases the Ea of hemicellulose degradation, while increases that of cellulose. Other parameters, as the biomass washing, has to be taken into account not to misunderstand the inorganics impact during biomass pyrolysis In presence of salts, the decomposition of aliphatic esters takes place at lower pyrolysis T. Salts addition brings to a slight increase of the char yield, probably due to the formation of more extended aromatic systems (graphitization), thus producing chars with higher specific surface and enhanced porosity. Pyrolysis of grape marc enriched in inorganics (possibly deriving from waste effluents) can be potentially used to produce high quality chars at lower pyrolysis temperature than that usually applied.

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The MICA Carnot Institute for the economical support in the frame of the Carbovit project.

Acknowledgement to:

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…. THANK YOU !!!

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