BIOCHAR PRODUCTION BY PYROLYSIS OF LIGNOCELLULOSIC BIOMASS IN

BIOCHAR PRODUCTION BY PYROLYSIS OF LIGNOCELLULOSIC BIOMASS IN A CONICAL SPOUTED BED REACTOR Maider Amutio, Gartzen Lopez, Maite Artetxe, Astrid Barona, Martin Olazar Chemical Engineering Department, University of the Basque Country UPV/EHU PO Box 644 – 48080 Bilbao. Spain. martin. olazar@ehu. es eman ta zabal zazu Universidad del País Vasco Euskal Herriko Unibertsitatea

Introduction Ü Biomass o Alternative to fossil fuels → the only renewable source of fixed carbon. o Biomass → Liquid, solid and gaseous fuels + heat and power. Ü Pyrolysis o One of the technologies with the best industrial perspectives. o Bio-oil as biorefinery feedstock (decouple bio-oil production). Ü Biomass flash pyrolysis T ~ 500 ºC o Maximum liquid production: Very high heating rates Short gas residence time Rapid char removal Minimize secondary cracking reactions o Products: Bio-oil = 60 -80 wt%. Alternative fuel or source of chemicals Gas = 10 -20 wt%. Supply energy to the pyrolysis plant Char = 15 -25 wt%. Fuel, activated carbon or soil amendment. Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Introduction Ü Vacuum pyrolysis o Improvement of the operational capacity of this technology: • Reduction of the mass flow-rate of the inert gas→ reduction in the energy requirement to heat the gas to the reaction temperature. • Simplification of the bio-oil condensation and collection section. o Advantages: • Reduction of secondary cracking reactions: rapid desorption and extraction of the volatile products from the reaction environment. • Improvement in char quality. Ü Reactors o Biomass flash pyrolysis: Fluidized bed reactors. o Biomass vacuum pyrolysis: Vacuum moving bed. Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Introduction Ü Conical spouted bed reactor (CSBR) Advantages: o. Simple design o. Less pressure drop than fluid beds Fountain Spout o Different particle diameters and irregular materials o Great versatility in gas flow (low Annulus residence time) o. Good heat and mass transfer o. Allows continuous extraction of char Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Introduction Ü Conical spouted bed reactor (CSBR) Advantages: o. Simple design o. Less pressure drop than fluid beds o Different particle diameters and irregular materials o Great versatility in gas flow (low Annulus residence time) o. Good heat and mass transfer o. Allows continuous extraction of char Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Experimental Ü Pyrolysis bench scale plant Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Experimental Ü Raw material: Pinewood (pinus insignis) sawdust Ü Experimental conditions o o o Temperature: 400 and 500 ºC Pressure: 0. 25 and 1 atm Biomass: 0. 1 -2 mm, 25 kg/min Bed: 20 kg sand (1 -2 mm) Inert gas flow rate (liters/s) o On line product analysis: GC, µGC and GC/MS Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Experimental Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Experimental Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Results: product yields Ü Fractions: gas, bio-oil and char. Yields in wet basis 400 ºC o o o 500 ºC High liquid yields: 77 % wt at 500 ºC and 0. 25 atm P ↓ → bio-oil ↑, char ↓ (reduction of secondary reactions) P ↓ → Desorption and diffusion of the volatiles in the biomass particle ↑ Residence time of volatiles in the particle ↓ Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Results: gas composition Ü Mainly made up of CO 2 and CO Ü P ↓ → CO 2 ↑, T ↑→ CO 2 ↓ Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Results: bio-oil composition Ü Water is the main compound ~ 25 %wt Ü Phenols: guaiacols (methoxy phenols), catechols (benzenediols) and alkyl-phenols. Ü Saccharides: levoglucosan yield increases at lower pressures. Ü Pressure has different influence at 400 ºC and 500 ºC Ü P ↓→ Bio-oil is composed of heavier compounds Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Results: bio-oil properties Ü P ↓→ Carbon content increases slightly (less water and more heavier and less oxygenated compounds) → Calorific value ↑ Ü Operating at subatmospheric pressure slightly improves bio-oil’s valorization prospects as fuel. However, its calorific value is low, so it has to be subjected to treatments. Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Results: characterization Ü Ü T ↑→ Carbon content and calorific value ↑ P ↓ → Carbon content and calorific value ↑ at 400 ºC but ↓ at 500 ºC. Carbon content > 75 %. Low ash content LHV higher than the ones of soft coal (29 MJ/kg) and lignite (20 MJ/kg) Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

Results: characterization Ü P ↓ → BET surface area ↑, pore diameter ↓ Ü 500 ºC, 0. 25 atm → mesopores of 100 Å and micropores of 19 Å are formed Ü Devolatilization and diffusion of volatiles through the biomass particle ↑ Blocking of the pores due to carbonaceous material deposits ↓ 500 ºC, 0. 25 atm Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv 500 ºC, 1 atm

Conclusions Ü Conical spouted bed reactor: suitable technology to perform vacuum biomass flash pyrolysis. Ü High bio-oil yields: 77 wt% at 500 ºC and 0. 25 atm. Ü Vacuum influence on product yields and properties: o Low influence on fraction yields, but bio-oil yield slightly increases. o Bio-oil: heavier compounds (phenols, levoglucosan, etc. ), less water. Calorific value ↑ o Char: Improvement of surface characteristics. Ü Vacuum increases process viability: Inert gas flow rate is lower → Less energy is required to heat the carrier gas and the condensation of the product stream is easier. Chemical Engineering Department. University of the Basque Country PO Box 644 – 48080 Bilbao. www. ehu. es/cpwv

BIOCHAR PRODUCTION BY PYROLYSIS OF LIGNOCELLULOSIC BIOMASS IN A CONICAL SPOUTED BED REACTOR Maider Amutio, Gartzen Lopez, Maite Artetxe, Astrid Barona, Martin Olazar Chemical Engineering Department, University of the Basque Country UPV/EHU PO Box 644 – 48080 Bilbao. Spain. martin. olazar@ehu. es eman ta zabal zazu Universidad del País Vasco Euskal Herriko Unibertsitatea