Optimization of Biochar Production by Co-Torrefaction of Microalgae and Lignocellulosic Biomass Using Response Surface Methodology

Catarina Viegas, Catarina Nobre, Ricardo Correia, Luísa Gouveia and Margarida Gonçalves
Additional contact information
Catarina Viegas: MEtRICs—Mechanical Engineering and Resource Sustainability Center, Department of Science and Technology of Biomass, Faculdade de Ciências e Tecnologia da Universidade NOVA de Lisboa (FCT-NOVA), Campus de Caparica, 2829-516 Caparica, Portugal
Catarina Nobre: CoLAB BIOREF—Collaborative Laboratory for Biorefineries, Rua Amieira Apartado 1089, 4466-901 São Mamede de Infesta, Portugal
Ricardo Correia: MEtRICs—Mechanical Engineering and Resource Sustainability Center, Department of Science and Technology of Biomass, Faculdade de Ciências e Tecnologia da Universidade NOVA de Lisboa (FCT-NOVA), Campus de Caparica, 2829-516 Caparica, Portugal
Luísa Gouveia: LNEG—Laboratório Nacional de Energia e Geologia, I.P./Bioenergy Unit, Estrada do Paço do Lumiar 22, 1649-038 Lisbon, Portugal
Margarida Gonçalves: MEtRICs—Mechanical Engineering and Resource Sustainability Center, Department of Science and Technology of Biomass, Faculdade de Ciências e Tecnologia da Universidade NOVA de Lisboa (FCT-NOVA), Campus de Caparica, 2829-516 Caparica, Portugal

Energies, 2021, vol. 14, issue 21, 1-23

Abstract: Co-torrefaction of microalgae and lignocellulosic biomass was evaluated as a method to process microalgae sludge produced from various effluents and to obtain biochars with suitable properties for energy or material valorization. The influence of four independent variables on biochar yield and properties was evaluated by a set of experiments defined by response surface methodology (RSM). The biochars were characterized for proximate and ultimate composition, HHV, and methylene blue adsorption capacity. HHV of the biochars was positively correlated with carbonization temperature, residence time, and lignocellulosic biomass content in the feed. Co-torrefaction conditions that led to a higher yield of biochar (76.5%) with good calorific value (17.4 MJ Kg ?1 ) were 250 °C, 60 min of residence time, 5% feed moisture, and 50% lignocellulosic biomass. The energy efficiency of the process was higher for lower temperatures (92.6%) but decreased abruptly with the increase of the moisture content of the feed mixture (16.9 to 57.3% for 70% moisture). Biochars produced using algal biomass grown in contaminated effluents presented high ash content and low calorific value. Dye removal efficiency by the produced biochars was tested, reaching 95% methylene blue adsorption capacity for the biochars produced with the least severe torrefaction conditions.

Keywords: Chlorella vulgaris; lignocellulosic biomass; biochar; torrefaction; carbonization; RSM (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

Downloads: (external link)
https://www.mdpi.com/1996-1073/14/21/7330/pdf (application/pdf)
https://www.mdpi.com/1996-1073/14/21/7330/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:14:y:2021:i:21:p:7330-:d:672155

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().