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Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes

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A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (30 May 2021) | Viewed by 27480

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Special Issue Editor

Dr. Shahabaldin Rezania

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Guest Editor

Department of Environment and Energy, Sejong University, Seoul 05006, Republic of Korea
Interests: wastewater treatment; biotechnology, fermentation; biofuel and bio energies; plant sciences; waste management
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The growing demand for energy is considered to be one of the most significant challenges of the 21st century. It is important to provide energy for different sectors, such as industry, transportation, and heating systems, from sustainable sources to reduce the harmful impacts of traditional fuels not only on human beings but also on the environment. Biofuels are green energy sources that are compatible with existing liquid transport fuel. As one of the main processes in biofuel production, pretreatment is the main economic and a crucial step. The feedstock, such as biomass, may require pretreatment in order to enhance its conversion into a valuable product in terms of process yield and/or productivity. Besides this, the selection of a proper pretreatment may be mandatory for waste management. It should be noted that an efficient pretreatment technique should minimize the energy requirement, maximize the production yield, and generate less waste and by-products. Chemical pretreatment is the application of different chemicals and reagents, such as alkalis, acids, solvents, and salts. Recent advances in chemical pretreatment techniques (e.g., application of green solvents, the use less solvents, or even a combination of different chemical pretreatment methods) has led to an improvement in the recovery of biofuels.

This Special Issue on “Recent Advances in Chemical Pretreatment Methods for Biofuel Production” aims to introduce novel advances in the development of different chemical pretreatment methods for biofuel production. Papers that describe new findings on chemical pretreatment methods; the development of new, efficient pretreatment processes; or environmental, energy, or economic assessments and modeling of pretreatment processes are welcome. Review articles are also recommended.

Topics of interest include, but are not limited to:

the development of new chemicals and reagents for chemical pretreatment in biofuel production;
the modeling and optimization of chemical pretreatment processes to increase the biofuel recovery rate;
the development of novel chemical reagents to enhance the efficiency of pretreatment; and
the evaluation of pretreatment efficiency in terms of less waste generation and by-products.

Dr. Shahabaldin Rezania
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

biofuel production
chemical pretreatment methods
environmentally sustainable reagents
less waste generation
biomass fractionation for biorefineries
pretreatment modeling and optimization

Published Papers (6 papers)

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Research

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15 pages, 746 KiB

Open AccessArticle

Upgrading of Coffee Biocrude Oil Produced by Pyrolysis of Spent Coffee Grounds: Behavior of Fatty Acids in Supercritical Ethanol Reaction and Catalytic Cracking

by Ji-Yeon Park, Md Amirul Alam Kanak and In-Gu Lee

Processes 2021, 9(5), 835; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9050835 - 10 May 2021

Cited by 5 | Viewed by 3604

Abstract

Spent coffee grounds contain lipids (fatty acids) in addition to cellulose, hemicellulose, and lignin. The reaction process for upgrading biocrude oil produced from spent coffee grounds is different from that followed for upgrading biomass pyrolysis oil, such as processes that utilize sawdust. The feasibility of upgrading coffee biocrude oil through a supercritical ethanol reaction with plastic pyrolysis oil and through catalytic cracking for the improvement of the undesirable properties of biocrude oil, caused by the presence of oxygenated compounds, was evaluated. The initial oxygen content of the coffee biocrude oil was 16.9 wt%. The oil comprised a total content of 40.9% fatty acids, as found by analyzing the GC-MS peak area. After the supercritical ethanol reaction at 340

^{\circ}

C, the oxygen content was decreased to 9.9 wt%. When the MgNiMo/AC catalyst was applied to the supercritical reaction, the oxygen content was further decreased to 8.5 wt%. The esterification of the fatty acids in the biocrude oil with ethanol converted them to esters. After the supercritical reaction of coffee biocrude oil with plastic pyrolysis oil (1:2 (w/w)), the oxygen content was 6.4 wt%. After the catalytic cracking of the biocrude oil by Ni/MCM-41 at 400

^{\circ}

C, the fatty acids were converted to hydrocarbons, C9 to C21, and the oxygen content decreased to a final value of 2.8 wt%. Full article

(This article belongs to the Special Issue Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes)

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10 pages, 1676 KiB

Open AccessArticle

Continuous Biodiesel Production from Waste Soybean Oil Using a Nano-Fe₃O₄ Microwave Catalysis

by Ching-Hsing Lin, Yi-Tang Chang, Mei-Chou Lai, Tai-Ying Chiou and Chien-Sen Liao

Processes 2021, 9(5), 756; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9050756 - 26 Apr 2021

Cited by 7 | Viewed by 1930

Abstract

In this study, we conducted an efficient microwave-assisted transesterification process combining homogeneous and heterogeneous catalytic phases to produce biodiesel from waste soybean oil. A cylindrical quartz reactor packed with nanoparticles of Fe₃O₄ as a co-catalyst was applied to improve the reaction. The process was carried out with a methanol-to-oil molar ratio of 6:1, power of 560 W, and residence time of 30 s. The specifications of the biodiesel produced in this study were compared with two standards, i.e., ASTM D6751 and EN 14214. We found that the continuous conversion of waste soybean oil to methyl ester was approximately 95%. The biodiesel showed a higher flash point and a higher carbon residue content than that of both standards, and the viscosity (5.356 mm²/s) and density (898.1 kg/m³) were both at a high level. Compared to a conventional heating plate, the energy consumption was significantly reduced by nearly 93%. It is expected that these findings will provide useful information for green and sustainable processes for the regeneration and reuse of oil. Full article

(This article belongs to the Special Issue Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes)

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13 pages, 2121 KiB

Open AccessArticle

Demineralization of Food Waste Biochar for Effective Alleviation of Alkali and Alkali Earth Metal Species

by Yoonah Jeong, Ye-Eun Lee, Dong-Chul Shin, Kwang-Ho Ahn, Jinhong Jung and I-Tae Kim

Processes 2021, 9(1), 47; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9010047 - 28 Dec 2020

Cited by 5 | Viewed by 2454

Abstract

Ash-related issues from a considerable amount of alkali and alkaline earth metal species in biochar are major obstacles to the widespread application of biomass in thermoelectric plants. In this study, food wastes were converted into biochar through pyrolysis at 450 °C or 500 °C and four different demineralization approaches, using deionized water, citric acid, nitric acid, and CO₂ saturated water. The chemical properties of the resulting biochars were investigated, including proximate analysis, concentrations of inorganic species in biochar and ash, and the crystalline structure. All demineralization treatments produced food waste biochar with sufficient calorific value (>4000 kcal/kg) and a chlorine concentration <0.5%. Among the inorganic species in biochar, Na and K exhibited a significantly higher removal rate through demineralization, which ranged from 54.1%–85.6% and 53.6%–89.9%, respectively; the removal rates of Ca and Mg were lower than 50.0%. The demineralization method was more critical than the pyrolysis temperature in the removal of alkali and alkaline earth metals. Especially, the lower slagging and fouling tendency was expected for the biochar demineralized with citric acid. Our results suggested that food waste biochar pyrolyzed at 500 °C and demineralized with citric acid is a promising co-firing material for electric power generation in thermoelectric power plants. Full article

(This article belongs to the Special Issue Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes)

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13 pages, 3166 KiB

Open AccessArticle

Hydrothermal Polymerization Catalytic Process Effect of Various Organic Wastes on Reaction Time, Yield, and Temperature

by Alexis F. Mackintosh, Taesung Shin, Hyunik Yang and Kangil Choe

Processes 2020, 8(3), 303; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8030303 - 06 Mar 2020

Cited by 8 | Viewed by 2948

Abstract

The purpose of this study is to optimize the processing conditions (temperature, pressure, process time, yield rate) for the conversion of biomass to a high-energy density biofuel. The hydrothermal polymerization (HTP) catalytic process has been developed for production of biofuel via hydrothermal processing using an acid-based catalyst. This study has shown that the HTP catalytic process for a reference feedstock lowered the temperature by 10 to 40 °C, reduced the pressure requirement by 1 to 2 MPa, increased the rate of yield by 22%, and shortened the total processing time by up to 3 h when compared to the conventional hydrothermal carbonization (HTC) process. FTIR spectrum analysis of the HTP catalytic biofuel has shown that lignin in the biomass is preserved, while the pure HTC process destroyed the lignin in the biomass. GC/MS analysis of the process liquid determined the changes of the intermediate soluble components as a function of time. By measuring the 2,5-hydroxymethyl furfuralde concentration in solution, an endpoint determination could be made. This study also determined the approximate analysis of the HTP biofuel from various organic wastes such as cotton, cow manure, wood waste, paper waste, sugarcane bagasse waste, and food waste. Full article

(This article belongs to the Special Issue Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes)

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Review

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13 pages, 22497 KiB

Open AccessReview

Microbial Fuel Cell Technology—A Critical Review on Scale-Up Issues

by Wei Han Tan, Siewhui Chong, Hsu-Wei Fang, Kuan-Lun Pan, Mardawani Mohamad, Jun Wei Lim, Timm Joyce Tiong, Yi Jing Chan, Chao-Ming Huang and Thomas Chung-Kuang Yang

Processes 2021, 9(6), 985; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9060985 - 03 Jun 2021

Cited by 43 | Viewed by 9003

Abstract

Microbial fuel cell (MFC) technology has attracted a great amount of attention due to its potential for organic and inorganic waste treatment concomitant with power generation. It is thus seen as a clean energy alternative. Modifications and innovations have been conducted on standalone and hybrid/coupled MFC systems to improve the power output to meet the end goal, namely, commercialization and implementation into existing wastewater treatment plants. As the energy generated is inversely proportional to the size of the reactor, the stacking method has been proven to boost the power output from MFC. In recent years, stacked or scale-up MFCs have also been used as a power source to provide off-grid energy, as well as for in situ assessments. These scale-up studies, however, encountered various challenges, such as cell voltage reversal. This review paper explores recent scale-up studies, identifies trends and challenges, and provides a framework for current and future research. Full article

(This article belongs to the Special Issue Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes)

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19 pages, 1532 KiB

Open AccessReview

Technical Aspects of Biofuel Production from Different Sources in Malaysia—A Review

by Shahabaldin Rezania, Bahareh Oryani, Jinwoo Cho, Farzaneh Sabbagh, Parveen Fatemeh Rupani, Amirreza Talaiekhozani, Negar Rahimi and Majid Lotfi Ghahroud

Processes 2020, 8(8), 993; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8080993 - 16 Aug 2020

Cited by 22 | Viewed by 6048

Abstract

Due to the depletion of fossil fuels, biofuel production from renewable sources has gained interest. Malaysia, as a tropical country with huge resources, has a high potential to produce different types of biofuels from renewable sources. In Malaysia, biofuels can be produced from various sources, such as lignocellulosic biomass, palm oil residues, and municipal wastes. Besides, biofuels are divided into two main categories, called liquid (bioethanol and biodiesel) and gaseous (biohydrogen and biogas). Malaysia agreed to reduce its greenhouse gas (GHG) emissions by 45% by 2030 as they signed the Paris agreement in 2016. Therefore, we reviewed the status and potential of Malaysia as one of the main biofuel producers in the world in recent years. The role of government and existing policies have been discussed to analyze the outlook of the biofuel industries in Malaysia. Full article

(This article belongs to the Special Issue Recent Advances in Chemical Pretreatment Methods for Biofuel Production Processes)

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