Special Issue "Advances in Biomass Densification Systems and Biomass Torrefaction Process"

A special issue of Bioengineering (ISSN 2306-5354).

Deadline for manuscript submissions: 10 February 2019

Special Issue Editor

Guest Editor
Dr. Jaya Shankar Tumuluru

Biofuels and Renewable Energy Technologies, Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415, USA
Website 1 | Website 2 | E-Mail
Phone: +1-208-526-0529
Interests: biomass; mechnical preprocessing; thermal pretreatements; biomass storage; extrusion of foods and feeds; modeling and optimziation

Special Issue Information

Dear Colleagues,

Biomass physical properties and chemical compostion impact biofuels production. Particle size, density, chemical composition of biomass are important specifications for both biochemical and thermochemical conversion pathways. Also these properties influence the feeding, handling, storage and transportation.

Size reduction, densification and torrefaction impact the biomass physical and chemical properties and make them suitable for biofuels production. Size reduction of biomass using grinding equipment helps to meet the desired specifications in terms of particle size. Densification ensures the biomass has a uniform format with consistent physical properties such as size and shape, density, and durability, which significantly influence storage, transportation and handling characteristics. A variety of densification systems, such as (i) pellet mill; (ii) cuber; (iii) screw extruder; (iv) briquette press; (v) roller press; (vi) tablet press; and (vii) agglomerator, are available for bioenergy applications. Torrefaction, which is a thermal pretreatment method, makes biomass brittle making it easier to grind (better particle size and shape), changes the chemical composition (removing the moisture and low-energy content of volatiles), and increases the net energy content of the biomass.

The emphasis of this Special Issue is to examine the advances in biomass size reduction, densification and torrefaction technologies and their impact on physical, chemical and energy properties for biofuels production.

The first round submission deadline: 1 December 2017

Dr. Jaya Shankar Tumuluru
Guest Editor

Manuscript Submission Information

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Keywords

  • Biomass

  • Physical properties

  • Flow properties

  • Chemical composition

  • Size reduction

  • Densification

  • Torrefaction

  • Thermo-chemical conversion

  • Biochemical conversion

Published Papers (5 papers)

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Research

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Open AccessArticle Microwave-Assisted Alkali Pre-Treatment, Densification and Enzymatic Saccharification of Canola Straw and Oat Hull
Bioengineering 2017, 4(2), 25; https://doi.org/10.3390/bioengineering4020025
Received: 1 December 2016 / Revised: 13 March 2017 / Accepted: 19 March 2017 / Published: 26 March 2017
Cited by 2 | PDF Full-text (4305 KB) | HTML Full-text | XML Full-text
Abstract
The effects of microwave-assisted alkali pre-treatment on pellets’ characteristics and enzymatic saccharification for bioethanol production using lignocellulosic biomass of canola straw and oat hull were investigated. The ground canola straw and oat hull were immersed in distilled water, sodium hydroxide and potassium hydroxide
[...] Read more.
The effects of microwave-assisted alkali pre-treatment on pellets’ characteristics and enzymatic saccharification for bioethanol production using lignocellulosic biomass of canola straw and oat hull were investigated. The ground canola straw and oat hull were immersed in distilled water, sodium hydroxide and potassium hydroxide solutions at two concentrations (0.75% and 1.5% w/v) and exposed to microwave radiation at power level 713 W and three residence times (6, 12 and 18 min). Bulk and particle densities of ground biomass samples were determined. Alkaline-microwave pre-treated and untreated samples were subjected to single pelleting test in an Instron universal machine, pre-set to a load of 4000 N. The measured parameters, pellet density, tensile strength and dimensional stability were evaluated and the results showed that the microwave-assisted alkali pre-treated pellets had a significantly higher density and tensile strength compared to samples that were untreated or pre-treated by microwave alone. The chemical composition analysis showed that microwave-assisted alkali pre-treatment was able to disrupt and break down the lignocellulosic structure of the samples, creating an area of cellulose accessible to cellulase reactivity. The best enzymatic saccharification results gave a high glucose yield of 110.05 mg/g dry sample for canola straw ground in a 1.6 mm screen hammer mill and pre-treated with 1.5% NaOH for 18 min, and a 99.10 mg/g dry sample for oat hull ground in a 1.6 mm screen hammer mill and pre-treated with 0.75% NaOH for 18 min microwave-assisted alkali pre-treatments. The effects of pre-treatment results were supported by SEM analysis. Overall, it was found that microwave-assisted alkali pre-treatment of canola straw and oat hull at a short residence time enhanced glucose yield. Full article
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Open AccessArticle Influence of Torrefaction on the Conversion Efficiency of the Gasification Process of Sugarcane Bagasse
Bioengineering 2017, 4(1), 22; https://doi.org/10.3390/bioengineering4010022
Received: 24 November 2016 / Revised: 28 February 2017 / Accepted: 7 March 2017 / Published: 10 March 2017
Cited by 1 | PDF Full-text (3004 KB) | HTML Full-text | XML Full-text
Abstract
Sugarcane bagasse was torrefied to improve its quality in terms of properties prior to gasification. Torrefaction was undertaken at 300 °C in an inert atmosphere of N2 at 10 °C·min−1 heating rate. A residence time of 5 min allowed for rapid
[...] Read more.
Sugarcane bagasse was torrefied to improve its quality in terms of properties prior to gasification. Torrefaction was undertaken at 300 °C in an inert atmosphere of N2 at 10 °C·min−1 heating rate. A residence time of 5 min allowed for rapid reaction of the material during torrefaction. Torrefied and untorrefied bagasse were characterized to compare their suitability as feedstocks for gasification. The results showed that torrefied bagasse had lower O–C and H–C atomic ratios of about 0.5 and 0.84 as compared to that of untorrefied bagasse with 0.82 and 1.55, respectively. A calorific value of about 20.29 MJ·kg−1 was also measured for torrefied bagasse, which is around 13% higher than that for untorrefied bagasse with a value of ca. 17.9 MJ·kg−1. This confirms the former as a much more suitable feedstock for gasification than the latter since efficiency of gasification is a function of feedstock calorific value. SEM results also revealed a fibrous structure and pith in the micrographs of both torrefied and untorrefied bagasse, indicating the carbonaceous nature of both materials, with torrefied bagasse exhibiting a more permeable structure with larger surface area, which are among the features that favour gasification. The gasification process of torrefied bagasse relied on computer simulation to establish the impact of torrefaction on gasification efficiency. Optimum efficiency was achieved with torrefied bagasse because of its slightly modified properties. Conversion efficiency of the gasification process of torrefied bagasse increased from 50% to approximately 60% after computer simulation, whereas that of untorrefied bagasse remained constant at 50%, even as the gasification time increased. Full article
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Open AccessArticle HHV Predicting Correlations for Torrefied Biomass Using Proximate and Ultimate Analyses
Bioengineering 2017, 4(1), 7; https://doi.org/10.3390/bioengineering4010007
Received: 26 October 2016 / Revised: 10 January 2017 / Accepted: 20 January 2017 / Published: 24 January 2017
Cited by 9 | PDF Full-text (1583 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Many correlations are available in the literature to predict the higher heating value (HHV) of raw biomass using the proximate and ultimate analyses. Studies on biomass torrefaction are growing tremendously, which suggest that the fuel characteristics, such as HHV, proximate analysis and ultimate
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Many correlations are available in the literature to predict the higher heating value (HHV) of raw biomass using the proximate and ultimate analyses. Studies on biomass torrefaction are growing tremendously, which suggest that the fuel characteristics, such as HHV, proximate analysis and ultimate analysis, have changed significantly after torrefaction. Such changes may cause high estimation errors if the existing HHV correlations were to be used in predicting the HHV of torrefied biomass. No study has been carried out so far to verify this. Therefore, this study seeks answers to the question: “Can the existing correlations be used to determine the HHV of the torrefied biomass”? To answer this, the existing HHV predicting correlations were tested using torrefied biomass data points. Estimation errors were found to be significantly high for the existing HHV correlations, and thus, they are not suitable for predicting the HHV of the torrefied biomass. New correlations were then developed using data points of torrefied biomass. The ranges of reported data for HHV, volatile matter (VM), fixed carbon (FC), ash (ASH), carbon (C), hydrogen (H) and oxygen (O) contents were 14.90 MJ/kg–33.30 MJ/kg, 13.30%–88.57%, 11.25%–82.74%, 0.08%–47.62%, 35.08%–86.28%, 0.53%–7.46% and 4.31%–44.70%, respectively. Correlations with the minimum mean absolute errors and having all components of proximate and ultimate analyses were selected for future use. The selected new correlations have a good accuracy of prediction when they are validated using another set of data (26 samples). Thus, these new and more accurate correlations can be useful in modeling different thermochemical processes, including combustion, pyrolysis and gasification processes of torrefied biomass. Full article
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Review

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Open AccessReview Comminution of Dry Lignocellulosic Biomass: Part II. Technologies, Improvement of Milling Performances, and Security Issues
Bioengineering 2018, 5(3), 50; https://doi.org/10.3390/bioengineering5030050
Received: 11 April 2018 / Revised: 11 June 2018 / Accepted: 20 June 2018 / Published: 22 June 2018
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Abstract
Lignocellulosic feedstocks present a growing interest in many industrial processes as they are an ecological alternative to petroleum-based products. Generally, the size of plant raw materials needs to be reduced by milling step(s), to increase density, facilitate transport and storage, and to increase
[...] Read more.
Lignocellulosic feedstocks present a growing interest in many industrial processes as they are an ecological alternative to petroleum-based products. Generally, the size of plant raw materials needs to be reduced by milling step(s), to increase density, facilitate transport and storage, and to increase reactivity. However, this unit operation can prove to be important in term of investments, functioning costs, and energy consumption if the process is not fully adapted to the histological structure of the plant material, possibly challenging the profitability of the whole chain of the biomass conversion. In this paper, the different technologies that can be used for the milling of lignocellulosic biomass were reviewed and different avenues are suggested to improve the milling performances thanks to thermal pretreatments. Based on examples on wheat straw milling, the main points to take into consideration in the choice of a milling technologies have been highlighted in regards to the specifications of ground powder. A specific focus on the hazards associated to the milling and the manipulation of fine biomass particles is also realized at the end of the paper from the perspective of industrial applications. Full article
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Open AccessReview Comminution of Dry Lignocellulosic Biomass, a Review: Part I. From Fundamental Mechanisms to Milling Behaviour
Bioengineering 2018, 5(2), 41; https://doi.org/10.3390/bioengineering5020041
Received: 11 April 2018 / Revised: 25 May 2018 / Accepted: 31 May 2018 / Published: 2 June 2018
PDF Full-text (3906 KB) | HTML Full-text | XML Full-text
Abstract
The comminution of lignocellulosic biomass is a key operation for many applications as bio-based materials, bio-energy or green chemistry. The grinder used can have a significant impact on the properties of the ground powders, of those of the end-products and on the energy
[...] Read more.
The comminution of lignocellulosic biomass is a key operation for many applications as bio-based materials, bio-energy or green chemistry. The grinder used can have a significant impact on the properties of the ground powders, of those of the end-products and on the energy consumption. Since several years, the milling of lignocellulosic biomass has been the subject of numerous studies most often focused on specific materials and/or applications but there is still a lack of generic knowledge about the relation between the histological structure of the raw materials, the milling technologies and the physical and chemical properties of the powders. This review aims to point out the main process parameters and plant raw material properties that influence the milling operation and their consequences on the properties of ground powders and on the energy consumption during the comminution. Full article
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