Effects of Particle Size on Cellulosic Biomass Pellets: A Literature Review

Author(s):  
Q. Zhang ◽  
P. F. Zhang ◽  
Z. J. Pei

Cellulosic biofuels are becoming an attractive alternative to conventional liquid transportation fuels. Cellulosic biomass is the feedstock for cellulosic biofuel manufacturing. However, high transportation and storage cost of cellulosic biomass due to its low density hinders large-scale and cost-effective manufacturing of cellulosic biofuels. Pelleting processes are used to produce biomass pellets which have higher density and are easier to handle in transportation and storage. Before going through pelleting processes, original cellulosic biomass materials are milled into particles. The particle size is an important input parameter in pelleting processes. Many investigations have been conducted on effects of biomass particle size on pellet quality (in terms of density, durability, stability, and strength). This paper reviews the literature about effects of particle size on pellet quality. Investigated biomass materials, selected range of particle size, utilized milling and pelleting processes are summarized. The approaches to evaluating pellet quality are also reviewed.

2013 ◽  
Vol 805-806 ◽  
pp. 151-155
Author(s):  
Kang Qi Fan ◽  
Yong Jun Tang ◽  
Yang Fang

Increasing concerns about reliable supplies and envi­ronmental consequences of petroleum-based fuels have made it important to develop sustainable green sources for liquid transportation fuels. One such source is cellulosic biomass. However, high costs associated with transportation and storage of low-density cellulosic biomass has hindered large-scale, cost-effective manufacturing of cellulosic biofuels. Ultrasonic vibration-assisted (UV-A) pelleting can increase biomass density, improve storability, and reduce transportation costs. This paper reviews the state of the art of this technique, covering the effects of different process parameters on pellet quality, pellet charring, pellet crack, and sugar yield. It can be concluded that pellet density increases with an increase in ultrasonic power and pelleting pressure, and with a decrease in biomass moisture content and particle size. However, large ultrasonic power may lead to the charring of cellulosic biomass, which adversely affects the conversion of cellulosic biomass to ethanol. In addition, some problems associated with UV-A pelletingof cellulosic biomass are proposed.


Author(s):  
Q. Zhang ◽  
P. F. Zhang ◽  
X. X. Song ◽  
M. Zhang ◽  
Z. J. Pei ◽  
...  

Biofuels are an alternative to petroleum-based liquid transportation fuels. Cellulosic biomass can be used as feedstocks for befoul manufacturing. Low density of cellulosic feedstocks causes difficulties in handling them during transportation and storage, thus hindering large-scale and cost-effective manufacturing of cellulosic biofuels. Pelleting can increase the density of cellulosic feedstocks by compacting bulky biomass into pellets. Pellet durability, an important quality parameter, measures the ability of pellets to withstand impact and other destructive forces during transportation and handling. ASABE standard S269.4 specifies a procedure to determine pellet durability using 500 grams of pellets. However, it does not provide any justification of choosing this amount of pellets. This paper investigates the feasibility of using a smaller amount of pellets (50 grams) to determine pellet durability. Results show that 50 grams of pellets can generate comparable durability results as 500 grams of pellets.


Author(s):  
P. F. Zhang ◽  
Z. J. Pei ◽  
D. H. Wang ◽  
X. R. Wu ◽  
W. L. Cong ◽  
...  

Increasing demands and concerns for the reliable supply of liquid transportation fuels makes it important to find alternative sources to petroleum based fuels. One such alternative is cellulosic biofuels. However, several technical barriers have hindered large-scale, cost-effective manufacturing of cellulosic biofuels, such as the low density of cellulosic feedstocks (causing high transportation and storage costs) and the lack of efficient pretreatment procedures for cellulosic biomass. This paper reports experimental investigations on ultrasonic vibration-assisted (UV-A) pelleting of cellulosic feedstocks. It studies effects of input variables (ultrasonic vibration, moisture content, and particle size) on output variables (pellet density, stability, durability, pelleting force, and yield of biofuel conversion) in UV-A pelleting. Results showed that UV-A pelleting could increase the density of cellulosic feedstocks and the yield of biofuel conversion.


Author(s):  
Qi Zhang ◽  
P. F. Zhang ◽  
Timothy Deines ◽  
Z. J. Pei ◽  
Donghai Wang ◽  
...  

Cellulosic biofuels can be used to replace traditional liquid transportation fuels. Cellulosic biomass is feedstock in manufacturing of cellulosic biofuels. However, the low density of cellulosic biomass feedstock hinders large-scale and cost-effective manufacturing of cellulosic biofuels. Another bottleneck factor in manufacturing of cellulosic biofuels is the low efficiency of the enzymatic hydrolysis of cellulosic biomass materials resulting in a low sugar yield. Ultrasonic vibration-assisted (UV-A) pelleting can increase the density of cellulosic biomass feedstocks via combined effects of mechanical compression and ultrasonic vibration of the tool on the cellulosic biomass. Meanwhile ultrasonic vibration may act as a beneficial pretreatment for enzymatic hydrolysis, which can possibly increase the efficiency of hydrolysis and obtain a higher sugar yield. The pressure and the ultrasonic power are important parameters in UV-A pelleting. Their effects on pellet quality (density, durability, and stability) and sugar yield (after hydrolysis) are experimentally investigated.


Author(s):  
Z. J. Pei ◽  
Donghai Wang ◽  
Robert Clark

Biofuels produced from cellulosic biomass (such as the fibrous, woody, and generally inedible portions of plant matter) can significantly reduce the nation’s dependence on foreign oil, create new jobs, improve rural economies, reduce greenhouse gas emissions, and improve national security. However, in the U.S., there are currently no cellulosic biofuel plants in commercial production. Several technical barriers have hindered large-scale cost-effective manufacturing of cellulosic biofuels. One such barrier is related to the low density of cellulosic feedstocks, causing their transportation and storage to be very expensive. Pelleting biomass can increase the overall efficiency by utilizing existing transportation infrastructure and storage systems for mega-ton quantities. If biomass is pelleted, it can be handled and transported with existing grain handling equipment in the field, on the road, and at the central biorefinery. This paper presents experimental study on ultrasonic vibration assisted pelleting of cellulosic feedstocks. The results show that ultrasonic vibration assistance could increase the mechanical strength of pellets by more than six times and the density by 50%.


Author(s):  
Pengfei Zhang ◽  
Timothy Deines ◽  
Daniel Nottingham ◽  
Z. J. Pei ◽  
Donghai Wang ◽  
...  

Increasing demands and concerns for the reliable supply of liquid transportation fuels make it important to find alternative sources to petroleum based fuels. One such alternative is cellulosic biofuels. However, several technical barriers have hindered large-scale, cost-effective manufacturing of cellulosic biofuels, such as the low density of cellulosic feedstocks (causing high transportation and storage costs) and the low efficiency of enzymatic hydrolysis process (causing longer processing time and low sugar yield). Ultrasonic vibration-assisted (UV-A) pelleting can increase the density of cellulosic materials by compressing them into pellets. UV-A pelleting can also increase the sugar yield of cellulosic biomass materials in hydrolysis. At present, the effects of process variables in UV-A pelleting on pellet quality (density, durability, and stability) and sugar yield have not been adequately investigated. This paper reports an experimental investigation on UV-A pelleting of wheat straw. A 24 factorial design is employed to evaluate the effects of process variables (moisture content, particle size, pelleting pressure, and ultrasonic power) on output variables (pellet density, durability, stability, and sugar yield).


Author(s):  
Hera Wu ◽  
Pengfei Zhang ◽  
Qi Zhang ◽  
Z. J. Pei

Cellulosic biofuels are an alternative to petroleum-based liquid transportation fuels. However, manufacturing costs of cellulosic biofuels are high partially due to low density and sugar yield of cellulosic biomass. Previous studies show that UV-A pelleting can increase the density and sugar yield of cellulosic biomass. A hypothesis for UV-A pelleting to increase the density and sugar yield of cellulosic biomass is that UV-A pelleting can reduce biomass particle size. To test this hypothesis, biomass particle sizes before and after UV-A pelleting need to be compared. Soaking pellets in water is an efficient and non-invasive method to separate pellets into particles. However, water soaking itself might change biomass particle size. This paper reports an investigation on effects of water soaking on biomass particle size. The biomass particle sizes before and after water soaking are measured and compared. Results show that effects of water soaking on biomass particle size are dependent on the initial particle size (particle size before water soaking) and time period of water soaking.


2007 ◽  
Vol 55 (4) ◽  
pp. 165-173
Author(s):  
T. Mietzel ◽  
K. Klepiszewski ◽  
G. Weiss

The water framework directive (CEC, 2000) asks for cost-effective measures for achieving good ecological conditions in receiving waters. Because of low operation costs and good pollutant removal efficiency, vortex separators (VS) are an attractive alternative to traditional stormwater tanks. The German design standard for CSO structures, ATV-A 128 (1992), demands long-term pollution load simulations. Today's simulation software, however, considers the removal processes in CSO structures either very rudimentarily or not at all. The higher pollutant removal efficiency of a structure like a VS cannot be taken into account. This might be one reason why VS are used still comparatively scarcely. A mathematical model describing the removal efficiency could increase the acceptance of VS. Several functions describing the removal efficiency have been derived from model tests or large-scale studies within the last few years. Within this paper, the data from three large-scale studies are used to verify the general applicability of one steady-state and one dynamic approach. The results show that the complex processes involved with CSO facilities and the large error related to monitoring make the validation of models a difficult task. Anyhow, especially the dynamic approach was applicable at all considered facilities.


Author(s):  
Xiaoxu Song ◽  
Meng Zhang ◽  
Z. J. Pei ◽  
Timothy Deines

Cellulosic biomass is an important source for making biofuels. However, there are several barriers to cost-effective manufacturing of biofuels using cellulosic biomass. One such barrier is related to the high transportation cost due to the low density of cellulosic biomass. Pelleting of cellulosic biomass is one way to increase its density. This paper reports an experimental study on ultrasonic vibration-assisted pelleting of cellulosic biomass. The study was focused on the effects of moisture content (MC) on pellet density of three kinds of cellulosic biomass (wheat straw, switchgrass, and sorghum). The experimental results show that sorghum has the highest density with three levels of MC among these biomass materials. The highest density was found with sorghum of 20% MC.


2007 ◽  
Vol 534-536 ◽  
pp. 773-776
Author(s):  
R. Cook ◽  
I.T.H. Chang ◽  
C. Lucien Falticeanu

P/M aluminium components are attracting interest in an increasing variety of industries due to the possibilities for weight saving in engineering parts. There are many processes for manufacturing from powder feedstocks that are either in production, becoming commercialised or still undergoing development. The nature of these processes and the required properties of the end products mean that powders of different particle size, shape, composition and microstructure must be produced. The requirements of various processes requiring aluminium and aluminium alloy powders for metal matrix composites, laser sintering, powder forging and metal injection moulding are discussed in relation to powder particle size and structure. The key requirement of the powder manufacturer is to supply cost effective materials for these different processes. This may require compromises to be made by the supplier and consumer while the techniques evolve from development to large scale production.


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